[Federal Register Volume 59, Number 182 (Wednesday, September 21, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-22131]


[[Page Unknown]]

[Federal Register: September 21, 1994]


_______________________________________________________________________

Part II





Environmental Protection Agency





_______________________________________________________________________



40 CFR Parts 80, 85, 86, 88 and 600




Standards for Emissions From Natural Gas-Fueled, and Liquefied 
Petroleum Gas-Fueled Motor Vehicles and Motor Vehicle Engines, and 
Certification Procedures for Aftermarket Conversions; Final Rule
ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 80, 85, 86, 88 and 600

[AMS-FRL-4892-8]

 
Standards for Emissions From Natural Gas-Fueled, and Liquefied 
Petroleum Gas-Fueled Motor Vehicles and Motor Vehicle Engines, and 
Certification Procedures for Aftermarket Conversions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: Today's rule provides emission standards and test procedures 
for the certification of new natural gas-fueled, and liquefied 
petroleum gas-fueled light-duty vehicles, light-duty trucks, heavy-duty 
engines and vehicles, and motorcycles. The regulations are effective 
with the 1997 model year, although optional certification prior to the 
1997 model year will be available. Today's rule also provides fuel 
economy test procedures and calculation equations for natural gas-
fueled light-duty vehicles and trucks, effective upon publication, to 
allow these vehicles to be included in a manufacturer's corporate 
average fuel economy (CAFE). Finally, today's rule provides procedures 
for the certification of aftermarket conversion equipment to allow a 
vehicle or engine to operate completely or in part on a fuel other than 
the fuel for which it was originally designed and manufactured.
    This action is being taken in order to remove the possibility that 
the absence of such standards could hinder the development of natural 
gas and liquefied petroleum gas as transportation fuels. These 
standards are intended to provide a comparable degree of environmental 
protection to that afforded by the standards applicable to gasoline, 
diesel and methanol vehicles, and to ensure that aftermarket 
conversions do not degrade the emissions performance of the vehicles or 
engines being converted.

DATES: Except as specified elsewhere in this DATES section, this final 
rule is effective September 21, 1994.
    The effective date of Secs. 80.32, 80.33, 86.001-9(d)(1)(iv), 
86.001-28(h), 86.004-9(d)(1)(iv), 86.004-28(h), 86.098-8(d)(1)(iv), 
86.098-28(h), 86.099-8(d)(1)(iv), 86.150-98(d) and 86.157-98 is 
November 21, 1994, unless notice is received by October 21, 1994 that 
interested parties wish to submit adverse or critical comments on these 
sections. If the effective date is changed, timely notice will be 
published in the Federal Register.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 21, 1994, except as specified elsewhere in this DATES 
section.
    40 CFR 85.503, 85.505, 86.542-90, 86.094-23, 86.095-24, 86.095-35, 
86.1242-90, 86.098-28, 86.113-94, 86.1344-94, 86.142-90, 86.150-98, 
86.513-94 and 600.113-93 are not effective until the Office of 
Management and Budget (OMB) has approved the information collection 
requirements contained in them. A document will be published in the 
Federal Register when OMB has approved the information collection 
requirements.

ADDRESSES: Written comments on those sections effective November 21, 
1994 should be submitted both to the contact person for this rule (see 
For Further Information Contact) and to the docket for this rulemaking 
at the following address. Materials relevant to this rule have been 
placed in Docket No. A-92-14 by EPA. The docket is located at: Air 
Docket Section, U.S. Environmental Protection Agency, 401 M Street, 
SW., Washington, DC 20460 in room M-1500, Waterside Mall (ground 
floor), and may be inspected between 8 a.m. and 4 p.m. on weekdays. EPA 
may charge a reasonable fee for copying docket materials. In addition, 
copies of the Summary and Analysis of Comments document, which develops 
certain issues relevant to this final rulemaking, may be obtained by 
request from the contact person below. This document contains the 
Agency's response to the public comments received in regard to the 
Notice of Proposed Rulemaking (NPRM).

FOR FURTHER INFORMATION CONTACT: Mr. John Mueller, Regulation 
Development and Support Division, U.S. Environmental Protection Agency, 
2565 Plymouth Road, Ann Arbor, Michigan 48105: phone (313) 668-4275. To 
obtain copies of this final rule or the Summary and Analysis of 
Comments document please contact Ms. Donna Hoover at (313) 668-4278 or 
at the above address.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Introduction
II. Description of Action
    A. Timing
    B. New Vehicle Standards
    C. Certification Test Fuel Specification
    D. Test Procedures
    E. Fuel Economy
    F. Aftermarket Conversions
    G. Fees
III. Public Participation
    A. Timing of Requirements
    B. Standards for HC
    1. NMHC vs. THC Standards
    2. Heavy-Duty NMHC Standards
    3. Evaporative Emission Standards
    C. Refueling Emission Standards
    1. Natural Gas
    2. LPG Vehicle/Pump Interface
    3. LPG Tank Venting
    D. Standards for CO and Crankcase Emissions
    1. Idle CO
    2. Crankcase Emissions
    E. On-Board Diagnostics
    F. HC Measurement
    G. Fuel Composition
    H. Fuel Economy
    I. Aftermarket Conversions
    1. Applicability
    2. Test Procedures
    3. On-board Diagnostics
    4. Liability
IV. Environmental Effects
V. Economic Impacts
VI. Statutory Authority
VII. Executive Order 12866
VIII. Reporting and Recordkeeping Requirements
IX. Impact on Small Entities
X. Judicial Review

I. Introduction

    Recently there has been increasing interest in the use of non-
petroleum transportation fuels for a variety of reasons, including the 
potential environmental benefits offered by these fuels. Natural gas 
and liquefied petroleum gas (LPG) are among the more prominent of these 
fuels, along with methanol and ethanol. EPA promulgated emission 
standards for methanol-fueled vehicles on April 11, 1989 (54 FR 14426) 
due to the imminent commercialization of those vehicles. However, there 
are currently no emission standards in place for vehicles which 
operate, all or in part, on natural gas and LPG. This lack of standards 
is seen as a potential barrier to the widespread commercial 
introduction of these vehicles into the marketplace due to the 
uncertainties the manufacturers face regarding potential future 
standards where EPA has not yet addressed any of the issues involved. 
In addition, the recent rise in interest in these fuels has resulted in 
increased interest in aftermarket conversions (i.e., the conversion of 
a vehicle or engine to operate on a fuel other than that for which it 
was originally designed and certified to operate). Again, the lack of 
defined certification procedures for conversions, as well as the 
absence of a method to demonstrate good emissions performance of such 
conversions, are seen as potential barriers to their more widespread 
use for two reasons. First, the lack of defined certification 
procedures leads to uncertainty among converters as to whether the 
conversions they perform constitute tampering and result in the 
potential associated liability. Second, the potential for environmental 
benefits associated with gaseous fuels has led to increased interest in 
marketing conversions as an environmental strategy. The lack of a 
recognized procedure for confirming emissions performance has been seen 
as hindering efforts to market conversions in this manner. Thus, in 
order to remove these potential barriers EPA published a Notice of 
Proposed Rulemaking (NPRM) proposing emission standards for natural gas 
and LPG vehicles, and certification procedures for aftermarket 
conversions on November 5, 1992 (57 FR 52912).
    A public hearing was held on December 3, 1992, in Ann Arbor, 
Michigan at which verbal comments on the NPRM were received. Written 
comments responding to the proposal were also received from 34 public 
and private parties. The Agency fully considered all comments received 
in developing today's final rule.
    The remaining sections of this preamble describe EPA's resolution 
of the issues associated with the rulemaking. Section II describes 
today's action and summarizes the new requirements. Section III reviews 
the major comments received on the NPRM and the Agency's analysis of 
those comments. Subsequent sections summarize the technical 
feasibility, leadtime requirements, environmental effects, and economic 
effects associated with today's action.

II. Description of Action

    This section describes each provision of today's rule. In general, 
today's rule extends the coverage of the existing federal motor vehicle 
emissions program to include natural gas and LPG vehicles (hereinafter 
referred to as gaseous-fueled vehicles). As such, EPA's current 
regulations governing certification, production line, and in-use 
requirements are for the most part adopted for gaseous-fueled vehicles. 
Rather than present an exhaustive review of the entire federal 
emissions program, this section contains a basic description of the 
gaseous-fueled vehicle regulations and highlights where these 
regulations differ from those currently in place for other vehicles. 
For additional information on the new or existing program requirements 
the reader is referred to the accompanying regulations appearing at the 
end of today's notice, and Title 40, parts 80, 85, 86, 88 and 600 of 
the Code of Federal Regulations, which this rulemaking amends.

A. Timing

    EPA proposed that these standards be effective with the 1994 model 
year, and explained that the Agency did not expect that significant 
lead-time for developing emission control technology would be required 
for compliance. Nonetheless, because this rule is not being promulgated 
until after the start of the 1994 model year, EPA no longer believes 
that there is sufficient time to certify vehicles and engines pursuant 
to these regulations for the 1994 model year. Further, EPA received 
several comments stating that leadtime was required for technology 
development, especially for durability demonstration, in addition to 
that required for the certification process alone. Therefore, EPA is 
promulgating the standards to be effective with the 1997 model year. 
Finally, the refueling requirements for gaseous-fueled vehicles will be 
implemented consistent with the recently finalized refueling emission 
standards for other vehicles (three year phase-in beginning with the 
1998 model year for light-duty vehicles and the 2001 model year for 
light-duty trucks).\1\ The requirements for refueling stations will 
take effect on January 1, 1998 for large volume stations, with a two 
year delay until January 1, 2000 for those stations which dispense less 
than 10,000 gallons per month on a gasoline equivalent basis. This 
phase in for smaller stations is consistent with the approach taken 
with the dispensing rate limits placed on gasoline refueling stations 
contained in the evaporative emissions final rule.\2\
---------------------------------------------------------------------------

    \1\59 FR 16262, April 6, 1994.
    \2\58 FR 16002, March 24, 1993.
---------------------------------------------------------------------------

    EPA proposed that manufacturers be allowed to certify engines and 
vehicles produced prior to the effective model year in order to include 
engines in the emissions trading and banking program, and to include 
vehicles in manufacturers' corporate average fuel economy. EPA received 
no adverse comments on this aspect of the proposal. For this reason, 
manufacturers may choose to comply prior to the 1997 model year, 
including the 1994 model year.
    Including 1994 model year engines in the emissions trading and 
banking program and raises an issue whether engines manufactured in 
model year 1994 prior to the promulgation of this rule may be included 
in the program. A similar situation was confronted in the original 
banking and trading rule. There, EPA allowed banking for the full 1990 
model year, even though the rule was promulgated on July 26, 1990. See 
55 FR 30584, 30587. In that case, EPA placed certain restrictions on 
the inclusion of 1990 model year engines, to ensure credits were only 
given for significant reductions below the 1990 standards. This was to 
ensure that ``windfall'' credits from exceeding the arguably ``lax'' 
pre-1991 standards would not be used in the transition to the more 
stringent 1991 standards. As a result, if no restrictions on trading 
and banking were imposed, then the engines that had always exceeded the 
1990 standards would for the first time be able to use the extra 
reductions as ``windfall'' credits to offset engines that did not yet 
meet the new and more stringent 1991 standards. See 55 FR at 30597.
    EPA does not believe such restrictions are necessary in this case. 
Since 1991, engines using other fuels, such as methanol, have been able 
to generate credits to offset higher emitting engines. EPA believes 
that gaseous-fueled engines should have an equal opportunity to use 
such credits as gasoline-, diesel-, and methanol-fueled engines, now 
that emissions standards and test procedures are in place in time for 
the 1994 model year. As EPA explained in the response to comments in 
the trading and banking final rule, CNG engines were not included at 
that time due to the absence of standards, test procedures, and 
certification protocols. See id at 30609. Now that these rules are in 
place, there is no longer any reason to disadvantage CNG engines vis a 
vis other fuels.
    In addition, EPA does not believe that the credits manufacturers 
might obtain from gaseous-fueled engines are ``windfall,'' since they 
arguably would not have manufactured such engines in model year 1994 
but for EPA's actions to provide an incentive to do so. Rather, EPA 
believes manufacturers had an incentive to manufacture gaseous-fueled 
engines based on EPA actions prior to this final rule. EPA proposed 
these standards in November 1992, and began developing these standards 
substantially before that. EPA believes this overall incentive further 
supports allowing manufacturers to include all 1994 model year engines 
in the trading and banking program.
    The aftermarket conversion certification procedures contained in 
today's rule are available to converters as a way of obtaining an 
exemption from the tampering prohibition. Since this procedure creates 
an exemption and is optional it will be available upon publication in 
the Federal Register. EPA's current policy toward conversions will 
continue to apply to aftermarket conversions which have not received an 
exemption under this new program.\3\
---------------------------------------------------------------------------

    \3\See March 4, 1993 Fact Sheet available in the public docket.
---------------------------------------------------------------------------

    The Administrative Procedure Act requires 30 days notice before a 
rule may become effective, except under certain circumstances such as 
when the rule recognizes an exemption or when the Agency can 
demonstrate good cause for immediate effect. The Agency believes it has 
good cause for this rule to take immediate effect in the case of the 
new vehicle standards since compliance with the new vehicle standards 
is optional until well after the 30 day period. In the case of 
aftermarket conversions, because this rule creates an exemption from 
the tampering prohibition under section 203 of the Act it does not 
require 30 days notice, and this exemption will be available upon 
publication in the Federal Register.

B. New Vehicle Standards

    The new gaseous-fueled vehicle and engine emission standards 
contained in today's notice are effective with the 1997 model year. 
Optional compliance prior to the 1997 model year is available to 
manufacturers who wish to include their vehicles and engines in 
emissions averaging, trading and banking programs, as well as the CAFE 
program in the case of natural gas-fueled vehicles.
    In general, the Agency seeks to control vehicles operated on 
alternative fuels so that their emissions are no greater than their 
petroleum-fueled counterparts. Thus, the exhaust emission standards for 
gaseous-fueled vehicles are numerically equivalent to those which apply 
to other, currently regulated vehicles and engines. The only 
significant departure from this approach is in the area of hydrocarbon 
(HC) standards for natural gas fueled vehicles and engines. Prior to 
the 1994 model year, regulated vehicles (i.e., gasoline, petroleum 
diesel and methanol) are only required to meet total hydrocarbon (THC) 
standards. However, beginning with the 1994 model year, currently 
regulated light-duty vehicles and light-duty trucks will also be 
required to meet separate nonmethane hydrocarbon (NMHC) standards as 
part of the Tier 1 requirements of the Clean Air Act.\4\ For natural 
gas-fueled light-duty vehicles and light-duty trucks only the NMHC 
standards will apply. In the case of natural gas-fueled heavy-duty 
engines, NMHC standards which provide the same degree of NMHC control 
as the current THC standards provide for petroleum-fueled vehicles will 
apply. In the case of LPG vehicles and engines, the HC standards are 
the same as those for currently regulated vehicles. A summary of 
today's gaseous-fueled vehicle emission standards is contained in 
Tables 1 through 4.
---------------------------------------------------------------------------

    \4\The Agency uses the phrase ``Tier 1'' to denote the 1994 and 
later model year standards in part because they are nearly identical 
to the Tier 1 standards prescribed by section 202(g) of the Clean 
Air Act for petroleum-fueled vehicles (56 FR 25724, June 5, 1991). 
Use of this phrase is not meant to suggest that gaseous-fueled 
vehicles are subject to the section 202(g) Tier 1 standards.

     Table 1.--Emission Standards for 1997 and Later Model Year Gaseous-Fueled Light-Duty Vehicles (q/mi)1      
----------------------------------------------------------------------------------------------------------------
                                                                                                     Evaporative
         Fuel               Standards\2\        THC       NMHC        CO         NOX       PM\3\    hydrocarbons
                                                                                                      (g/test)  
----------------------------------------------------------------------------------------------------------------
                                      Intermediate Useful Life Standards\4\                                     
                                                                                                                
----------------------------------------------------------------------------------------------------------------
Natural Gas............  Tier 0............  .........       0.34        3.4        1.0       0.20          2.0 
Natural Gas............  Tier 1............  .........       0.25        3.4        0.4       0.08          2.0 
                                                                                                                
----------------------------------------------------------------------------------------------------------------
LPG....................  Tier 0............       0.41  .........        3.4        1.0       0.20          2.0 
LPG....................  Tier 1............       0.41       0.25        3.4        0.4       0.08          2.0 
                                                                                                                
----------------------------------------------------------------------------------------------------------------
                                          Full Useful Life Standards\5\                                         
                                                                                                                
----------------------------------------------------------------------------------------------------------------
Natural Gas............  Tier 1............  .........       0.31        4.2        0.6       0.10  ............
LPG....................  TIer 1............  .........       0.31        4.2        0.6       0.10  ............
----------------------------------------------------------------------------------------------------------------
\1\Crankcase emissions are prohibited. Standards apply at all altitudes. For Tier 1 standards, vehicles are     
  required to meet both the intermediate and full useful life standards.                                        
\2\The Tier 1 standards apply to 40 percent of a manufacturer's optionally certified 1994 model year vehicles,  
  80 percent of optionally certified 1995 vehicles, and 100 percent of optionally certified 1996 vehicles. The  
  Tier 0 standards apply to optionally certified pre-1996 model year vehicles not covered by the Tier 1         
  standards.                                                                                                    
\3\Tier 0 particulate standards apply to diesel-cycle vehicles only. Tier 1 particulate standards apply to all  
  vehicles.                                                                                                     
\4\Five years or 50,000 miles, whichever occurs first.                                                          
\5\Ten years or 100,000 miles, whichever occurs first. No full useful life Tier 0 standards.                    


                      Table 2.--Emissions Standards for 1997 and Later Model Year Gaseous-Fueled Light Light-Duty Trucks (g/mi)\1\                      
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                             Evaporative
                 Fuel                   LVW (lb)\2\  Standards\3\      THC         NMHC         CO         NOx        PM\4\     Idle CO (%  hydrocarbons
                                                                                                                                  conc.)      (g/test)  
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          Intermediate Useful Life Standards\5\                                                         
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
Natural Gas...........................       0-3750  Tier 1......  ...........        0.25         3.4         0.4        0.08  ..........  ............
Natural Gas...........................    3751-5750  Tier 1......  ...........        0.32         4.4         0.7        0.08  ..........  ............
LPG...................................       0-3750  Tier 1......  ...........        0.25         3.4         0.4        0.08  ..........  ............
LPG...................................    3751-5750  Tier 1......  ...........        0.32         4.4         0.7        0.08  ..........  ............
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Full Useful Life Standards\6\                                                              
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
Natural Gas...........................       0-3750  Tier 0......  ...........  0.67(0.83)      10(14)         1.2        0.26        0.50     2.0(2.6) 
Natural Gas...........................       0-3750  Tier 1......  ...........        0.31         4.2         0.6        0.10        0.50     2.0(2.6) 
Natural Gas...........................    3751-5750  Tier 0......  ...........  0.67(0.83)      10(14)         1.7        0.13        0.50     2.0(2.6) 
Natural Gas...........................    3751-5750  Tier 1......  ...........        0.40         5.5        0.97        0.10        0.50     2.0(2.6) 
LPG...................................       0-3750  Tier 0......    0.80(1.0)  ..........      10(14)         1.2        0.26        0.50     2.0(2.6) 
LPG...................................       0-3750  Tier 1......         0.80        0.31         4.2         0.6        0.10        0.50     2.0(2.6) 
LPG...................................    3751-5750  Tier 0......    0.80(1.0)  ..........      10(14)         1.7        0.13        0.50     2.0(2.6) 
LPG...................................    3751-5750  Tier 1......         0.80        0.40         5.5        0.97        0.10        0.50    2.0(2.6)  
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\Crankcase emissions are prohibited. Standards in parenthesis apply to vehicles sold in specified high-altitude counties. For the Tier 1 standards,   
  vehicles are required to meet both the intermediate and full useful life standards.                                                                   
\2\Loaded vehicle weight (i.e., curb weight plus 300 lb.).                                                                                              
\3\The Tier 1 standards apply to 40 percent of a manufacturer's optionally certified 1994 model year vehicles, 80 percent of optionally certified 1995  
  vehicles, and 100 percent of optionally certified 1996 model year vehicles. The Tier 0 standards apply to optionally certified pre-1996 model year    
  vehicles not covered by the Tier 1 standards.                                                                                                         
\4\Tier 0 particulate standards apply to diesel-cycle vehicles only. Tier 1 particulate standards apply to all vehicles, but are phased in beginning one
  year later than the other Tier 1 standards.                                                                                                           
\5\Five years or 50,000 miles, whichever occurs first.                                                                                                  
\6\For Tier 0 standards eleven years or 120,000 miles, whichever occurs first. For Tier 1 standards ten years or 100,000 miles, whichever occurs first. 


                      Table 3.--Emissions Standards for 1997 and Later Model Year Gaseous-Fueled Heavy Light-Duty Trucks (g/mi)\1\                      
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                   Idle CO   Evaporative
                     Fuel                        Weight\2\     Standards\3\       THC          NMHC        CO      NOX     PM\4\      (%    hydrocarbons
                                                                                                                                   conc.)     (g/test)  
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          Intermediate Useful Life Standards\5\                                                         
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
Natural Gas..................................  3751-5750....          Tier 1  ...........         0.32      4.4      0.7  .......  .......  ............
Natural Gas..................................  >5750........          Tier 1  ...........         0.39      5.0      1.1  .......  .......  ............
LPG..........................................  3751-5750....          Tier 1  ...........         0.32      4.4      0.7  .......  .......  ............
LPG..........................................  >5750........          Tier 1  ...........         0.39      5.0      1.1  .......  .......  ............
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Full Useful Life Standards\6\                                                             
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
Natural Gas..................................  0-3750.......          Tier 0  ...........   0.67(0.83)   10(14)      1.2     0.26     0.50      2.0(2.6)
Natural Gas..................................  >3750........          Tier 0  ...........   0.67(0.83)   10(14)      1.7     0.13     0.50      2.0(2.6)
Natural Gas..................................  3751-5750....          Tier 1  ...........         0.46      6.4     0.98     0.10     0.50      2.0(2.6)
Natural Gas..................................  >5750........          Tier 1                      0.56      7.3     1.53     0.12     0.50      2.0(2.6)
LPG..........................................  0-3750.......          Tier 0    0.80(1.0)                10(14)      1.2     0.26     0.50      2.0(2.6)
LPG..........................................  >5750........          Tier 0    0.80(1.0)                10(14)      1.7     0.13     0.50      2.0(2.6)
LPG..........................................  3751-5750....          Tier 1    0.80(1.0)         0.46      6.4     0.98     0.10     0.50      2.0(2.6)
LPG..........................................  >5750........          Tier 1    0.80(1.0)         0.56      7.3     1.53     0.12     0.50     2.0(2.6) 
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\Crankcase emissions are prohibited. Standards in parentheses apply to vehicles sold in specified high-altitude counties. For the Tier 1 standards,   
  vehicles are required to meet both the intermediate and full useful life standards.                                                                   
\2\For Tier 0 standards the weight classification is loaded vehicle weight (i.e., curb weight plus 300 lb). For Tier 1 standards the weight             
  classification is adjusted loaded vehicle weight (i.e., the average of curb weight and gross vehicle weight).                                         
\3\The Tier 1 standards apply to 50 percent of a manufacturer's optionally certified 1996 model year vehicles, and 100 percent of 1997 and later        
  vehicles. The Tier 0 standards are optional before the 1995 model year and apply to optionally certified 1995 and 1996 model year vehicles not covered
  by the Tier 1 standards.                                                                                                                              
\4\The Tier 0 particulate standards apply to diesel-cycle vehicles only. The Tier 1 particulate standards apply to all vehicles, but are phased in      
  beginning one year later than the other Tier 1 standards.                                                                                             
\5\Five years or 50,000 miles, whichever occurs first.                                                                                                  
\6\Eleven years or 120,000 miles, whichever occurs first.                                                                                               


                       Table 4.--Emissions Standards for 1997 and Later Model Year Gaseous-Fueled Heavy-Duty Engines g/BHP-hr\1\                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                   Idle CO   Evaporative
                        Fuel                             Combustion        GVW          THC     NMHC      CO     NOX\2\     PM        (%    hydrocarbons
                                                           cycle                                                                   conc.)     (g/test)  
--------------------------------------------------------------------------------------------------------------------------------------------------------
Natural Gas..........................................  Otto.........      8501-14000  .......      0.9     14.4      5.0  .......     0.50         3.0  
Natural Gas..........................................  Otto.........          >14000  .......      1.7     37.1      5.0  .......     0.50         4.0  
LPG..................................................  Otto.........      8501-14000      1.1  .......     14.4      5.0  .......     0.50         3.0  
LPG..................................................  Otto.........          >14000      1.9  .......     37.1      5.0  .......     0.50         4.0  
Natural Gas..........................................  Diesel.......      8501-14000  .......      1.2     15.5      5.0  \3\0.10     0.50         3.0  
Natural Gas..........................................  Diesel.......          >14000  .......      1.2     15.5      5.0  \3\0.10     0.50         4.0  
LPG..................................................  Diesel.......      8501-14000      1.3  .......     15.5      5.0  \3\0.10     0.50         3.0  
LPG..................................................  Diesel.......          >14000      1.3  .......     15.5      5.0  \3\0.10     0.50        4.0   
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\g/BHP-hr = grams per brake horsepower hour. Crankcase emissions are prohibited beginning with the 1998 model year.                                   
\2\The NOX standard is 4.0 g/BHP-hr for all 1998 and later model year HDEs.                                                                             
\3\For optional compliance prior to the 1997 model year this standard is 0.10 g/BHP-hr for the 1994 and later model year, except for urban bus engines. 
  For urban bus engines the optional standards are 0.07 g/BHP-hr for the 1994 and 1995 model years, and 0.05 g/BHP-hr for the 1996 model year. The      
  required standard for 1997 and later model year urban bus engines is 0.05 g/BHP-hr.                                                                   

    For the purposes of these standards, the current scheme of 
classifying vehicles as either Otto-cycle or diesel is being extended 
to gaseous-fueled vehicles, with some modifications as described below. 
This classification scheme was promulgated with the methanol standards 
to group engines regardless of fuel type in a manner that would provide 
equivalent control.
    Although there are other factors to consider, in general an Otto-
cycle engine is considered to be one that is throttled during normal 
operation whereas a diesel is not. The Agency recognizes, however, that 
in some cases this criterion may not be adequate or appropriate to 
determine a vehicle's classification. For example, a gaseous-fueled 
engine which is derived from a particular Otto-cycle or diesel base 
engine, and is expected to be used in similar applications as the base 
engine, would most appropriately be classified the same as the base 
engine from which it was derived. In such cases the Administrator will 
take into account other relevant factors, such as compression ratio, 
combustion and thermodynamic characteristics, or intended in-use duty 
cycle when classifying the vehicle.
    Today's rule establishes the same evaporative emission requirements 
for gaseous-fueled vehicles which were recently adopted for other 
vehicles.\5\ The Agency recognizes that due to the sealed nature of 
gaseous-fueled vehicle fuel systems, emissions of unburned fuel from 
the fuel system are expected to be near-zero. However, the evaporative 
requirements are being adopted to assure leak-free fuel systems.
---------------------------------------------------------------------------

    \5\58 FR 16002, March 24, 1993.
---------------------------------------------------------------------------

    Today's rule establishes refueling requirements for gaseous-fueled 
light-duty vehicles and light-duty trucks, as well as refueling 
stations. Natural gas-fueled vehicles must be equipped with a refueling 
receptacle which meets the requirements of the recently adopted ANSI/
AGA NGV1 standard for refueling couplings. Natural gas refueling 
stations will not be allowed to vent more than 1.2 grams natural gas 
due to refueling nozzle disconnect. The applicable dates for these 
standards are discussed in the timing section of today's rule.
    For LPG vehicles there are two requirements. First, all LPG vehicle 
refueling stations will be required to use nozzles which have very low 
dead volume (2.0 cm\3\) from which fuel would be vented upon nozzle 
disconnect. This requirement was derived from the recently promulgated 
onboard refueling vapor recovery standard. For a complete description 
of the derivation please consult the summary and analysis of comments 
document. Second, LPG-fueled light-duty vehicles and light-duty trucks 
will be subject to the onboard refueling emission standards, adjusted 
for the difference in LPG energy density as compared to gasoline. This 
adjusted standard is 0.15 grams per gallon of LPG dispensed. The 
applicable dates for these standards are discussed in the timing 
section of today's rule. Additionally, for any LPG vehicle that 
contains a fixed liquid level valve (i.e., ``outage valve''), the 
refueling test will be performed with the liquid level valve in the 
open position unless the manufacturer can demonstrate to the 
satisfaction of the Administrator, that the fixed liquid level gauge 
would not be opened during refueling in ordinary use due to 
inaccessibility or other reasons.
    EPA recognizes that, although it did propose the control of 
refueling emissions from gaseous-fueled vehicles, the proposal did not 
include specific numerical standards as contained in today's rule. 
However, EPA believes that this action will be noncontroversial, and 
the Agency anticipates no significant comments regarding it.
    Nonetheless, the public is advised that these elements of today's 
action dealing with refueling emissions will be effective 60 days from 
the date of this Federal Register notice, unless notice is received 
within 30 days that interested parties wish to submit adverse or 
critical comments on that element of this action. If such notice is 
received, this action will be withdrawn and two subsequent notices will 
be published. One notice, which would be published before the effective 
date, will withdraw the final action. Another notice will begin a new 
rulemaking by announcing a proposal of the action and establishing a 
comment period.
    There is reason to believe that, in the case of some of the above-
mentioned pollutants and vehicle classes, the levels of emissions will 
normally be substantially below the levels of the applicable standards. 
In such cases today's rule includes provisions for a waiver of 
certification testing requirements which allow a manufacturer to 
certify the vehicle or engine without performing the actual 
certification testing for which a waiver has been granted, similar to 
the waivers available for heavy-duty diesel engine CO, methanol vehicle 
and engine smoke and particulate, and Otto-cycle light-duty vehicle and 
light-duty truck particulate standards.\6\ A certification testing 
waiver can be obtained by demonstrating that, by virtue of a vehicle's 
design, it will always meet the standard for which the waiver was 
granted. This demonstration can be in the form of development testing 
data or other engineering data. It should be noted that these waivers 
only apply to certification testing requirements and do not relieve the 
manufacturer of liability for meeting the standard. Vehicles which have 
been certified using these waiver provisions also remain subject to 
selective enforcement audit (SEA) and in-use testing. The waivers 
provided in today's rule are available for all gaseous-fueled vehicle 
evaporative and refueling standards, gaseous-fueled heavy-duty diesel 
CO (including idle CO), particulate and smoke standards, and 
particulate standards for light-duty vehicles and light-duty trucks.
---------------------------------------------------------------------------

    \6\47 FR 49811, November 2, 1982; 54 FR 14426, April 11, 1989; 
and 56 FR 25724, June 5, 1991.
---------------------------------------------------------------------------

    Today's rule allows gaseous-fueled vehicles to demonstrate 
compliance with emission standards through averaging, trading and 
banking in the same manner as vehicles operated on other fuels. 
Gaseous-fueled vehicles will be treated similarly to methanol-fueled 
vehicles with respect to the constraints of the various programs. For a 
more detailed discussion of how gaseous-fueled vehicles fit into these 
programs please consult the public docket for this rulemaking.\7\ As 
explained above, in addition to new vehicles and engines, today's rule 
allows manufacturers to include in the averaging, trading and banking 
programs 1994 model year vehicles and engines manufactured before the 
rule's effective date, but identical to 1994 model year vehicles and 
engines manufactured after the effective date.
---------------------------------------------------------------------------

    \7\Public docket A-92-14, item III-B-2.
---------------------------------------------------------------------------

    Today's rule delays the applicability of federal on-board 
diagnostics (OBD) requirements for natural gas-fueled light-duty 
vehicles and light-duty trucks until the 1998 model year. As finalized 
in the February 19, 1993 OBD rule\8\ those requirements were scheduled 
to take effect with the 1994 model year for all vehicles for which 
emission standards exist. However, due to the feasibility issues unique 
to natural gas-fueled vehicles, these requirements are being delayed 
until the 1998 model year. OBD I requirements will apply to natural gas 
vehicles in the 1997 model year, as well as those natural gas vehicles 
optionally certified prior to the 1997 model year. The OBD requirements 
contained in the OBD rule will apply to liquefied petroleum gas-fueled 
light-duty vehicles and light-duty trucks beginning with optionally 
certified vehicles in the 1994 model year.
---------------------------------------------------------------------------

    \8\58 FR 9468, February 19, 1993.
---------------------------------------------------------------------------

C. Certification Test Fuel Specification

    The certification test fuels in today's rule are intended to 
represent the actual fuels gaseous-fueled vehicles are likely to see 
in-use. Given the wide range of in-use fuel compositions, the 
certification fuels are broadly defined. In the case of natural gas, 
the certification fuel specifications include a minimum methane content 
of 89 percent, as well as maximum levels for the other prominent 
hydrocarbons found in natural gas (e.g., ethane, propane). 
Certification fuel under this approach reflects over 90 percent of the 
natural gas available in the United States. Most of the gas not meeting 
this criteria is gas being sold in high altitude areas, where higher 
levels of inert gases are added to the natural gas.
    Significantly less is known about the variability of in-use LPG 
composition. However, the Agency believes that the composition of LPG 
is more consistent than that of natural gas due to common carrier 
pipeline and import tariff constraints. Thus, the Agency is adopting 
commercially available LPG as the certification fuel for LPG vehicles. 
As more information becomes available on LPG composition, and as 
experience with LPG vehicles increases, the need for a more well-
defined LPG certification fuel may become apparent. Should this happen, 
EPA would take steps at that time to develop an appropriate LPG 
certification fuel specification. It should be noted that the Agency is 
not including any controls on in-use natural gas or LPG in today's 
rule, but intends to monitor in-use fuels to ensure that the 
certification fuels remain representative.

D. Test Procedures

    For the most part, the current test cycles, and measurement and 
analytical procedures can be directly applied to gaseous-fueled 
vehicles. Thus, the test procedures contained in today's rule are 
largely the same as those which apply to other, currently regulated 
vehicles. The only exception of note is the procedure for measuring 
NMHC emissions from natural gas-fueled vehicles. The current procedure 
for measuring NMHC emissions was adopted in the Tier 1 rule.\9\ While 
this procedure works fairly well for currently regulated vehicles, it 
is not nearly as accurate for natural gas-fueled vehicles due to their 
much higher levels of exhaust methane. Thus, today's rule contains some 
slight modifications to the NMHC test procedures adopted for the Tier 1 
standards\10\ to allow more accurate NMHC measurement from natural gas-
fueled vehicles. These changes include accounting for the different 
flame ionization detector (FID) response to methane as opposed to the 
other hydrocarbons, as well as the use of fuel densities and H/C ratios 
in the calculations which are more appropriate to natural gas vehicles. 
The Agency views this as an interim measure and is currently working 
with the California Air Resources Board and the American Automobile 
Manufacturers Association as part of a cooperative research and 
development agreement to develop a more accurate procedure for the 
direct measurement of NMHC.
---------------------------------------------------------------------------

    \9\56 FR 25724, June 5, 1991.
    \10\56 FR 25724, June 5, 1994.
---------------------------------------------------------------------------

E. Fuel Economy

    Today's rule contains fuel economy test procedures and calculations 
for measuring the fuel economy of natural gas-fueled light-duty 
vehicles and light-duty trucks. The driving cycles adopted for natural 
gas vehicles are the same as those currently in place for gasoline-
fueled vehicles. Also, the measurement and calculation procedures for 
natural gas vehicles rely on the same principle of carbon balance as 
the current gasoline procedures, but include a gasoline/natural gas 
equivalency factor of 100 standard cubic feet of natural gas equalling 
0.823 gallons of gasoline.
    These procedures and calculations will allow these vehicles to be 
included in a manufacturer's corporate average fuel economy (CAFE) 
under the Motor Vehicle Information and Cost Savings Act (MVICSA), 15 
U.S.C. Sec. 2001 et seq. The Alternative Motor Fuels Act of 1988,\11\ 
provides that alternative fueled vehicles (including natural gas-fueled 
vehicles) may be included in a manufacturer's CAFE calculation on a 
favorable basis in order to encourage the manufacture of such vehicles. 
The AMFA provides that, for purposes of including natural gas vehicles 
in the CAFE calculation, fuel consumption of natural gas vehicles is 
only fifteen percent of equivalent gasoline fuel consumption. The AMFA 
also mandates the 0.823 gasoline/natural gas equivalency factor 
included in today's rule. Regulations governing the calculation and use 
of natural gas vehicle CAFE credits are contained in a separate 
rulemaking action.\12\
---------------------------------------------------------------------------

    \11\Public Law 100-494, October 14, 1988.
    \12\56 FR 8856, March 1, 1991.
---------------------------------------------------------------------------

    As will be discussed further in the Public Participation section of 
this rule, the Agency is not promulgating fuel economy procedures for 
LPG vehicles today, but will do so in a separate rulemaking action.

F. Aftermarket Conversions

    Today's rule contains provisions for the certification of 
aftermarket conversions (i.e., conversions which allow a vehicle or 
engine to operate on a fuel other than the fuel for which it was 
originally designed and certified). An exemption from the tampering 
prohibitions contained in section 203(a)(3) of the Clean Air Act can be 
secured through this certification process. The provisions contained in 
today's rule for securing such an exemption consist of three main 
parts: applicable standards, test procedures, and warranty/liability 
issues.
    It has always been the Agency's policy that an aftermarket 
conversion not degrade the emissions performance of the original 
vehicle as a condition of being exempt from prosecution for tampering 
violations. Today's rule merely clarifies that policy by providing 
specific procedures by which one can certify that a conversion does 
meet this requirement, and thus secure an exemption from the tampering 
prohibition. Consistent with this policy, the emission standards which 
an aftermarket conversion shall meet in order to secure the tampering 
prohibition exemption are essentially the same standards the original 
vehicle was certified as meeting. In the case of conversions to natural 
gas, the converted vehicle would not be required to meet the THC 
standard, but must meet an NMHC standard which provides an equivalent 
amount of NMHC control as that afforded by the original THC standard. 
In the case of conversion to multi-fuel operation (i.e., where the 
vehicle has the ability to switch between two fuels, such as gasoline 
and natural gas, or where the vehicle operates on two fuels 
simultaneously, but retains the ability to operate exclusively on the 
original fuel), the vehicle would still be required to meet the 
emission standards it was originally certified to when operating on the 
original fuel, in addition to meeting the applicable requirements on 
the new fuel.
    The test procedures applicable to aftermarket conversions under 
this program are those currently in place new vehicle certification as 
outlined in 40 CFR Part 86. The small volume manufacturers 
certification program contained in 40 CFR 86.092-14 is also available 
for aftermarket conversion certification provided the company or 
individual seeking certification meets the sales limits described in 
that section. These procedures utilize the same test cycles and 
analytical procedures that are used for new vehicle certification. In 
the case of aftermarket conversions a certificate of conformity must be 
sought for each engine family/conversion system combination and for 
each model year vehicle for which the system is intended.
    As a condition of exemption from the tampering prohibition, 
conversion manufacturers and installers must accept in-use liability 
for warranty and recall as outlined in section 207 of the Act and its 
implementing regulations.\13\ This is consistent with EPA's policy that 
aftermarket conversions not degrade the emissions performance of the 
original vehicle. It will also assure that the conversion will meet the 
applicable emission standards throughout its useful life. Since 
conversions generally rely, at least in part, on emission control 
equipment already on the original vehicle for emissions control, the 
useful life of a conversion will not extend beyond the useful life of 
the original vehicle.
---------------------------------------------------------------------------

    \13\Code of Federal Regulations, Title 40, Part 86.
---------------------------------------------------------------------------

G. Fees

    Under section 217 of the Clean Air Act, EPA may establish fees to 
recover all reasonable costs incurred for activities associated with 
the Motor Vehicle and Engine Compliance Program (MVECP). The MVECP 
includes all compliance and enforcement activities performed by EPA 
which are associated with certification, fuel economy, Selective 
Enforcement Auditing (SEA), and in-use compliance activities. In July 
of 1992 EPA established these fees, to be effective with the 1993 model 
year.\14\ These fees, as stated in the fees rule, cover all direct and 
indirect costs incurred by EPA for the MVECP, and automatically apply 
to gaseous-fueled vehicles and engines now that the MVECP applies to 
such vehicles and engines. Since the fees are based on the costs 
incurred by EPA, and since today's regulations are basically an 
extension of the current MVECP, the fees currently in effect for other 
vehicles apply to gaseous-fueled vehicles, without modification. No 
regulatory changes are needed and none are being made. The applicable 
fee must be paid, for each engine family, before the Certification 
Division can begin a review of the application for certification.
---------------------------------------------------------------------------

    \14\57 FR 30044, July 7, 1992.
---------------------------------------------------------------------------

III. Public Participation

    A number of interested parties commented on EPA's November 5, 1992 
NPRM. The comments include written submittals to the rulemaking docket 
and those presented at the December 3, 1992 public hearing, which was 
held in Ann Arbor, Michigan. The Agency has fully considered these 
comments in developing today's final rule.
    This section describes the major issues of the rulemaking, as 
reflected in the public comments. The discussion of each issue opens 
with a brief description of what was proposed followed by a summary of 
the significant comments and EPA's analysis of the issue. The reader is 
referred to the Summary and Analysis of Comments document for the 
complete details of EPA's analysis. That document is available in the 
rulemaking docket. (For information on access to the docket, see the 
``Addresses'' section above.)

A. Timing of Requirements

    Summary of the proposal: As was stated in the NPRM, the Agency 
believes that the proposed standards are not technology-forcing, and 
that they could be met largely through currently available technology. 
Thus, the only leadtime requirement for meeting the proposed standards 
would be that of actually going through the certification process 
itself, including the required durability showing. The Agency, 
therefore, proposed that the new vehicle emission standards be 
effective with the 1994 model year, and that the aftermarket 
conversions take effect on January 1, 1994. Additionally, the Agency 
proposed that manufacturers have the option of complying with these 
standards prior to the effective date in order to participate in any 
applicable emissions averaging, trading and banking programs, as well 
as the CAFE program in the case of natural gas-fueled light-duty 
vehicles and light-duty trucks.
    Summary of the comments: In general, the comments received in 
response to the issue of leadtime supported EPA's assessment that these 
standards are not technology-forcing in the sense that fundamentally 
new technology must be developed. However, a number of commenters 
raised concerns that, although the basic technology required to meet 
these standards has been demonstrated at low mileage, the durability of 
this technology in many cases remains to be proven. Additionally, one 
commenter pointed out that there are several mandated requirements 
taking effect in the next few years for new vehicles, including Tier 1 
and cold CO standards, on-board diagnostics, and revised evaporative 
procedures, and that mandating gaseous-fueled vehicle certification 
with little leadtime may seriously impair the introduction of these 
vehicles into the marketplace. Most commenters suggested that, given 
the need for technology refinement and durability work, these 
requirements should not take effect until the 1996 or 1997 model year. 
In addition, the heavy-duty engine manufacturers asserted that, under 
section 202(a)(3)(C) of the Clean Air Act, EPA is required to provide 
four years leadtime in the case of any new emission standards. In most 
cases commenters stated that, regardless of what effective date EPA 
finalizes, they support the option of being able to certify prior to 
the effective date.
    EPA response to comments: The Agency agrees that, while current 
gaseous-fueled vehicle technology is generally capable of meeting the 
emission standards contained in today's rule, work remains in some 
cases to meet the durability requirements. While the Agency believes 
that some current gaseous-fueled engine technologies are capable of 
demonstrating the required emissions durability, it does not believe 
this is the case with some of the newest technologies being developed. 
Given that each engine family must demonstrate durability during the 
new vehicle certification process, the Agency believes that not 
providing adequate leadtime may hinder the further development of new 
gaseous-fueled vehicle technology in the short term, which is contrary 
to the stated intent of this rule. Thus, today's requirements for new 
vehicles and engines will take effect with the 1997 model year as 
requested by some commenters. Manufacturers will have the option to 
comply with these provisions prior to the 1997 model year if they 
choose.
    The Agency does not believe that this amount of leadtime will be a 
problem from an environmental standpoint for two reasons. First, the 
volume of new gaseous-fueled vehicles produced prior to the 1997 model 
year is not expected to be that large, given the relatively young 
nature of the new gaseous-fueled vehicle market. Second, the Agency 
expects that any new vehicle or engine family which might be sold in 
any significant volume prior to the 1997 model year would have 
demonstrated adequate durability. Since there is much incentive for 
early compliance in the form of CAFE credits and the emissions banking 
and trading program, the Agency would expect the manufacturers of these 
vehicles to certify them in order to take advantage of these credits.
    Additionally, the Agency does not believe that it is required to 
provide four years leadtime for new gaseous-fueled heavy-duty engine 
standards because these standards are being promulgated under the 
general authority of section 202(a)(1). However, as will be discussed 
in the section on CO and crankcase emissions, the Agency has elected to 
provide four years of leadtime in the case of crankcase emission 
controls. For further discussion of the four year leadtime issue please 
consult the summary and analysis of comments document in the docket. 
Finally, manufacturers have the option of complying with these 
requirements prior to their effective date (including certification 
retroactive to the beginning of the 1994 model year) and can include 
such certified engines in the averaging, banking and trading program.

B. Standards for HC

1. NMHC vs. THC Standards
    Summary of the proposal: Since natural gas is primarily methane, 
natural gas-fueled vehicles (NGV) tend to have fairly high levels of 
methane emissions in their exhaust HC. Due to the difficulty current 
catalyst formulations have in oxidizing methane, it is not currently 
feasible for NGVs to meet the same THC standards that other vehicles 
meet. Thus, only NMHC standards were proposed for NGVs, with the Agency 
deferring any action on THC standards for NGVs until such time as the 
necessary methane control technology can be developed. LPG fuel, 
however, contains no methane, and the exhaust methane levels associated 
with LPG vehicles tend to be much closer to those from petroleum-fueled 
vehicles. Thus, all applicable THC and NMHC standards were proposed for 
LPG vehicles.
    Summary of the comments: The Agency's decision to defer action on 
THC standards for NGVs received very broad support. Only the 
Manufacturers of Emission Controls Association (MECA) disagreed with 
this approach. MECA contended that without some form of technology-
forcing THC standard for NGVs, most work on methane control technology 
would likely stop. MECA also pointed out that the Agency has, in the 
past, used technology-forcing standards as impetus for the development 
of new emission control technology.
    Several commenters suggested that the approach of exempting NGVs 
from THC standards should be applied to LPG vehicles as well, citing a 
potential unfair advantage for NGVs if LPG vehicles were required to 
meet THC standards. Additionally, the LP Gas Clean Fuels Coalition 
stated that LPG vehicles have substantially higher levels of methane 
emissions than their petroleum-fueled counterparts, and thus should 
also be exempt from meeting the THC standards. The Coalition, however, 
did not submit any data in support of this claim.
    EPA response to the comments: The Agency continues to believe that 
action on the THC standards for NGVs should be deferred. The Agency 
continues to be concerned that compliance with the THC standard 
currently in place for other fuels is infeasible for NGVs. While the 
Agency has received data suggesting that the THC standards are 
technically achievable for NGVs, no data has been submitted concerning 
the cost of refining and implementing the necessary technology on a 
commercial level. Cost is a component of feasibility, and without cost 
information the Agency cannot conclude that compliance with the THC 
standards is feasible. Moreover, technical issues remain to be 
resolved. The data suggesting that THC standards are technically 
achievable was limited to vehicles operating at a stoichiometric fuel/
air ratio, and operation under other conditions (i.e., lean burn) 
remains an issue. Additionally, the durability of methane-specific 
catalysts remains an unknown.
    Also, for the reasons explained in the proposal, EPA does not 
believe it can establish a technology-forcing standard. EPA continues 
to believe that the amount of lead-time required for adequate 
technology development still cannot be readily determined, because the 
durability of a methane catalyst formulation has not been established. 
EPA does not agree that the absence of a technology-forcing standard 
would bring work on methane control technology to a stop. The engine 
manufacturing industry has indicated that its research will continue 
based on the belief that THC standards will be imposed in the future. 
Also, as noted in the proposal, EPA believes that strong growth in the 
NGV market in the near-term is important to provide resources for 
technology development. Of course, EPA will continue to monitor work on 
methane catalyst development. If information becomes available 
establishing the technology's feasibility (including cost information), 
EPA will consider adopting THC standards for NGVs. Also, if future 
events further demonstrate the need for a technology-forcing standard, 
EPA will further consider this option as well.
    As was stated in the NPRM, the Agency believes it most appropriate 
to, wherever possible, apply the same standards to alternative-fueled 
vehicles that apply to their petroleum-fueled counterparts. In the case 
of NGVs there are circumstances, as discussed above, which justify 
deviating from this basic philosophy. However, the Agency has seen no 
emissions data which would suggest that a similar set of circumstances 
exists for LPG vehicles. Thus, LPG vehicles will be required to meet 
the same THC standards as currently apply to other vehicles.
2. Heavy-Duty NMHC Standards
    Summary of the proposal: In setting NMHC standards for natural gas-
fueled heavy-duty engines (HDE), the Agency intends to establish 
standards which would provide the same level of NMHC control as the THC 
standards in effect for petroleum diesel and gasoline HDEs. In the 
absence of speciated exhaust HC data on HDEs (i.e., data on the level 
of the individual HC components in the exhaust), EPA applied the 
results of an analysis done on light-duty vehicles and light-duty 
trucks to arrive at NMHC standards which were 82.5 percent of the level 
of the corresponding THC standards. The resultant standards were very 
close to those adopted by the California Air Resources Board (CARB), 
and in the NPRM the Agency requested comment on whether it should adopt 
CARB's standards instead.
    Summary of the comments: Every commenter who expressed an opinion 
on this issue urged EPA to adopt the CARB standards in order that the 
California and federal standards be harmonized.
    EPA response to the comments: The Agency believes that the 
differences between its proposed NMHC standards and CARB's are so small 
as not to be an air quality issue. Further, EPA has learned since the 
NPRM that the CARB standards were based on speciated data from HDEs. 
Thus, as EPA believes that the speciated data provides a sounder basis 
than EPA's, the Agency is adopting CARB's NMHC standards for HDEs.
3. Evaporative Emission Standards
    Summary of the proposal: In the NPRM it was noted that, due to the 
sealed nature of gaseous-fueled vehicle fuel systems, their 
``evaporative'' emissions (i.e., emissions of unburned fuel from the 
fuel storage system) are expected to be near-zero. Nonetheless, the 
Agency proposed evaporative emission controls for gaseous- fueled 
vehicles in order to assure that the fuel systems are not leaking. EPA 
proposed that the evaporative provisions for gasoline and methanol-
fueled vehicles, which were in the process of being revised at the time 
of the proposal for this rule, be applicable to gaseous-fueled vehicles 
as well, with modifications to the test procedures as necessary to 
accommodate gaseous fuels. The Agency also proposed that certification 
testing waivers be available for evaporative testing in order to reduce 
the testing burden as much as possible, given the likelihood of near-
zero emissions.
    Summary of the comments: Although one commenter supported the 
proposed evaporative requirements for gaseous-fueled vehicles, citing 
potential fuel leaks from the vehicle refueling receptacle, most of the 
comments received expressed opposition. In general, most commenters 
said that, for safety reasons, as well as to simply prevent the 
complete escape of fuel from the vehicle for economic reasons, the fuel 
systems must be sealed. Since sealed systems are a practical 
requirement of gaseous-fueled vehicles, they argued, there is no need 
for EPA to regulate evaporative emissions. As a result, any 
certification testing required would be unnecessary. Some commenters 
felt that if EPA were to require some form of evaporative emissions 
showing that it should be in the form of an engineering evaluation of 
the system, or simply a one hour diurnal test.
    EPA response to comments: The Agency agrees with the general 
comment that there are practical considerations other than emissions 
concerns which force the use of sealed fuel systems on gaseous-fueled 
vehicles. As a result, EPA would expect their evaporative emissions to 
be near-zero. However, the Agency believes that it is prudent to have 
some kind of evaporative emission standard which can be enforced, in 
order to assure that fuel system leaks do not become a problem. Thus, 
the same new evaporative provisions applicable to other vehicles 
beginning with the 1996 model year will also be applied to gaseous-
fueled vehicles at that time, recognizing that compliance with these 
standards is optional prior to the 1997 model year. The Agency does 
recognize, however, that it is likely that, by virtue of their design, 
gaseous-fueled vehicles will emit well below the applicable standards. 
Therefore, certification testing waivers will be available for all 
gaseous-fueled vehicle evaporative provisions if the manufacturer can 
show that, by virtue of the vehicle's design, it will always meet the 
applicable standards.

C. Refueling Emission Standards

1. Natural Gas
    Summary of the proposal: In the NPRM the Agency proposed that, in 
the case of natural gas refueling facilities, no refueling hoses which 
need to be vented down prior to disconnect shall be vented to the 
atmosphere. Rather, as is the case with many current natural gas 
refueling facilities, EPA expects that such vent-down gases should be 
routed back to the compressor inlet rather than being vented to the 
atmosphere. The timing of this requirement was not explicit in the NPRM 
preamble. However, the regulatory text stated that the provisions would 
take effect with the 1994 model year.
    Summary of the comments: In general, the comments received in 
response to the issue of natural gas refueling hose venting opposed, to 
some degree, the proposed prohibition on venting emissions. Some 
commenters suggested that this requirement is not needed at all given 
the extremely small contribution to total methane emissions that vent-
down gases represent. Several commenters pointed out that the upcoming 
ANSI/AGA NGV1 standard would address EPA's concerns about refueling 
emissions from natural gas refueling stations. One commenter pointed 
out that this proposed requirement could be interpreted as a zero-
emission standard and questioned the feasibility of such an approach. 
Some commenters suggested that more leadtime was needed than was 
proposed. Several commenters pointed out that the cost of controlling 
these emissions varied quite a bit depending on the inlet pressure of 
the compressor. In cases where the natural gas supply line is at fairly 
low pressure (i.e., 15 psi or less) the gas could be routed directly 
into the compressor inlet at low cost. However, in cases where the gas 
supply pressure is higher, additional compression equipment would be 
needed to compress the vent-down gas in order to route it back into the 
compressor, raising costs substantially. Also, the cost of such 
controls would be much higher for existing installations than for new 
stations because existing stations would likely require excavation for 
the return line plumbing. Finally, some commenters stated that EPA 
should not control natural gas refueling emissions since they are 
primarily methane, and the Agency only proposed NMHC standards for 
tailpipe emissions.
    EPA response to comments: In the NPRM the Agency mentioned that the 
natural gas industry was moving toward the establishment of standard 
refueling equipment specifications. That effort, known as the ANSI/AGA 
NGV1 standard, was recently adopted by the American National Standards 
Institute (ANSI) as the standard for natural gas vehicle fueling 
connection devices. While in its various draft forms, this standard 
contained a provision limiting the amount of natural gas that can be 
vented due to nozzle disconnect. This provision was based on the 
proposed onboard refueling vapor recovery (ORVR) standard for gasoline-
fueled vehicles of 0.05 grams per gallon of dispensed gasoline.\15\ As 
indicated in the draft ANSI standard contained in the public docket for 
this rule, the venting provision was deleted from the final ANSI 
standard since, at the time of final balloting on the standard, the 
ORVR rule had not yet been promulgated. The ORVR final rule was 
recently promulgated and included a gasoline-fueled vehicle refueling 
emission standard of 0.20 grams per gallon of dispensed gasoline.\16\
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    \15\52 FR 31162, August 19, 1987.
    \16\59 FR 16262, April 6, 1994.
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    The Agency agrees that a zero-emission standard for natural gas 
vehicles is not reasonable and believes that, in its draft form, the 
NGV1 standard addressed EPA's concerns with natural gas vehicle 
refueling emissions. Thus, the Agency is using the methodology in draft 
NGV1 standard to apply the 0.20 gram per gallon refueling standard to 
natural gas vehicles. Using this approach, natural gas refueling 
stations will be allowed to vent no more than 1.2 grams of natural gas 
due to nozzle disconnect. This standard is based on the ORVR standard 
of 0.20 grams per gallon of fuel dispensed and a nominal fuel tank 
capacity of six gallons gasoline equivalent natural gas, as was assumed 
in the draft NGV1 standard. For a more complete discussion of how this 
standard was derived please consult the summary and analysis of 
comments document for this rule. This requirement will take effect 
January 1, 1998 for high volume stations, with a two year extension 
until January 1, 2000 for small volume stations (those which dispense 
less than the energy equivalent of 10,000 gallons of gasoline per month 
based on the AMFA fuel equivalency factor).
    In addition to the requirements for natural gas refueling stations, 
EPA is also requiring in today's rule natural gas-fueled light-duty 
vehicles and light-duty trucks be equipped with refueling receptacles 
which comply with the recently adopted ANSI/AGA NGV1 standard. This 
requirement will be implemented consistent with the timing of the ORVR 
provisions for other vehicles (three year phase-in beginning with the 
1998 model year for light-duty vehicles and the 2001 model year for 
light-duty trucks). The Agency expects, however, that all new natural 
gas- fueled vehicles will have ANSI/AGA NGV1 nozzles long before this 
due to the desire for standardized refueling coupling geometry within 
the industry.
    EPA does not believe that the cost of the refueling station 
controls is prohibitive and believes that today's requirement is both 
feasible and reasonable. Consistent with this view, most new stations 
being installed would meet this requirement. The Agency agrees that in 
certain cases, such as those where additional compression equipment is 
needed, the cost of retrofitting may not be reasonable. Thus, for in-
use refueling stations which must be retrofitted to meet this 
requirement, the Agency will waive the requirement in situations where 
the station operator can demonstrate, to the satisfaction of the 
Administrator, that compliance with this provision would require the 
use of additional compression equipment, or other similar costs. The 
impact of such waivers should be minimal given the small number of 
stations currently operating, and the small percentage of those 
stations which would not currently meet these requirements.
    As was discussed earlier, the lack of exhaust THC standards in 
today's rule is a function of cost and legal constraints, and the 
Agency believes that control of methane is appropriate where it is 
feasible and economically reasonable. Thus, EPA does not believe that 
the desire to control refueling emissions from natural gas vehicles is 
inconsistent with the adoption of exhaust NMHC standards.
2. LPG Vehicle/Pump Interface
    Summary of the proposal: Since LPG is transferred in a sealed 
system there is little concern about refueling emissions at the 
vehicle/pump interface during the actual fuel transfer. Of concern to 
the Agency, however, are emissions released when the nozzle is 
disconnected from the vehicle. At this point any fuel which is trapped 
in the dead space between the nozzle and the vehicle receptacle is 
released. In the NPRM the Agency proposed that refueling equipment be 
designed so as to prevent this escape of fuel, such as through the use 
of low-loss, no-bleed couplings, although no specific numerical 
standards were included. As with the natural gas provisions in the 
NPRM, the timing of this requirement was not explicit in the NPRM 
preamble. However, the regulatory text stated that the provisions would 
take effect with the 1994 model year.
    Summary of the comments: The Agency received few comments on this 
particular aspect of the proposed refueling provisions. The comments 
that addressed this issue tended to agree with the need for control. 
However, the comments otherwise differed. One commenter suggested that 
any hardware requirement be performance-based, rather than 
prescriptive, so as to be consistent with EPA's previous consideration 
of refueling controls for gasoline vehicles. Also, the lack of a 
numerical standard was interpreted as being a zero-emission standard, 
which one commenter suggested is infeasible. Another commenter stated 
that just requiring new refueling nozzles at all current LPG fueling 
facilities would cost about $30 million, but provided no supporting 
documentation for that claim.
    EPA response to comments: The Agency believes that it is 
appropriate to minimize the amount of LPG fuel which is vented from the 
dead space between the refueling nozzle check valve and the vehicle 
refueling receptacle check valve but also agrees that a zero-emission 
standard is unreasonable. Both the nozzle and the vehicle receptacle 
geometries play an integral role in the size of this dead space. Thus, 
any performance specification for vehicle/pump interface refueling 
emissions would have to address the nozzle and receptacle as a single 
system. In the case of LPG, there is not a standardized geometry for 
refueling nozzles, at least in terms of the parameters which would 
affect this dead space. Thus, it is difficult for the Agency to define 
a performance specification such as that which has been considered for 
gasoline vehicles based upon an industry standard nozzle geometry. The 
Agency is aware that the LPG industry is developing nozzles which 
dramatically reduce the dead space, especially when used in conjunction 
with low-bleed inserts in the vehicle receptacle.
    For the reasons just mentioned EPA is finalizing a two-fold 
approach to refueling emissions for LPG vehicles. First, today's rule 
includes a requirement that LPG refueling nozzles have no more than 2.0 
cm3 dead space, as measured from the face of the nozzle which 
seals against the vehicle receptacle ``O'' ring. Second, a refueling 
standard and SHED-based test consistent with the recently promulgated 
ORVR requirement is being adopted for LPG-fueled light duty vehicles 
and light-duty trucks. The vehicle standard, adjusted for the 
difference in energy density between gasoline and LPG, is 0.15 grams 
per dispensed gallon of fuel. This approach will ensure that the LPG 
vehicles will have refueling emissions similar to those of other 
vehicles meeting the ORVR standards. A certification testing waiver 
will be available for all classes of LPG vehicles to which this 
standard applies if the manufacturer can demonstrate, through the use 
of development or other data, that the vehicle will meet the standard. 
For a complete discussion of how the 2.0 cm3 standard for LPG 
vehicle refueling nozzles was derived please consult the summary and 
analysis of comments document for this rule.
    This standard for LPG vehicles will apply to the same classes and 
model years as the ORVR rule (i.e., three year phase-in beginning with 
the 1998 model year for light-duty vehicles and the 2001 model year for 
light-duty trucks). The requirement for the refueling nozzles will take 
effect January 1, 1998 for high volume stations, with a two year 
extension until January 1, 2000 for small volume stations (those which 
dispense less than the energy equivalent of 10,000 gallons of gasoline 
per month). The Agency believes that this amount of leadtime for 
refueling stations will allow for the replacement or retrofit of LPG 
nozzles during the normal course of replacement or repair of in-use 
nozzles due to wear.
3. LPG Tank Venting
    Summary of the proposal: Fuel tanks for LPG vehicles currently have 
a device known as a fixed liquid level valve, or outage valve, at the 
proper fill level. This is a small orifice which can be opened during 
refueling in order to indicate that, upon the release of liquid from 
the valve, the tank is filled and refueling should stop. Although LPG 
tanks are now constructed with built-in automatic shutoff devices to 
prevent overfilling, they still have outage valves on them. The Agency 
proposed a prohibition on all non-safety-related valves on gaseous-
fueled vehicles in order to prevent the emissions of LPG from outage 
valves during refueling.
    Summary of the comments: The Agency received a variety of comments 
expressing concern about the proposal to eliminate outage valves from 
LPG vehicles. First, several commenters pointed out that outage valves 
are required under the National Fire Protection Association standard 58 
(NFPA 58), and that the NFPA code has been adopted by many state and 
local fire marshals as the applicable fire code. Second, some 
commenters stated that the regulatory language as proposed precluded 
the use of all types of valves on gaseous-fueled vehicles, including 
such things as manual fuel shutoff valves. Third, some comments were 
received expressing concern that this requirement would preclude the 
use of liquefied natural gas (LNG) altogether due to the need to 
occasionally vent excess pressure from LNG fuel tanks to prevent 
overpressurization. Finally, one commenter expressed concern about the 
application of this requirement to LPG vehicles already in service and 
the possibility of having to retrofit those vehicles.
    EPA response to comments: The Agency understands the apparent 
conflict between its proposal and the requirements of NFPA 58. EPA 
believes that with the newer requirement in NFPA 58 for automatic 
shutoff (overfill prevention) mechanisms, the requirement for outage 
valves on vehicle fuel tanks is obsolete, and should be removed from 
NFPA 58. Due to this conflict, however, the Agency has chosen not to 
finalize its proposed requirements prohibiting outage valves, but is 
working with the industry and NFPA to have this requirement deleted 
from NFPA. While the Agency believes it has the authority to preempt 
NFPA 58 as adopted by fire marshals through the adoption of the 
proposed requirement to eliminate outage valves, it prefers to work 
with the industry to remove that requirement from NFPA 58 before 
superseding state and local law through EPA regulation. Given that the 
proposed language prohibiting non-safety-related valves is not being 
finalized, the other concerns expressed in the comments are alleviated.
    While the Agency is not finalizing the proposed requirements 
concerning outage valves, they remain a concern as a source of 
emissions. This is especially true for LPG vehicles which are intended 
to be certified as ILEVs. Thus, for any LPG vehicle, the above-
mentioned refueling test procedure will be performed with the outage 
valve opened, unless the manufacturer can demonstrate, to the 
satisfaction of the Administrator, that the outage valve or any other 
such gauges or valves would not be opened during refueling in-use due 
to inaccessibility or other design features that would prevent or make 
it very unlikely that they could be opened.

D. Standards for CO and Crankcase Emissions

1. Idle CO
    Summary of the proposal: Until the methanol emission standards were 
promulgated in 1989, idle CO standards were only applied to Otto-cycle 
engines. EPA reasoned that diesel vehicles always operate at such lean 
fuel/air ratios that their idle CO emissions would always be well below 
the standards. The methanol rule applied idle CO standards to all 
methanol-fueled vehicles because the Agency was aware of diesel 
methanol vehicles which were throttled at idle. This same reasoning was 
applied to gaseous-fueled vehicles, and EPA proposed that idle CO 
standards apply to all gaseous-fueled vehicles, not just Otto-cycle 
vehicles.
    Summary of the comments: The few comments EPA received on this 
issue were in opposition to idle CO standards for engines which operate 
at lean fuel/air ratios. The commenters stated that lean burn engines 
emit very low CO levels, and that there is no need to regulate and test 
for emissions which are inherently low.
    EPA response to the comments: The Agency recognizes that lean burn 
engines do traditionally have much lower CO emissions than vehicles 
operating at stoichiometric fuel/air ratios. However, EPA believes that 
not enough data yet exists on diesel gaseous-fueled vehicles to justify 
their exemption from the idle CO standards. The Agency is especially 
concerned about those diesel designs which employ throttling at idle. 
It is likely that these vehicles will have no problem meeting the idle 
CO standards by virtue of their design and that, this being the case, 
the only burden this standard presents is that of the actual 
certification testing and reporting. Thus, certification testing 
waivers for diesel gaseous-fueled vehicle idle CO standards will be 
available to manufacturers that can demonstrate through emissions test 
data or other engineering data that a vehicle will, by virtue of its 
design, always emit at levels well below that of the applicable idle CO 
standard.
2. Crankcase Emissions
    Summary of the proposal: Currently, all vehicles and engines, with 
the exception of non-naturally aspirated petroleum heavy-duty diesel 
engines (HDDE), are prohibited from discharging crankcase emissions 
into the atmosphere. The current prohibition is not applicable to non-
naturally aspirated petroleum HDDEs due to concerns that the routing of 
oil mist-laden crankcase gases through turbochargers and other air 
handling equipment may foul this equipment. With the issuance of the 
methanol vehicle emission standards in 1989 this prohibition was 
applied to all methanol HDDEs whether they were naturally aspirated or 
not. The reasoning was that methanol engine crankcase gases were 
expected to be cleaner than petroleum diesel engine crankcase gases, 
and closer to gasoline engine crankcase emissions which are been 
routinely routed through turbochargers. Given that gaseous-fueled 
vehicles are also expected to have cleaner crankcase emissions than 
petroleum diesels, this prohibition on crankcase emissions was proposed 
to be applicable to all gaseous-fueled vehicles and engines as well, 
with no exemption for non-naturally aspirated, gaseous-fueled HDDEs.
    Summary of the comments: In general, the comments received in this 
area were in opposition to crankcase controls for gaseous-fueled 
vehicles and engines. Some commenters suggested that crankcase controls 
only be applied to naturally-aspirated gaseous-fueled engines, as is 
currently the case with petroleum HDDEs. Others stated that, due to 
their inherently low emissions, gaseous-fueled vehicles and engines 
should be exempt from all crankcase emission provisions. One commenter 
expressed concern about crankcase gases possibly fouling turbochargers, 
and then went on to say that gaseous-fueled vehicle crankcase emissions 
will be inherently clean and thus do not need to be regulated.
    EPA response to comments: In the absence of compelling data showing 
that gaseous-fueled vehicle crankcase emissions are cleaner than those 
of their petroleum-fueled counterparts, the Agency believes it is 
prudent to extend the coverage of the current prohibition on crankcase 
emissions to include gaseous-fueled HDDEs. Additionally, EPA believes 
that, since the crankcase prohibition for methanol-fueled HDDEs is not 
limited to naturally-aspirated engines, as well as the fact that 
crankcase emissions are routinely routed through gasoline engine 
turbochargers, there is no reason to exempt non-naturally aspirated 
gaseous-fueled vehicles and engines from the crankcase emissions 
prohibition. As was noted in the leadtime discussion, the Agency 
expects that current technology gaseous-fueled engines will be able to 
meet these standards, and therefore the minimum amount of leadtime to 
allow for certification has been given. However, since turbocharged 
gaseous-fueled HDDEs are generally derived from turbocharged petroleum 
HDDEs they do not tend to have crankcase emission controls. The Agency 
believes that, while the four year leadtime requirement in section 
203(a)(3)(C) of the Act is not legally binding in the case of gaseous-
fueled heavy-duty engines, in circumstances where the manufacturers 
must make changes to engine designs similar to those made to comply 
with changes in gasoline or petroleum diesel requirements, section 
203(a)(3)(C) may constitute a proper default period. In order to allow 
for the early introduction of gaseous-fueled HDDEs, the Agency is 
providing four years leadtime for crankcase controls on turbocharged 
gaseous-fueled HDDEs in the absence of factors indicating that another 
period is more appropriate. Thus, this provision will take effect for 
the 1998 model year. It should be noted that the four years of leadtime 
only applies to turbocharged gaseous-fueled HDDEs, and that the 
crankcase emission provisions for all other classes of gaseous-fueled 
vehicles will take effect with the 1997 model year mandatory 
certification, as well as for vehicles and engines certified optionally 
prior to the 1997 model year.

E. On-Board Diagnostics

    Summary of the proposal: EPA did not specifically address in the 
November 5, 1992 proposal the applicability of on-board diagnostics 
(OBD) requirements to gaseous-fueled vehicles. This is because the OBD 
regulations were not promulgated until after the gaseous-fueled vehicle 
standards were proposed.\17\ However, EPA proposed that emission 
standards for gaseous-fueled vehicles generally be equivalent to those 
for other vehicles. Implicit in that proposal is that gaseous-fueled 
vehicles would be required to meet the same OBD requirements as other 
vehicles (OBD II or Federal OBD, as applicable by model year).
---------------------------------------------------------------------------

    \17\58 FR 9468, February 19, 1993.
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    Summary of the comments: The Agency received several comments 
concerning OBD. These comments fell into two general areas. First, 
several commenters requested that the Agency clarify the applicability 
of OBD requirements to gaseous-fueled vehicles. Second, comments were 
received stating that additional leadtime should be allowed for natural 
gas-fueled vehicles to comply with OBD. The OBD provisions as 
promulgated require OBD systems to monitor for conditions which would 
result in certain increases in THC emissions. The argument for 
additional leadtime centered around the fact that natural gas vehicles 
will only be subject to NMHC standards while all other vehicles are 
subject to THC standards. During the course of the OBD rulemaking 
comments were received suggesting that natural gas systems only be 
required to measure NMHC emission effects. Commenters argued that the 
technology likely to be used to monitor for increases in THC could not 
be readily adapted to monitor for increases in NMHC. The Agency 
received a comment suggesting that a delay until 1998 would allow 
sufficient leadtime to develop the technology needed for natural gas-
fueled vehicles to meet the OBD requirements.
    EPA response to comments: The OBD requirements contained in the 
February 19, 1993 rule were established pursuant to section 202(m) of 
the Clean Air Act. That subsection provides, in pertinent part:

    (1) [T]he Administrator shall promulgate regulations under 
subsection (a) requiring manufacturers to install on all new light 
duty vehicles and light duty trucks diagnostic systems capable of--
    (A) accurately identifying * * * emission-related systems 
deterioration or malfunction * * * which could cause or result in 
failure of the vehicles to comply with emission standards 
established under this section.

    By its terms, the OBD provision applies only to vehicles for which 
emission standards have been established under section 202. The 
regulations promulgated on February 19, 1993 simply add a new 
requirement that all new light-duty vehicles and light-duty trucks be 
equipped with an emission control diagnostic system capable of 
identifying emissions-related deterioration and malfunction as detailed 
in the regulations.\18\ Therefore, this provision would seem to apply 
automatically to gaseous-fueled vehicles as soon as mandatory emissions 
standards are established for those vehicles.
---------------------------------------------------------------------------

    \18\58 FR at 9485; 40 CFR 86.094-17.
---------------------------------------------------------------------------

    EPA agrees that leadtime until the 1998 model year is necessary for 
full implementation of the Federal OBD requirements for natural gas-
fueled vehicles. Therefore, under today's regulations, implementation 
of Federal OBD systems will not be required for certification prior to 
model year 1998. This is the case for both for voluntary certification 
prior to model year 1997, and for mandatory certification in model year 
1997. However, consistent with the approach taken in the OBD rule for 
vehicles granted a waiver from Federal OBD requirements on feasibility 
grounds, natural gas-fueled vehicles certified in the 1997 model year 
or optionally prior to the 1997 model year will be required to comply 
with OBD I provisions.
    EPA believes that allowing leadtime for natural gas-fueled vehicles 
until the 1998 model year is legally consistent with sections 202(m) 
and 202(a). To be sure, section 202(m)(2) specifically provides that 
the required OBD regulations shall take effect in model year 1994, 
subject to the Administrator's authority to waiver application of the 
regulations for model years 1994 and/or 1995 for any vehicle for which 
the Administrator determines the regulations would be infeasible in 
those model years. But EPA believes that Congress intended this 
effective date provision to apply only to vehicles for which standards 
existed at the time of the enactment of the Clean Air Act Amendments of 
1990. EPA does not believe that Congress intended this provision to 
require OBD to be implemented immediately upon promulgation of any 
emission standards under section 202(a)(1) for new kinds of 
alternative-fueled vehicles at any point after 1995. EPA cannot adopt 
new emission standards for natural gas-fueled vehicles that would 
trigger a mandatory OBD requirement that is not feasible. It is also 
unreasonable to believe Congress intended that EPA refrain from 
establishing mandatory emission standards for natural gas-fueled 
vehicles simply because an infeasible OBD requirement would 
automatically apply once such standards are established. The Agency's 
efforts to ensure that natural gas fueled vehicles' emissions are no 
greater than their petroleum-fueled counterparts should not be 
frustrated by a concern that compliance with an OBD requirement 
requires more leadtime than compliance with the emission standards 
themselves.
    Rather, EPA believes that the OBD requirements under section 
202(m)(1), to be promulgated under section 202(a), incorporate the 
general leadtime provision in section 202(a)(2). Section 202(a)(2) 
specifically states that ``[a]ny regulation prescribed under paragraph 
(1) of this subsection (and any revision thereof) shall take effect 
after such period as the Administrator finds necessary to permit the 
development and application of the requisite technology, giving 
appropriate consideration to the cost of compliance within such 
period.'' EPA believes that this leadtime provision applies to all 
aspects of new standards established with respect to previously 
unregulated alternative-fueled vehicles. EPA agrees with commenters 
that leadtime until model year 1998 is necessary for implementation of 
Federal OBD systems for natural gas-fueled vehicles. Therefore, Federal 
OBD requirements will not apply for certification of such vehicles 
until model year 1998; compliance with OBD I provisions is required for 
any natural gas-fueled vehicles certified prior to the 1998 model year, 
as discussed above.
    EPA also recognizes that the current OBD regulations apply to 
vehicles subject to a THC standard. As long as only a NMHC standard 
applies to natural gas-fueled vehicles, these regulations should 
arguably be amended to monitor deterioration and malfunction regarding 
NMHC emissions performance. EPA anticipates commencing a rulemaking to 
make these changes to the OBD regulations as applicable to natural gas-
fueled vehicles in the near future in time for the changes to apply in 
the 1998 model year. This issue does not effect the feasibility of 
compliance with OBD I requirements.
    As was noted above, the Agency did not formally propose any 
specific requirements concerning the applicability of OBD requirements 
to gaseous-fueled vehicles. However, the Agency believes that this 
issue was fairly raised and sufficiently considered prior to the 
promulgation of this final rule since EPA's initial proposal intended 
to extend all applicable emission standards to gaseous-fueled vehicles, 
and the Agency received several comments on OBD in response to that 
proposal. For more discussion of this issue please consult the summary 
and analysis document.

F. HC Measurement

    Summary of the proposal: The current method for measuring exhaust 
NMHC, which was adopted for the Tier 1 tailpipe standards, involves 
measuring THC and methane, and subtracting methane from THC to obtain 
NMHC. For NGVs the exhaust HC is primarily methane, whereas for other 
vehicles the exhaust methane tends to be a much lower percentage of 
THC. As a result, the current procedure is much less accurate for NGVs 
than for other vehicles, and the need for a better measurement 
technique is obvious. The NPRM discussed several potential options for 
improved, direct NMHC measurement. However, none of these techniques 
was developed sufficiently enough to warrant proposal. Thus, the Agency 
proposed, as an interim procedure, some slight modifications to the 
current procedure to improve its accuracy for NGVs. Additionally, EPA 
proposed that if a better technique had not been developed within the 
first two years of these standards' applicability then full gas 
chromatograph (GC) analysis would be required. This was intended to 
provide the industry with incentive to develop a better alternative 
since the inaccuracies of the current procedure clearly preclude it 
from being a long term solution.
    Summary of the comments: EPA received little comment on this aspect 
of the proposal. A few commenters voiced support for the interim 
procedure, while some expressed concern over how resource-intensive 
full GC analysis would be for routine certification work.
    EPA response to comments: The Agency agrees with the commenters 
that the modifications to the current procedure constitute the best 
interim option, and this is the technique that is contained in today's 
rule. Additionally, EPA has entered into a Cooperative Research and 
Development Agreement (CRADA) with the California Air Resources Board 
and the American Automobile Manufacturers Association to address a 
variety of test procedures needs which have arisen out of the Clean Air 
Act Amendments. One of the projects the CRADA is addressing is that of 
an accurate technique for the direct measurement of NMHC. The Agency 
believes that since it is participating in the development process 
through the CRADA a technology-forcing approach is not necessary at 
this time. Thus, rather than finalize a requirement for full GC 
analysis, the best approach would be to continue to work through the 
CRADA to develop an NMHC technique which can be adopted as the 
certification procedure upon its completion. However, if an appropriate 
technique is not developed through the CRADA, EPA will consider a more 
accurate procedure such as the GC for the required procedure.

G. Fuel Composition

    Summary of the proposal: It is the Agency's belief that 
certification test fuels should resemble the fuels that a vehicle is 
likely to encounter in-use. Given the wide range of natural gas 
compositions currently available throughout the United States, the 
Agency proposed very broad specifications for natural gas certification 
fuel. These specifications included a range for methane content of 74 
to 98.5 percent, as well as broad ranges for several other parameters. 
In the case of LPG fuel, much less information is available about 
composition variability nationally. Thus, commercially available LPG 
was proposed as the certification fuel, with no specific ranges set on 
any parameters other than that the primary constituent be propane. The 
NPRM contained no provisions for the regulation of in-use composition 
of either fuel.
    Summary of the comments: Although the Agency received some comments 
in support of its proposed certification fuel specifications, in 
general commenters believed that the proposed specifications were much 
too broad. In terms of natural gas specifications, the comments in 
favor of tighter specifications fell into two general categories. 
First, several commenters stated that they agreed with EPA's general 
approach of a broadly defined specification in order that certification 
fuel be representative of in-use fuel. These commenters, however, felt 
that the proposed fuel specification was much too broad and encompassed 
fuels which could not be considered representative of most natural gas. 
Other commenters felt that, in order to be able to meaningfully compare 
results from different tests, a very narrowly defined test fuel 
specification is needed. Most of these commenters recommended that EPA 
adopt the California Air Resources Board (CARB) certification fuel (90% 
methane,  1%, among other requirements) as the federal 
certification fuel. Some of the commenters who recommended a narrower 
range of specifications suggested that EPA adopt a range of 
specifications which would allow the use of CARB certification fuel 
(e.g., 89% methane, minimum, etc.).
    The Agency received little comment on the proposed LPG 
certification fuel specifications. A few commenters suggested that EPA 
adopt the CARB LPG certification fuel specifications (93.5% propane, 
1%, etc.) as the federal certification fuel. Some 
commenters agreed with the proposal, stating that it allowed for the 
use of butane mixtures in LPG vehicles.
    In addition to comments about certification fuel specifications, 
several comments were received requesting that the Agency adopt in-use 
fuel specifications. These comments generally came from engine and 
vehicle manufacturers. These commenters explained that in order to get 
maximum emission benefits from gaseous-fueled vehicles it is important 
to minimize in-use fuel composition variability. In addition, heavy-
duty diesel engine manufacturers stated that, unlike stoichiometric 
engines utilizing oxygen sensor feedback control systems, lean-burn 
diesel engines have no way of accounting for fuel composition 
variability, and thus may encounter operational difficulties on some 
fuels.
    EPA response to comments: The Agency both understands and sees the 
merits in the arguments for tighter certification fuel specifications. 
However, as was previously stated, EPA also believes it is important 
that certification fuel be representative of in-use fuel. Thus, in 
developing today's final rule the Agency has attempted to find a middle 
ground between these seemingly conflicting needs. In the case of 
natural gas certification fuel, the Agency is adopting the approach 
suggested by some commenters that the specification remain somewhat 
broad, but allow for the use of CARB certification fuel. This 
specification includes a minimum methane content of 89 percent, among 
other parameters. For the complete certification fuel specifications 
please see the regulatory text of today's rule. These specifications 
were chosen both because they encompass over 90 percent of natural gas 
sold in the country and because there was some general support for them 
in the comments as a good compromise between EPA's proposed 
specifications and CARB certification fuel.
    Almost all of the gas not covered by this specification (i.e., gas 
with a methane content below 89 percent) is sold in high altitude areas 
where the gas tends to contain higher levels of inert gases than that 
sold at low altitudes. The Agency believes that excluding high altitude 
gas from the specifications should not present a problem for vehicles 
which are certified using the 89 percent minimum methane certification 
fuel but are operated at high altitudes because, in general, vehicles 
which will be certified under the provisions of today's rule are 
expected to utilize electronic feedback control systems for proper 
management of the fuel/air ratio. The Agency believes that these 
systems will be able to account for any differences in fuel composition 
between high altitude natural gas and natural gas in the rest of the 
country.
    It should be noted that, while the natural gas certification fuel 
specifications contained in today's rule are much broader than CARB's, 
CARB certification fuel does fall within the federal specifications, 
and thus could be used for certification testing. For a further 
discussion of this issue please consult the summary and analysis of 
comments document available in the public docket.
    The Agency would like to take a similar approach for LPG 
certification fuel as it took for natural gas certification fuel. 
However, there is little information available about in-use LPG 
composition upon which such a fuel specification could be based. Thus, 
EPA believes it prudent to adopt commercial LPG as the certification 
fuel at this time. Should adequate information on in-use LPG 
composition become available at some point in the future, EPA may elect 
to define a certification fuel specification for LPG at that time.
    Today's rule contains no controls on in-use fuel composition for 
either natural gas or LPG. EPA does not believe that the need for such 
in-use controls has been adequately demonstrated. Further, the cost-
effectiveness of such controls is not likely to justify such action. 
The Agency is concerned, however, about the possibility of in-use fuel 
composition changes over time, and urges the natural gas and LPG 
industries to take steps to minimize such variations. Should the in-use 
compositions of these fuels change in such a way as to adversely impact 
the emissions performance of gaseous-fueled vehicles the Agency would 
likely take steps to address the issue at that time, either through 
corresponding changes in certification fuel specifications, or possibly 
through in-use fuel composition specifications.

H. Fuel Economy

    Summary of the proposal: The NPRM included test procedures and 
calculations for determining the fuel economy of natural gas-fueled 
light-duty vehicles and light-duty trucks for purposes of allowing them 
to be included in a manufacturer's CAFE calculation. The proposed 
procedures for determining the fuel economy of natural gas vehicles 
(NGV) utilize the same principles as those used in the procedures 
currently in place for gasoline vehicles. Availability of CAFE credits 
for NGVs was mandated in the Alternative Motor Fuels Act (AMFA) of 1988 
(Public Law 100-494, October 14, 1988), to be effective with the 1993 
model year. No CAFE provisions regarding LPG vehicles were proposed.
    Summary of the comments: In general, the comments regarding the 
CAFE provisions for NGVs were very supportive. Some commenters urged 
EPA to quickly finalize this rule in order to assure that CAFE credits 
will be available for 1993 model year NGVs. The lack of fuel economy 
provisions for LPG vehicles, however, was perceived by many as an 
unfair disadvantage for LPG vehicles. Additionally, many commenters 
pointed out that the National Energy Policy Act of 1992 mandated the 
availability of CAFE credits for LPG vehicles, and urged EPA to 
finalize fuel economy test procedures and calculations for LPG 
vehicles.
    EPA response to comments: The Agency did not propose fuel economy 
measurement procedures for LPG vehicles because prior to the National 
Energy Policy Act of 1992 the determination of whether LPG vehicles 
should be included in the CAFE program was required to be made by the 
Secretary of Transportation under the Energy Policy and Conservation 
Act (U.S.C. 2001(5)). At the time EPA issued the NPRM for today's 
action the Secretary of Transportation had not made a determination to 
include LPG vehicles in the CAFE program. The Energy Policy Act 
allowing LPG vehicles to participate in the CAFE program was signed 
into law just as EPA issued its proposal. Thus, no fuel economy 
provisions were proposed for LPG vehicles. There are two reasons why 
EPA is not adopting fuel economy provisions for LPG vehicles in this 
rule. First, before EPA can adopt fuel economy test procedures and 
calculations for LPG vehicles, the U.S. Department of Transportation 
(DOT) is required by the Energy Policy Act to determine a fuel 
equivalency factor equating gasoline and LPG so that fuel economy can 
be calculated on a gasoline gallon- equivalent basis. This fuel 
equivalency factor has not yet been set by DOT. Second, the Agency 
believes that the required new fuel economy measurement provisions for 
LPG vehicles must be subject to public notice and comment. Thus, the 
Agency will work with DOT to develop the fuel equivalency factor, and, 
upon determination of that factor, will propose LPG fuel economy 
provisions in a separate Agency rulemaking action.

I. Aftermarket Conversions

1. Applicability
    Summary of the proposal: It is the Agency's policy that, based on 
the tampering provisions of section 203(a)(3) of the Act, aftermarket 
conversions should not degrade the emissions performance of the vehicle 
being converted, and that following a conversion a vehicle should still 
meet the emission standards it was originally certified as meeting on 
any fuels it is capable of using. Under this policy any conversion 
which degrades the emissions performance of the vehicle is considered 
tampering. In order to clarify how compliance with this policy can be 
demonstrated, the Agency proposed that converters can certify as new 
vehicle manufacturers using the current new vehicle certification 
procedures applicable to small volume manufacturers. The Agency 
requested comment on whether the volume limit of 10,000 units that 
currently defines a small volume manufacturer should apply to 
conversions as well, or whether, as proposed, the small volume 
procedures should apply to all converters, regardless of the conversion 
sales volume of the company seeking the certification. These 
certification requirements were proposed to apply to all aftermarket 
conversions performed or sold after December 31, 1993, regardless of 
the class or model year of the vehicle being converted. In the proposal 
the Agency stated its belief that this rule would not require any 
leadtime for technology development and that the only leadtime required 
would be for the actual certification process.
    Summary of the comments: In general, the comments received on the 
aftermarket conversion provisions were very supportive, with several 
commenters expressing the need for such requirements, and none 
completely opposed. One commenter suggested that these requirements 
should only apply to conversions in areas which are not in attainment 
with national ambient air quality standards. Comments were received 
both in favor of and opposed to applying the 10,000 limit to the use of 
the small volume procedures for conversions. Other comments received 
indicated that there was some confusion as to the applicability of the 
proposed requirements to conversions done before 1994, as well as to 
conversions of pre-1994 model year vehicles performed after December 
31, 1993.
    EPA response to comments: As was stated in the description of 
today's rule, an aftermarket conversion company can choose to comply 
with these provisions to obtain an exemption from the tampering 
prohibition. Only conversions which are intended to generate some form 
of credit, such as clean-fueled fleet vehicle purchase credits, will be 
required to comply with these provisions. Converters which choose not 
to obtain an exemption from the tampering prohibition under this 
procedure will be handled under the current tampering policy. Given 
that this is an optional certification procedure for conversions the 
issues of leadtime and mandatory start date are less relevant.
    The Agency agrees with the comment that the production volume 
limits that currently define a small volume manufacturer also apply to 
converters seeking to certify as manufacturers under today's program. 
The Agency expects that the demand for aftermarket conversions will 
grow dramatically over the next few years in response to a variety of 
state and federal programs. It seems reasonable to require the larger 
conversion companies to undergo full new vehicle certification if they 
choose to get an exemption from the tampering prohibition by certifying 
as a manufacturer. Thus, the volume limits that currently apply to 
manufacturers seeking to certify under the small volume manufacturers 
provisions will also apply to converters seeking to certify as 
manufacturers. The Agency recognizes that, while the current small 
volume manufacturers limit applies to sales for a particular model 
year, conversions are routinely performed on older vehicles, and a 
conversion company may offer conversion systems for vehicles from 
several different model years at any given time. Thus, the 10,000 sales 
volume limit for certifying under the small volume manufacturers 
procedures will apply to calendar year sales for the purposes of 
aftermarket conversions. For a further discussion of how this volume 
limit will be applied see the summary and analysis of comments 
document.
2. Test Procedures
    Summary of the proposal: In the NPRM the Agency proposed using the 
same test procedures for conversions that are used for new vehicle and 
engine certification. This approach was proposed because the Agency 
believes that this is the only way of truly measuring the emissions 
performance of a conversion relative to the emission standards 
applicable to the original vehicle or engine.
    Summary of the comments: Most of the comments received on the issue 
of test procedures for aftermarket conversions concerned the 
differences between EPA's proposed procedures and those adopted by 
CARB. In general, where there are differences between CARB's procedures 
and those proposed by EPA the commenters requested that the Agency 
adopt the CARB procedures instead of what it proposed. In the case of 
procedures for converted light-duty vehicles and light-duty trucks 
EPA's proposed test procedures are essentially the same as CARB's. 
Thus, there is no issue in the case of light-duty vehicle and light-
duty truck certification procedures for aftermarket conversions.
    EPA's proposed procedures for conversions of vehicles whose engines 
were originally certified on an engine dynamometer (i.e., most heavy-
duty engines) are quite different than CARB's. As was previously 
mentioned, the Agency proposed that conversions in this category be 
certified using the test procedure used to certify the original engine. 
That procedure is the engine dynamometer-based heavy-duty transient 
test. CARB's procedures use the chassis dynamometer-based urban 
dynamometer driving cycle for conversions of vehicles 14,000 pounds and 
under gross vehicle weight (GVW). For conversions of vehicles greater 
than 14,000 pounds GVW, CARB's procedures allow for either steady-state 
chassis dynamometer testing or an engine dynamometer test approved by 
the CARB Executive Officer. Most of the comments received on this issue 
requested that, in order to reduce compliance costs, EPA adopt the CARB 
test procedures for aftermarket conversions. One commenter also 
suggested that it is unfair to require conversions for heavy-duty 
engines to be certified using the heavy-duty transient test because 
there are few available testing facilities at which one could get the 
required testing done.
    EPA response to comments: The Agency continues to believe that the 
most appropriate way to determine whether an aftermarket conversion 
meets the emission standards that the original vehicle or engine was 
certified to is to use the same test procedures that were used in 
certifying the original vehicle or engine. As the comments suggest, 
this is only an issue for the conversions intended for vehicles 
originally certified using the engine dynamometer procedures. While the 
Agency understands the concerns voiced by the commenters, it does not 
believe that there is an adequate alternative to using the original 
test procedures when attempting to demonstrate compliance with the 
original standards. In the case of the CARB procedures, CARB uses an 
approach whereby compliance is determined by comparing post-conversion 
emissions performance with pre-conversion performance, and allowing for 
some increase in emissions to account for test to test variability. 
Given this approach, it is not nearly as important for CARB to use the 
same test procedures that were used to certify the original vehicle 
because the standards being certified to are not those the vehicle was 
originally certified as meeting. However, by taking this approach it is 
possible that an aftermarket conversion which exceeds the original 
configuration's emissions standards could be certified, which is in 
conflict with the anti-tampering provisions of the Act.
    In the case of vehicles over 14,000 pounds GVW, CARB allows the use 
of eight mode steady-state testing, using the same pre-conversion, 
post-conversion comparison as for vehicles under 14,000 pounds GVW. 
Again, the Agency believes that it is possible with this approach to 
certify an aftermarket conversion which exceeds the original 
configuration's emissions standards. Also, the Agency does not believe 
that steady-state testing is appropriate under any circumstances. It is 
well-understood that emission control systems can be designed for low 
emissions when tested using steady-state test procedures, but provide 
little emissions control under real-world, transient conditions.\19\ It 
is for this reason that EPA adopted the heavy-duty transient test cycle 
in place of the thirteen mode steady state test for all heavy-duty 
engine certification, effective in the mid-1980s. Thus, EPA does not 
believe that it would be appropriate to adopt the CARB test procedures 
for these vehicles. It should be noted that CARB does allow for 
alternative test cycles for vehicles over 14,000 pounds GVW, subject to 
advance approval from the Executive Officer. It is the Agency's belief 
that, given the transient test is the test cycle which these vehicles 
would have originally been certified on, it is likely that CARB would 
approve its use for conversion certification, thus eliminating the need 
for two separate certification procedures for vehicles over 14,000 
pounds GVW.
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    \19\45 FR 4136, January 21, 1980.
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3. On-Board Diagnostics
    Summary of the proposal: The Agency recently adopted requirements, 
effective for the 1994 model year and thereafter, which require on-
board diagnostics (OBD) systems on new light-duty vehicles and light-
duty trucks.\20\ The purpose of the OBD system is, in part, to monitor 
the performance of a vehicle's emission control systems and signal to 
the vehicle operator if a system is malfunctioning. The Agency did not 
propose any specific requirements regarding how aftermarket conversions 
would interact with new vehicle OBD systems, but required that 
converted vehicles remain in compliance with all applicable Clean Air 
Act Title II emission requirements.
---------------------------------------------------------------------------

    \20\58 FR 9468, February 19, 1993.
---------------------------------------------------------------------------

    Summary of the comments: The Agency only received a few comments on 
the issue of aftermarket conversions and OBD. These comments tended not 
to be specific, but rather asked the Agency to clarify what the 
requirements were for an aftermarket conversion on an OBD-equipped 
vehicle. A few commenters suggested that EPA require new vehicle 
manufacturers to provide some means of shutting off the OBD system 
during alternative fuel operation in order to prevent the system from 
storing faulty trouble codes.
    EPA response to comments: As explained in the preamble to the 
proposed rule, EPA believes that a tampering exemption should be 
conditioned upon certification demonstrating that the converted vehicle 
has the ability to comply with the applicable emission standards and 
will have demonstrated adequate durability. As was mentioned above, 
shortly after publication of the proposal for this rule, the Agency 
adopted requirements, effective for the 1994 model year, which require 
OBD systems on new light-duty vehicles and light-duty trucks.
    While the aftermarket conversions proposal did not explicitly make 
clear that compliance with the OBD requirements (as well as certain 
other title II requirements) must be demonstrated to obtain a 
certification, the Agency believes this is implicit in the discussion 
of the justification for the exemption. The Agency explained in the 
proposal that ``Congress intended to prohibit tampering that would 
result in emission noncompliance,'' and that ``[t]he language of the 
tampering provisions emphasizes the compliance of the vehicle with the 
title II regulations.''
    EPA's justification for the exemption for conversions from 
tampering restrictions was based on the incongruity of prohibiting 
conversions that result in a vehicle meeting emission standards 
applicable to vehicles of the fuel type to which the vehicles have been 
converted. The OBD requirements, even if not ``emissions standards'' in 
the traditional sense, clearly have an underlying emissions control 
purpose. And the tampering prohibitions of section 203(a)(3) of the Act 
explicitly apply to the disabling of any device ``installed on or in a 
motor vehicle or motor vehicle engine in compliance with regulations 
under this title. . .'' Disabling an OBD system is clearly prohibited 
as tampering. It is therefore not at all clear that EPA would have 
authority to provide an exemption from the tampering prohibition for a 
conversion that do not meet the same OBD requirements as the vehicle 
would have had to meet had it been originally manufactured to operate 
on fuel type to which it has been converted.
    The logic of the Agency's tampering exemption for aftermarket 
conversions thus indicates that the Agency intended that the exemption 
be conditioned on compliance with all title II requirements applicable 
to the converted vehicle when operating on either fuel. Certainly, even 
if the proposal did not specifically make clear that it intended to 
require compliance with OBD as a condition for a tampering exemption, 
that requirement is a logical outgrowth of the discussion in the 
proposal. The comments of interested parties reflect a recognition of 
EPA's authority to require compliance with OBD as a condition of the 
tampering exemption. These comments demonstrate the adequacy of 
notice.\21\
---------------------------------------------------------------------------

    \21\See Shell Oil Co. v. EPA, 950 F.2nd 741, (Dec. 6, 1991).
---------------------------------------------------------------------------

4. Liability
    Summary of the proposal: In the NPRM the Agency proposed that, in 
order to be exempt from the Clean Air Act's tampering prohibition, the 
manufacturers and installers of aftermarket conversions must accept in-
use liability for warranty and recall as outlined in section 207 of the 
Act and its implementing regulations.\22\ Additionally, EPA proposed 
that the vehicle's original manufacturer remain liable for the in-use 
performance of any systems which retain their original purpose 
following conversion, except in cases where the failure of such a 
system is determined to be caused by the conversion. The Agency 
proposed that the useful life of a conversion be the same as that of 
the vehicle being converted, and requested comment on whether the 
useful life of the conversion should be measured from the time of the 
conversion or from the time of the original vehicle's manufacture.
---------------------------------------------------------------------------

    \22\40 CFR Part 85.
---------------------------------------------------------------------------

    Summary of the comments: The Agency received a variety of comments 
on the proposed liability scheme. In general, commenters agreed on the 
need for in-use liability for warranty and recall, but differed on 
where or with whom this liability should be placed. Some commenters 
suggested that the primary liability should be with the conversion 
system manufacturer, and that the installer should only be held liable 
for the proper installation of the conversion system. Other commenters 
agreed with EPA's proposed liability suggesting both that this approach 
would protect the conversion consumer in the event that one party went 
out of business, and that it would allow manufacturers and installers 
to negotiate risk of failure between them. Comments received on the 
issue of liability of the vehicle's original manufacturer for the 
proper functioning of original equipment also supported both sides of 
the issue, with some commenters suggesting that the original 
manufacturer's liability should end at the time of conversion and 
others supporting the Agency's proposed approach. Finally, all comments 
received on the issue of when the useful life begins were in favor of 
reducing the useful life requirement of the conversion by the amount of 
the original vehicle's useful life which had already passed at the time 
of conversion. These commenters suggested that, because aftermarket 
conversions generally depend on the original vehicle equipment to some 
extent for emissions performance, it would not be appropriate to 
require the conversion to continue meeting applicable emission 
standards after the original equipment had exceeded its useful life.
    EPA response to the comments: The Agency believes that by holding 
the entity which certifies the conversion system liable for the in-use 
performance of the converted vehicle it has the greatest chance of 
assuring quality conversions which will meet applicable emission 
standards throughout their useful lives. If poor installation were a 
defense to liability, then certifiers would have no interest in 
insuring their installers are competent. Such an approach does not rely 
on who manufactures or installs the system, but on who certifies the 
system as meeting applicable standards. At the time of vehicle 
conversion the system certifier assumes liability for the converted 
vehicle's in-use emissions performance. The certifier may elect to have 
outside agents conduct installations. However, the certifier will be 
solely responsible for the converted vehicle's in-use emission 
performance. For this reason the Agency recommends that those 
certifiers electing to have outside agents conduct installations work 
to assure quality system installation.
    EPA believes that it is appropriate to hold the original vehicle 
manufacturer liable for the performance of any parts or systems which 
retain their original function following conversion. If the failure of 
such a part or system could be traced to the conversion then the 
liability would lie with the conversion certifier. A good indication of 
where the liability lies in such situations would be whether the 
failure of a part or system is also occurring in non-converted 
configurations of the same vehicle.
    The Agency agrees with the comments that it is not appropriate to 
extend the useful life of a conversion past that of the original 
vehicle, given that conversions generally rely on many original vehicle 
components for proper operation. Thus, the applicable useful life of 
any conversion will be reduced by the amount of mileage on the vehicle 
at the time of conversion (i.e., the useful life of a conversion will 
end at the same point that the useful life of the original vehicle 
ends).

IV. Environmental Effects

    The general goal of today's emission standards is to provide a 
level playing field for gaseous-fueled vehicles relative to other 
currently regulated vehicles, and to remove a potential barrier to 
their commercial production. Thus, this rule is not intended to 
generate significant emission reductions beyond those achieved by 
vehicles operating on other fuel types. As such, the Agency has not 
attempted to accurately quantify the environmental effects of today's 
rule. However, there are likely to be some beneficial differences 
between the emissions from gaseous-fueled vehicles and conventional 
vehicles, including possible benefits in the areas of NMHC, CO and air 
toxics, as well as benefits associated with improved aftermarket 
conversions. For a complete discussion of these potential benefits 
please consult the discussion of environmental effects contained in the 
NPRM.\23\
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    \23\57 FR 52912, November 5, 1992.
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V. Economic Impacts

    The Agency expects the emission standards contained in this rule to 
be attainable using emission control technology which is similar to 
that used on current vehicles. Indeed, this has been the case thus far 
with the vehicles which have shown the ability to comply with the 
standards. Thus, EPA expects that the cost of emission controls for 
natural gas- and liquefied petroleum gas-fueled vehicles will be 
similar to that for current vehicles. There are two instances, however, 
where compliance with the standards may be less costly for gaseous-
fueled vehicles than for current vehicles: evaporative emissions, and 
exhaust aftertreatment for gaseous-fueled heavy-duty diesel engines. 
For a complete discussion of these potential benefits please consult 
the discussion of economic impacts contained in the NPRM.\24\
---------------------------------------------------------------------------

    \24\57 FR 52912, November 5, 1992.
---------------------------------------------------------------------------

    It is not expected that these regulations will have a significant 
impact on the cost of aftermarket conversions of conventional-fueled 
vehicles to operate on gaseous fuels. The chief area of change in 
response to these regulations will be in the area of durability 
improvements. This may involve some increase in cost, but overall the 
impacts should be small.
    Since the purpose of today's standards is to remove the regulatory 
uncertainty associated with gaseous-fueled vehicles and to place them 
on an equal footing with other vehicles, and not necessarily to achieve 
emission reductions, the Agency does not believe it is appropriate to 
perform a cost-effectiveness analysis for these standards. Although the 
Agency does expect some emission reductions to result from these 
standards, that is not the purpose of these regulations. Thus, the 
benefits cannot be readily quantified in terms of pollutant inventory 
reductions, nor is it appropriate to do this. For these reasons no cost 
effectiveness analysis was performed.

VI. Statutory Authority

    Authority for the actions in this rule is granted to EPA by 
sections 202, 203 and 301(a) of the Clean Air Act (42 U.S.C. 7521 and 
7601(a)).

VII. Executive Order 12866

    Under Executive Order 12866,\25\ the Agency must determine whether 
the regulatory action is ``significant'' and therefore subject to 
Office of Management and Budget (OMB) review and the requirements of 
the Executive Order. The Order defines ``significant regulatory 
action'' as one that is likely to result in a rule that may:
---------------------------------------------------------------------------

    \25\58 FR 51735, October 4, 1993.
---------------------------------------------------------------------------

    (1) have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local or tribal governments or communities;
    (2) create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs or the rights and obligations of recipients 
thereof; or
    (4) raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    Pursuant to the terms of Executive Order 12866, OMB has notified 
EPA that it considers this a ``significant regulatory action'' within 
the meaning of the Executive Order. EPA has submitted this action to 
OMB for review. Changes made in response to OMB suggestions or 
recommendations will be documented in the public record.

VIII. Reporting and Recordkeeping Requirements

    The information collection requirements contained in this rule have 
been submitted for approval to the Office of Management and Budget 
(OMB) under the provisions of the Paperwork Reduction Act, 44 U.S.C. 
3501 et seq. Public recordkeeping burden is estimated to average 115 
hours per response. It is not anticipated that the revisions being 
promulgated today will have any impact on the recordkeeping burden. 
These requirements are not effective until OMB approves them and a 
technical amendment to that effect is published in the Federal 
Register.
    Send comments regarding the burden estimate, including suggestions 
for reducing this burden to Chief, Information Policy Branch, EPA, 401 
M St., SW. (2136), Washington, DC 20460; and to the Office of 
Information and Regulatory Affairs, Office of Management and Budget, 
Washington, DC 20503, marked ``Attention: Desk Officer for EPA.''

IX. Impact on Small Entities

    Under the Regulatory Flexibility Act, 5 U.S.C. 601 et seq., EPA is 
required to determine whether a regulation will have a significant 
adverse impact on a substantial number of small entities. Pursuant to 
section 605(b) of the Regulatory Flexibility Act, 5 U.S.C. 605(b), the 
Administrator certifies that this rule will not have a significant 
economic impact on a substantial number of small entities. The new 
vehicle standards will affect only manufacturers of motor vehicles and 
motor vehicle engines, a group which does not contain a substantial 
number of small entities. The aftermarket conversion portions of 
today's regulations will not significantly impact the small businesses 
in the aftermarket conversion industry because the provisions are 
voluntary, and the cost of voluntary compliance with these requirements 
will be small when spread over the projected volumes of conversions 
expected to be sold in the near future.

X. Judicial Review

    Under section 307(b)(1) of the Clean Air Act, EPA hereby finds that 
these regulations are of national applicability. Accordingly, judicial 
review of this action is available only by filing a petition for review 
in the United States Court of Appeals for the District of Columbia 
Circuit by September 21, 1994. Under section 307(b)(2) of the Act, the 
requirements which are the subject of today's notice may not be 
challenged later in judicial proceedings brought by EPA to enforce 
these requirements.

List of Subjects

40 CFR Part 80

    Environmental protection, Administrative practice and procedures, 
Air pollution control, Motor vehicle pollution.

40 CFR Part 85

    Imports, Labeling, Motor vehicle pollution, Reporting and 
recordkeeping requirements, Research, Warranties.

40 CFR Part 86

    Administrative practice and procedures, Air pollution control, 
Incorporation by reference, Motor vehicles, Labeling, Motor vehicle 
pollution, Reporting and recordkeeping requirements.

40 CFR Part 88

    Administrative practice and procedures, Air pollution control, 
Motor vehicle pollution, Reporting and recordkeeping requirements.

40 CFR Part 600

    Administrative practice and procedures, Fuel economy, Incorporation 
by reference, Motor vehicles, Reporting and recordkeeping requirements.

    Dated: May 27, 1994.
Carol M. Browner,
Administrator.

    For the reasons set forth in the preamble, parts 80, 85, 86, 88 and 
600 of chapter I of title 40 of the Code of Federal Regulations are 
amended, as set forth below:

PART 80--[AMENDED]

    1. The authority citation for part 80 continues to read as follows:

    Authority: Secs. 144, 211, and 301(a) of the Clean Air Act as 
amended (42 U.S.C. 7414, 7545, and 7601(a)).

    2. Section 80.2 of subpart A is amended by revising paragraphs (j) 
and (o), and adding new paragraphs (oo), (tt) and (uu), to read as 
follows:


Sec. 80.2  Definitions.

* * * * *
    (j) Retail outlet means any establishment at which gasoline, diesel 
fuel, methanol, natural gas or liquefied petroleum gas is sold or 
offered for sale for use in motor vehicles.
* * * * *
    (o) Wholesale purchaser-consumer means any organization that is an 
ultimate consumer of gasoline, diesel fuel, methanol, natural gas or 
liquefied petroleum gas and which purchases or obtains gasoline, diesel 
fuel, natural gas or liquefied petroleum gas from a supplier for use in 
motor vehicles and, in the case of gasoline, diesel fuel, methanol or 
liquefied petroleum gas, receives delivery of that product into a 
storage tank of at least 550-gallon capacity substantially under the 
control of that organization.
* * * * *
    (oo) Liquefied petroleum gas means a liquid hydrocarbon fuel that 
is stored under pressure and is composed primarily of species that are 
gases at atmospheric conditions (temperature = 25 deg.C and pressure = 
1 atm), excluding natural gas.
* * * * *
    (tt) Natural gas means a fuel whose primary constituent is methane.
    (uu) Methanol means any fuel sold for use in motor vehicles and 
commonly known or commercially sold as methanol or MXX, where XX is the 
percent methanol (CH3OH) by volume.
    3. Section 80.22 of subpart B is amended by revising the title to 
read as follows:


Sec. 80.22  Controls applicable to gasoline and methanol retailers and 
wholesale purchaser consumers.

* * * * *
    4. A new Sec. 80.32 is added to subpart B, to read as follows:


Sec. 80.32  Controls applicable to liquefied petroleum gas retailers 
and wholesale purchaser-consumers.

    After January 1, 1998 every retailer and wholesale purchaser- 
consumer handling over 13,660 gallons of liquefied petroleum gas per 
month shall equip each pump from which liquefied petroleum gas is 
introduced into motor vehicles with a nozzle that has no greater than 
2.0 cm3 dead space from which liquefied petroleum gas will be 
released upon nozzle disconnect from the vehicle, as measured from the 
nozzle face which seals against the vehicle receptacle ``O'' ring, and 
as determined by calculation of the geometric shape of the nozzle. 
After January 1, 2000 this requirement applies to every liquefied 
petroleum gas retailer and wholesale purchaser- consumer. Any 
dispensing pump shown to be dedicated to heavy-duty vehicles is exempt 
from this requirement.
    5. A new Sec. 80.33 is added to Subpart B, to read as follows:


Sec. 80.33  Controls applicable to natural gas retailers and wholesale 
purchaser-consumers.

    (a) After January 1, 1998 every retailer and wholesale purchaser-
consumer handling over 1,215,000 standard cubic feet of natural gas per 
month shall equip each pump from which natural gas is introduced into 
natural gas motor vehicles with a nozzle and hose configuration which 
vents no more than 1.2 grams of natural gas to the atmosphere per 
refueling of a vehicle complying with Sec. 86.098-8(d)(1)(iv) of this 
chapter, as determined by calculation of the geometric shape of the 
nozzle and hose. After January 1, 2000 this requirement applies to 
every natural gas retailer and wholesale purchaser-consumer. Any 
dispensing pump shown to be dedicated to heavy-duty vehicles is exempt 
from this requirement.
    (b) The provisions of paragraph (a) of this section can be waived 
for refueling stations which were in operation on or before January 1, 
1998 provided the station operator can demonstrate, to the satisfaction 
of the Administrator, that compliance with paragraph (a) of this 
section would require additional compression equipment or other 
modifications with costs similar to or greater than the cost of 
additional compression equipment.

PART 85--[AMENDED]

    6. The authority citation for part 85 continues to read as follows:

    Authority: 42 U.S.C. 7521, 7522, 7524, 7525, 7541, 7542, 7543, 
7547, and 7601(a), unless otherwise noted.

    7. A new subpart F is added to part 85 to read as follows:

Subpart F--Exemption of Aftermarket Conversions From Tampering 
Prohibition

Sec.
85.501 General applicability.
85.502 Definitions.
85.503 Conditions of exemption.
85.504 Applicable standards.
85.505 Labeling.

Subpart F--Exemption of Aftermarket Conversions From Tampering 
Prohibition


Sec. 85.501  General applicability.

    Sections 85.501 through 85.505 are applicable to aftermarket 
conversion systems for which an enforcement exemption is sought from 
the tampering prohibitions contained in section 203 of the Act.


Sec. 85.502  Definitions.

    (a) The Act means the Clean Air Act as amended (42 U.S.C. 7501 et 
seq.).
    (b) Administrator means the Administrator of the Environmental 
Protection Agency or his or her authorized representative.
    (c) Aftermarket conversion system means any combination of 
hardware, including but not limited to fuel storage and fuel metering 
hardware, which is installed on a light-duty vehicle, light-duty truck, 
heavy-duty vehicle, or heavy-duty engine with the effect of allowing 
the vehicle or engine to operate on a fuel other than the fuel which 
the vehicle or engine was originally certified to use. Components which 
do not affect the emissions performance of the converted vehicle or 
engine, as determined by the Administrator, are not included for the 
purposes of this subpart.
    (d) Aftermarket conversion installer means any company or 
individual which installs an aftermarket conversion system on a light-
duty vehicle, light-duty truck, heavy-duty vehicle, or heavy-duty 
engine with the effect of allowing the vehicle or engine to operate on 
a fuel other than the fuel which the vehicle or engine was originally 
certified to use.
    (e) Aftermarket conversion certifier means any company or 
individual which assembles the various aftermarket conversion hardware 
components into a particular combination or configuration and certifies 
that combination or configuration according to the provisions of this 
subpart.
    (f) Model Year means the manufacturer's annual production period 
(as determined by the Administrator) which includes January 1 of such 
calendar year: Provided, That if the manufacturer has no annual 
production period, the term model year shall mean the calendar year.


Sec. 85.503  Conditions of exemption.

    (a) As a condition of receiving an enforcement exemption from the 
tampering prohibitions contained in section 203 of the Act, an 
aftermarket conversion certifier must certify the aftermarket 
conversion system, using the applicable procedures in part 86 of this 
chapter, and meeting the applicable standards and requirements in 
Secs. 85.504 and 85.505, and accept liability for in- use performance 
of the aftermarket conversion system as outlined in this part.
    (b) As a condition of receiving an enforcement exemption from the 
tampering prohibitions contained in section 203 of the Act, an 
aftermarket conversion installer must:
    (1) Install a conversion which has been certified as a new vehicle 
or engine, using the applicable procedures in part 86 of this chapter, 
and meeting the applicable standards and requirements in Secs. 85.504 
and 85.505; and
    (2) Accept liability for in-use performance of the aftermarket 
conversion system as outlined in this part.


Sec. 85.504  Applicable standards.

    (a) The emission standards applicable to conversions of 1993 and 
later model year vehicles and engines are:
    (1) All of the requirements that would apply if the conversion were 
being certified as if it were a new vehicle or engine.
    (2) If a vehicle or engine to be converted was originally certified 
to a NOX or particulate family emission limit other than the 
applicable new vehicle NOX or particulate standard, the family 
emission limit is the applicable standard.
    (b) The emission standards applicable to conversions of 1992 and 
earlier model year vehicles and engines are:
    (1) Exhaust hydrocarbons (as applicable by fuel type). The Tier 0 
hydrocarbon standards, as applicable by vehicle class, contained in 
Secs. 86.094-8 and 86.094-9 of this chapter, and the hydrocarbon 
standards, as applicable by engine class, contained in Secs. 86.094-10 
and 86.094-11 of this chapter;
    (2) CO, NOX and particulate. The applicable CO, NOX and 
particulate standards or NOX and particulate family emission 
limits the vehicle or engine was originally certified as meeting;
    (3) Evaporative hydrocarbons. Any evaporative requirements 
applicable to the original vehicle or engine will remain applicable to 
the conversion if the converted vehicle or engine retains the ability 
to operate on the fuel which it was designed and certified to use.


Sec. 85.505  Labeling.

    (a) The aftermarket conversion certifier shall provide with each 
aftermarket conversion system a supplemental emission control 
information label, which shall be affixed by the aftermarket conversion 
installer in a permanent manner to each converted vehicle, in a 
location adjacent to the original emission control information label 
required in Sec. 86.092-35 of this chapter. If the supplemental label 
cannot be placed adjacent to the original label, it shall be placed in 
a location where it will be seen by a person viewing the original 
label.
    (b) The supplemental label shall be affixed in such a manner that 
it cannot be removed without destroying or defacing the label. The 
label shall not be affixed to any equipment which is easily detached 
from the vehicle.
    (c) The supplemental label shall clearly state that the vehicle has 
been equipped with an aftermarket conversion system designed to allow 
it to operate on a fuel other than the fuel it was originally 
manufactured to operate on, and shall identify the fuel(s) which the 
vehicle is designed to use.
    (d) The supplemental label shall show the vehicle model year; the 
aftermarket conversion certifier's name, address and telephone number; 
the installer's name, address, and telephone number; the date on which 
the aftermarket conversion system was installed; the mileage of the 
vehicle at the time of the conversion; and shall state that the 
converted vehicle complies with federal emission requirements.
    (e) The supplemental label shall list any original parts that were 
removed during installation of the aftermarket conversion system, as 
well as any changes in tune-up specifications required for the 
aftermarket conversion system.

PART 86--[AMENDED]

    8. The authority citation for Part 86 continues to read as follows:

    Authority: Secs. 202, 203, 205, 206, 207, 208, 215, 216, 217 and 
301(a) of the Clean Air Act as amended; 42 U.S.C. 7521, 7522, 7524, 
7525, 7541, 7542, 7549, 7550, 7552 and 7601(a)).

    9. Section 86.1 is amended by revising the table in paragraph 
(b)(1) and adding a new paragraph (b)(3), to read as follows:


Sec. 86.1  Reference materials.

* * * * *
    (b) * * *
    (1) * * *

------------------------------------------------------------------------
     Document number and name             40 CFR part 86 reference      
------------------------------------------------------------------------
ASTM E29-67 (Reapproved 1980),       86.094-26; 86.094-28; 86.1105-87   
 Standard Recommended Practice for                                      
 Indicating Which Places of Figures                                     
 Are To Be Considered Significant                                       
 in Specified Limiting Values.                                          
ASTM E29-90, Standard Practice for   86.609-84; 86.609-96; 86.1009-84;  
 Using Significant Digits in Test     86.1009-96; 86.1442               
 Data To Determine Conformance with                                     
 Specifications.                                                        
ASTM D2163-91, Standard Test Method  86.113-91; 86.113-94; 86.1213-94;  
 for Analysis of Liquefied            86.1313-90                        
 Petroleum (LP) Gases and Propane                                       
 Concentrates by Gas Chromatography.                                    
ASTM D1945-91, Standard Test Method  86.113-91; 86.113-94; 86.513-90;   
 for Analysis of Natural Gas By Gas   86.1213-94; 86.1313-90            
 Chromatography.                                                        
------------------------------------------------------------------------

* * * * *
    (3) ANSI material. The following table sets forth material from the 
American National Standards Institute that has been incorporated by 
reference. The first column lists the number and name of the material. 
The second column lists the section(s) of this part, other than 
Sec. 86.1, in which the matter is referenced. The second column is 
presented for information only and may not be all inclusive. Copies of 
these materials may be obtained from the American National Standards 
Institute, 11 West 42nd Street, 13th Floor, New York, NY 10036.

------------------------------------------------------------------------
     Document number and name             40 CFR part 86 reference      
------------------------------------------------------------------------
ANSI/AGA NGV1-1994, Standard for     86.001-9; 86.004-9; 86.098-8;      
 Compressed Natural Gas Vehicle       86.099-8; 86.099-9                
 (NGV) Fueling Connection Devices.                                      
------------------------------------------------------------------------

    10. The title of subpart A of part 86 is revised to read as 
follows:

Subpart A--General Provisions for Emission Regulations for 1977 and 
later Model Year New Light-Duty Vehicles, Light-Duty Trucks and 
Heavy-Duty Engines, and for 1985 and Later Model Year New Gasoline 
Fueled, Natural Gas-Fueled, Liquefied Petroleum Gas-Fueled and 
Methanol-Fueled Heavy-Duty Vehicles

    11. Section 86.001-9 of subpart A is amended by adding new 
paragraphs (d)(1)(iii) and (d)(1)(iv), to read as follows:


Sec. 86.001-9  Emission standards for 2001 and later model year light-
duty trucks.

* * * * *
    (d) * * *
    (1) * * *
    (iii) Hydrocarbons (for liquefied petroleum gas-fueled vehicles). 
0.15 gram per gallon (0.04 gram per liter) of fuel dispensed.
    (iv) Refueling receptacle (for natural gas-fueled vehicles). 
Refueling receptacles on natural gas-fueled vehicles shall comply with 
the receptacle provisions of the ANSI/AGA NGV1-1994 standard (as 
incorporated by reference in Sec. 86.1).
* * * * *
    12. Section 86.001-28 of subpart A is amended by adding a new 
paragraph (h) to read as follows:


Sec. 86.001-28  Compliance with emission standards.

* * * * *
    (h) Fixed liquid level gauge waiver. Liquefied petroleum gas-fueled 
vehicles which contain fixed liquid level gauges or other gauges or 
valves which can be opened to release fuel or fuel vapor during 
refueling, and which are being tested for refueling emissions, are not 
required to be tested with such gauges or valves open, as outlined in 
Sec. 86.157-98(d)(2), provided the manufacturer can demonstrate, to the 
satisfaction of the Administrator, that such gauges or valves would not 
be opened during refueling in-use due to inaccessibility or other 
design features that would prevent or make it very unlikely that such 
gauges or valves could be opened.
    13. Section 86.004-9 of subpart A is amended by adding new 
paragraphs (d)(1)(iii) and (d)(1)(iv), to read as follows:


Sec. 86.004-9  Emission standards for 2004 and later model year light-
duty trucks.

* * * * *
    (d) * * *
    (1) * * *
    (iii) Hydrocarbons (for liquefied petroleum gas-fueled vehicles). 
0.15 gram per gallon (0.04 gram per liter) of fuel dispensed.
    (iv) Refueling receptacle (for natural gas-fueled vehicles). 
Refueling receptacles on natural gas-fueled vehicles shall comply with 
the receptacle provisions of the ANSI/AGA NGV1-1994 standard (as 
incorporated by reference in Sec. 86.1).
* * * * *
    14a. Section 86.004-28 of subpart A is amended by adding a new 
paragraph (h) to read as follows:


Sec. 86.004-28  Compliance with emission standards.

* * * * *
    (h) Fixed liquid level gauge waiver. Liquefied petroleum gas-fueled 
vehicles which contain fixed liquid level gauges or other gauges or 
valves which can be opened to release fuel or fuel vapor during 
refueling, and which are being tested for refueling emissions, are not 
required to be tested with such gauges or valves open, as outlined in 
Sec. 86.157-98(d)(2), provided the manufacturer can demonstrate, to the 
satisfaction of the Administrator, that such gauges or valves would not 
be opened during refueling in-use due to inaccessibility or other 
design features that would prevent or make it very unlikely that such 
gauges or valves could be opened.
    14b. Section 86.084-4 is amended by redesignating paragraph (b) as 
paragraph (c) and adding a new paragraph (b) to read as follows:


Sec. 86.084-4  Section numbering; construction.

* * * * *
    (b) A section reference without a model year suffix refers to the 
section applicable for the appropriate model year.
* * * * *
    15. Section 86.091-10 of subpart A is amended by revising 
paragraphs (a)(1) introductory text, (a)(1)(i) introductory text, 
(a)(1)(i)(B)(2), (a)(1)(ii) introductory text, (a)(1)(ii)(B)(2) and 
(a)(3), and by adding paragraphs (a)(1)(i)(C)(3), (a)(1)(ii)(C)(3), 
(a)(1)(v), and (a)(1)(vi), to read as follows:


Sec. 86.091-10  Emission standards for 1991 and later model year Otto-
cycle heavy-duty engines and vehicles.

    (a)(1) Exhaust emissions from new 1991 and later model year Otto-
cycle heavy-duty engines shall not exceed (compliance with these 
standards is optional through the 1996 model year natural gas- and 
liquefied petroleum gas-fueled heavy-duty engines):
    (i) For Otto-cycle heavy-duty engines fueled with either gasoline 
or liquefied petroleum gas, and intended for use in all vehicles except 
as provided in paragraph (a)(3) of this paragraph.
* * * * *
    (B) * * *
    (2) For Otto-cycle heavy-duty engines fueled with either gasoline 
or liquefied petroleum gas and utilizing aftertreatment technology. 
0.50 percent of exhaust gas flow at curb idle.
    (C) * * *
    (3) A manufacturer may elect to include any or all of its liquefied 
petroleum gas-fueled Otto-cycle heavy-duty engine families in any or 
all of the NOX averaging, trading, or banking programs for heavy-
duty engines, within the restrictions described in Sec. 86.091-15. If 
the manufacturer elects to include engine families in any of these 
programs, the NOX FELs may not exceed 6.0 grams per brake 
horsepower-hour (2.2 grams per megajoule). This ceiling value applies 
whether credits for the family are derived from averaging, trading or 
banking programs.
    (ii) For Otto-cycle heavy-duty engines fueled with either gasoline 
or liquefied petroleum gas, and intended for use only in vehicles with 
a Gross Vehicle Weight Rating of greater than 14,000 lbs.
* * * * *
    (B) * * *
    (2) For Otto-cycle heavy-duty engines fueled with either gasoline 
or liquefied petroleum gas and utilizing aftertreatment technology. 
0.50 percent of exhaust gas flow at curb idle.
    (C) * * *
    (3) A manufacturer may elect to include any or all of its liquefied 
petroleum gas-fueled Otto-cycle heavy-duty engine families in any or 
all of the NOX averaging, trading or banking programs for heavy-
duty engines, within the restrictions described in Sec. 86.091-15. If 
the manufacturer elects to include engine families in any of these 
programs, the NOX FELs may not exceed 6.0 grams per brake 
horsepower-hour (2.2 grams per megajoule). This ceiling value applies 
whether credits for the family are derived from averaging, trading or 
banking programs.
* * * * *
    (v) For natural gas-fueled Otto-cycle heavy-duty engines intended 
for use in all vehicles except as provided in paragraph (a)(3) of this 
section.
    (A) Nonmethane hydrocarbons. 0.9 gram per brake horsepower-hour 
(0.33 gram per megajoule), as measured under transient operating 
conditions.
    (B) Carbon monoxide. (1) 14.4 grams per brake horsepower-hour (5.36 
grams per megajoule), as measured under transient operating conditions.
    (2) For natural gas-fueled Otto-cycle heavy-duty engines utilizing 
aftertreatment technology. 0.50 percent of exhaust flow at curb idle.
    (C) Oxides of nitrogen. (1) 5.0 grams per brake horsepower-hour 
(1.9 grams per megajoule), as measured under transient operating 
conditions.
    (2) A manufacturer may elect to include any or all of its natural 
gas-fueled Otto-cycle heavy-duty engine families in any or all of the 
NOX averaging, trading or banking programs for heavy-duty engines, 
within the restrictions described in Sec. 86.091-15. If the 
manufacturer elects to include engine families in any of these 
programs, the NOX FELs may not exceed 6.0 grams per brake 
horsepower-hour (2.2 grams per megajoule). This ceiling value applies 
whether credits for the family are derived from averaging, trading or 
banking programs.
    (vi) For natural gas-fueled Otto-cycle engines intended for use 
only in vehicles with a Gross Vehicle Weight Rating of greater than 
14,000 lbs.
    (A) Nonmethane hydrocarbons. 1.7 grams per brake horsepower-hour 
(0.63 gram per megajoule), as measured under transient operating 
conditions.
    (B) Carbon monoxide. (1) 37.1 grams per brake horsepower-hour (13.8 
grams per megajoule), as measured under transient operating conditions.
    (2) For natural gas-fueled Otto-cycle heavy-duty engines utilizing 
aftertreatment technology. 0.50 percent of exhaust gas flow at curb 
idle.
    (C) Oxides of nitrogen. (1) 5.0 grams per brake horsepower-hour 
(1.9 grams per megajoule), as measured under transient operating 
conditions.
    (2) A manufacturer may elect to include any or all of its natural 
gas-fueled Otto-cycle heavy-duty engine families in any or all of the 
NOX averaging, trading or banking programs for heavy-duty engines, 
within the restrictions described in Sec. 86.091-15. If the 
manufacturer elects to include engine families in any of these 
programs, the NOX FELs may not exceed 6.0 grams per brake 
horsepower-hour (2.2 grams per megajoule). This ceiling value applies 
whether credits for the family are derived from averaging, trading or 
banking programs.
* * * * *
    (3)(i) A manufacturer may certify one or more Otto-cycle heavy-duty 
engine configurations intended for use in all vehicles to the emission 
standards set forth in paragraphs (a)(1)(ii), (a)(1)(iv) or (a)(1)(vi) 
of this section: Provided, that the total model year sales of such 
configuration(s), segregated by fuel type, being certified to the 
emission standards in paragraph (a)(1)(ii) of this section represent no 
more than five percent of total model year sales of each fuel type 
Otto-cycle heavy-duty engine intended for use in vehicles with a Gross 
Vehicle Weight Rating of up to 14,000 pounds by the manufacturer.
    (ii) The configurations certified to the emission standards of 
paragraphs (a)(1) (ii), (iv) and (vi) of this section under the 
provisions of paragraph (a)(3)(i) of this section shall still be 
required to meet the evaporative emission standards set forth in 
paragraphs (b)(1)(i), (b)(2)(i) and (b)(3)(i) of this section.
* * * * *
    16. Section 86.091-28 of subpart A is amended by revising 
paragraphs (a)(4)(i) introductory text, (a)(4)(i)(C), (a)(4)(ii)(B), 
(a)(7)(i), (b)(4)(ii), (b)(4)(iii), (b)(6)(i), (c)(4)(ii), 
(c)(4)(iii)(A)(1), (c)(4)(iii)(A)(2), (c)(4)(iii)(B)(1), 
(c)(4)(iii)(B)(2) and (d)(1) to read as follows:


Sec. 86.091-28  Compliance with emission standards.

    (a) * * *
    (4) * * *
    (i) Separate emission deterioration factors shall be determined 
from the exhaust emission results of the durability-data vehicle(s) for 
each engine-system combination. A separate factor shall be established, 
as required for compliance with applicable emission standards for 
exhaust HC, exhaust OMHCE, exhaust NMHC, exhaust CO, exhaust NOX 
and exhaust particulate for each engine-system combination. A separate 
evaporative emission deterioration factor, as required for compliance 
with applicable emission standards, shall be determined for each 
evaporative emission family-evaporative emission control system 
combination from the testing conducted by the manufacturer.
* * * * *
    (C)(1) An evaporative emissions deterioration factor shall be 
determined from the testing conducted as described in Sec. 86.090-
21(b)(4)(i), for each evaporative emission family- evaporative emission 
control system combination to indicate the evaporative emission level 
at 50,000 miles relative to the evaporative emission level at 4,000 
miles as follows:

Factor = Evaporative emission level at 50,000 miles minus the 
evaporative emission level at 4,000 miles.

    (2) The factor in paragraph (a)(4)(i)(C)(1) of this section shall 
be established to a minimum of two places to the right of the decimal.
    (ii) * * * 
    (B) The official evaporative emission test results for each 
evaporative emission-data vehicle at the selected test point shall be 
adjusted by addition of the appropriate deterioration factor: Provided, 
that if a deterioration factor as computed in paragraph (a)(4)(i)(C) of 
this section is less than zero, that deterioration factor shall be zero 
for the purposes of this paragraph.
* * * * *
    (7) * * * 
    (i) Separate deterioration factors shall be determined from the 
exhaust emission results of the durability-data vehicles for each 
engine family group. A separate factor as necessary to establish 
compliance with applicable emission standards shall be established for 
exhaust HC, exhaust OMHCE, exhaust NMHC, exhaust CO and exhaust 
NOX for each engine family group. The evaporative emission 
deterioration factor for each evaporative family will be determined and 
applied in accordance with paragraph (a)(4) of this section.
* * * * *
    (b) * * * 
    (4) * * * 
    (ii) Separate exhaust emission deterioration factors, determined 
from tests of vehicles, engines, subsystems or components conducted by 
the manufacturer, shall be supplied for each engine-system combination. 
Separate factors shall be established as required for compliance with 
applicable emission standards for transient HC, OMHCE, NMHC, CO, and 
NOX, idle CO and exhaust particulate.
    (iii) For transient HC, OMHCE, NMHC and CO, and NOX, idle CO 
and/or exhaust particulate as appropriate, the official exhaust 
emission results for each emission-data vehicle at the selected test 
point shall be adjusted by multiplication by the appropriate 
deterioration factor. However, if the deterioration factor supplied by 
the manufacturer is less than one, it shall be one for the purposes of 
this paragraph.
* * * * *
    (6) * * * 
    (i) Separate deterioration factors shall be determined from the 
exhaust emission results of the durability-data vehicles for each 
engine family group. A separate factor shall be established for exhaust 
HC, exhaust OMHCE or exhaust NMHC as appropriate, and exhaust CO and 
exhaust NOX for each engine family group. The evaporative emission 
deterioration factor for each evaporative family will be determined and 
applied in accordance with paragraph (b)(6) of this section.
* * * * *
    (c) * * * 
    (4) * * * 
    (ii) Separate exhaust emission deterioration factors, determined 
from tests of engines, subsystems or components conducted by the 
manufacturer, shall be supplied for each engine-system combination. For 
Otto-cycle engines, separate factors shall be established for transient 
HC, OMHCE or NMHC as appropriate, CO and NOX; and idle CO, for 
those engines utilizing aftertreatment technology (e.g., catalytic 
converters). For diesel engines, separate factors shall be established 
for transient HC, OMHCE or NMHC as appropriate, CO, NOX and 
exhaust particulate. For diesel smoke testing, separate factors shall 
also be established for the acceleration mode (designated as ``A''), 
the lugging mode (designated as ``B''), and peak opacity (designated as 
``C'').
    (iii)(A) * * * 
    (1) Otto-cycle heavy-duty engines not utilizing aftertreatment 
technology (e.g., catalytic converters). For transient HC, OMHCE or 
NMHC as appropriate, CO and NOX, the official exhaust emission 
results for each emission-data engine at the selected test point shall 
be adjusted by the addition of the appropriate deterioration factor. 
However, if the deterioration factor supplied by the manufacturer is 
less than zero, it shall be zero for the purposes of this paragraph.
    (2) Otto-cycle heavy-duty engines utilizing aftertreatment 
technology (e.g., catalytic converters). For transient HC, OMHCE or 
NMHC as appropriate, CO and NOX, and for idle CO, the official 
exhaust emission results for each emission-data engine at the selected 
test point shall be adjusted by multiplication by the appropriate 
deterioration factor. However, if the deterioration factor supplied by 
the manufacturer is less than one, it shall be one for the purposes of 
this paragraph.
    (B) * * * 
    (1) Diesel heavy-duty engines not utilizing aftertreatment 
technology (e.g., particulate traps). For transient HC, OMHCE or NMHC 
as appropriate, CO, NOX and exhaust particulate, the official 
exhaust emission results for each emission-data engine at the selected 
test point shall be adjusted by the addition of the appropriate 
deterioration factor. However, if the deterioration factor supplied by 
the manufacturer is less than zero, it shall be zero for the purposes 
of this paragraph.
    (2) Diesel heavy-duty engines utilizing aftertreatment technology 
(e.g., particulate traps). For transient HC, OMHCE or NMHC as 
appropriate, CO, NOX and exhaust particulate, the official exhaust 
emission results for each emission-data engine at the selected test 
point shall be adjusted by multiplication by the appropriate 
deterioration factor. However, if the deterioration factor supplied by 
the manufacturer is less than one, it shall be one for the purposes of 
this paragraph.
* * * * *
    (d)(1) Paragraph (d) of this section applies to heavy-duty vehicles 
required to comply with evaporative emission standards.
* * * * *
     17. Section 86.092-1 of subpart A is amended by revising paragraph 
(a) to read as follows:


Sec. 86.092-1  General applicability.

    (a) The provisions of this subpart apply to 1992 and later model 
year new Otto-cycle and diesel light-duty vehicles, 1992 and later 
model year new Otto-cycle and diesel light-duty trucks, and 1992 and 
later model year new Otto-cycle and diesel heavy-duty engines. The 
provisions of this subpart are optional for vehicles fueled with either 
natural gas or liquefied petroleum gas for the 1994 through 1996 model 
years. The provisions of this subpart also apply to aftermarket 
conversions of all model year Otto-cycle and diesel light-duty 
vehicles, Otto-cycle and diesel light-duty trucks, and Otto-cycle and 
diesel heavy-duty engines certified under the provisions of 40 CFR Part 
85, Subpart F.
* * * * *
    18. Section 86.094-2 of subpart A is amended by revising the 
introductory paragraph and by adding the following definitions in 
alphabetical order, to read as follows:


Sec. 86.094-2  Definitions.

    The definitions of Sec. 86.093-2 remain effective. The definitions 
listed in this section are effective beginning with the 1994 model 
year.
* * * * *
    Gaseous fuel means natural gas or liquefied petroleum gas.
* * * * *
    Liquefied petroleum gas means a liquid hydrocarbon fuel that is 
stored under pressure and is composed primarily of species that are 
gases at atmospheric conditions (temperature = 25 deg.C and pressure = 
1 atm), excluding natural gas.
    Multi-fuel means capable of operating on two or more different fuel 
types, either separately or simultaneously.
    Natural gas means a fuel whose primary constituent is methane.
    Petroleum fuel means liquid fuels normally derived from crude oil, 
excluding liquefied petroleum gas. Gasoline and diesel fuel are 
petroleum fuels.
* * * * *
    19. Section 86.094-3 of subpart A is amended by revising paragraph 
(b) to read as follows:


Sec. 86.094-3  Abbreviations.

* * * * *
    (b) The abbreviations in this section apply to this subpart, and 
also to Subparts B, E, F, H, M, N and P of this part, and have the 
following meanings:

ALVW--Adjusted Loaded Vehicle Weight
OMNMHCE--Organic Material Non-Methane Hydrocarbon Equivalent
PM--Particulate Matter
THC--Total Hydrocarbons
LPG--Liquefied Petroleum Gas
NMHC--Nonmethane Hydrocarbons

    20. Section 86.094-8 of subpart A is amended by revising paragraph 
(a)(1)(i) introductory text and Tables A94-2, A94-3, A94-5 and A94-6 at 
the end of paragraph (a)(1)(i)(A) to read as follows:


Sec. 86.094-8  Emission standards for 1994 and later model year light-
duty vehicles.

* * * * *
    (a)(1) Standards. (i) Exhaust emissions from 1994 and later model 
year vehicles (optional for 1994 through 1996 model year gaseous-fueled 
vehicles) shall meet all standards in Tables A94-2, A94-3, A94-5 and 
A94-6 in the rows designated with the applicable fuel type, according 
to the implementation schedule in Tables A94-1 and A94-4, as follows:
    (A) * * *
* * * * *

       Table A94-2.--Intermediate Useful Life Standards (g/mi) for Light-Duty Vehicles for HCs, CO and NOX      
----------------------------------------------------------------------------------------------------------------
              Fuel                 Standards       THC        NMHC      OMHCE     OMNMHCE       CO        NOX   
----------------------------------------------------------------------------------------------------------------
Gasoline.......................  Tier 0.......       0.41  .........  .........  .........        3.4        1.0
Gasoline.......................  Tier 1.......       0.41       0.25  .........  .........        3.4        0.4
Diesel.........................  Tier 0.......       0.41  .........  .........  .........        3.4        1.0
Diesel.........................  Tier 1.......       0.41       0.25  .........  .........        3.4        1.0
Methanol.......................  Tier 0.......  .........  .........       0.41  .........        3.4        1.0
Methanol.......................  Tier 1.......  .........  .........       0.41       0.25        3.4        0.4
Natural Gas....................  Tier 0.......  .........       0.34  .........  .........        3.4        1.0
Natural Gas....................  Tier 1.......  .........       0.25  .........  .........        3.4        0.4
LPG............................  Tier 0.......       0.41  .........  .........  .........        3.4        1.0
LPG............................  Tier 1.......       0.41       0.25  .........  .........        3.4        0.4
----------------------------------------------------------------------------------------------------------------


          Table A94-3.--Full Useful Life Standards (g/mi) for Light-Duty Vehicles for HCs , CO and NOX          
----------------------------------------------------------------------------------------------------------------
             Fuel                 Standards       THC        NMHC      OMHCE     OMNMHCE       CO        NOX    
----------------------------------------------------------------------------------------------------------------
Gasoline......................  Tier 0.......  .........  .........  .........  .........  .........  ..........
Gasoline......................  Tier 1.......  .........       0.31  .........  .........        4.2        0.6 
Diesel........................  Tier 0.......  .........  .........  .........  .........  .........  ..........
Diesel........................  Tier 1.......  .........       0.31  .........  .........        4.2        1.25
Methanol......................  Tier 0.......  .........  .........  .........  .........  .........  ..........
Methanol......................  Tier 1.......  .........  .........  .........       0.31        4.2        0.6 
Natural Gas...................  Tier 0.......  .........  .........  .........  .........  .........  ..........
Natural Gas...................  Tier 1.......  .........       0.31  .........  .........        4.2        0.6 
LPG...........................  Tier 0.......  .........  .........  .........  .........  .........  ..........
LPG...........................  Tier 1.......  .........       0.31  .........  .........        4.2        0.6 
----------------------------------------------------------------------------------------------------------------

* * * * * 

 Table A94-5.--Intermediate Useful Life Standards (g/mi) for Light-Duty 
                            Vehicles for PM                             
------------------------------------------------------------------------
                     Fuel                         Standards       PM    
------------------------------------------------------------------------
Gasoline......................................  Tier 0.......  .........
Gasoline......................................  Tier 1.......       0.08
Diesel........................................  Tier 0.......       0.20
Diesel........................................  Tier 1.......       0.08
Methanol......................................  Tier 0.......    \1\0.20
Methanol......................................  Tier 1.......       0.08
Natural Gas...................................  Tier 0.......    \1\0.20
Natural Gas...................................  Tier 1.......       0.08
LPG...........................................  Tier 0.......    \1\0.20
LPG...........................................  Tier 1.......      0.08 
------------------------------------------------------------------------
\1\Applicable only to diesel-cycle vehicles.                            


 Table A94-6.--Full Useful Life Standards (g/mi) for Light-Duty Vehicles
                                 for PM                                 
------------------------------------------------------------------------
                     Fuel                         Standards       PM    
------------------------------------------------------------------------
Gasoline......................................  Tier 0.......  .........
Gasoline......................................  Tier 1.......       0.10
Diesel........................................  Tier 0.......  .........
Diesel........................................  Tier 1.......       0.10
Methanol......................................  Tier 0.......  .........
Methanol......................................  Tier 1.......       0.10
Natural Gas...................................  Tier 0.......  .........
Natural Gas...................................  Tier 1.......       0.10
LPG...........................................  Tier 0.......  .........
LPG...........................................  Tier 1.......      0.10 
------------------------------------------------------------------------

* * * * *
    21. Section 86.094-9 of subpart A is amended by revising Tables 
A94-8, A94-9, A94-11 and A94-12 at the end of paragraph (a)(1)(i)(A), 
Tables A94-14 and A94-15 at the end of paragraph (a)(1)(ii)(A), and 
paragraph (d)(1)(i)(A) and by adding paragraph (d)(1)(i)(C) to read as 
follows:


Sec. 86.094-9  Emission standards for 1994 and later model year light-
duty trucks.

    (a)(1) * * *
    (i) * * *
    (A) * * *
 * * * * *

    Table A94-8.--Intermediate Useful Life Standards (g/mi) for Light Light-Duty Trucks for HCs, CO and NOX     
----------------------------------------------------------------------------------------------------------------
       Fuel          LVW (lbs)     Standards       THC        NMHC      OMHCE     OMNMHCE       CO        NOX   
----------------------------------------------------------------------------------------------------------------
Gasoline.........  0-3750        Tier 0.......  .........  .........  .........  .........  .........  .........
Gasoline.........  0-3750        Tier 1.......  .........       0.25  .........  .........        3.4        0.4
Gasoline.........  3751-5750     Tier 0.......  .........  .........  .........  .........  .........  .........
Gasoline.........  3751-5750     Tier 1.......  .........       0.32  .........  .........        4.4        0.7
Diesel...........  0-3750        Tier 0.......  .........  .........  .........  .........  .........  .........
Diesel...........  0-3750        Tier 1.......  .........       0.25  .........  .........        3.4        1.0
Diesel...........  3751-5750     Tier 0.......  .........  .........  .........  .........  .........  .........
Diesel...........  3751-5750     Tier 1.......  .........       0.32  .........  .........        4.4  .........
Methanol.........  0-3750        Tier 0.......  .........  .........  .........  .........  .........  .........
Methanol.........  0-3750        Tier 1.......  .........  .........  .........       0.25        3.4        0.4
Methanol.........  3751-5750     Tier 0.......  .........  .........  .........  .........  .........  .........
Methanol.........  3751-5750     Tier 1.......  .........  .........  .........       0.32        4.4        0.7
Natural Gas......  0-3750        Tier 0.......  .........  .........  .........  .........  .........  .........
Natural Gas......  0-3750        Tier 1.......  .........       0.25  .........  .........        3.4        0.4
Natural Gas......  3751-5750     Tier 0.......  .........  .........  .........  .........  .........  .........
Natural Gas......  3751-5750     Tier 1.......  .........       0.32  .........  .........        4.4        0.7
LPG..............  0-3750        Tier 0.......  .........  .........  .........  .........  .........  .........
LPG..............  0-3750        Tier 1.......  .........       0.25  .........  .........        3.4        0.4
LPG..............  3751-5750     Tier 0.......  .........  .........  .........  .........  .........  .........
LPG..............  3751-5750     Tier 1.......  .........       0.32  .........  .........        4.4        0.7
----------------------------------------------------------------------------------------------------------------


        Table A94-9.--Full Useful Life Standards (g/mi) for Light Light-Duty Trucks for HCs, CO and NOX         
----------------------------------------------------------------------------------------------------------------
      Fuel         LVW (lbs)     Standards       THC1       NMHC      OMHCE1    OMNMHCE       CO          NOX   
----------------------------------------------------------------------------------------------------------------
Gasoline.......  0-3750        Tier 0.......       0.80  .........  .........  .........       10           1.2 
Gasoline.......  0-3750        Tier 1.......       0.80       0.31  .........  .........        4.2         0.6 
Gasoline.......  3751-5750     Tier 0.......       0.80  .........  .........  .........       10           1.7 
Gasoline.......  3751-5750     Tier 1.......       0.80       0.40  .........  .........        5.5         0.97
Diesel.........  0-3750        Tier 0.......       0.80  .........  .........  .........       10           1.2 
Diesel.........  0-3750        Tier 1.......       0.80       0.31  .........  .........        4.2         1.25
Diesel.........  3751-5750     Tier 0.......       0.80  .........  .........  .........       10           1.7 
Diesel.........  3751-5750     Tier 1.......       0.80       0.40  .........  .........        5.5         0.97
Methanol.......  0-3750        Tier 0.......  .........  .........       0.80  .........       10           1.2 
Methanol.......  0-3750        Tier 1.......  .........  .........       0.80       0.31        4.2         0.6 
Methanol.......  3751-5750     Tier 0.......  .........  .........       0.80  .........       10           1.7 
Methanol.......  3751-5750     Tier 1.......  .........  .........       0.80       0.40        5.5         0.97
Natural Gas....  0-3750        Tier 0.......  .........       0.67  .........  .........       10           1.2 
Natural Gas....  0-3750        Tier 1.......  .........       0.31  .........  .........        4.2         0.6 
Natural Gas....  3751-5750     Tier 0.......  .........       0.67  .........  .........       10           1.7 
Natural Gas....  3751-5750     Tier 1.......  .........       0.40  .........  .........        5.5         0.97
LPG............  0-3750        Tier 0.......       0.80  .........  .........  .........       10           1.2 
LPG............  0-3750        Tier 1.......       0.80       0.31  .........  .........        4.2         0.6 
LPG............  3751-5750     Tier 0.......       0.80  .........  .........  .........       10           1.7 
LPG............  3751-5750     Tier 1.......       0.80       0.40  .........  .........        5.5         0.97 
----------------------------------------------------------------------------------------------------------------
\1\Full useful life is 11 years or 120,000 miles, whichever occurs first.                                       

* * * * *

TABLE A94-11.--Intermediate Useful Life Standards (g/mi) for Light Light-
                           Duty Trucks for PM                           
------------------------------------------------------------------------
              Fuel                 LVW (lbs)      Standards       PM    
------------------------------------------------------------------------
Gasoline........................  0-3750        Tier 0.......  .........
Gasoline........................  0-3750        Tier 1.......       0.08
Gasoline........................  3751-5750     Tier 0.......  .........
Gasoline........................  3751-5750     Tier 1.......       0.08
Diesel..........................  0-3750        Tier 0.......  .........
Diesel..........................  0-3750        Tier 1.......       0.08
Diesel..........................  3751-5750     Tier 0.......  .........
Diesel..........................  3751-5750     Tier 1.......       0.08
Methanol........................  0-3750        Tier 0.......  .........
Methanol........................  0-3750        Tier 1.......       0.08
Methanol........................  3751-5750     Tier 0.......  .........
Methanol........................  3751-5750     Tier 1.......       0.08
Natural Gas.....................  0-3750        Tier 0.......  .........
Natural Gas.....................  0-3750        Tier 1.......       0.08
Natural Gas.....................  3751-5750     Tier 0.......  .........
Natural Gas.....................  3751-5750     Tier 1.......       0.08
LPG.............................  0-3750        Tier 0.......  .........
LPG.............................  0-3750        Tier 1.......       0.08
LPG.............................  3751-5750     Tier 0.......  .........
LPG.............................  3751-5750     Tier 1.......      0.08 
------------------------------------------------------------------------


  Table A94-12.--Full Useful Life Standards (g/mi) for Light Light-Duty 
                             Trucks for PM                              
------------------------------------------------------------------------
              Fuel                  LVW (lbs)     Standards       PM    
------------------------------------------------------------------------
Gasoline........................  0-3750        Tier 0.......  .........
Gasoline........................  0-3750        Tier 1.......       0.10
Gasoline........................  3751-5750     Tier 0.......  .........
Gasoline........................  3751-5750     Tier 1.......       0.10
Diesel..........................  0-3750        Tier 0.......       0.26
Diesel..........................  0-3750        Tier 1.......       0.10
Diesel..........................  3751-5750     Tier 0.......       0.13
Diesel..........................  3751-5750     Tier 1.......       0.10
Methanol........................  0-3750        Tier 0.......    \1\0.26
Methanol........................  0-3750        Tier 1.......       0.10
Methanol........................  3751-5750     Tier 0.......    \1\0.13
Methanol........................  3751-5750     Tier 1.......       0.10
Natural Gas.....................  0-3750        Tier 0.......    \1\0.26
Natural Gas.....................  0-3750        Tier 1.......       0.10
Natural Gas.....................  3751-5750     Tier 0.......    \1\0.13
Natural Gas.....................  3751-5750     Tier 1.......       0.10
LPG.............................  0-3750        Tier 0.......    \1\0.26
LPG.............................  0-3750        Tier 1.......       0.10
LPG.............................  3751-5750     Tier 0.......    \1\0.13
LPG.............................  3751-5750     Tier 1.......      0.10 
------------------------------------------------------------------------
\1\Applicable only to diesel-cycle vehicles.                            

* * * * *
    (ii) * * *
    (A) * * *
* * * * *

                      Table A94-14.--Intermediate Useful Life Standards (g/mi) for Heavy Light-Duty Trucks for HCs, CO, NOX and PM                      
--------------------------------------------------------------------------------------------------------------------------------------------------------
                      Fuel                        ALVW (lbs)    Standards       THC        NMHC      OMHCE     OMNMHCE       CO        NOX        PM    
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gasoline.......................................    3751-5750  Tier 0.......  .........  .........  .........  .........  .........  .........  .........
Gasoline.......................................    3751-5750  Tier 1.......  .........       0.32  .........  .........        4.4        0.7  .........
Gasoline.......................................       > 5750  Tier 0.......  .........  .........  .........  .........  .........  .........  .........
Gasoline.......................................       > 5750  Tier 1.......  .........       0.39  .........  .........        5.0        1.1  .........
Diesel.........................................    3751-5750  Tier 0.......  .........  .........  .........  .........  .........  .........  .........
Diesel.........................................    3751-5750  Tier 1.......  .........       0.32  .........  .........        4.4  .........  .........
Diesel.........................................       > 5750  Tier 0.......  .........  .........  .........  .........  .........  .........  .........
Diesel.........................................       > 5750  Tier 1.......  .........       0.39  .........  .........        5.0  .........  .........
Methanol.......................................    3751-5750  Tier 0.......  .........  .........  .........  .........  .........  .........  .........
Methanol.......................................    3751-5750  Tier 1.......  .........  .........  .........       0.32        4.4        0.7  .........
Methanol.......................................       > 5750  Tier 0.......  .........  .........  .........  .........  .........  .........  .........
Methanol.......................................       > 5750  Tier 1.......  .........  .........  .........       0.39        5.0        1.1  .........
Natural Gas....................................    3751-5750  Tier 0.......  .........  .........  .........  .........  .........  .........  .........
Natural Gas....................................    3751-5750  Tier 1.......  .........       0.32  .........  .........        4.4        0.7  .........
Natural Gas....................................       > 5750  Tier 0.......  .........  .........  .........  .........  .........  .........  .........
Natural Gas....................................       > 5750  Tier 1.......  .........       0.39  .........  .........        5.0        1.1  .........
LPG............................................    3751-5750  Tier 0.......  .........  .........  .........  .........  .........  .........  .........
LPG............................................    3751-5750  Tier 1.......  .........       0.32  .........  .........        4.4        0.7  .........
LPG............................................       > 5750  Tier 0.......  .........  .........  .........  .........  .........  .........  .........
LPG............................................       > 5750  Tier 1.......  .........       0.39  .........  .........        5.0        1.1  .........
--------------------------------------------------------------------------------------------------------------------------------------------------------


                         Table A94-15.--Full Useful Life Standards (g/mi) for Heavy Light-Duty Trucks for HCs, CO, NOX  and PM                          
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             ALVW (lbs)                                                                                 
                     Fuel                        LVW (lbs)                Standards      THC     NMHC     OMHCE    OMNMHCE      CO       NOX       PM   
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gasoline.......................................      0-3750  ..........  Tier 0......     0.80  .......  .......  .........     10         1.2   .......
Gasoline.......................................       >3750  ..........  Tier 0......     0.80  .......  .......  .........     10         1.7   .......
Gasoline.......................................  ..........   3751-5750  Tier 1......     0.80     0.46  .......  .........      6.4       0.98     0.10
Gasoline.......................................  ..........       >5750  Tier 1......     0.80     0.56  .......  .........      7.3       1.53     0.12
Diesel.........................................      0-3750  ..........  Tier 0......     0.80  .......  .......  .........     10         1.20     0.26
Diesel.........................................       >3750  ..........  Tier 0......     0.80  .......  .......  .........     10         1.7      0.13
Diesel.........................................  ..........   3751-5750  Tier 1......     0.80     0.46  .......  .........      6.4       0.98     0.10
Diesel.........................................  ..........       >5750  Tier 1......     0.80     0.56  .......  .........      7.3       1.53     0.12
Methanol.......................................      0-3750  ..........  Tier 0......  .......  .......     0.80  .........     10         1.2   \1\0.26
Methanol.......................................       >3750  ..........  Tier 0......  .......  .......     0.80  .........     10         1.7   \1\0.13
Methanol.......................................  ..........   3751-5750  Tier 1......  .......  .......     0.80       0.46      6.4       0.98     0.10
Methanol.......................................  ..........       >5750  Tier 1......  .......  .......     0.80       0.56      7.3       1.53     0.12
Natural Gas....................................      0-3750  ..........  Tier 0......  .......     0.67  .......  .........     10         1.2   \1\0.26
Natural Gas....................................       >3750  ..........  Tier 0......  .......     0.67  .......  .........     10         1.7   \1\0.13
Natural Gas....................................  ..........   3751-5750  Tier 1......  .......     0.46  .......  .........      6.4       0.98     0.10
Natural Gas....................................  ..........       >5750  Tier 1......  .......     0.56  .......  .........      7.3       1.53     0.12
LPG............................................      0-3750  ..........  Tier 0......     0.80  .......  .......  .........     10         1.2   \1\0.26
LPG............................................       >3750  ..........  Tier 0......     0.80  .......  .......  .........     10         1.7   \1\0.13
LPG............................................  ..........   3751-5750  Tier 1......     0.80     0.46  .......  .........      6.4       0.98     0.10
LPG............................................  ..........       >5750  Tier 1......     0.80     0.56  .......  .........      7.3       1.53    0.12 
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\Applicable only to diesel-cycle vehicles.                                                                                                            

* * * * *
    (d) * * *
    (1) * * *
    (i)(A) Hydrocarbons (for Otto-cycle and diesel light-duty trucks 
when fueled with petroleum fuel and/or liquefied petroleum gas). 1.0 
grams per vehicle mile (0.62 grams per vehicle kilometer).
* * * * *
    (C) Nonmethane hydrocarbons (for Otto-cycle and diesel light-duty 
trucks when fueled with natural gas). 0.83 gram per vehicle mile (0.52 
gram per vehicle kilometer).
* * * * *
    22. Section 86.094-11 of subpart A is amended by revising the 
section heading, by revising paragraphs (a)(1) introductory text, 
(a)(1)(i)(A), (a)(1)(ii) (B) and (c), and adding a new paragraph 
(a)(1)(i)(C) to read as follows:


Sec. 86.094-11  Emission standards for 1994 and later model year diesel 
heavy-duty engines and vehicles.

    (a)(1) Exhaust emissions from new 1994 and later model year diesel 
heavy-duty engines shall not exceed the following (optional for 1994 
through 1996 model year new natural gas- and liquefied petroleum gas-
fueled heavy-duty engines):
    (i)(A) Hydrocarbons (for diesel engines fueled with either 
petroleum-fuel or liquefied petroleum gas). 1.3 grams per brake 
horsepower-hour (0.48 gram per megajoule), as measured under transient 
operating conditions.
* * * * *
    (C) Nonmethane hydrocarbons (for natural gas-fueled diesel 
engines). 1.2 grams per brake horsepower-hour (0.45 gram per 
megajoule), as measured under transient operating conditions.
    (ii) * * *
    (B) 0.50 percent of exhaust gas flow at curb idle (methanol-, 
natural gas- and liquefied petroleum gas-fueled diesel only).
* * * * *
    (c) No crankcase emissions shall be discharged into the ambient 
atmosphere from any new 1994 or later model year methanol-fueled 
diesel, or any naturally-aspirated diesel heavy-duty engine (optional 
for 1994 through 1996 model year natural gas- and liquefied petroleum 
gas-fueled engines). For petroleum-, natural gas- and liquefied 
petroleum gas-fueled engines only; this provision does not apply to 
engines using turbochargers, pumps, blowers, or superchargers for air 
induction.
* * * * *
    23. Section 86.094-17 of subpart A is amended by revising paragraph 
(a) introductory text to read as follows:


Sec. 86.094-17  Emission control diagnostic system for 1994 and later 
light-duty vehicles and light-duty trucks.

    (a) All light-duty vehicles and light-duty trucks shall be equipped 
with an emission control diagnostic system capable of identifying, for 
each vehicle's useful life, the following types of deterioration or 
malfunction which could cause emission increases greater than or 
exceeding the following threshold levels as measured and calculated in 
accordance with test procedures set forth in subpart B of this part. 
Paragraphs (a)(2) and (a)(3) of this section do not apply to diesel 
cycle light-duty vehicles or light-duty trucks. Paragraphs (a)(1) 
through (a)(4) of this section do not apply to natural gas-fueled 
light-duty vehicles and light-duty trucks until the 1998 model year.
* * * * *
    24. Section 86.094-23 of subpart A is amended by revising 
paragraphs (b)(3), (b)(4), (c)(1) and (c)(2)(i), to read as follows:


Sec. 86.094-23  Required data.

* * * * *
    (b) * * *
    (3) For heavy-duty vehicles equipped with gasoline-fueled, natural 
gas-fueled, liquefied petroleum gas-fueled or methanol-fueled engines, 
evaporative emission deterioration factors for each evaporative 
emission family-evaporative emission control system combination 
identified in accordance with Sec. 86.091-21(b)(4)(ii). Furthermore, a 
statement that the test procedure(s) used to derive the deterioration 
factors includes, but need not be limited to, a consideration of the 
ambient effects of ozone and temperature fluctuations and the service 
accumulation effects of vibration, time, vapor saturation and purge 
cycling. The deterioration factor test procedure shall be designed and 
conducted in accordance with good engineering practice to assure that 
the vehicles covered by a certificate issued under Sec. 86.091-30 will 
meet the evaporative emission standards in Sec. 86.091-10 and 
Sec. 86.091-11 in actual use for the useful life of the engine. 
Furthermore, a statement that a description of the test procedure, as 
well as all data, analyses and evaluations, is available to the 
Administrator upon request.
    (4)(i) For heavy-duty vehicles with a Gross Vehicle Weight Rating 
of up to 26,000 pounds and equipped with gasoline-fueled, natural gas-
fueled, liquefied petroleum gas-fueled or methanol-fueled engines, a 
written statement to the Administrator certifying that the 
manufacturer's vehicles meet the standards of Sec. 86.091-10 or 
Sec. 86.091-11 (as applicable) as determined by the provisions of 
Sec. 86.091-28. Furthermore, a written statement to the Administrator 
that all data, analyses, test procedures, evaluations and other 
documents, on which the above statement is based, are available to the 
Administrator upon request.
    (ii) For heavy-duty vehicles with a Gross Vehicle Weight Rating of 
greater than 26,000 pounds and equipped with gasoline-fueled, natural 
gas-fueled, liquefied petroleum gas-fueled or methanol-fueled engines, 
a written statement to the Administrator certifying that the 
manufacturer's evaporative emission control systems are designed, using 
good engineering practice, to meet the standards of Sec. 86.091-10 or 
Sec. 86.091-11 (as applicable) as determined by the provisions of 
Sec. 86.091-28. Furthermore, a written statement to the Administrator 
that all data, analyses, test procedures, evaluations and other 
documents, on which the above statement is based, are available to the 
Administrator upon request.
    (c) * * *
    (1) Emission data, including in the case of methanol fuel, 
methanol, formaldehyde and organic material hydrocarbon equivalent, 
exhaust methane data in the case of vehicles meeting a non-methane 
hydrocarbon standard on such vehicles tested in accordance with 
applicable test procedures and in such numbers as specified. These data 
shall include zero-mile data, if generated, and emission data generated 
for certification as required under Sec. 86.090-26(a)(3)(i) or 
Sec. 86.090-26(a)(3)(ii). In lieu of providing emission data the 
Administrator may, on request of the manufacturer, allow the 
manufacturer to demonstrate (on the basis of previous emission tests, 
development tests or other information) that the engine will conform 
with certain applicable emission standards of Sec. 86.094-8 or 
Sec. 86.094-9. Standards eligible for such manufacturer requests are 
those for idle CO emissions, smoke emissions, or particulate emissions 
from methanol-fueled, natural gas-fueled and liquefied petroleum gas-
fueled diesel-cycle certification vehicles, on evaporative emissions or 
refueling emissions from natural gas-fueled or liquefied petroleum gas-
fueled vehicles (light-duty and heavy-duty), and those for particulate 
emissions from model year 1994 and later gasoline-fueled, methanol-
fueled, natural gas-fueled or liquefied petroleum gas-fueled Otto-cycle 
certification vehicles that are not certified to the Tier 0 standards 
of Sec. 86.094-9 (a)(1)(i), (a)(1)(ii), or Sec. 86.094-8(a)(1)(i). Also 
eligible for such requests are standards for total hydrocarbon 
emissions from model year 1994 and later certification vehicles that 
are not certified to the Tier 0 standards of Sec. 86.094-9 (a)(1)(i), 
(a)(1)(ii) or Sec. 86.094-8(a)(1)(i). By separate request, including 
appropriate supporting test data, the manufacturer may request that the 
Administrator also waive the requirement to measure particulate 
emissions when conducting Selective Enforcement Audit testing of Otto-
cycle vehicles, or the requirement to measure evaporative emissions 
when conducting Selective Enforcement Audit testing of natural gas or 
liquefied petroleum gas-fueled vehicles.
    (2) * * *
    (i) Emission data on such engines tested in accordance with 
applicable emission test procedures of this subpart and in such numbers 
as specified. These data shall include zero-hour data, if generated, 
and emission data generated for certification as required under 
Sec. 86.090-26(c)(4). In lieu of providing emission data on idle CO 
emissions, smoke emissions or particulate emissions from methanol-
fueled, natural gas-fueled or liquefied petroleum gas-fueled diesel 
certification engines, or on CO emissions from petroleum-fueled, 
natural gas-fueled, liquefied petroleum gas-fueled, or methanol-fueled 
diesel certification engines the Administrator may, on request of the 
manufacturer, allow the manufacturer to demonstrate (on the basis of 
previous emission tests, development tests or other information) that 
the engine will conform with the applicable emission standards of 
Sec. 86.091-11, or Sec. 86.094-11.
* * * * *
    25. Section 86.094-24 of subpart A is amended by revising 
paragraphs (a)(5), (a)(6) introductory text, (a)(12), (a)(13) 
introductory text, (a)(14) introductory text and (a)(15), by removing 
``; and'' from the end of paragraph (a)(13)(i) and adding a period in 
its place, and by adding paragraphs (a)(6)(iv) and (a)(13)(iii), to 
read as follows:


Sec. 86.094-24  Test vehicles and engines.

    (a) * * *
    (5) Light-duty vehicles and light-duty trucks covered by an 
application for certification will be divided into groupings (e.g., by 
fuel type) which are expected to have similar evaporative emission 
characteristics throughout their useful life. Each group of vehicles 
with similar evaporative emission characteristics shall be defined as a 
separate evaporative emission family.
    (6) For light-duty vehicles and light-duty trucks to be classed in 
the same evaporative emission family, vehicles must be similar with 
respect to:
* * * * *
    (iv) Fuel type.
* * * * *
    (12) Vehicles powered by heavy-duty engines covered by an 
application for certification and using fuels for which there is an 
applicable evaporative emission standard will be divided into groupings 
of vehicles on the basis of physical features, including fuel type, 
which are expected to affect evaporative emissions. Each group of 
vehicles with similar features shall be defined as a separate 
evaporative emission family.
    (13) For vehicles equipped with heavy-duty engines using fuels for 
which there are applicable evaporative emission standards to be classed 
in the same evaporative emission family, vehicles must be identical 
with respect to:
* * * * *
    (iii) Fuel type.
    (14) For vehicles equipped with heavy-duty engines using fuels for 
which there are applicable evaporative emission standards to be classed 
in the same evaporative emission control system family, vehicles must 
be identical with respect to:
* * * * *
    (15) Where vehicles equipped with heavy-duty engines using fuels 
for which there are applicable evaporative emission standards and which 
cannot be divided into evaporative emission family-control system 
combinations based on the criteria listed above, the Administrator will 
establish evaporative emission family-control system combinations for 
those vehicles based on features most related to their evaporative 
emission characteristics.
* * * * *
    26. Section 86.095-35 of subpart A is amended by revising 
paragraphs (a)(4) heading, (a)(4)(i), (a)(4)(iii)(D), (a)(4)(iii)(E), 
(c)(1)(ii)(A), (c)(1)(ii)(B)(1), and (g)(1), to read as follows:


Sec. 86.095-35  Labeling.

* * * * *
    (a) * * *
    (4) Heavy-duty vehicles employing a fuel or fuels covered by 
evaporative emission standards. (i) A permanent, legible label shall be 
affixed in a readily visible position in the engine compartment. If 
such vehicles do not have an engine compartment, the label required in 
paragraphs (a)(4) and (g)(1) of this section shall be affixed in a 
readily available position on the operator's enclosure or on the 
engine.
* * * * *
    (iii) * * *
    (D) The maximum nominal fuel tank capacity (in gallons) for which 
the evaporative control system is certified (this requirement does not 
apply to vehicles whose evaporative control system efficiency is not 
dependent on fuel tank capacity); and
    (E) An unconditional statement of compliance with the appropriate 
model year U.S. Environmental Protection Agency regulations which apply 
to XXX-fueled heavy-duty vehicles.
* * * * *
    (c)(1) * * *
    (ii)(A) For light-duty vehicles, the statement: ``This Vehicle 
Conforms to U.S. EPA Regulations Applicable to XXX-Fueled 19XX Model 
Year New Motor Vehicles.''
    (B) * * *
    (1) the statement: ``This vehicle conforms to U.S. EPA regulations 
applicable to XXX-Fueled 19XX Model Year New Light-Duty Trucks.''
* * * * *
    (g) * * *
    (1) Incomplete heavy-duty vehicles employing a fuel or fuels which 
are nominally liquid at normal atmospheric pressure and temperature for 
which evaporative emission standards exist shall have the following 
prominent statement printed on the label required in paragraph (a)(4) 
of this section: ``(Manufacturer's corporate name) has determined that 
this vehicle conforms to U.S. EPA regulations applicable to 19XX Model 
Year New XXX-Fueled Heavy-Duty Vehicles when completed with a nominal 
fuel tank capacity not to exceed XXX gallons. Persons wishing to add 
fuel tank capacity beyond the above maximum must submit a written 
statement to the Administrator that the hydrocarbon storage system has 
been upgraded according to the requirements of 40 CFR 86.095-
35(g)(2).''
* * * * *
    27. Section 86.096-8 of subpart A is amended by revising paragraph 
(a)(1)(i) including Tables A96-1 and A96-2, and paragraph (b)(1), to 
read as follows:


Sec. 86.096-8  Emission standards for 1996 and later model year light-
duty vehicles.

    (a)(1) * * *
    (i) Exhaust emissions from 1996 and later model year light-duty 
vehicles (optional for 1996 model year natural gas-fueled and liquefied 
petroleum gas-fueled light-duty vehicles) shall meet all standards in 
Tables A96-1 and A96-2 in the rows designated with the applicable fuel 
type. Light-duty vehicles shall not exceed the applicable standards in 
Table A96-1 and shall not exceed the applicable standards in Table A96-
2. 

                Table A96-1.--Intermediate Useful Life Standards (g/mi) for Light-Duty Vehicles                 
----------------------------------------------------------------------------------------------------------------
               Fuel                     THC       NMHC       OMHCE     OMNMHCE      CO         NOX         PM   
----------------------------------------------------------------------------------------------------------------
Gasoline...........................       0.41       0.25  .........  .........        3.4        0.4       0.08
Diesel.............................       0.41       0.25  .........  .........        3.4        1.0       0.08
Methanol...........................  .........  .........       0.41       0.25        3.4        0.4       0.08
Natural Gas........................  .........       0.25  .........  .........        3.4        0.4       0.08
LPG................................       0.41       0.25  .........  .........        3.4        0.4      0.08 
----------------------------------------------------------------------------------------------------------------


                    Table A96-2.--Full Useful Life Standards (g/mi) for Light-Duty Vehicles                     
----------------------------------------------------------------------------------------------------------------
               Fuel                    THC        NMHC      OMHCE     OMNMHCE       CO         NOX         PM   
----------------------------------------------------------------------------------------------------------------
Gasoline..........................  .........       0.31  .........  .........        4.2        0.6        0.10
Diesel............................  .........       0.31  .........  .........        4.2        1.25       0.10
Methanol..........................  .........  .........  .........       0.31        4.2        0.6        0.10
Natural Gas.......................  .........       0.31  .........  .........        4.2        0.6        0.10
LPG...............................  .........       0.31  .........  .........        4.2        0.6       0.10 
----------------------------------------------------------------------------------------------------------------

* * * * *
    (b) * * *
    (1) Hydrocarbons (for gasoline-fueled, natural gas-fueled and 
liquefied petroleum gas-fueled vehicles). (i)(A) For the full three-
diurnal test sequence described in Sec. 86.130-96, diurnal plus hot 
soak measurements: 2.0 grams per test.
    (B) For the supplemental two-diurnal test sequence described in 
Sec. 86.130-96, diurnal plus hot soak emissions (gasoline-fueled 
vehicles only): 2.5 grams per test.
    (ii) Running loss test (gasoline-fueled vehicles only): 0.05 grams 
per mile.
    (iii) Fuel dispensing spitback test (gasoline-fueled vehicles 
only): 1.0 grams per test.
* * * * *
    28. Section 86.096-9 of subpart A is amended by revising paragraphs 
(b)(1) heading, (b)(1)(i)(A) introductory text, (b)(1)(i)(B)(2), 
(b)(1)(ii) and (b)(1)(iii), to read as follows:


Sec. 86.096-9  Emission standards for 1996 and later model year light-
duty trucks.

* * * * *
    (b)* * *
    (1) Hydrocarbons (for gasoline-fueled, natural gas-fueled and 
liquefied petroleum gas-fueled vehicles). (i)(A) For gasoline-fueled 
heavy light-duty trucks with a nominal fuel tank capacity of at least 
30 gallons:
* * * * *
    (B)* * *
    (2) For the supplemental two-diurnal test sequence described in 
Sec. 86.130-96, diurnal plus hot soak measurements (gasoline-fueled 
vehicles only): 2.5 grams per test.
    (ii) Running loss test (gasoline-fueled vehicles only): 0.05 grams 
per mile.
    (iii) Fuel dispensing spitback test (gasoline-fueled vehicles 
only): 1.0 grams per test.
* * * * *
    29. Section 86.096-10 of subpart A is amended by revising 
paragraphs (b)(1) heading, (b)(1)(i)(A)(2), (b)(1)(i)(B), (b)(1)(i)(C), 
(b)(1)(ii)(A)(2) and (b)(1)(ii)(B), to read as follows:


Sec. 86.096-10  Emission standards for 1996 and later model year Otto-
cycle heavy-duty engines and vehicles.

* * * * *
    (b)* * *
    (1) Hydrocarbons (for vehicles equipped with gasoline-fueled, 
natural gas-fueled or liquefied petroleum gas-fueled engines).
    (i)* * *
    (A)* * *
    (2) For the supplemental two-diurnal test sequence described in 
Sec. 86.1230-96, diurnal plus hot soak measurements (gasoline-fueled 
vehicles only): 3.5 grams per test.
    (B) Running loss test (gasoline-fueled vehicles only): 0.05 grams 
per mile.
    (C) Fuel dispensing spitback test (gasoline-fueled vehicles only): 
1.0 gram per test.
    (ii)* * *
    (A)* * *
    (2) For the supplemental two-diurnal test sequence described in 
Sec. 86.1230-96, diurnal plus hot soak measurements (gasoline-fueled 
vehicles only): 4.5 grams per test.
    (B) Running loss test (gasoline-fueled vehicles only): 0.05 grams 
per mile.
* * * * *
    30. Section 86.096-11 of subpart A is amended by revising the 
section heading, by revising paragraphs (a)(1)(i), (a)(2)(ii) and (c), 
redesignating paragraph (b)(4) as paragraph (b)(5) and revising it, and 
adding new paragraphs (a)(1)(iii) and (b)(4), to read as follows:


Sec. 86.096-11  Emission standards for 1996 and later model year diesel 
heavy-duty engines and vehicles.

    (a)* * *
    (1)(i) Hydrocarbons (for diesel engines fueled with either 
petroleum-fuel or liquefied petroleum gas). 1.3 grams per brake 
horsepower-hour (0.48 gram per megajoule), as measured under transient 
operating conditions.
* * * * *
    (iii) Nonmethane hydrocarbons (for natural gas-fueled diesel 
engines). 1.2 grams per brake horsepower-hour (0.45 gram per 
megajoule), as measured under transient operating conditions.
    (2)* * *
    (ii) 0.50 percent of exhaust gas flow at curb idle (methanol-, 
natural gas-, and liquefied petroleum gas-fueled diesel only).
* * * * *
    (b)* * *
    (4) Evaporative emissions from 1996 and later model year heavy-duty 
vehicles equipped with natural gas-fueled or liquefied petroleum gas-
fueled heavy-duty engines shall not exceed the following standards. The 
standards apply equally to certification and in-use vehicles.
    (i) For vehicles with a Gross Vehicle Weight Rating of up to 14,000 
pounds for the full three-diurnal test sequence described in 
Sec. 86.1230-96, diurnal plus hot soak measurements: 3.0 grams per 
test.
    (ii) For vehicles with a Gross Vehicle Weight Rating of greater 
than 14,000 pounds for the full three-diurnal test sequence described 
in Sec. 86.1230-96, diurnal plus hot soak measurements: 4.0 grams per 
test.
    (5)(i) For vehicles with a Gross Vehicle Weight Rating of up to 
26,000 pounds, the standards set forth in paragraphs (b)(3) and (b)(4) 
of this section refer to a composite sample of evaporative emissions 
collected under the conditions set forth in subpart M of this part and 
measured in accordance with those procedures.
    (ii) For vehicles with a Gross Vehicle Weight Rating greater than 
26,000 pounds, the standards set forth in paragraphs (b)(3)(ii) and 
(b)(4)(ii) of this section refer to the manufacturer's engineering 
design evaluation using good engineering practice (a statement of which 
is required in Sec. 86.091-23(b)(4)(ii)).
    (c) No crankcase emissions shall be discharged into the ambient 
atmosphere from any new 1996 or later model year methanol-fueled 
diesel, or any naturally-aspirated diesel heavy-duty engine. For 
petroleum-, natural gas-, and liquefied petroleum gas-fueled engines 
only, this provision does not apply to engines using turbochargers, 
pumps, blowers, or superchargers for air induction.
* * * * *
    31. Section 86.097-9 of subpart A is amended by revising Tables 
A97-1 and A97-2 in paragraph (a)(1)(i)(A), and Tables A97-3 and A97-4 
in paragraph (a)(1)(ii)(A), to read as follows:


Sec. 86.097-9  Emission standards for 1997 and later model year light-
duty trucks.

    (a)(1) * * *
    (i) * * *
    (A) * * *

              Table A97-1.--Intermediate Useful Life Standards (g/mi) for Light Light-Duty Trucks               
----------------------------------------------------------------------------------------------------------------
         Fuel            LVW (lbs)      THC        NMHC      OMHCE     OMNMHCE       CO        NOX         PM   
----------------------------------------------------------------------------------------------------------------
Gasoline..............       0-3750  .........       0.25  .........  .........        3.4        0.4       0.08
Gasoline..............    3751-5750  .........       0.32  .........  .........        4.4        0.7       0.08
Diesel................       0-3750  .........       0.25  .........  .........        3.4        1.0       0.08
Diesel................    3751-5750  .........       0.32  .........  .........        4.4  .........       0.08
Methanol..............       0-3750  .........  .........  .........       0.25        3.4        0.4       0.08
Methanol..............    3751-5750  .........  .........  .........       0.32        4.4        0.7       0.08
Natural Gas...........       0-3750  .........       0.25  .........  .........        3.4        0.4       0.08
Natural Gas...........    3751-5750  .........       0.32  .........  .........        4.4        0.7       0.08
LPG...................       0-3750  .........       0.25  .........  .........        3.4        0.4       0.08
LPG...................    3751-5750  .........       0.32  .........  .........        4.4        0.7       0.08
----------------------------------------------------------------------------------------------------------------


                  Table A97-2.--Full Useful Life Standards (g/mi) for Light Light-Duty Trucks                   
----------------------------------------------------------------------------------------------------------------
         Fuel            LVW (lbs)     THC\1\      NMHC     OMHCE\1\   OMNMHCE       CO        NOX         PM   
----------------------------------------------------------------------------------------------------------------
Gasoline..............       0-3750       0.80       0.31  .........  .........        4.2        0.6       0.10
Gasoline..............    3751-5750       0.80       0.40  .........  .........        5.5       0.97       0.10
Diesel................       0-3750       0.80       0.31  .........  .........        4.2       1.25       0.10
Diesel................    3751-5750       0.80       0.40  .........  .........        5.5       0.97       0.10
Methanol..............       0-3750  .........  .........       0.80       0.31        4.2        0.6       0.10
Methanol..............    3751-5750  .........  .........       0.80       0.40        5.5       0.97       0.10
Natural Gas...........       0-3750  .........       0.31  .........  .........        4.2        0.6       0.10
Natural Gas...........    3751-5750  .........       0.40  .........  .........        5.5       0.97       0.10
LPG...................       0-3750       0.80       0.31  .........  .........        4.2        0.6       0.10
LPG...................    3751-5750       0.80       0.40  .........  .........        5.5       0.97      0.10 
----------------------------------------------------------------------------------------------------------------
\1\Full useful life is 11 years or 120,000 miles, whichever occurs first.                                       

* * * * *
    (ii) * * *
    (A) * * *

              Table A97-3.--Intermediate Useful Life Standards (g/mi) for Heavy Light-Duty Trucks               
----------------------------------------------------------------------------------------------------------------
         Fuel            ALVW (lbs)     THC        NMHC      OMHCE     OMNMHCE       CO        NOX         PM   
----------------------------------------------------------------------------------------------------------------
Gasoline..............    3751-5750  .........       0.32  .........  .........        4.4        0.7  .........
Gasoline..............        >5750  .........       0.39  .........  .........        5.0        1.1  .........
Diesel................    3751-5750  .........       0.32  .........  .........        4.4  .........  .........
Diesel................        >5750  .........       0.39  .........  .........        5.0  .........  .........
Methanol..............    3751-5750  .........  .........  .........       0.32        4.4        0.7  .........
Methanol..............        >5750  .........  .........  .........       0.39        5.0        1.1  .........
Natural Gas...........    3751-5750  .........       0.32  .........  .........        4.4        0.7  .........
Natural Gas...........        >5750  .........       0.39  .........  .........        5.0        1.1  .........
LPG...................    3751-5750  .........       0.32  .........  .........        4.4        0.7  .........
LPG...................        >5750  .........       0.39  .........  .........        5.0        1.1  .........
----------------------------------------------------------------------------------------------------------------


                  Table A97-4.--Full Useful Life Standards (g/mi)  for Heavy Light-Duty Trucks                  
----------------------------------------------------------------------------------------------------------------
         Fuel            ALVW (lbs)     THC        NMHC      OMHCE     OMNMHCE       CO        NOX         PM   
----------------------------------------------------------------------------------------------------------------
Gasoline..............    3751-5750       0.80       0.46  .........  .........        6.4       0.98       0.10
Gasoline..............        >5750       0.80       0.56  .........  .........        7.3       1.53       0.12
Diesel................    3751-5750       0.80       0.46  .........  .........        6.4       0.98       0.10
Diesel................        >5750       0.80       0.56  .........  .........        7.3       1.53       0.12
Methanol..............    3751-5750  .........  .........       0.80       0.46        6.4       0.98       0.10
Methanol..............        >5750  .........  .........       0.80       0.56        7.3       1.53       0.12
Natural Gas...........    3751-5750  .........       0.46  .........  .........        6.4       0.98       0.10
Natural Gas...........        >5750  .........       0.56  .........  .........        7.3       1.53       0.12
LPG...................    3751-5750       0.80       0.46  .........  .........        6.4       0.98       0.10
LPG...................        >5750       0.80       0.56  .........  .........        7.3       1.53       0.12
----------------------------------------------------------------------------------------------------------------

* * * * *
    32. Section 86.098-2 of subpart A is amended by adding the 
definition for ``Fixed liquid level gauge'' in alphabetical order, to 
read as follows:


Sec. 86.098-2  Definitions.

* * * * *
    Fixed liquid level gauge means a type of liquid level gauge used on 
liquefied petroleum gas-fueled vehicles which uses a relatively small 
positive shutoff valve and is designed to indicate when the liquid 
level in the fuel tank being filled reaches the proper fill level. The 
venting of fuel vapor and/or liquid fuel to the atmosphere during the 
refueling event is generally associated with the use of the fixed 
liquid level gauge.
* * * * *
    33. Section 86.098-8 of subpart A is amended by adding new 
paragraphs (d)(1)(iii) and (d)(1)(iv), to read as follows:


Sec. 86.098-8  Emission standards for 1998 and later model year light-
duty vehicles.

* * * * *
    (d) * * *
    (1) * * *
    (iii) Hydrocarbons (for liquefied petroleum gas-fueled vehicles). 
0.15 gram per gallon (0.04 gram per liter) of fuel dispensed.
    (iv) Refueling receptacle (for natural gas-fueled vehicles). 
Refueling receptacles on natural gas-fueled vehicles shall comply with 
the receptacle provisions of the ANSI/AGA NGV1 standard-1994 (as 
incorporated by reference in Sec. 86.1).
* * * * *
    34. Section 86.098-10 of subpart A is amended by revising 
paragraphs (a)(1)(i) introductory text, (a)(1)(i)(B)(2), (a)(1)(ii) 
introductory text, (a)(1)(ii)(B)(2), (a)(3)(i) and (a)(3)(ii), and by 
adding new paragraphs (a)(1)(i)(C)(3), (a)(1)(ii)(C)(3), (a)(1)(v) and 
(a)(1)(vi), to read as follows:


Sec. 86.098-10  Emission standards for 1998 and later model year Otto-
cycle heavy-duty engines and vehicles.

* * * * *
    (a)(1) * * *
    (i) For Otto-cycle heavy-duty engines fueled with either gasoline 
or liquefied petroleum gas, and intended for use in all vehicles except 
as provided in paragraph (a)(3) of this paragraph.
* * * * *
    (B) * * *
    (2) For Otto-cycle heavy-duty engines fueled with either gasoline 
or liquefied petroleum gas and utilizing aftertreatment technology: 
0.50 percent of exhaust gas flow at curb idle.
    (C) * * *
    (3) A manufacturer may elect to include any or all of its liquified 
petroleum gas-fueled Otto-cycle heavy-duty engine families in any or 
all of the NOX averaging, trading or banking programs for heavy-
duty engines, within the restrictions described in Sec. 86.094-15. If 
the manufacturer elects to include engine families in any of these 
programs, the NOX FELs may not exceed 5.0 grams per brake 
horsepower-hour (1.9 grams per megajoule). This ceiling value applies 
whether credits for the family are derived from averaging, trading or 
banking programs.
    (ii) For Otto-cycle heavy-duty engines fueled with either gasoline 
or liquefied petroleum gas, and intended for use only in vehicles with 
a Gross Vehicle Weight Rating of greater than 14,000 pounds.
* * * * *
    (B) * * *
    (2) For Otto-cycle heavy-duty engines fueled with either gasoline 
or liquefied petroleum gas and utilizing aftertreatment technology: 
0.50 percent of exhaust gas flow at curb idle.
    (C) * * *
    (3) A manufacturer may elect to include any or all of its liquified 
petroleum gas-fueled Otto-cycle heavy-duty engine families in any or 
all of the NOX averaging, trading or banking programs for heavy-
duty engines, within the restrictions described in Sec. 86.094-15. If 
the manufacturer elects to include engine families in any of these 
programs, the NOX FELs may not exceed 5.0 grams per brake 
horsepower-hour (1.9 grams per megajoule). This ceiling value applies 
whether credits for the family are derived from averaging, trading or 
banking programs.
* * * * *
    (v) For natural gas-fueled Otto-cycle heavy-duty engines intended 
for use in all vehicles except as provided in paragraph (a)(3) of this 
section.
    (A) Nonmethane hydrocarbons. 0.9 gram per brake horsepower-hour 
(0.33 gram per megajoule), as measured under transient operating 
conditions.
    (B) Carbon monoxide. (1) 14.4 grams per brake horsepower-hour (5.36 
grams per megajoule), as measured under transient operating conditions.
    (2) For natural gas-fueled Otto-cycle heavy-duty engines utilizing 
aftertreatment technology. 0.50 percent of exhaust flow at curb idle.
    (C) Oxides of nitrogen. (1) 5.0 grams per brake horsepower-hour 
(1.9 grams per megajoule), as measured under transient operating 
conditions.
    (2) A manufacturer may elect to include any or all of its natural 
gas-fueled Otto-cycle heavy-duty engine families in any or all of the 
NOX averaging, trading or banking programs for heavy-duty engines, 
within the restrictions described in Sec. 86.094-15. If the 
manufacturer elects to include engine families in any of these 
programs, the NOX FELs may not exceed 5.0 grams per brake 
horsepower-hour (1.9 grams per megajoule). This ceiling value applies 
whether credits for the family are derived from averaging, trading or 
banking programs.
    (vi) For natural gas-fueled Otto-cycle engines intended for use 
only in vehicles with a Gross Vehicle Weight Rating of greater than 
14,000 pounds.
    (A) Nonmethane hydrocarbons. 1.7 grams per brake horsepower-hour 
(0.63 gram per megajoule), as measured under transient operating 
conditions.
    (B) Carbon monoxide. (1) 37.1 grams per brake horsepower-hour (13.8 
grams per megajoule), as measured under transient operating conditions.
    (2) For natural gas-fueled Otto-cycle heavy-duty engines utilizing 
aftertreatment technology. 0.50 percent of exhaust gas flow at curb 
idle.
    (C) Oxides of nitrogen. (1) 5.0 grams per brake horsepower-hour 
(1.9 grams per megajoule), as measured under transient operating 
conditions.
    (2) A manufacturer may elect to include any or all of its natural 
gas-fueled Otto-cycle heavy-duty engine families in any or all or the 
NOX averaging, trading or banking programs for heavy-duty engines, 
within the restrictions described in Sec. 86.094-15. If the 
manufacturer elects to include engine families in any of these 
programs, the NOX FELs may not exceed 5.0 grams per brake 
horsepower-hour (1.9 grams per megajoule). This ceiling value applies 
whether credits for the family are derived from averaging, trading or 
banking programs.
* * * * *
    (3)(i) A manufacturer may certify one or more Otto-cycle heavy-duty 
engine configurations intended for use in all vehicles to the emission 
standards set forth in paragraphs (a)(1)(ii), (a)(1)(iv) or (a)(1)(vi) 
of this paragraph: Provided, that the total model year sales of such 
configuration(s), segregated by fuel type, being certified to the 
emission standards in paragraph (a)(1)(ii) of this section represent no 
more than five percent of total model year sales of each fuel type 
Otto-cycle heavy-duty engine intended for use in vehicles with a Gross 
Vehicle Weight Rating of up to 14,000 pounds by the manufacturer.
    (ii) The configurations certified to the emission standards of 
paragraphs (a)(1) (ii) and (vi) of this section under the provisions of 
paragraph (a)(3)(i) of this section shall still be required to meet the 
evaporative emission standards set forth in paragraphs Sec. 86.096-
10(b)(1)(i), (b)(2)(i) and (b)(3)(i).
* * * * *
    35. Section 86.098-11 of subpart A is amended by revising the 
section heading, by revising paragraphs (a)(1)(i), (a)(2)(ii) and (c), 
and adding new paragraphs (a)(1)(iii) and (b)(4), to read as follows:


Sec. 86.098-11  Emission standards for 1998 and later model year diesel 
heavy-duty engines and vehicles.

    (a) * * *
    (1)(i) Hydrocarbons (for diesel engines fueled with either 
petroleum-fuel or liquefied petroleum gas). 1.3 grams per brake 
horsepower-hour (0.48 gram per megajoule), as measured under transient 
operating conditions.
* * * * *
    (iii) Nonmethane hydrocarbons (for natural gas-fueled diesel 
engines). 1.2 grams per brake horsepower-hour (0.45 gram per 
megajoule), as measured under transient operating conditions.
    (2) * * *
    (ii) 0.50 percent of exhaust gas flow at curb idle (methanol-, 
natural gas-, and liquefied petroleum gas-fueled diesel only).
* * * * *
    (b) * * *
    (4) Evaporative emissions from 1998 and later model year heavy-duty 
vehicles equipped with natural gas-fueled or liquefied petroleum gas-
fueled heavy-duty engines shall not exceed the following standards. The 
standards apply equally to certification and in-use vehicles.
    (i) For vehicles with a Gross Vehicle Weight Rating of up to 14,000 
pounds for the full three-diurnal test sequence described in 
Sec. 86.1230-96, diurnal plus hot soak measurements: 3.0 grams per 
test.
    (ii) For vehicles with a Gross Vehicle Weight Rating of greater 
than 14,000 pounds for the full three-diurnal test sequence described 
in Sec. 86.1230-96, diurnal plus hot soak measurements: 4.0 grams per 
test.
    (iii)(A) For vehicles with a Gross Vehicle Weight Rating of up to 
26,000 pounds, the standards set forth in paragraph (b)(4) of this 
section refer to a composite sample of evaporative emissions collected 
under the conditions set forth in subpart M of this part and measured 
in accordance with those procedures.
    (B) For vehicles with a Gross Vehicle Weight Rating greater than 
26,000 lbs, the standards set forth in paragraphs (b)(3)(ii) and 
(b)(4)(ii) of this section refer to the manufacturer's engineering 
design evaluation using good engineering practice (a statement of which 
is required in Sec. 86.091-23(b)(4)(ii)).
    (c) No crankcase emissions shall be discharged into the ambient 
atmosphere from any new 1998 or later model year methanol-, natural 
gas-, or liquefied petroleum gas-fueled diesel, or any naturally-
aspirated diesel heavy-duty engine. For petroleum-fueled engines only, 
this provision does not apply to engines using turbochargers, pumps, 
blowers, or superchargers for air induction.
* * * * *
    36. Section 86.098-28 of subpart A is amended by adding a new 
paragraph (h) to read as follows:


Sec. 86.098-28  Compliance with emission standards.

* * * * *
    (h) Fixed liquid level gauge waiver. Liquefied petroleum gas-fueled 
vehicles which contain fixed liquid level gauges or other gauges or 
valves which can be opened to release fuel or fuel vapor during 
refueling, and which are being tested for refueling emissions, are not 
required to be tested with such gauges or valves open, as outlined in 
Sec. 86.157-98(d)(2), provided the manufacturer can demonstrate, to the 
satisfaction of the Administrator, that such gauges or valves would not 
be opened during refueling in-use due to inaccessibility or other 
design features that would prevent or make it very unlikely that such 
gauges or valves could be opened.
    37. Section 86.099-8 of subpart A is amended by revising paragraph 
(b)(1), and adding new paragraphs (d)(1)(iii) and (d)(1)(iv), to read 
as follows:


Sec. 86.099-8  Emission standards for 1999 and later model year light-
duty vehicles.

* * * * *
    (b) * * *
    (1) Hydrocarbons (for gasoline-fueled, natural gas-fueled, and 
liquefied petroleum gas-fueled vehicles). (i)(A) For the full three-
diurnal test sequence described in Sec. 86.130-96, diurnal plus hot 
soak measurements: 2.0 grams per test.
    (B) For the supplemental two-diurnal test sequence described in 
Sec. 86.130-96, diurnal plus hot soak emissions (gasoline-fueled 
vehicles only): 2.5 grams per test.
    (ii) Running loss test (gasoline-fueled vehicles only): 0.05 grams 
per mile.
    (iii) Fuel dispensing spitback test (gasoline-fueled vehicles 
only): 1.0 grams per test.
* * * * *
    (d) * * *
    (1) * * *
    (iii) Hydrocarbons (for liquefied petroleum gas-fueled vehicles). 
0.15 gram per gallon (0.04 gram per liter) of fuel dispensed.
    (iv) Refueling receptacle (for natural gas-fueled vehicles). 
Refueling receptacles on natural gas-fueled vehicles shall comply with 
the receptacle provisions of the ANSI/AGA NGV1-1994 standard (as 
incorporated by reference in Sec. 86.1).
* * * * *
    38. Section 86.099-9 of subpart A is amended by revising paragraphs 
(b)(1) heading, (b)(1)(i)(A) introductory text, (b)(1)(i)(B)(2), 
(b)(1)(ii) and (b)(1)(iii), to read as follows:


Sec. 86.099-9  Emission standards for 1999 and later model year light-
duty trucks.

* * * * *
    (b) * * *
    (1) Hydrocarbons (for gasoline-fueled, natural gas-fueled, and 
liquefied petroleum gas-fueled vehicles). (i)(A) For gasoline-fueled 
heavy light-duty trucks with a nominal fuel tank capacity of at least 
30 gallons:
* * * * *
    (B) * * *
    (2) For the supplemental two-diurnal test sequence described in 
Sec. 86.130-96, diurnal plus hot soak measurements (gasoline-fueled 
vehicles only): 2.5 grams per test.
    (ii) Running loss test (gasoline-fueled vehicles only): 0.05 grams 
per mile.
    (iii) Fuel dispensing spitback test (gasoline-fueled vehicles 
only): 1.0 grams per test.
* * * * *
    39. Section 86.099-10 of subpart A is amended by revising 
paragraphs (b)(1) heading, (b)(1)(i)(A)(2), (b)(1)(i)(B), (b)(1)(i)(C), 
(b)(1)(ii)(A)(2) and (b)(1)(ii)(B), to read as follows:


Sec. 86.099-10  Emission standards for 1999 and later model year Otto-
cycle heavy-duty engines and vehicles.

* * * * *
    (b) * * *
    (1) Hydrocarbons (for vehicles equipped with gasoline-fueled, 
natural gas-fueled or liquefied petroleum gas-fueled engines).
    (i) * * *
    (A) * * *
    (2) For the supplemental two-diurnal test sequence described in 
Sec. 86.1230-96, diurnal plus hot soak measurements (gasoline-fueled 
vehicles only): 3.5 grams per test.
    (B) Running loss test (gasoline-fueled vehicles only): 0.05 grams 
per mile.
    (C) Fuel dispensing spitback test (gasoline-fueled vehicles only): 
1.0 gram per test.
    (ii) * * *
    (A) * * *
    (2) For the supplemental two-diurnal test sequence described in 
Sec. 86.1230-96, diurnal plus hot soak measurements (gasoline-fueled 
vehicles only): 4.5 grams per test.
    (B) Running loss test (gasoline-fueled vehicles only): 0.05 grams 
per mile.
* * * * *
    40. Section 86.099-11 of subpart A is amended by revising 
paragraphs (a)(1)(i), (a)(2)(ii) and (c), and adding new paragraphs 
(a)(1)(iii) and (b)(4), to read as follows:


Sec. 86.099-11  Emission standards for 1999 and later model year diesel 
heavy-duty engines and vehicles.

    (a) * * *
    (1)(i) Hydrocarbons (for diesel engines fueled with either 
petroleum-fuel or liquefied petroleum gas). 1.3 grams per brake 
horsepower-hour (0.48 gram per megajoule), as measured under transient 
operating conditions.
* * * * *
    (iii) Nonmethane hydrocarbons (for natural gas-fueled diesel 
engines). 1.2 grams per brake horsepower-hour (0.45 gram per 
megajoule), as measured under transient operating conditions.
    (2) * * *
    (ii) 0.50 percent of exhaust gas flow at curb idle (methanol-, 
natural gas-, and liquefied petroleum gas-fueled diesel only).
* * * * *
    (b) * * *
    (4) Evaporative emissions from 1999 and later model year heavy-duty 
vehicles equipped with natural gas-fueled or liquefied petroleum gas-
fueled heavy-duty engines shall not exceed the following standards. The 
standards apply equally to certification and in-use vehicles.
    (i) For vehicles with a Gross Vehicle Weight Rating of up to 14,000 
pounds for the full three-diurnal test sequence described in 
Sec. 86.1230-96, diurnal plus hot soak measurements: 3.0 grams per 
test.
    (ii) For vehicles with a Gross Vehicle Weight Rating of greater 
than 14,000 pounds for the full three-diurnal test sequence described 
in Sec. 86.1230-96, diurnal plus hot soak measurements: 4.0 grams per 
test.
    (iii)(A) For vehicles with a Gross Vehicle Weight Rating of up to 
26,000 pounds, the standards set forth in paragraph (b)(4) of this 
section refer to a composite sample of evaporative emissions collected 
under the conditions set forth in subpart M of this part and measured 
in accordance with those procedures.
    (B) For vehicles with a Gross Vehicle Weight Rating greater than 
26,000 pounds, the standards set forth in paragraphs (b)(3)(ii) and 
(b)(4)(ii) of this section refer to the manufacturer's engineering 
design evaluation using good engineering practice (a statement of which 
is required in Sec. 86.091-23(b)(4)(ii)).
    (c) No crankcase emissions shall be discharged into the ambient 
atmosphere from any new 1999 or later model year methanol-, natural 
gas-, or liquefied petroleum gas-fueled diesel, or any naturally-
aspirated diesel heavy-duty engine. For petroleum-fueled engines only, 
this provision does not apply to engines using turbochargers, pumps, 
blowers, or superchargers for air induction.
* * * * *
    41. Section 86.101 of subpart B is amended by revising paragraph 
(a)(3) to read as follows:


Sec. 86.101  General applicability.

    (a) * * *
    (3) Sections 86.150 through 86.157 describe the refueling test 
procedures for light-duty vehicles and light-duty trucks and apply for 
model years 1998 and later.
* * * * *
    42. Section 86.104 of subpart B is amended by redesignating 
paragraph (b) as paragraph (c) and revising it, and adding a new 
paragraph (b) to read as follows:


Sec. 86.104  Section numbering; construction.

* * * * *
    (b) A section reference without a model year suffix refers to the 
section applicable for the appropriate model year.
    (c) Unless indicated otherwise, all provisions in this subpart 
apply to petroleum-fueled, natural gas-fueled, liquefied petroleum gas-
fueled and methanol-fueled vehicles.
    43. Section 86.105 of subpart B is amended by revising paragraph 
(b) to read as follows:


Sec. 86.105  Introduction; structure of subpart.

* * * * *
    (b) Three topics are addressed in this subpart. Sections 86.106 
through 86.115 set forth specifications and equipment requirements; 
Secs. 86.116 through 86.126 discuss calibration methods and frequency; 
test procedures and data requirements are listed in Secs. 86.127 
through 86.157.
    44. Section 86.106-94 of subpart B is amended by revising paragraph 
(a) to read as follows:


Sec. 86.106-94  Equipment required; overview.

    (a) This subpart contains procedures for exhaust emissions tests on 
petroleum-fueled, natural gas-fueled, liquefied petroleum gas-fueled 
and methanol-fueled light-duty vehicles and light-duty trucks, and for 
evaporative emission tests on gasoline-fueled, natural gas-fueled, 
liquefied petroleum gas-fueled and methanol-fueled light-duty vehicles 
and light-duty trucks. Certain items of equipment are not necessary for 
a particular test, e.g., evaporative enclosure when testing petroleum-
fueled diesel vehicles. Alternate sampling systems may be used if shown 
to yield equivalent results and if approved in advance by the 
Administrator. Equipment required and specifications are as follows:
    (1) Evaporative emission tests. The evaporative emission test is 
closely related to and connected with the exhaust emission test. All 
vehicles tested for evaporative emissions must be tested for exhaust 
emissions. Further, unless the evaporative emission test is waived by 
the Administrator under Sec. 86.090-26, all vehicles must undergo both 
tests. (Petroleum-fueled diesel vehicles are excluded from the 
evaporative emission standard.) Section 86.107 specifies the necessary 
equipment.
    (2) Exhaust emission tests. All vehicles subject to this subpart 
are subject to testing for both gaseous and particulate exhaust 
emissions using the CVS concept (Sec. 86.109), except where exemptions 
or waivers are expressly provided in subpart A of these regulations. 
Vehicles subject to the ``Tier 0'' (i.e., phase-out) standards 
described under subpart A are exempted from testing for methane 
emissions (except natural gas-fueled vehicles). Otto-cycle vehicles 
subject to the ``Tier 0'' standards are waived from testing for 
particulates. For vehicles waived from the requirement for measuring 
particulate emissions, use of a dilution tunnel is not required 
(Sec. 86.109). The CVS must be connected to the dilution tunnel if 
particulate emission sampling is required (Sec. 86.110). Petroleum- and 
methanol-fueled diesel-cycle vehicle testing requires that a PDP-CVS or 
CFV with heat exchanger be used. (This equipment may be used with 
methanol-fueled Otto-cycle vehicles; however, particulates need not be 
measured for vehicles that are waived from the requirement). All 
gasoline-fueled, methanol-fueled, natural gas-fueled and liquified 
petroleum gas-fueled vehicles are either tested for evaporative 
emissions or undergo a diurnal heat build. Petroleum-fueled diesel-
cycle vehicles are excluded from this requirement. Equipment necessary 
and specifications appear in Secs. 86.108 through 86.114.
    (3) Fuel, analytical gas, and driving schedule specifications. Fuel 
specifications for exhaust and evaporative emissions testing and for 
mileage accumulation are specified in Sec. 86.113. Analytical gases are 
specified in Sec. 86.114. The EPA Urban Dynamometer Driving Schedule 
(UDDS) for use in exhaust emissions tests is specified in Sec. 86.115 
and Appendix I of this part.
* * * * *
    45. Section 86.106-96 of subpart B is amended by revising paragraph 
(a) to read as follows:


Sec. 86.106-96  Equipment required; overview.

    (a) This subpart contains procedures for exhaust emissions tests on 
petroleum-fueled, natural gas-fueled, liquefied petroleum gas-fueled 
and methanol-fueled light-duty vehicles and light-duty trucks, and for 
evaporative emission tests on gasoline-fueled, natural gas-fueled, 
liquefied petroleum gas-fueled and methanol-fueled light-duty vehicles 
and light-duty trucks. Certain items of equipment are not necessary for 
a particular test, e.g., evaporative enclosure when testing petroleum-
fueled diesel vehicles. Alternate sampling systems may be used if shown 
to yield equivalent results and if approved in advance by the 
Administrator. Equipment required and specifications are as follows:
    (1) Evaporative emission tests. The evaporative emission test is 
closely related to and connected with the exhaust emission test. All 
vehicles tested for evaporative emissions must undergo testing 
according to the test sequences described in Sec. 86.130-96; however, 
the Administrator may omit measurement of exhaust emissions to test for 
evaporative emissions. The Administrator may truncate a test after any 
valid emission measurement without affecting the validity of the test. 
Further, unless the evaporative emission test is waived by the 
Administrator under Sec. 86.090-26, all vehicles must undergo both 
tests. (Petroleum-fueled diesel vehicles are excluded from the 
evaporative emission standard.) Section 86.107 specifies the necessary 
equipment.
    (2) Exhaust emission tests. All vehicles subject to this subpart 
are subject to testing for both gaseous and particulate exhaust 
emissions using the CVS concept (see Sec. 86.109), except where 
exemptions or waivers are expressly provided in subpart A of this part. 
Vehicles subject to the ``Tier 0'' (i.e., phase-out) standards 
described under subpart A of this part are exempted from testing for 
methane emissions. Otto-cycle vehicles subject to the ``Tier 0'' 
standards are waived from testing for particulates. For vehicles waived 
from the requirement for measuring particulate emissions, use of a 
dilution tunnel is not required (see Sec. 86.109). The CVS must be 
connected to the dilution tunnel if particulate emission sampling is 
required (see Sec. 86.110). Petroleum- and methanol-fueled diesel-cycle 
vehicle testing requires that a PDP-CVS or CFV-CVS with heat exchanger 
be used. (This equipment may be used with methanol-fueled Otto-cycle 
vehicles; however, particulates need not be measured for vehicles that 
are waived from the requirement). All vehicles equipped with 
evaporative canisters are preconditioned by loading the canisters with 
hydrocarbon vapors. Petroleum-fueled diesel vehicles are excluded from 
this requirement.
    (3) Fuel, analytical gas, and driving schedule specifications. Fuel 
specifications for exhaust and evaporative emissions testing and for 
mileage accumulation are specified in Sec. 86.113. Analytical gases are 
specified in Sec. 86.114. The EPA Urban Dynamometer Driving Schedule 
(UDDS) for use in exhaust emissions tests is specified in Sec. 86.115 
and Appendix I of this part.
* * * * *
    46. Section 86.107-96 of subpart B is amended by revising paragraph 
(b)(1) to read as follows:


Sec. 86.107-96  Sampling and analytical system; evaporative emissions.

* * * * *
    (b) * * *
    (1) For gasoline-fueled, natural gas-fueled, liquefied petroleum 
gas-fueled and methanol-fueled vehicles a hydrocarbon analyzer 
utilizing the hydrogen flame ionization principle (FID) shall be used 
to monitor the atmosphere within the enclosure (a heated FID 
(HFID)(235 deg.15 deg.F (113 deg.8 deg.C)) is 
required for methanol-fueled vehicles). For natural gas-fueled 
vehicles, the FID may be calibrated using methane, or if calibrated 
using propane the FID response to methane shall be determined and 
applied to the FID hydrocarbon reading. Provided evaporative emission 
results are not effected, a probe may be used to detect or verify 
hydrocarbon sources during a running loss test. Instrument bypass flow 
may be returned to the enclosure. The FID shall have a response time to 
90 percent of final reading of less than 1.5 seconds.
* * * * *
    47. Section 86.109-94 of subpart B is amended by revising 
paragraphs (b)(4) and (c)(4), to read as follows:


Sec. 86.109-94  Exhaust gas sampling system; Otto-cycle vehicles not 
requiring particulate emission measurement.

* * * * *
    (b) * * *
    (4) The flow capacity of the CVS shall be large enough to eliminate 
water condensation in the system. (300 to 350 cfm (0.142 to 0.165 m\3\/
s) is sufficient for most petroleum-fueled vehicles. Higher flow rates 
are required for methanol-fueled vehicles and may be required for 
natural gas-fueled and liquefied petroleum gas-fueled vehicles. 
Procedures for determining CVS flow rates are detailed in ``Calculation 
of Emissions and Fuel Economy When Using Alternative Fuels,'' EPA 460/
3-83-009. (Copies may be obtained from the U.S. Department of Commerce, 
NTIS, Springfield, Virginia 22161; order #PB 84104702.)
* * * * *
    (c) * * *
     (4) The flow capacity of the CVS shall be large enough to 
virtually eliminate water condensation in the system (300 to 350 cfm 
(0.142 to 0.165 m\3\/s) is sufficient for most petroleum-fueled 
vehicles). Higher flow rates are required with methanol-fueled vehicles 
and may be required for natural gas-fueled and liquefied petroleum gas-
fueled vehicles. Procedures for determining CVS flow rates are detailed 
in ``Calculation of Emission and Fuel Economy When Using Alternative 
Fuels,'' EPA 460/3-83-009.
* * * * *
    48. Section 86.110-94 of subpart B is amended by revising 
paragraphs (a)(2), (b) heading and introductory text and (b)(3), by 
redesignating paragraphs (a)(6) and (a)(7) as paragraphs (a)(7) and 
(a)(8), and by adding a new paragraph (a)(6), to read as follows:


Sec. 86.110-94  Exhaust gas sampling system; diesel vehicles and Otto-
cycle vehicles requiring particulate emissions measurements.

* * * * *
    (a) * * *
    (2) Bag, continuous HFID (required for petroleum-fueled diesel-
cycle and optional for methanol-fueled, natural gas-fueled and 
liquefied petroleum gas-fueled diesel-cycle vehicles), and particulate 
sampling capabilities as shown in Figure B94-5 (or Figure B94-6) are 
required to provide both gaseous and particulate emissions sampling 
capabilities from a single system.
* * * * *
    (6) For natural gas-fueled and liquefied petroleum gas-fueled 
diesel vehicles either a heated flame ionization detector (HFID) 
[375 deg.20 deg.F (191 deg.11 deg.C)] or a non-
heated flame ionization detector may be used for hydrocarbon analysis.
* * * * *
* * * * *
    (b) Component description--Otto-cycle, petroleum-fueled and 
liquefied petroleum gas-fueled diesel-cycle vehicles. The components 
necessary for petroleum-fueled and liquefied petroleum gas-fueled 
diesel-cycle and Otto-cycle vehicle exhaust sampling shall meet the 
following requirements:
* * * * *
    (3) For gasoline-fueled, natural gas-fueled and liquefied petroleum 
gas-fueled Otto-cycle and petroleum-fueled, natural gas- fueled and 
liquefied petroleum gas-fueled diesel-cycle vehicles, the transfer of 
heat from the vehicle exhaust gas shall be minimized between the point 
where it leaves the vehicle tailpipe(s) and the point where it enters 
the dilution tunnel airstream. To accomplish this, a short length (not 
more than 12 feet (365 cm) if uninsulated, or not more than 20 feet 
(610 cm) if insulated) of smooth stainless steel tubing from the 
tailpipe to the dilution tunnel is required. This tubing shall have a 
maximum inside diameter of 4.0 inches (10.2 cm). Short sections of 
flexible tubing at connection points are allowed.
* * * * *
    49. Section 86.111-94 of subpart B is amended by revising 
paragraphs (b)(3) introductory text and (b)(3)(v) to read as follows:


Sec. 86.111-94  Exhaust gas analytical system.

* * * * *
    (b) * * *
    (3) For petroleum-fueled diesel vehicles (and if selected, for 
methanol-fueled, natural gas-fueled and liquefied petroleum gas-fueled 
diesel vehicles) a continuous hydrocarbon sample shall be measured 
using a heated analyzer train as shown in Figure B90-5 (or B90-6). The 
train shall include a heated probe, a heated continuous sampling line, 
a heated particulate filter and a heated hydrocarbon instrument (HFID) 
complete with heated pump, filter and flow control system.
* * * * *
    (v) For petroleum-fueled, natural gas-fueled and liquefied 
petroleum gas-fueled diesel vehicles, the sample line and filter shall 
be heated to maintain a sample gas temperature of 375 deg. 
10 deg.F (191 deg. 6 deg.C) before the filter 
and before the HFID.
* * * * *
    50. Section 86.113-94 of subpart B is revised to read as follows:


Sec. 86.113-94  Fuel specifications.

    (a) Gasoline fuel. (1) Gasoline having the following specifications 
will be used by the Administrator in exhaust and evaporative emission 
testing of petroleum-fueled Otto-cycle vehicles. Gasoline having the 
following specification or substantially equivalent specifications 
approved by the Administrator, shall be used by the manufacturer in 
exhaust and evaporative testing except that octane specifications do 
not apply;

----------------------------------------------------------------------------------------------------------------
                                   Item                                     ASTM test method No.       Value    
----------------------------------------------------------------------------------------------------------------
Octane, Research, Min.....................................................  D2699                             93
Sensitivity, Min..........................................................  ....................             7.5
Lead (organic):                                                                                                 
    g/U.S. gal. (g/liter).................................................  D3237                       \1\0.050
                                                                                                      \1\(0.013)
Distillation Range:                                                                                             
    IBP:\2\  deg.F ( deg.C)...............................................  D86                            75-95
                                                                                                       (23.9-35)
    10 pct. point:  deg.F ( deg.C)........................................  D86                          120-135
                                                                                                     (48.9-57.2)
    50 pct. point:  deg.F ( deg.C)........................................  D86                          200-230
                                                                                                      (93.3-110)
    90 pct. point:  deg.F ( deg.C)........................................  D86                          300-325
(148.9-162.8):                                                                                                  
    EP, max:  deg.F ( deg.C)..............................................  D86                              415
                                                                                                         (212.8)
Sulfur, weight pct. max...................................................  D1266                           0.10
Phosphorus, max. g/U.S. gal. (g/liter)....................................  D3231                          0.005
                                                                                                        (0.0013)
RVP3,4, psi (kPa).........................................................  D3231                        8.7-9.2
                                                                                                     (60.0-63.4)
Hydrocarbon composition:                                                                                        
    Olefins, max. pct.....................................................  D1319                             10
    Aromatics, max. pct...................................................  D1319                             35
    Saturates.............................................................  D1319                          (\5\)
----------------------------------------------------------------------------------------------------------------
\1\Maximum.                                                                                                     
\2\For testing at altitudes above 1,219 m (4,000 ft), the specified range is 75 deg.-105 deg.F (23.9 deg.-40.6  
  deg.C).                                                                                                       
\3\For testing which is unrelated to evaporative emission control, the specified range is 8.0-9.2 psi (55.2-63.4
  kPa).                                                                                                         
\4\For testing at altitudes above 1,219 m (4,000 ft), the specified range is 7.6-8.0 psi (52-55 kPa).           
\5\Remainder.                                                                                                   

    (2)(i) Unleaded gasoline representative of commercial gasoline 
which will be generally available through retail outlets shall be used 
in service accumulation. Leaded gasoline will not be used in service 
accumulation.
    (ii) The octane rating of the gasoline used shall be no higher than 
1.0 Research octane number above the minimum recommended by the 
manufacturer and have a minimum sensitivity of 7.5 octane numbers, 
where sensitivity is defined as the Research octane number minus the 
Motor octane number.
    (iii) The Reid Vapor Pressure of the gasoline used shall be 
characteristic of the motor fuel used during the season in which the 
service accumulation takes place.
    (3) The specification range of the gasoline to be used under 
paragraph (a) of this section shall be reported in accordance with 
Sec. 86.094-21(b)(3).
    (b) Petroleum diesel test fuel. (1) The petroleum fuels employed 
for testing diesel vehicles shall be clean and bright, with pour and 
cloud points adequate for operability. The petroleum diesel fuel may 
contain nonmetallic additives as follows: Cetane improver, metal 
deactivator, antioxidant, dehazer, antirust, pour depressant, dye, 
dispersant and biocide. Fuels specified for emissions testing are 
intended to be representative of commercially available in-use fuels.
    (2) Petroleum fuel for diesel vehicles meeting the following 
specifications, or substantially equivalent specifications approved by 
the Administrator, shall be used in exhaust emission testing. The grade 
of petroleum diesel fuel recommended by the engine manufacturer, 
commercially designated as ``Type 2-D'' grade diesel, shall be used:

----------------------------------------------------------------------------------------------------------------
                                  Item                                    ASTM test method No.      Type 2-D    
----------------------------------------------------------------------------------------------------------------
Cetane Number...........................................................  D613                             42-50
Distillation range:                                                                                             
    IBP:  deg.F ( deg.C)................................................  D86                            340-400
                                                                                                   (171.1-204.4)
    10 pct. point:  deg.F ( deg.C)......................................  D86                            400-460
                                                                                                   (204.4-237.8)
    50 pct. point:  deg.F ( deg.C)......................................  D86                            470-540
                                                                                                   (243.3-282.2)
    90 pct. point:  deg.F ( deg.C)......................................  D86                            560-630
                                                                                                   (293.3-332.2)
    EP:  deg.F ( deg.C).................................................  D86                            610-690
                                                                                                   (321.1-365.6)
Gravity  deg.API........................................................  D287                             32-37
Total sulfur pct........................................................  D2622                        0.03-0.05
Hydrocarbon composition:                                                                                        
    Aromatics, min. pct.................................................  D1319                               27
    Paraffins, Naphthenes, Olefins......................................  D1319                            (\1\)
Flashpoint, min.  deg.F ( deg.C)........................................  D93                                130
                                                                                                          (54.4)
Viscosity, centistokes..................................................  D445                           2.0-3.2
----------------------------------------------------------------------------------------------------------------
\1\Remainder.                                                                                                   

    (3) Petroleum fuel for diesel vehicles meeting the following 
specifications, or substantially equivalent specifications approved by 
the Administrator, shall be used in service accumulation. The grade of 
petroleum diesel fuel recommended by the engine manufacturer, 
commercially designated as ``Type 2-D'' grade diesel fuel, shall be 
used:

----------------------------------------------------------------------------------------------------------------
                                  Item                                    ASTM test method No.      Type 2-D    
----------------------------------------------------------------------------------------------------------------
Cetane number...........................................................  D613                             38-58
Distillation range:                                                                                             
    90 pct. point:  deg.F ( deg.C)......................................  D86                            430-630
                                                                                                   (221.1-332.2)
Gravity,  deg.API.......................................................  D287                             30-42
Total sulfur, pct.......................................................  D2622                        0.03-0.05
Flashpoint, min.  deg.F ( deg.C)........................................  D93                                130
                                                                                                          (54.4)
Viscosity centistokes...................................................  D445                           1.5-4.5
----------------------------------------------------------------------------------------------------------------

    (4) Other petroleum distillate fuels may be used for testing and 
service accumulation provided:
    (i) They are commercially available; and
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Use of a fuel listed under paragraphs (b)(2) and (b)(3) of 
this section would have a detrimental effect on emissions or 
durability; and
    (iv) Written approval from the Administrator of the fuel 
specifications is provided prior to the start of testing.
    (5) The specification range of the fuels to be used under 
paragraphs (b)(2), (b)(3) and (b)(4) of this section shall be reported 
in accordance with Sec. 86.094-21(b)(3).
    (c) Methanol fuel. (1) Methanol fuel used for exhaust and 
evaporative emission testing and in service accumulation shall be 
representative of commercially available methanol fuel and shall 
consist of at least 50 percent methanol by volume.
    (i) Manufacturers shall recommend the methanol fuel to be used for 
testing and service accumulation.
    (ii) The Administrator shall determine the methanol fuel to be used 
for testing and service accumulation.
    (2) Other methanol fuels may be used for testing and service 
accumulation provided:
    (i) They are commercially available; and
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Use of a fuel listed under paragraph (c)(1) of this section 
would have a detrimental effect on emissions or durability; and
    (iv) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (3) The specification range of the fuels to be used under 
paragraphs (c)(1) and (c)(2) of this section shall be reported in 
accordance with Sec. 86.094-21(b)(3).
    (d) Mixtures of petroleum and methanol fuels for flexible fuel 
vehicles. (1) Mixtures of petroleum and methanol fuels used for exhaust 
and evaporative emission testing and service accumulation for flexible 
fuel vehicles shall be within the range of fuel mixtures for which the 
vehicle was designed.
    (2) Manufacturer testing and service accumulation may be performed 
using only those mixtures (mixtures may be different for exhaust 
testing, evaporative testing and service accumulation) expected to 
result in the highest emissions, provided:
    (i) The fuels which constitute the mixture will be used in customer 
service; and
    (ii) Information, acceptable to the Administrator, is provided by 
the manufacturer to show that the designated fuel mixtures would result 
in the highest emissions; and
    (iii) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (3) The specification range of the fuels to be used under 
paragraphs (d)(1) and (d)(2) of this section shall be reported in 
accordance with Sec. 86.094-21(b)(3).
    (e) Natural gas fuel. (1) Natural gas fuel having the following 
specifications will be used by the Administrator for exhaust and 
evaporative emission testing of natural gas-fueled vehicles: 

------------------------------------------------------------------------
                                          ASTM test method No.          
         Item                                                     Value 
------------------------------------------------------------------------
Methane...............  min. mole pct...  D1945                     89.0
Ethane................  max. mole pct...  D1945                      4.5
C3 and higher.........  max. mole pct...  D1945                      2.3
C6 and higher.........  max. mole pct...  D1945                      0.2
Oxygen................  max. mole pct...  D1945                      0.6
Inert gases:                                                            
    Sum of CO2 and N2.  max. mole pct...  D1945                      4.0
Odorant\1\                                                              
------------------------------------------------------------------------
\1\The natural gas at ambient conditions must have a distinctive odor   
  potent enough for its presence to be detected down to a concentration 
  in air of not over \1/5\ (one-fifth) of the lower limit of            
  flammability.                                                         

    (2) Natural gas representative of commercially available natural 
gas fuel which will be generally available through retail outlets shall 
be used in service accumulation for natural gas- fueled vehicles.
    (3) Other natural gas fuels may be used for testing and service 
accumulation provided:
    (i) They are commercially available; and
    (ii) Information acceptable to the Administrator is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (4) The specification range of the fuels to be used under 
paragraphs (e)(1), (e)(2) and (e)(3) of this section shall be reported 
in accordance with Sec. 86.094-21(b)(3).
    (f) Liquefied petroleum gas fuel. (1) Liquefied petroleum gas fuel 
used for exhaust and evaporative emission testing and in service 
accumulation shall be commercially available liquefied petroleum gas 
fuel.
    (i) Manufacturers shall recommend the liquefied petroleum gas fuel 
to be used for testing and service accumulation.
    (ii) The Administrator shall determine the liquefied petroleum gas 
fuel to be used for testing and service accumulation.
    (2) Other liquefied petroleum gas fuels may be used for testing and 
service accumulation provided:
    (i) They are commercially available; and
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (3) The specification range of the fuel to be used under paragraphs 
(f)(1) and (f)(2) of this section shall be measured in accordance with 
ASTM D2163-61 and reported in accordance with Sec. 86.094-21(b)(3).
    (g) Fuels not meeting the specifications set forth in this section 
may be used only with the advance approval of the Administrator.
    51. Section 86.121-90 of subpart B is amended by revising 
paragraphs (a)(2) and (b)(3), and adding a new paragraph (d), to read 
as follows:


Sec. 86.121-90  Hydrocarbon analyzer calibration.

* * * * *
    (a) * * *
    (2) Optimize on the most common operating range. Introduce into the 
analyzer a propane (methane as appropriate) in air mixture (methanol in 
air mixture for methanol-fueled vehicles when optional methanol 
calibrated HFID procedure is used during the 1994 model year) with a 
propane (or methane or methanol as appropriate) concentration equal to 
approximately 90 percent of the most common operating range.
* * * * *
    (b) * * *
    (3) Calibrate on each normally used operating range with propane in 
air calibration gases (either methanol or methane in air as 
appropriate) having nominal concentrations of 15, 30, 45, 60, 75 and 90 
percent of that range. For each range calibrated, if the deviation from 
a least squares best-fit straight line is two percent or less of the 
value at each data point, concentration values may be calculated by use 
of a single calibration factor for that range. If the deviation exceeds 
two percent at any point, the best-fit non-linear equation which 
represents the data to within two percent of each test point shall be 
used to determine concentration.
* * * * *
    (d) FID response factor to methane. When the FID analyzer is to be 
used for the analysis of natural gas-fueled vehicle hydrocarbon 
samples, the methane response factor of the analyzer shall be 
established. To determine the total hydrocarbon FID response to 
methane, known methane in air concentrations traceable to the National 
Institute of Standards and Technology (NIST) shall be analyzed by the 
FID. Several methane concentrations shall be analyzed by the FID in the 
range of concentrations in the exhaust sample. The total hydrocarbon 
FID response to methane is calculated as follows:

rCH4=FIDppm/SAMppm

Where:

(1) rCH4=FID response factor to methane.
(2) FIDppm=FID reading in ppmC.
(3) SAMppm=the known methane concentration in ppmC.

    52. Section 86.127-96 of subpart B is amended by revising 
paragraphs (a)(1), (a)(3), (a)(4), (b), (d) introductory text, (d)(2) 
and (e), to read as follows:


Sec. 86.127-96  Test procedures; overview.

* * * * *
    (a) * * *
    (1) Gaseous exhaust THC, CO, NOX, CO2 (for petroleum-
fueled and gaseous-fueled vehicles), plus CH3OH and HCHO for 
methanol-fueled vehicles, plus CH4 (for vehicles subject to the 
NMHC and OMNMHCE standards).
* * * * *
    (3) Evaporative HC (for gasoline-fueled, methanol-fueled and 
gaseous-fueled vehicles) and CH3OH (for methanol-fueled vehicles). 
The evaporative testing portion of the procedure occurs after the 
exhaust emission test; however, exhaust emissions need not be sampled 
to complete a test for evaporative emissions.
    (4) Fuel spitback (this test is not required for gaseous-fueled 
vehicles).
    (b) The Otto-cycle exhaust emission test is designed to determine 
gaseous THC, CO, CO2, CH4, NOX, and particulate mass 
emissions from gasoline-fueled, methanol-fueled and gaseous-fueled 
Otto-cycle vehicles as well as methanol and formaldehyde from methanol-
fueled Otto-cycle vehicles, while simulating an average trip in an 
urban area of 11 miles (18 kilometers). The test consists of engine 
start-ups and vehicle operation on a chassis dynamometer through a 
specified driving schedule. A proportional part of the diluted exhaust 
is collected continuously for subsequent analysis, using a constant 
volume (variable dilution) sampler or critical flow venturi sampler.
* * * * *
    (d) The evaporative emission test (gasoline-fueled vehicles, 
methanol-fueled and gaseous-fueled vehicles) is designed to determine 
hydrocarbon and methanol evaporative emissions as a consequence of 
diurnal temperature fluctuation, urban driving and hot soaks following 
drives. It is associated with a series of events that a vehicle may 
experience and that may result in hydrocarbon and/or methanol vapor 
losses. The test procedure is designed to measure:
* * * * *
    (2) Running losses resulting from a simulated trip performed on a 
chassis dynamometer, measured by the enclosure or point-source 
technique (see Sec. 86.134; this test is not required for gaseous-
fueled vehicles); and
* * * * *
    (e) Fuel spitback emissions occur when a vehicle's fuel fill neck 
cannot accommodate dispensing rates. The vehicle test for spitback 
consists of a short drive followed immediately by a complete refueling 
event. This test is not required for gaseous-fueled vehicles.
* * * * *
    53. Section 86.130-96 of subpart B is amended by revising 
paragraphs (a) and (b), to read as follows:


Sec. 86.130-96  Test sequence; general requirements.

    (a) (1) Gasoline- and methanol-fueled vehicles. The test sequence 
shown in figure B96-10 shows the steps encountered as the test vehicle 
undergoes the procedures subsequently described to determine conformity 
with the standards set forth. The full three- diurnal sequence depicted 
in figure B96-10 tests vehicles for all sources of evaporative 
emissions. The supplemental two-diurnal test sequence is designed to 
verify that vehicles sufficiently purge their evaporative canisters 
during the exhaust emission test. Sections 86.132-96, 86.133-96 and 
86.138-96 describe the separate specifications of the supplemental two-
diurnal test sequence.
    (2) Gaseous-fueled vehicles. The test sequence shown in figure B96-
10 shows the steps encountered as the test vehicle undergoes the 
procedures subsequently described to determine conformity with the 
standards set forth, with the exception that the fuel drain and fill 
and precondition canister steps are not required for gaseous-fueled 
vehicles. In addition, the supplemental two-diurnal test and the 
running loss test are not required.
    (b) The vehicle test for fuel spitback during fuel dispensing is 
conducted as a stand-alone test (see Sec. 86.146). This test is not 
required for gaseous-fueled vehicles.
* * * * *
    54. Section 86.132-90 of subpart B is amended by revising 
paragraphs (a)(4) introductory text and (a)(4)(ii) introductory text, 
to read as follows:


Sec. 86.132-90  Vehicle preconditioning.

    (a) * * *
    (4) The Administrator may also choose to conduct or require the 
conduct of additional preconditioning to insure that the evaporative 
emission control system is stabilized in the case of gasoline-fueled 
and methanol-fueled vehicles, or to insure that the exhaust system is 
stabilized in the case of petroleum-fueled, natural gas-fueled, 
liquefied petroleum gas-fueled and methanol-fueled diesel vehicles.
* * * * *
    (ii) Petroleum-fueled diesel vehicles, natural gas-fueled and 
liquefied petroleum gas-fueled vehicles. The preconditioning shall 
consist of either of the following:
* * * * *
    55. Section 86.132-96 of subpart B is amended by revising 
paragraphs (b), (e)(2) heading and introductory text and (f), to read 
as follows:


Sec. 86.132-96  Vehicle preconditioning.

* * * * *
    (b)(1) Gasoline- and Methanol-Fueled Vehicles. Drain the fuel 
tank(s) and fill with test fuel, as specified in Sec. 86.113, to the 
``tank fuel volume'' defined in Sec. 86.082-2. The fuel cap(s) shall be 
installed within one minute after refueling.
    (2) Gaseous-Fueled Vehicles. Vehicle fuel tanks to be filled with 
fuel that meets the specifications in Sec. 86.113. Fuel tanks shall be 
filled to a minimum of 75% of service pressure for natural gas-fueled 
vehicles or a minimum of 75% of available fill volume for liquefied 
petroleum gas-fueled vehicles. Prior draining of the fuel tanks is not 
called for if the fuel in the tanks already meets the specifications in 
Sec. 86.113.
* * * * *
    (e) * * *
    (2) For petroleum-fueled diesel, methanol-fueled diesel, and 
gaseous-fueled vehicles. The preconditioning shall consist of either of 
the following:
* * * * *
    (f) (1) Gasoline- and Methanol-Fueled Vehicles. Within five minutes 
of completion of the preconditioning drive, the vehicle shall be driven 
off the dynamometer and parked. For gasoline- and methanol-fueled 
vehicles, drain the fuel tank(s) and fill with test fuel, as specified 
in Sec. 86.113, to the ``tank fuel volume'' defined in Sec. 86.082-2. 
The vehicle shall be refueled within one hour of completion of the 
preconditioning drive. The fuel cap(s) shall be installed within one 
minute after refueling.
    (2) Gaseous-Fueled Vehicles. Within five minutes of completion of 
the preconditioning drive, the vehicle shall be driven off the 
dynamometer and parked. Vehicle fuel tanks shall be refilled with fuel 
that meets the specifications in Sec. 86.113. Fuel tanks shall be 
filled to a minimum of 75% of service pressure for natural gas-fueled 
vehicles or a minimum of 75% of available fill volume for liquefied 
petroleum gas-fueled vehicles. Prior draining of the fuel tanks is not 
called for if the fuel in the tanks already meets the specifications in 
Sec. 86.113.
* * * * *
    56. Section 86.133-96 of subpart B is amended by revising 
paragraphs (a)(1) and (a)(3), to read as follows:


Sec. 86.133-96  Diurnal emission test.

    (a)(1) The diurnal emission test for gasoline-, methanol- and 
gaseous-fueled vehicles consists of three 24-hour test cycles following 
the hot soak test. Emissions are measured for each 24-hour cycle, with 
the highest emission level used to determine compliance with the 
standards specified in subpart A of this part. The Administrator may 
truncate a test after any 24-hour cycle without affecting the validity 
of the collected data. Sampling of emissions from the running loss and 
hot soak tests is not required as preparation for the diurnal emission 
test. The diurnal emission test may be conducted as part of either the 
three- diurnal test sequence or the supplemental two-diurnal test 
sequence, as described in Sec. 86.130-96.
* * * * *
    (3) For the supplemental two-diurnal test sequence, the diurnal 
emission test outlined in paragraph (p) of this section follows the 
alternate hot soak test specified in Sec. 86.138-96(k). This test is 
not required for gaseous-fueled vehicles.
* * * * *
    57. Section 86.134-96 of subpart B is amended by revising paragraph 
(a) to read as follows:


Sec. 86.134-96  Running loss test.

    (a) Overview. Gasoline- and methanol-fueled vehicles are to be 
tested for running loss emissions during simulated high-temperature 
urban driving; this test is not required for gaseous-fueled vehicles. 
During operation, tank temperatures are controlled according to a 
prescribed profile to simulate in-use conditions. If the vehicle is 
determined to have exceeded the standard before the end of the running 
loss test, the test may be terminated without invalidating the data. 
The test can be run either in a sealed enclosure or with the point-
source method, as specified in paragraph (g) of this section.
* * * * *
    58. Section 86.135-94 of subpart B is amended by revising paragraph 
(a) to read as follows:


Sec. 86.135-94  Dynamometer procedure.

* * * * *
    (a) Overview. The dynamometer run consists of two tests, a ``cold'' 
start test, after a minimum 12-hour and a maximum 36-hour soak 
according to the provisions of Secs. 86.132 and 86.133, and a ``hot'' 
start test following the ``cold'' start by 10 minutes. Engine startup 
(with all accessories turned off), operation over the UDDS and engine 
shutdown make a complete cold start test. Engine startup and operation 
over the first 505 seconds of the driving schedule complete the hot 
start test. The exhaust emissions are diluted with ambient air in the 
dilution tunnel as shown in Figure B94-5 and Figure B94-6. A dilution 
tunnel is not required for testing vehicles waived from the requirement 
to measure particulates. Six particulate samples are collected on 
filters for weighing; the first sample plus backup is collected during 
the first 505 seconds of the cold start test; the second sample plus 
backup is collected during the remainder of the cold start test 
(including shutdown); the third sample plus backup is collected during 
the hot start test. Continuous proportional samples of gaseous 
emissions are collected for analysis during each test phase. For 
gasoline-fueled, natural gas-fueled and liquefied petroleum gas-fueled 
Otto-cycle vehicles, the composite samples collected in bags are 
analyzed for THC, CO, CO2, CH4 and NOX. For petroleum-
fueled diesel-cycle vehicles (optional for natural gas-fueled, 
liquefied petroleum gas-fueled and methanol-fueled diesel-cycle 
vehicles), THC is sampled and analyzed continuously according to the 
provisions of Sec. 86.110. Parallel samples of the dilution air are 
similarly analyzed for THC, CO, CO2, CH4 and NOX. For 
natural gas-fueled, liquefied petroleum gas-fueled and methanol-fueled 
vehicles, bag samples are collected and analyzed for THC (if not 
sampled continuously), CO, CO2, CH4 and NOX. For 
methanol-fueled vehicles, methanol and formaldehyde samples are taken 
for both exhaust emissions and dilution air (a single dilution air 
formaldehyde sample, covering the total test period may be collected). 
Parallel bag samples of dilution air are analyzed for THC, CO, 
CO2, CH4 and NOX. Methanol and formaldehyde samples may 
be omitted for 1990 through 1994 model years when a FID calibrated on 
methanol is used.
* * * * *
    59. Section 86.136-90 of subpart B is amended by revising 
paragraphs (a) heading and introductory text and (b), to read as 
follows:


Sec. 86.136-90  Engine starting and restarting.

    (a) Otto-cycle vehicles. Paragraph (a) of this section applies to 
Otto-cycle vehicles.
* * * * *
    (b) Diesel vehicles. The engine shall be started according to the 
manufacturers recommended starting procedures in the owners manual. The 
initial 20-second idle period shall begin when the engine starts. The 
transmission shall be placed in gear 15 seconds after the engine is 
started. If necessary, braking may be employed to keep the drive wheels 
from turning.
* * * * *
    60. Section 86.138-96 of subpart B is amended by revising paragraph 
(a) to read as follows:


Sec. 86.138-96  Hot soak test.

    (a) (1) Gasoline- and methanol-fueled vehicles. For gasoline- and 
methanol-fueled vehicles, the hot soak test shall be conducted 
immediately following the running loss test. However, sampling of 
emissions from the running loss test is not required as preparation for 
the hot soak test.
    (2) Gaseous-fueled vehicles. Since gaseous-fueled vehicles are not 
required to perform a running loss test, the hot soak test shall be 
conducted within five minutes of the hot start exhaust test.
* * * * *
    61. Section 86.140-94 of subpart B is amended by revising 
paragraphs (a) introductory text and (b) introductory text, to read as 
follows:


Sec. 86.140-94  Exhaust sample analysis.

* * * * *
    (a) For CO, CO2, CH4, NOX, and for Otto-cycle and 
methanol-fueled, natural gas-fueled and liquefied petroleum gas-fueled 
(if non-heated FID option is used) diesel vehicle HC:
* * * * *
    (b) For petroleum-fueled, natural gas-fueled and liquefied 
petroleum gas-fueled (if HFID is used) diesel vehicle HC:
* * * * *
    62. Section 86.142-90 of subpart B is amended by revising paragraph 
(o) introductory text and adding paragraphs (q) and (r), to read as 
follows:


Sec. 86.142-90  Records required.

* * * * *
    (o) Additional records required for diesel vehicles:
* * * * *
    (q) Additional required records for natural gas-fueled vehicles. 
Composition, including all carbon containing compounds; e.g. CO2, 
of the natural gas-fuel used during the test. C1 and C2 
compounds shall be individually reported. C3 and heavier 
hydrocarbons, and C6 and heavier compounds may be reported as a 
group.
    (r) Additional required records for liquefied petroleum gas-fueled 
vehicles. Composition of the liquefied petroleum gas-fuel used during 
the test. Each hydrocarbon compound present, through C4 compounds, 
shall be individually reported. C5 and heavier hydrocarbons may be 
reported as a group.
    63. Section 86.143-96 of subpart B is amended by revising 
paragraphs (a) and (b)(1)(ii)(B), to read as follows:


Sec. 86.143-96  Calculations; evaporative emissions.

    (a) The following equations are used to calculate the evaporative 
emissions from gasoline- and methanol-fueled vehicles, and for gaseous-
fueled vehicles.
    (b) * * *
    (1) * * *
    (ii) * * *
    (B) CHC = FID hydrocarbon concentration as ppm including FID 
response to methanol (or methane, as appropriate) in the sample.
* * * * *
    64. Section 86.144-94 of subpart B is amended by revising 
paragraphs (a)(1), (c)(1)(ii), (c)(3)(iv)(C), (c)(5)(ii), (c)(6)(ii), 
(c)(8)(i) and (c)(8)(ii); redesignating paragraphs (c)(7)(iii) through 
(c)(7)(xiii) as paragraphs (c)(7)(iv) through (xiv) and revising them; 
and adding new paragraphs (b)(10), (c)(7)(iii), (c)(8)(vi) and (c)(9), 
to read as follows:


Sec. 86.144-94  Calculations; exhaust emissions.

* * * * *
    (a) * * *
    (1) YWM = Weighted mass emissions of each pollutant, i.e., 
THC, CO, OMHCE, NMHC, OMNMHCE, CH4, NOX, or CO2, in 
grams per vehicle mile.
* * * * *
    (b) * * *

(10) Methane mass:
    CH4MASS=Vmix=DensityCH4=(CH4conc/1,000,000)

    (c) * * *
    (1) * * *
    (ii) DensityHC=Density of total hydrocarbon.
    (A) For gasoline-fuel, diesel-fuel and methanol fuel; 
DensityHC=16.33 g/ft\3\-carbon atom (0.5768 kg/m\3\-carbon atom), 
assuming an average carbon to hydrogen ratio of 1:1.85, at 68  deg.F 
(20  deg.C) and 760 mm Hg (101.3 kPa) pressure.
    (B) For natural gas and liquefied petroleum gas-fuel; 
DensityHC=1.1771 (12.011+H/C (1.008)) g/ft\3\-carbon atom 
(0.04157(12.011+H/C (1.008))kg/m\3\-carbon atom), where H/C is the 
hydrogen to carbon ratio of the hydrocarbon components of the test 
fuel, at 68  deg.F (20  deg.C) and 760 mm Hg (101.3 kPa) pressure.
* * * * *
    (3) * * *
    (iv) * * *
    (C) COe=[1-(0.01+0.005HCR) CO2e-0.000323R]COem for 
methanol-fuel or natural gas-fuel or liquefied petroleum gas-fuel, 
where HCR is hydrogen-to-carbon ratio as measured for the fuel used.
* * * * *
    (5) * * *
    (ii) DensityCH3OH=Density of methanol is 37.71 g/ft3-
carbon atom (1.332 kg/m3-carbon atom), at 68  deg.F (20  deg.C) 
and 760 mm Hg (101.3 kPa) pressure.
* * * * *
    (6) * * *
    (ii) DensityHCHO=Density of formaldehyde is 35.36 g/ft3- 
carbon atom (1.249 kg/m3-carbon atom), at 68  deg.F (20  deg.C) 
and 760 mm Hg (101.3 kPa) pressure.
* * * * *
    (7) * * *

TR21SE94.001

for natural gas-fueled or liquefied petroleum gas-fueled vehicles where 
fuel composition is CxHy as measured for the fuel used.
    (iv)(A) KH=Humidity correction factor.
    (B) KH=1/[1-0.0047(H-75)].
    (C) For SI units, KH=1 x [1-0.0329(H x 10.71)].

    Where:

    (v) (A) H=Absolute humidity in grains (grams) of water per pound 
(kilogram) of dry air.
    (B) H=[(43.478)Ra  x  Pd]/[PB-(Pd  x  Ra/
100)].
    (C) For SI units, H=[(6.211)Ra  x  Pd]/
[PB x (Pd  x  Ra/100)].
    (vi) Ra=Relative humidity of the ambient air, percent.
    (vii) Pd=Saturated vapor pressure, mm Hg (kPa) at the ambient 
dry bulb temperature.
    (viii) PB=Barometric pressure, mm Hg (kPa).
    (ix) (A) Vmix=Total dilute exhaust volume in cubic feet per 
test phase corrected to standard conditions (528 deg.R (293 deg.K) and 
760 mm Hg (101.3 kPa)).
    (B) For PDP-CVS, Vmix is:

TR21SE94.002

    (C) For SI units, 

TR21SE94.003

Where:

    (x) Vo=Volume of gas pumped by the positive displacement pump, 
in cubic feet (m3) per revolution. This volume is dependent on the 
pressure differential across the positive displacement pump.
    (xi) N=Number of revolutions of the positive displacement pump 
during the test phase while samples are being collected.
    (xii) PB=Barometric pressure, mm Hg (kPa).
    (xiii) P4=Pressure depression below atmospheric measured at 
the inlet to the positive displacement pump, in mm Hg (kPa) (during an 
idle mode).
    (xiv) Tp=Average temperature of dilute exhaust entering 
positive displacement pump during test,  deg.R( deg.K).
    (8)(i) NMHCconc=HCconc-(rCH4 x CH4conc).
    (ii) DensityNMHC=The density of non-methane hydrocarbon.
    (A) For gasoline-fuel and diesel-fuel; DensityNMHC=16.33 g/
ft3-carbon atom (0.5768 kg/m3-carbon atom), assuming an 
average carbon to hydrogen ratio of 1:1.85 at 68  deg.F (20  deg.C) and 
760 mm Hg (101.3 kPa) pressure.
    (B) For natural gas and liquefied petroleum gas-fuel; 
DensityNMHC=1.1771(12.011+H/C (1.008)) g/ft3-carbon atom 
(0.04157(12.011+H/C (1.008))kg/m3-carbon atom), where H/C is the 
hydrogen to carbon ratio of the hydrocarbon components of the test 
fuel, at 68  deg.F (20  deg.C) and 760 mm Hg(101.3 kPa) pressure.
* * * * *
    (vi) rCH4=HC FID response to methane for natural gas-fueled 
vehicles as measured in Sec. 86.121(d). For all other vehicles 
rCH4=1.
    (9)(i) CH4mass=Methane emissions, in grams per test phase.
    (ii) DensityCH4=Density of methane is 18.89 g/ft3-carbon 
atom (0.6672 kg/m3-carbon atom), at 68  deg.F (20  deg.C) and 760 
mm Hg (101.3 kPa) pressure.
* * * * *
    65. Section 86.150-98 of subpart B is amended by revising the 
section heading and adding a new paragraph (d) to read as follows:


Sec. 86.150-98  Refueling test procedure; overview.

* * * * *
    (d) For liquefied petroleum gas-fueled vehicles only. Refueling 
test procedures for light-duty vehicles and light-duty trucks operated 
on liquefied petroleum gas are described in Sec. 86.157.
    66. A new section 86.157-98 is added to subpart B to read as 
follows:


Sec. 86.157-98  Refueling test procedures for liquefied petroleum gas-
fueled vehicles.

    (a) Equipment. (1) The sampling and analytical system shall meet 
the specifications in Sec. 86.107-98(a) through (i).
    (2) The refueling equipment nozzle specifications shall meet the 
requirements described in Sec. 80.32.
    (b) General requirements. (1) The refueling test procedure for 
light-duty liquefied petroleum gas-fueled vehicles and trucks starts 
with the preconditioning of the vehicle followed by a refueling 
emissions measurement. The test is conducted by following paragraphs 
(c) through (f) of this section in order.
    (2) Ambient temperature levels encountered by the test vehicle 
throughout the test sequence shall not be less than 68 deg.F (20 deg.C) 
nor more than 86 deg.F (30 deg.C).
    (3) The vehicle shall be approximately level during all phases of 
the test sequence to prevent abnormal fuel distribution.
    (c) Vehicle preconditioning. (1) The vehicle fuel tanks are to be 
filled with fuel that meets the specifications in Sec. 86.113. Fuel 
tanks shall be filled to 10 percent of nominal fuel tank capacity, 
determined to the nearest one-tenth of a U.S. gallon (0.38 liter).
    (2) The vehicle shall be parked (without starting the engine) 
within the temperature range specified in paragraph (a)(2) of this 
section for a minimum of one hour and a maximum of six hours.
    (d) Measurement procedure. (1) The steps prior to the actual 
refueling event described in Sec. 86.154-98(b) through (e)(5) shall be 
performed.
    (2) Within one minute of obtaining the initial FID (or HFID) 
reading, the dispensed fuel nozzle shall be attached to the vehicle 
fuel receptacle, and the refueling operation shall be started. If the 
vehicle is equipped with a fixed liquid level gauge or other gauge or 
valve which could be opened to release fuel or fuel vapor during 
refueling, and has not received an exemption as outlined in 
Secs. 86.098-28(h), 86.001-28(h) or 86.004-28(h), the fixed level gauge 
or other gauges or valves shall be opened after the dispensing nozzle 
is attached, but prior to the start of the refueling operation. The 
dispensed fuel must be at a temperature stabilized to approximately the 
same temperature as the vehicle was in paragraph (c)(2) of this 
section. The dispensing rate must be typical of in-use dispensing rates 
for liquefied petroleum gas into light-duty vehicles and trucks.
    (3) The fuel flow shall continue until the amount of fuel dispensed 
is at least 85 percent of nominal fuel tank capacity, determined to the 
nearest one-tenth of a U.S. gallon (0.38 liter).
    (4) Following the fuel shut-off the fixed liquid level gauge or 
other gauges or valves, if open, shall be closed and the nozzle 
disconnected.
    (5) The final reading of the evaporative enclosure FID (or HFID) 
analyzer shall be taken 60 5 seconds following the 
disconnect of the refueling nozzle. This is the final hydrocarbon 
concentration, CHCf, required in Sec. 86.143. The elapsed time, in 
minutes, between the initial and final FID (or HFID) readings shall be 
recorded.
    (6) For vehicles equipped with more than one fuel tank, the 
procedures described in this section shall be performed for each fuel 
tank.
    (e) Records required. (1) Test: test number, system or device 
tested (brief description), date and time of day, instrument operated, 
operator, enclosure barometric pressure and temperature, recorder 
charts (identify zero, span, and enclosure gas traces), fuel dispensing 
rate(s) and dispensed fuel volume.
    (2) Vehicle: ID number, manufacturer, model year, engine family, 
evaporative/refueling emission family, fuel tank(s) capacity, basic 
fuel system description and odometer reading.
    (3) All pertinent instrument information including nozzle and fuel 
delivery system description. As an alternative, a reference to a 
vehicle test cell number may be used, with advance approval of the 
Administrator, provided test cell calibration records show the 
pertinent instrument information.
    (4) All additional information necessary for the calculations 
specified in paragraph (f) of this section.
    (f) Calculations. (1) The calculation of the net hydrocarbon mass 
change in the enclosure is used to determine refueling mass emissions. 
The mass is calculated from initial and final hydrocarbon 
concentrations in ppm carbon, initial and final enclosure ambient 
temperatures, initial and final barometric pressures and net volume 
using the equations of Sec. 86.143. For vehicles with multiple tanks, 
the results for each tank shall be calculated and then summed to 
determine overall refueling emissions.
    (2) The final results for comparison with the refueling control 
emission standard shall be computed by dividing the total refueling 
mass emissions by the total gallons of fuel dispensed in the refueling 
test (see paragraph (d)(3) of this section).
    (3) The results of all emission tests shall be rounded, in 
accordance with ASTM E 29-67 to the number of decimal places contained 
in the applicable emission standard expressed to one additional 
significant figure. This procedure has been incorporated by reference 
(see Sec. 86.1).
    67. A new section 86.401-97 is added to subpart E, to read as 
follows:


Sec. 86.401-97  General applicability.

    (a) This subpart applies to 1978 and later model year, new, 
gasoline-fueled motorcycles built after 31 December, 1977, and to 1990 
and later model year, new, methanol-fueled motorcycles built after 31 
December, 1989 and to 1997 and later model year, new, natural gas-
fueled and liquefied petroleum gas-fueled motorcycles built after 31 
December, 1996.
    (b) Motorcycles with engine displacements less than 50 cc (3.1 cu 
in) are excluded from the requirements of this subpart.
    (c) Motorcycles are excluded from the requirements of this subpart, 
if with an 80 kg (176 lb) driver, it cannot:
    (1) Start from a dead stop using only the engine; or
    (2) Exceed a maximum speed of 40 km/h (25 mph) on level paved 
surfaces.
    68. Section 86.410-90 of subpart E is amended by revising paragraph 
(a)(1) introductory text, to read as follows:


Sec. 86.410-90  Emission standards for 1990 and later model year 
motorcycles.

    (a)(1) Exhaust emissions from 1990 and later model year gasoline-
fueled, natural gas-fueled and liquefied petroleum gas-fueled 
motorcycles shall not exceed (compliance with these standards is 
optional prior to the 1997 model year for natural gas-fueled and 
liquefied petroleum gas-fueled motorcycles):
* * * * *
    69. Section 86.509-90 of subpart F is amended by revising paragraph 
(c)(4), to read as follows:


Sec. 86.509-90  Exhaust gas sampling system.

* * * * *
    (c) * * *
    (4) The location of the dilution air inlet shall be placed so as to 
use test-cell air for dilution air and the flow capacity of the CVS 
shall be large enough to virtually eliminate water condensation in the 
system. Control of water condensation with methanol-fueled vehicles is 
critical. Additional care may also be required to eliminate water 
condensation when testing natural gas and liquefied petroleum gas-
fueled vehicles. Procedures for determining CVS flow rates are detailed 
in ``Calculation of Emissions And Fuel Economy When Using Alternate 
Fuels,'' EPA 460/3-83-009.
* * * * *
    70. A new section 86.513-94 is added to subpart F to read as 
follows:


Sec. 86.513-94  Fuel and engine lubricant specifications.

    (a) Gasoline. (1) Gasoline having the following specifications will 
be used by the Administrator in exhaust emission testing of gasoline-
fueled motorcycles. Gasoline having the following specifications or 
substantially equivalent specifications approved by the Administrator, 
shall be used by the manufacturer for emission testing except that the 
octane specifications do not apply.

----------------------------------------------------------------------------------------------------------------
                               Item                                         ASTM                  Value         
----------------------------------------------------------------------------------------------------------------
Octane, research, minimum.........................................  D2699                 96                    
Lead (organic):                                                                                                 
    g/liter (g/U.S. gal.).........................................  D3237                 \1\0.013              
                                                                                          \1\(0.050)            
Distillation range:                                                                                             
    IBP:  deg.C ( deg.F)..........................................  D86                   23.9-35               
                                                                                          (75-95)               
    10 pct. point:  deg.C ( deg.F)................................  D86                   48.9-57.2             
                                                                                          (120-135)             
    50 pct. point:  deg.C ( deg.F)................................  D86                   93.3-110              
                                                                                          (200-230)             
    90 pct. point:  deg.C ( deg.F)................................  D86                   148.9-162.8           
                                                                                          (300-325)             
    EP: max.  deg.C ( deg.F)......................................  D86                   212.8                 
                                                                                          (415)                 
Sulfur, max. wt. %................................................  D1266                 0.10                  
Phosphorus: max. g/liter (g/U.S. gal.)............................  D3231                 0.0013                
                                                                                          (0.005)               
RVP kPa (psi).....................................................  D323                  55.2-63.4             
                                                                                          (8.0-9.2)             
Hydrocarbon composition:                                                                                        
    Olefins, max., %..............................................  D1319                 10                    
    Aromatics, max., %............................................  D1319                 35                    
    Saturates.....................................................  D1319                 Remainder             
----------------------------------------------------------------------------------------------------------------
\1\Maximum.                                                                                                     

    (2) Unleaded gasoline and engine lubricants representative of 
commercial fuels and engine lubricants which will be generally 
available through retail outlets shall be used in service accumulation.
    (3) The octane rating of the gasoline used shall be no higher than 
4.0 Research octane numbers above the minimum recommended by the 
manufacturer.
    (4) The Reid Vapor Pressure of the gasoline used shall be 
characteristic of commercial gasoline fuel during the season in which 
the service accumulation takes place.
    (b) Methanol fuel. (1) Methanol fuel used for exhaust and 
evaporative emission testing and in service accumulation of methanol-
fueled motorcycles shall be representative of commercially available 
methanol fuel and shall consist of at least 50 percent methanol by 
volume.
    (2) Manufacturers shall recommend the methanol fuel to be used for 
testing and service accumulation in accordance with paragraph (b)(1) of 
this section.
    (3) The Administrator shall determine the methanol fuel to be used 
for testing and service accumulation.
    (4) Other methanol fuels may be used for testing and service 
accumulation provided:
    (i) They are commercially available; and
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Use of a fuel listed under paragraphs (b)(1), (b)(2) or 
(b)(3) of this section would have a detrimental effect on emissions or 
durability; and
    (iv) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (c) Mixtures of petroleum and methanol fuels for flexible fuel 
motorcycles. (1) Mixtures of petroleum and methanol fuels used for 
exhaust and evaporative emission testing and service accumulation for 
flexible fuel motorcycles shall be within the range of fuel mixtures 
for which the motorcycle was designed.
    (2) Manufacturer testing and service accumulation may be performed 
using only those mixtures (mixtures may be different for exhaust 
testing, evaporative testing and service accumulation) expected to 
result in the highest emissions, provided:
    (i) The fuels which constitute the mixture will be used in customer 
service;
    (ii) Information, acceptable to the Administrator, is provided by 
the manufacturer to show that the designated fuel mixtures would result 
in the highest emissions; and
    (iii) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (d) Natural gas-fuel. (1) Natural gas-fuel having the following 
specifications will be used by the Administrator for exhaust and 
evaporative emission testing of natural gas-fueled motorcycles. Natural 
gas-fuel having the following specifications or substantially similar 
specifications approved by the Administrator, shall be used by the 
manufacturer for emission testing. 

                                 Natural Gas Certification Fuel Specifications                                  
----------------------------------------------------------------------------------------------------------------
                                                                                  ASTM test method              
                 Item                                                                    No.            Value   
----------------------------------------------------------------------------------------------------------------
Methane................................  min. mole pct.........................  D1945                      89.0
Ethane.................................  max. mole pct.........................  D1945                       4.5
C3 and higher..........................  max. mole pct.........................  D1945                       2.3
C6 and higher..........................  max. mole pct.........................  D1945                       0.2
Oxygen.................................  max. mole pct.........................  D1945                       0.6
Inert gases:                                                                                                    
    Sum of CO2 and N2..................  max. mole pct.........................  D1945                       4.0
Odorant\1\                                                                                                      
----------------------------------------------------------------------------------------------------------------
\1\The natural gas at ambient conditions must have a distinctive odor potent enough for its presence to be      
  detected down to a concentration in air of not over 1/5 (one-fifth) of the lower limit of flammability.       

    (2) Natural gas-fuel and engine lubricants representative of 
commercial fuels and engine lubricants which will be generally 
available through retail outlets shall be used in service accumulation.
    (3) Other natural gas-fuels may be used for testing and service 
accumulation provided:
    (i) They are commercially available;
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service;
    (iii) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (e) Liquefied petroleum gas-fuel. (1) Liquefied petroleum gas-fuel 
used for exhaust and evaporative emission testing and in service 
accumulation of liquefied petroleum gas-fueled motorcycles shall be 
commercially available liquefied petroleum gas-fuel.
    (2) Manufacturers shall recommend the liquefied petroleum gas-fuel 
to be used for testing and service accumulation in accordance with 
paragraph (e)(1) of this section.
    (3) The Administrator shall determine the liquefied petroleum gas-
fuel to be used for testing and service accumulation.
    (4) Other liquefied petroleum gas-fuels may be used for testing and 
service accumulation provided:
    (i) They are commercially available;
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (f) Lubricants. (1) If the manufacturer specifies several 
lubricants to be used by the ultimate purchaser, the Administrator will 
select one to be used during service accumulation.
    (2) The same lubricant(s) shall be used for both service 
accumulation and emission testing.
    (g) The specification range of the fuels and of the engine 
lubricants to be used under paragraphs (a), (b), (c), (d) and (e) of 
this section shall be reported in accordance with Sec. 86.416.
    (h) Written approval from the Administrator of the fuel and 
lubricant specifications must be provided prior to the start of 
testing.
    71. Section 86.521-90 of subpart F is amended by revising 
paragraphs (b) introductory text, (b)(2) and (c)(3), and adding a new 
paragraph (e), to read as follows:


Sec. 86.521-90  Hydrocarbon analyzer calibration.

* * * * *
    (b) Initial and periodic optimization of detector response. Prior 
to its introduction into service and at least annually thereafter, the 
FID hydrocarbon analyzer shall be adjusted for optimum hydrocarbon 
response. Analyzers used with petroleum fuels and liquefied petroleum 
gas-fuel shall be optimized using propane. Analyzers used with natural 
gas-fuel for measurement of hydrocarbons shall be optimized using 
methane. If a single analyzer is used for all measurements, it shall be 
optimized using propane and its response factor for methane shall be 
determined and accounted for in measurements of total hydrocarbons from 
natural gas-fuel. Alternate methods yielding equivalent results may be 
used, if approved in advance by the Administrator.
* * * * *
    (2) Optimize on the most common operating range. Introduce into the 
analyzer a propane (methane as appropriate) in air mixture (methanol in 
air mixture for methanol-fueled vehicles when optional methanol 
calibrated FID procedure is used during the 1990 through 1994 model 
year) with a propane (or methane or methanol as appropriate) 
concentration equal to approximately 90 percent of the most common 
operating range.
* * * * *
    (c) * * *
    (3) Calibrate on each normally used operating range with propane in 
air (or methanol or methane in air as appropriate) calibration gases 
having nominal concentrations of 15, 30, 45, 60, 75 and 90 percent of 
that range. For each range calibrated, if the deviation from a least 
squares best-fit straight line is two percent or less of the value at 
each data point, concentration values may be calculated by use of a 
single calibration factor for that range. If the deviation exceeds two 
percent at any point, the best-fit non-linear equation which represents 
the data to within two percent of each test point shall be used to 
determine concentration.
* * * * *
    (e) FID response factor to methane. When the FID analyzer is to be 
used for the analysis of natural gas-fueled motorcycle hydrocarbon 
samples, the methane response factor of the analyzer shall be 
established. To determine the total hydrocarbon FID response to 
methane, known methane in air concentrations traceable to National 
Institute of Standards and Technology (NIST) shall be analyzed by the 
FID. Several methane concentrations shall be analyzed by the FID in the 
range of concentrations in the exhaust sample. The total hydrocarbon 
FID response to methane is calculated as follows:
 rCH4 = FIDppm/SAMppm

Where:

(1) rCH4 = FID response factor to methane.
(2) FIDppm = FID reading in ppmC.
(3) SAMppm = the known methane concentration in ppmC.
    72. Section 86.527-90 of subpart F is amended by revising 
paragraphs (a), (c) and (d), to read as follows:


Sec. 86.527-90  Test procedures, overview.

    (a) The procedures described in this and subsequent sections are 
used to determine the conformity of motorcycles with the standards set 
forth in subpart E of this part.
* * * * *
    (c) The exhaust emission test is designed to determine hydrocarbon 
(gasoline-fueled, natural gas-fueled and liquefied petroleum gas-fueled 
motorcycles), methanol, formaldehyde, and hydrocarbon (methanol-fueled 
motorcycles), carbon monoxide and oxides of nitrogen mass emissions 
while simulating an average trip in an urban area. The test consists of 
engine startups and motorcycle operation on a chassis dynamometer, 
through a specified driving schedule. A proportional part of the 
diluted exhaust emissions is collected continuously for subsequent 
analysis, using a constant volume (variable dilution) sampler.
    (d) Except in cases of component malfunction or failure, all 
emission control systems installed on or incorporated in a new 
motorcycle shall be functioning during all procedures in this Subpart. 
Maintenance to correct component malfunction or failure shall be 
authorized in accordance with subpart E of this part.
    73. Section 86.540-90 of subpart F is amended by revising paragraph 
(a) introductory text to read as follows:


Sec. 86.540-90  Exhaust sample analysis.

* * * * *
    (a) For CO, CO2, gasoline-fueled, natural gas-fueled, 
liquefied petroleum gas-fueled and methanol-fueled motorcycle HC and, 
if appropriate, NOX:
* * * * *
    74. Section 86.542-90 of subpart F is amended by adding paragraphs 
(q) and (r), to read as follows:


Sec. 86.542-90  Records required.

* * * * *
    (q) Additional required records for natural gas-fueled vehicles. 
Composition, including all carbon containing compounds; e.g. CO2, 
of the natural gas-fuel used during the test. C1 and C2 
compounds shall be individually reported. C3 and heavier 
hydrocarbons and C6 and heavier compounds may be reported as a 
group.
    (r) Additional required records for liquefied petroleum gas-fueled 
vehicles. Composition of the liquefied petroleum gas-fuel used during 
the test. Each hydrocarbon compound present, through C4 compounds, 
shall be individually reported. C5 and heavier hydrocarbons may be 
reported as a group.
    75. Section 86.544-90 of subpart F is amended by revising 
paragraphs (c)(1)(ii), (c)(1)(v), (c)(1)(ix), (c)(3)(iv)(C) and 
(c)(7)(ii), to read as follows:


Sec. 86.544-90  Calculations; exhaust emissions.

* * * * *
    (c) * * *
    (1) * * *
     (ii) DensityHC=Density of HC in exhaust gas.
     (A) For gasoline-fuel; DensityHC=576.8 g/m3-carbon atom 
(16.33 g/ft3-carbon atom), assuming an average carbon to hydrogen 
ratio of 1:1.85, at 20  deg.C (68  deg.F) and 101.3 kPa (760 mm Hg) 
pressure.
    (B) For natural gas and liquefied petroleum gas-fuel; 
DensityHC=41.57(12.011+H/C(1.008)) g/m3-carbon atom 
(1.1771(12.011+H/C(1.008)) g/ft3-carbon atom) where H/C is the 
hydrogen to carbon ratio of the hydrocarbon components of test fuel, at 
20  deg.C (68  deg.F) and 101.3 kPa (760mm Hg) pressure.
* * * * *
    (v) FID HCe=Concentration of hydrocarbon (plus methanol if 
methanol-fueled motorcycle is tested) in dilute exhaust as measured by 
the FID ppm carbon equivalent.
* * * * *
    (ix) FID HCd=Concentration of hydrocarbon (plus methanol if 
methanol-fueled motorcycle is tested) in dilution air as measured by 
the FID, ppm carbon equivalent.
* * * * *
    (3) * * *
    (iv) * * *
    (C) COe=[1 - (0.01+0.005HCR) CO2e - 0.000323R]COem 
for methanol-fueled, natural gas-fueled or liquefied petroleum gas-
fueled motorcycles, where HCR is hydrogen to carbon ratio as measured 
for the fuel used.
* * * * *
    (7) * * *
For methanol-fueled, natural gas-fueled or liquefied petroleum gas-
fueled motorcycles where fuel composition is CxHyOz as 
measured for the fuel used (for natural gas-fuel and liquefied 
petroleum gas-fuel, Z=0).
* * * * *

TR21SE94.004

    76. Section 86.708-94 of subpart H is amended by revising Tables 
H94-3, H94-4, H94-6 and H94-7 following paragraph (a)(1)(i)(A)(3) to 
read as follows:


Sec. 86.708-94  In-use emission standards for 1994 and later model year 
light duty vehicles.

* * * * *
    (a)(1) * * *
    (i) * * *
    (A) * * *
    (3) * * *
* * * * *

     Table H94-3.--Intermediate Useful Life\1\ Standards (g/mi) for LIght-Duty Vehicles for HCs, CO and NOX     
----------------------------------------------------------------------------------------------------------------
                  Fuel                        Standards       THC     NMHC   OMHCE     OMNMHCE      CO      NOX 
----------------------------------------------------------------------------------------------------------------
Gasoline.................................  Tier 0..........    0.41  ......  ......  ...........     3.4     1.0
Gasoline.................................  Tier 1I.........    0.41    0.32  ......  ...........     3.4     0.4
Gasoline.................................  Tier 1..........    0.41    0.25  ......  ...........     3.4     0.4
Diesel...................................  Tier 0..........    0.41  ......  ......  ...........     3.4     1.0
Diesel...................................  Tier 1I.........    0.41    0.32  ......  ...........     3.4     1.0
Diesel...................................  Tier 1..........    0.41    0.25  ......  ...........     3.4     1.0
Methanol.................................  Tier 0..........  ......  ......    0.41  ...........     3.4     1.0
Methanol.................................  Tier 1I.........  ......  ......    0.41         0.32     3.4     0.4
Methanol.................................  Tier 1..........  ......  ......    0.41         0.25     3.4     0.4
Natural Gas..............................  Tier 0..........  ......    0.34  ......  ...........     3.4     1.0
Natural Gas..............................  Tier 1I.........  ......    0.32  ......  ...........     3.4     0.4
Natural Gas..............................  Tier 1..........  ......    0.25  ......  ...........     3.4     0.4
LPG......................................  Tier 0..........    0.41  ......  ......  ...........     3.4     1.0
LPG......................................  Tier 1I.........    0.41    0.32  ......  ...........     3.4     0.4
LPG......................................  Tier 1..........    0.41    0.25  ......  ...........     3.4    0.4 
----------------------------------------------------------------------------------------------------------------
\1\The applicable useful life is 5 years or 50,000 miles, whichever first occurs.                               


         Table H94-4.--Full Useful Life\1\ Standards (g/mi) for Light-Duty Vehicles for HCs, CO and NOX         
----------------------------------------------------------------------------------------------------------------
                  Fuel                        Standards       THC     NMHC   OMHCE     OMNMHCE      CO      NOX 
----------------------------------------------------------------------------------------------------------------
Gasoline.................................  Tier 0..........  ......  ......  ......  ...........  ......  ......
Gasoline.................................  Tier 1..........  ......    0.31  ......  ...........     4.2    0.60
Diesel...................................  Tier 0..........  ......  ......  ......  ...........  ......  ......
Diesel...................................  Tier 1..........  ......    0.31  ......  ...........     4.2    1.25
Methanol.................................  Tier 0..........  ......  ......  ......  ...........  ......  ......
Methanol.................................  Tier 1..........  ......  ......  ......         0.31     4.2    0.60
Natural Gas..............................  Tier 0..........  ......  ......  ......  ...........  ......  ......
Natural Gas..............................  Tier 1..........  ......    0.31  ......  ...........     4.2    0.60
LPG......................................  Tier 0..........  ......  ......  ......  ...........  ......  ......
LPG......................................  Tier 1..........  ......    0.31  ......  ...........     4.2    0.60
----------------------------------------------------------------------------------------------------------------
\1\The applicable useful life is 10 years or 100,000 miles, whichever first occurs, except that no enforcement  
  testing will be done beyond 7 years or 75,000 miles, whichever first occurs.                                  

* * * * * 

  Table H94-6.--Intermediate Useful Life\1\ Standards (g/mi) for Light- 
                          Duty Vehicles for PM                          
------------------------------------------------------------------------
                     Fuel                           Standards        PM 
------------------------------------------------------------------------
Gasoline.......................................  Tier 0..........  .....
Gasoline.......................................  Tier 1..........   0.08
Diesel.........................................  Tier 0..........   0.20
Diesel.........................................  Tier 1..........   0.08
Methanol.......................................  Tier 0..........  \2\0.
                                                                   20   
Methanol.......................................  Tier 1..........  10.08
Natural Gas....................................  Tier 0..........  \2\0.
                                                                   20   
Natural Gas....................................  Tier 1..........   0.08
LPG............................................  Tier 0..........  \2\0.
                                                                   20   
LPG............................................  Tier 1..........   0.08
------------------------------------------------------------------------
\1\The applicable useful life is 5 years or 50,000 miles, whichever     
  first occurs.                                                         
\2\Applicable only to diesel-cycle vehicles.                            


    Table H94-7.--Full Useful Life\1\ Standards (g/mi) for Light-Duty   
                             Vehicles for PM                            
------------------------------------------------------------------------
                     Fuel                          Standards        PM  
------------------------------------------------------------------------
Gasoline......................................  Tier 0..........  ......
Gasoline......................................  Tier 1..........    0.10
Diesel........................................  Tier 0..........  ......
Diesel........................................  Tier 1..........    0.10
Methanol......................................  Tier 0..........  ......
Methanol......................................  Tier 1..........    0.10
Natural Gas...................................  Tier 0..........  ......
Natural Gas...................................  Tier 1..........    0.10
LPG...........................................  Tier 0..........  ......
LPG...........................................  Tier 1..........   0.10 
------------------------------------------------------------------------
\1\The applicable useful life is 10 years or 100,000 miles, whichever   
  first occurs, except that no enforcement testing will be done beyond 7
  years or 75,000 miles, whichever first occurs.                        

* * * * *
    77. Section 86.708-98 of subpart H is amended by revising Tables 
H98-1 and H98-2 following paragraph (a)(1)(i) to read as follows:


Sec. 86.708-98  In-use emission standards for 1998 and later model year 
light-duty vehicles.

* * * * *
    (a)(1)(i)* * *

               Table H98-1.--Intermediate Useful Life\1\ Standards (g/mi) for Light-Duty Vehicles               
----------------------------------------------------------------------------------------------------------------
                       Fuel                           THC     NMHC   OMHCE     OMNMHCE      CO     NOx      PM  
----------------------------------------------------------------------------------------------------------------
Gasoline...........................................    0.41    0.25  ......  ...........     3.4     0.4    0.08
Diesel.............................................    0.41    0.25  ......  ...........     3.4     1.0    0.08
Methanol...........................................  ......  ......    0.41         0.25     3.4     0.4    0.08
Natural Gas........................................  ......    0.25  ......  ...........     3.4     0.4    0.08
LPG................................................    0.41    0.25  ......  ...........     3.4     0.4    0.08
----------------------------------------------------------------------------------------------------------------
\1\The applicable useful life is 5 years or 50,000 miles, whichever first occurs.                               


                   Table H98-2.--Full Useful Life\1\ Standards (g/mi) for Light-Duty Vehicles                   
----------------------------------------------------------------------------------------------------------------
                       Fuel                           THC     NMHC   OMHCE     OMNMHCE      CO     NOx      PM  
----------------------------------------------------------------------------------------------------------------
Gasoline...........................................  ......    0.31  ......  ...........     4.2     0.6    0.10
Diesel.............................................  ......    0.31  ......  ...........     4.2    1.25    0.10
Methanol...........................................  ......  ......  ......         0.31     4.2     0.6    0.10
Natural Gas........................................  ......    0.31  ......  ...........     4.2     0.6    0.10
LPG................................................  ......    0.31  ......  ...........     4.2     0.6    0.10
----------------------------------------------------------------------------------------------------------------
\1\The applicable useful life is 10 years or 100,000 miles, whichever first occurs, except that no enforcement  
  testing will be done beyond 7 years or 75,000 miles, whichever first occurs.                                  

* * * * *
    78. Section 86.709-94 of subpart H is amended by revising Tables 
H94-9, H94-10, H94-12 and H94-13 following paragraph (a)(1)(i)(A)(3), 
and Tables H94-15, H94-16 and H94-18 following paragraph 
(a)(1)(ii)(A)(2), to read as follows:


Sec. 86.709-94  In-use emission standards for 1994 and later model year 
light-duty trucks.

* * * * *
    (a)(1)* * *
    (i)* * *
    (A)* * *
    (3)* * *
* * * * *

   Table H94-9.--Intermediate Useful Life\1\ Standards (g/mi) for Light Light-Duty Trucks for HCs, CO and NOX   
----------------------------------------------------------------------------------------------------------------
      Fuel          LVW (lbs)     Standards      THC        NMHC      OMHCE     OMNMHCE       CO         NOx    
----------------------------------------------------------------------------------------------------------------
Gasoline.........       0-3750  Tier 0......       0.80  .........  .........  .........        10          1.2 
Gasoline.........       0-3750  Tier 1......       0.80       0.32  .........  .........         5.2        0.4 
Gasoline.........       0-3750  Tier 1......       0.80       0.25  .........  .........         3.4        0.4 
Gasoline.........    3751-5750  Tier 0......       0.80  .........  .........  .........        10          1.7 
Gasoline.........    3751-5750  Tier 11.....       0.80       0.41  .........  .........         6.7        0.7 
Gasoline.........    3751-5750  Tier 1......       0.80       0.32  .........  .........         4.4        0.7 
Diesel...........       0-3750  Tier 0......       0.80  .........  .........  .........        10          1.2 
Diesel...........       0-3750  Tier 11.....       0.80       0.32  .........  .........         5.2        1.2 
Diesel...........       0-3750  Tier 1......       0.80       0.25  .........  .........         3.4        1.0 
Diesel...........    3751-5750  Tier 0......       0.80  .........  .........  .........        10          1.7 
Diesel...........    3751-5750  Tier 11.....       0.80       0.41  .........  .........         6.7        1.7 
Diesel...........    3751-5750  Tier 1......       0.80       0.32  .........  .........         4.4        0.97
Methanol.........       0-3750  Tier 0......  .........  .........       0.80  .........        10          1.2 
Methanol.........       0-3750  Tier 11.....  .........  .........       0.80       0.32         5.2        0.4 
Methanol.........       0-3750  Tier 1......  .........  .........       0.80       0.25         3.4        0.4 
Methanol.........    3751-5750  Tier 0......  .........  .........       0.80  .........        10          1.7 
Methanol.........    3751-5750  Tier 11.....  .........  .........       0.80       0.41         6.7        0.7 
Methanol.........    3751-5750  Tier 1......  .........  .........       0.80       0.32         4.4        0.7 
Natural Gas......       0-3750  Tier 0......  .........       0.67  .........  .........        10          1.2 
Natural Gas......       0-3750  Tier 11.....  .........       0.32  .........  .........         5.2        0.4 
Natural Gas......       0-3750  Tier 1......  .........       0.25  .........  .........         3.4        0.4 
Natural Gas......    3751-5750  Tier 0......  .........       0.67  .........  .........        10          1.7 
Natural Gas......    3751-5750  Tier 11.....  .........       0.41  .........  .........         6.7        0.7 
Natural Gas......    3751-5750  Tier 1......  .........       0.32  .........  .........         4.4        0.7 
LPG..............       0-3750  Tier 0......       0.80  .........  .........         10         1.2            
LPG..............       0-3750  Tier 11.....       0.80       0.32  .........  .........         5.2        0.4 
LPG..............       0-3750  Tier 1......       0.80       0.25  .........  .........         3.4        0.4 
LPG..............    3751-5750  Tier 0......       0.80  .........  .........         10         1.7            
LPG..............    3751-5750  Tier 11.....       0.80       0.41  .........        6.7         0.7            
LPG..............    3751-5750  Tier 1......       0.80       0.32  .........  .........         4.4        0.7 
----------------------------------------------------------------------------------------------------------------
\1\The applicable useful life is 5 years or 50,000 miles, whichever first occurs.                               


                            Table H94-10.--Full Useful Life Standards (g/mi) for Light Light-Duty Trucks for HCs, CO and NOX                            
--------------------------------------------------------------------------------------------------------------------------------------------------------
                        Fuel                           LVW (lbs)     Standards     THC\2\    NMHC\1\    OMHCE\2\    OMNMHCE\1\       CO\1\      NOX\1\  
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gasoline............................................       0-3750  Tier 0......       0.80  .........  .........  ..............        10          1.2 
Gasoline............................................       0-3750  Tier 1......       0.80       0.31  .........  ..............         4.2        0.60
Gasoline............................................    3751-5750  Tier 0......       0.80  .........  .........  ..............        10          1.7 
Gasoline............................................    3751-5750  Tier 1......       0.80       0.40  .........  ..............         5.5        0.97
Diesel..............................................       0-3750  Tier 0......       0.80  .........  .........  ..............        10          1.2 
Diesel..............................................       0-3750  Tier 1......       0.80       0.31  .........  ..............         4.2        1.25
Diesel..............................................    3751-5750  Tier 0......       0.80  .........  .........  ..............        10          1.7 
Diesel..............................................    3751-5750  Tier 1......       0.80       0.40  .........  ..............         5.5        0.97
Methanol............................................       0-3750  Tier 0......  .........  .........       0.80  ..............        10          1.2 
Methanol............................................       0-3750  Tier 1......  .........  .........       0.80            0.31         4.2        0.60
Methanol............................................    3751-5750  Tier 0......  .........  .........       0.80  ..............        10          1.7 
Methanol............................................    3751-5750  Tier 1......  .........  .........       0.80            0.40         5.5        0.97
Natural Gas.........................................       0-3750  Tier 0......       2.93       0.67  .........  ..............        10          1.2 
Natural Gas.........................................       0-3750  Tier 1......       2.93       0.31  .........  ..............         4.2        0.60
Natural Gas.........................................    3751-5750  Tier 0......       2.93       0.67  .........  ..............        10          1.7 
Natural Gas.........................................    3751-5750  Tier 1......       2.93       0.40  .........  ..............         5.5        0.97
LPG.................................................       0-3750  Tier 0......       0.80  .........  .........  ..............        10          1.2 
LPG.................................................       0-3750  Tier 1......       0.80       0.31  .........  ..............         4.2        0.60
LPG.................................................    3751-5750  Tier 0......       0.80  .........  .........  ..............        10          1.7 
LPG.................................................    3751-5750  Tier 1......       0.08       0.40  .........  ..............         5.5        0.97
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\The applicable useful life is 10 years or 100,000 miles, which ever first occurs, except that no enforcement testing will be done beyond 7 years or  
  75,000 miles, whichever first occurs.                                                                                                                 
\2\The applicable useful life is 11 years or 120,000 miles, whichever first occurs.                                                                     

* * * * *

  Table H94-12.--Intermediate Useful Life\1\ Standards (g/mi) for Light 
                        Light-Duty Trucks for PM                        
------------------------------------------------------------------------
              Fuel                 LVW (lbs)      Standards       PM    
------------------------------------------------------------------------
Gasoline........................  0-3750        Tier 0.......  .........
Gasoline........................  0-3750        Tier 1.......       0.08
Gasoline........................  3751-5750     Tier 0.......  .........
Gasoline........................  3751-5750     Tier 1.......       0.08
Diesel..........................  0-3750        Tier 0.......       0.26
Diesel..........................  0-3750        Tier 1.......       0.08
Diesel..........................  3751-5750     Tier 0.......       0.13
Diesel..........................  3751-5750     Tier 1.......       0.08
Methanol........................  0-3750        Tier 0.......  .........
Methanol........................  0-3750        Tier 1.......       0.08
Methanol........................  3751-5750     Tier 0.......  .........
Methanol........................  3751-5750     Tier 1.......       0.08
Natural Gas.....................  0-3750        Tier 0.......    \2\0.26
Natural Gas.....................  0-3750        Tier 1.......       0.08
Natural Gas.....................  3751-5750     Tier 0.......    \2\0.13
Natural Gas.....................  3751-5750     Tier 1.......       0.08
LPG.............................  0-3750        Tier 0.......    \2\0.26
LPG.............................  0-3750        Tier 1.......       0.08
LPG.............................  3751-5750     Tier 0.......    \2\0.13
LPG.............................  3751-5750     Tier 1.......      0.08 
------------------------------------------------------------------------
\1\The applicable useful life is 5 years or 50,000 miles, whichever     
  first occurs.                                                         
\2\Applicable only to diesel-cycle vehicles.                            


Table H94-13.--Full Useful Life\1\ Standards (g/mi) for Light Light-Duty
                             Trucks for PM                              
------------------------------------------------------------------------
              Fuel                 LVW (lbs)     Standards        PM    
------------------------------------------------------------------------
Gasoline.......................  0-3750        Tier 0.......  ..........
Gasoline.......................  0-3750        Tier 1.......        0.10
Gasoline.......................  3751-5750     Tier 0.......  ..........
Gasoline.......................  3751-5750     Tier 1.......        0.10
Diesel.........................  0-3750        Tier 0.......        0.26
Diesel.........................  0-3750        Tier 1.......        0.10
Diesel.........................  3751-5750     Tier 0.......        0.13
Diesel.........................  3751-5750     Tier 1.......        0.10
Methanol.......................  0-3750        Tier 0.......  ..........
Methanol.......................  0-3750        Tier 1.......        0.10
Methanol.......................  3751-5750     Tier 0.......  ..........
Methanol.......................  3751-5750     Tier 1.......        0.10
Natural Gas....................  0-3750        Tier 0.......     \2\0.26
Natural Gas....................  0-3750        Tier 1.......        0.10
Natural Gas....................  3751-5750     Tier 0.......     \2\0.13
Natural Gas....................  3751-5750     Tier 1.......        0.10
LPG............................  0-3750        Tier 0.......     \2\0.26
LPG............................  0-3750        Tier 1.......        0.10
LPG............................  3751-5750     Tier 0.......     \2\0.13
LPG............................  3751-5750     Tier 1.......        0.10 
------------------------------------------------------------------------
\1\The applicable useful life is 10 years or 100,000 miles, whichever   
  first occurs, except that no enforcement testing will be done beyond 7
  years or 75,000 miles, whichever first occurs.                        
\2\Applicable only to diesel-cycle vehicles.                            

* * * * *
    (ii) * * *
    (A) * * *
    (2) * * *
* * * * *

                      Table H94-15.--Intermediate Useful Life\1\ Standards (g/mi)i for Heavy Light-Duty Trucks for HCs, CO and NOX                      
--------------------------------------------------------------------------------------------------------------------------------------------------------
                 Fuel                    LVW (lbs)   ALVW (lbs)   Standards       THC         NMHC        OMHCE      OMNMHCE        CO           NOX    
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gasoline..............................       0-3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.2 
Gasoline..............................       > 3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.7 
Gasoline..............................  ...........    3751-5750  Tier 1I...         0.80         0.40  ..........  ..........         5.5          0.88
Gasoline..............................  ...........    3751-5750  Tier 1....         0.80         0.32  ..........  ..........         4.4          0.7 
Gasoline..............................  ...........       > 5750  Tier 1I...         0.80         0.49  ..........  ..........         6.2          1.38
Gasoline..............................  ...........       > 5750  Tier 1....         0.80         0.39  ..........  ..........         5.0          1.1 
Diesel................................       0-3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.2 
Diesel................................       > 3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.7 
Diesel................................       0-3750    3751-5750  Tier 1I...         0.80         0.40  ..........  ..........         5.5          1.2 
Diesel................................       > 3750    3751-5750  Tier 1I...         0.80         0.40  ..........  ..........         5.5          1.7 
Diesel................................  ...........    3751-5750  Tier 1....         0.80         0.32  ..........  ..........         4.4          0.98
Diesel................................       0-3750       > 5750  Tier 1I...         0.80         0.49  ..........  ..........         6.2          1.2 
Diesel................................       > 3750       > 5750  Tier 1I...         0.80         0.49  ..........  ..........         6.2          1.7 
Diesel................................  ...........       > 5750  Tier 1....         0.80         0.39  ..........  ..........         5.0          1.53
Methanol..............................       0-3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.2 
Methanol..............................       > 3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.7 
Methanol..............................  ...........    3751-5750  Tier 1I...  ...........  ...........        0.80        0.40         5.5          0.88
Methanol..............................  ...........    3751-5750  Tier 1....  ...........  ...........        0.80        0.32         4.4          0.7 
Methanol..............................  ...........       > 5750  Tier 1I...  ...........  ...........        0.80        0.49         6.2          1.38
Methanol..............................  ...........       > 5750  Tier 1....  ...........  ...........        0.80        0.39         5.0          1.1 
Natural Gas...........................       0-3570  ...........  Tier 0....  ...........         0.67  ..........  ..........        10            1.2 
Natural Gas...........................       > 3750  ...........  Tier 0....  ...........         0.67  ..........  ..........        10            1.7 
Natural Gas...........................  ...........    3751-5750  Tier 1I...  ...........         0.40  ..........  ..........         5.5          0.88
Natural Gas...........................  ...........    3751-5750  Tier 1....  ...........         0.32  ..........  ..........         4.4          0.7 
Natural Gas...........................  ...........       > 5750  Tier 1I...  ...........         0.49  ..........  ..........         6.2          1.38
Natural Gas...........................  ...........       > 5750  Tier 1....  ...........         0.39  ..........  ..........         5.0          1.1 
LPG...................................       0-3570  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.2 
LPG...................................       > 3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.7 
LPG...................................  ...........    3751-5750  Tier 1I...         0.80         0.40  ..........  ..........         5.5          0.88
LPG...................................  ...........    3751-5750  Tier 1....         0.80         0.32  ..........  ..........         4.4          0.7 
LPG...................................  ...........       > 5750  Tier 1I...         0.80         0.49  ..........  ..........         6.2          1.38
LPG...................................  ...........       > 5750  Tier 1....         0.80         0.39  ..........  ..........         5.0          1.1 
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\The applicable useful life is 5 years or 50,000 miles, whichever first occurs.                                                                       


                            Table H94-16.--Full Useful Life Standards (g/mi) for Heavy Light-Duty Trucks for HCs, CO and NOX                            
--------------------------------------------------------------------------------------------------------------------------------------------------------
                 Fuel                    LVW (lbs)   ALVW (lbs)   Standards      THC\2\      NMHC\1\     OMHCE\2\   OMNMHCE\1\     CO\1\        NOX\1\  
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gasoline..............................       0-3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.2 
Gasoline..............................       > 3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.7 
Gasoline..............................  ...........    3751-5750  Tier 1....         0.80         0.46  ..........  ..........         6.4          0.98
Gasoline..............................  ...........       > 5750  Tier 1....         0.80         0.56  ..........  ..........         7.3          1.53
Diesel................................       0-3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.2 
Diesel................................       > 3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.7 
Diesel................................  ...........    3751-5750  Tier 1....         0.80         0.46  ..........  ..........         6.4          0.98
Diesel................................  ...........       > 5750  Tier 1....         0.80         0.56  ..........  ..........         7.3          1.53
Methanol..............................       0-3750  ...........  Tier 0....  ...........  ...........        0.80  ..........        10            1.2 
Methanol..............................       > 3750  ...........  Tier 0....  ...........  ...........        0.80  ..........        10            1.7 
Methanol..............................  ...........    3751-5750  Tier 1....  ...........  ...........        0.80        0.46         6.4          0.98
Methanol..............................  ...........       > 5750  Tier 1....  ...........  ...........        0.80        0.56         7.3          1.53
Natural Gas...........................       0-3750  ...........  Tier 0....  ...........         0.67  ..........  ..........        10            1.2 
Natural Gas...........................       > 3750  ...........  Tier 0....  ...........         0.67  ..........  ..........        10            1.7 
Natural Gas...........................  ...........    3751-5750  Tier 1....  ...........         0.46  ..........  ..........         6.4          0.98
Natural Gas...........................  ...........       > 5750  Tier 1....  ...........         0.56  ..........  ..........         7.3          1.53
LPG...................................       0-3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.2 
LPG...................................       > 3750  ...........  Tier 0....         0.80  ...........  ..........  ..........        10            1.7 
LPG...................................  ...........    3751-5750  Tier 1....         0.80         0.46  ..........  ..........         6.4          0.98
LPG...................................  ...........       > 5750  Tier 1....         0.80         0.56  ..........  ..........         7.3          1.53
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\The applicable useful life is 11 years or 120,000 miles, whichever first occurs, except that no enforcement testing will be done beyond 7 years or   
  90,000 miles, whichever first occurs.                                                                                                                 
\2\The applicable useful life is 11 years or 120,000 miles, whichever first occurs.                                                                     

* * * * *

  Table H94-18.--Intermediate Useful Life\1\ Standards (g/mi) for Heavy 
                        Light-Duty Trucks for PM                        
------------------------------------------------------------------------
        Fuel           LVW (lbs)    ALVW (lbs)    Standards        PM   
------------------------------------------------------------------------
Gasoline............       0-3750  ...........  Tier 0.......  .........
Gasoline............       > 3750  ...........  Tier 0.......  .........
Gasoline............  ...........    3751-5750  Tier 1.......       0.10
Gasoline............  ...........       > 5750  Tier 1.......       0.12
Diesel..............       0-3750  ...........  Tier 0.......       0.26
Diesel..............       > 3750  ...........  Tier 0.......       0.13
Diesel..............  ...........    3751-5750  Tier 1.......       0.10
Diesel..............  ...........       > 5750  Tier 1.......       0.12
Methanol............       0-3750  ...........  Tier 0.......  .........
Methanol............       > 3750  ...........  Tier 0.......  .........
Methanol............  ...........    3751-5750  Tier 1.......       0.10
Methanol............  ...........       > 5750  Tier 1.......       0.12
Natural Gas.........       0-3750  ...........  Tier 0.......    \2\0.26
Natural Gas.........       > 3750  ...........  Tier 0.......    \2\0.13
Natural Gas.........  ...........    3751-5750  Tier 1.......       0.10
Natural Gas.........  ...........       > 5750  Tier 1.......       0.12
LPG.................       0-3750  ...........  Tier 0.......    \2\0.26
LPG.................       > 3750  ...........  Tier 0.......    \2\0.13
LPG.................  ...........    3751-5750  Tier 1.......       0.10
LPG.................  ...........       > 5750  Tier 1.......       0.12
------------------------------------------------------------------------
\1\The applicable useful life is 5 years or 50,000 miles, whichever     
  first occurs.                                                         
\2\Applicable only to diesel-cycle vehicles.                            

* * * * *
    79. Section 86.709-99 of subpart H is amended by revising Tables 
H99-1 and H99-2 following paragraph (a)(1)(i)(A), and Tables H99-3 and 
H99-4 following paragraph (a)(1)(ii)(A), to read as follows:


Sec. 86.709-99  In-use emission standards for 1999 and later model year 
light-duty trucks.

* * * * *
    (a)(1)(i)(A) * * *

             Table H99-1.--Intermediate Useful Life\1\ Standards (g/mi) for Light Light-Duty Trucks             
----------------------------------------------------------------------------------------------------------------
        Fuel            LVW (lbs)      THC        NMHC      OMHCE     OMNMHCE       CO         NOX         PM   
----------------------------------------------------------------------------------------------------------------
Gasoline............  0-3750        .........       0.25  .........  .........        3.4        0.4        0.08
Gasoline............  3751-5750     .........       0.32  .........  .........        4.4        0.7        0.08
Diesel..............  0-3750        .........       0.25  .........  .........        3.4        1.0        0.08
Diesel..............  3751-5750     .........       0.32  .........  .........        4.4        0.97       0.08
Methanol............  0-3750        .........  .........  .........       0.25        3.4        0.4        0.08
Methanol............  3751-5750     .........  .........  .........       0.32        4.4        0.7        0.08
Natural Gas.........  0-3750        .........       0.25  .........  .........        3.4        0.4        0.08
Natural Gas.........  3751-5750     .........       0.32  .........  .........        4.4        0.7        0.08
LPG.................  0-3750        .........       0.25  .........  .........        3.4        0.4        0.08
LPG.................  3751-5750     .........       0.32  .........  .........        4.4        0.7        0.08
----------------------------------------------------------------------------------------------------------------
\1\The applicable useful life is 5 years or 50,000 miles, whichever first occurs.                               


                   Table H99-2.--Full Useful Life Standards (g/mi) for Light Light-Duty Trucks                  
----------------------------------------------------------------------------------------------------------------
        Fuel           LVW (lbs)     THC\2\    NMHC\1\    OMHCE\2\  OMNMHCE\1\    CO\1\      NOX\1\      PM\1\  
----------------------------------------------------------------------------------------------------------------
Gasoline...........  0-3750             0.80       0.31  .........  ..........        4.2        0.6        0.10
Gasoline...........  3751-5750          0.80       0.40  .........  ..........        5.5        0.97       0.10
Diesel.............  0-3750             0.80       0.31  .........  ..........        4.2        1.25       0.10
Diesel.............  3751-5750          0.80       0.40  .........  ..........        5.5        0.97       0.10
Methanol...........  0-3750        .........  .........       0.80        0.31        4.2        0.6        0.10
Methanol...........  3751-5750     .........  .........       0.80        0.40        5.5        0.97       0.10
Natural Gas........  0-3750        .........       0.31  .........  ..........        4.2        0.6        0.10
Natural Gas........  3751-5750     .........       0.40  .........  ..........        5.5        0.97       0.10
LPG................  0-3750             0.80       0.31  .........  ..........        4.2        0.6        0.10
LPG................  3751-5750          0.80       0.40  .........  ..........        5.5        0.97       0.10
----------------------------------------------------------------------------------------------------------------
\1\The applicable useful life is 10 yeras or 100,000 miles, whichever first occurs, except that no enforcement  
  testing will be done beyond 7 years or 75,000 miles, whichever first occurs.                                  
\2\The applicable useful life is 11 years or 120,000 miles, whichever first occurs.                             

* * * * *
    (ii)(A) * * *

             Table H99-3.--Intermediate Useful Life\1\ Standards (g/mi) for Heavy Light-Duty Trucks             
----------------------------------------------------------------------------------------------------------------
         Fuel            ALVW (lbs)     THC        NMHC      OMHCE     OMNMHCE       CO        NOX        PM    
----------------------------------------------------------------------------------------------------------------
Gasoline..............    3751-5750       0.80       0.32  .........  .........        4.4        0.7       0.10
Gasoline..............        >5750       0.80       0.39  .........  .........        5.0        1.1       0.12
Diesel................    3751-5750       0.80       0.32  .........  .........        4.4       0.98       0.10
Diesel................        >5750       0.80       0.39  .........  .........        5.0       1.53       0.12
Methanol..............    3751-5750  .........  .........       0.80       0.32        4.4        0.7       0.10
Methanol..............        >5750  .........  .........       0.80       0.39        5.0        1.1       0.12
Natural Gas...........    3751-5750  .........       0.32  .........  .........        4.4        0.7       0.10
Natural Gas...........        >5750  .........       0.39  .........  .........        5.0        1.1       0.12
LPG...................    3751-5750       0.80       0.32  .........  .........        4.4        0.7       0.10
LPG...................        >5750       0.80       0.39  .........  .........        5.0        1.1      0.12 
----------------------------------------------------------------------------------------------------------------
\1\The applicable useful life is 5 years or 50,000 miles, whichever first occurs.                               


                 Table H99-4.--Full Useful Life\1\ Standards (g/mi) for Heavy Light-Duty Trucks                 
----------------------------------------------------------------------------------------------------------------
         Fuel           ALVW (lbs)    THC\2\    NMHC\1\    OMHCE\2\  OMNMHCE\1\    CO\1\      NOX\1\     PM\1\  
----------------------------------------------------------------------------------------------------------------
Gasoline.............    3751-5750       0.80       0.46  .........  ..........        6.4       0.98       0.10
Gasoline.............        >5750       0.80       0.56  .........  ..........        7.3       1.53       0.12
Diesel...............    3751-5750       0.80       0.46  .........  ..........        6.4       0.98       0.10
Diesel...............        >5750       0.80       0.56  .........  ..........        7.3       1.53       0.12
Methanol.............    3751-5750  .........  .........       0.80        0.46        6.4       0.98       0.10
Methanol.............        >5750  .........  .........       0.80        0.56        7.3       1.53       0.12
Natural Gas..........    3751-5750  .........       0.46  .........  ..........        6.4       0.98       0.10
Natural Gas..........        >5750  .........       0.56  .........  ..........        7.3       1.53       0.12
LPG..................    3751-5750       0.80       0.46  .........  ..........        6.4       0.98       0.10
LPG..................        >5750       0.80       0.56  .........  ..........        7.3       1.53      0.12 
----------------------------------------------------------------------------------------------------------------
\1\The applicable useful life is 11 years or 120,000 miles, whichever first occurs, except that no enforcement  
  testing will be done beyond 7 years or 90,000 miles, whichever first occurs.                                  
\2\The applicable useful life is 11 years or 120,000 miles, whichever first occurs.                             

* * * * *
    80a. Section 86.884-1 of subpart I is revised to read as follows:


Sec. 86.884-1  General applicability.

    The provisions of this subpart are applicable to new petroleum-
fueled diesel heavy-duty engines beginning with the 1984 model year, 
methanol-fueled diesel heavy-duty engines beginning with the 1990 model 
year and natural gas-fueled and liquefied petroleum gas-fueled diesel 
heavy-duty engines beginning with the 1997 model year. The provisions 
of this subpart are optional prior to the 1997 model year for natural 
gas-fueled and liquefied petroleum gas-fueled diesel heavy-duty 
engines.


Sec. 86.884-4  [Amended].

    80b. Section 86.884-4 is amended by revising the words ``86.084-
4(a)'' to read ``86.084-4''.
    81. The title of subpart M is revised to read as follows:

Subpart M--Evaporative Emission Test Procedures for New Gasoline-
Fueled, Natural Gas-Fueled, Liquefied Petroleum Gas-Fueled and 
Methanol-Fueled Heavy-Duty Vehicles

    82a. Section 86.1201-90 of subpart M is amended by revising 
paragraph (a) to read as follows:


Sec. 86.1201-90  Applicability.

    (a) The provisions of this subpart are applicable to new gasoline-
fueled, natural gas-fueled, liquefied petroleum gas-fueled and 
methanol-fueled heavy-duty vehicles.
* * * * *
    82b. Section 86.1204 is added to subpart M to read as follows:


Sec. 86.1204  Section numbering.

    The section numbering system set forth in Sec. 86.104 applies to 
this subpart.
    83. Section 86.1205-90 of subpart M is amended by revising 
paragraph (a) to read as follows:


Sec. 86.1205-90  Introduction; structure of subpart.

    (a) This subpart describes the equipment required and the 
procedures to follow in order to determine evaporative emission levels 
from gasoline-fueled, natural gas-fueled, liquefied petroleum gas-
fueled and methanol-fueled heavy-duty vehicles.
* * * * *
    84. Section 86.1206-96 of subpart M is amended by revising the 
introductory text to read as follows:


Sec. 86.1206-96  Equipment required; overview.

    This subpart specifies procedures for testing of gasoline-fueled, 
natural gas-fueled, liquefied petroleum gas-fueled and methanol-fueled 
heavy-duty vehicles. Equipment required and specifications are as 
follows:
* * * * *
    85. Section 86.1207-96 of subpart M is amended by revising 
paragraph (b)(1) to read as follows:


Sec. 86.1207-96  Sampling and analytical systems; evaporative 
emissions.

* * * * *
    (b) * * *
    (1) For gasoline-fueled, liquefied petroleum gas-fueled, natural 
gas-fueled and methanol-fueled vehicles a hydrocarbon analyzer 
utilizing the hydrogen flame ionization principle (FID) shall be used 
to monitor the atmosphere within the enclosure (a heated FID (HFID) 
(235 deg. 15 deg.F (113 8 deg.C)) is required 
for methanol-fueled vehicles). Provided evaporative emission results 
are not affected, a probe may be used to detect or verify hydrocarbon 
sources during a running loss test. Instrument bypass flow may be 
returned to the enclosure. The FID shall have a response time to 90 
percent of final reading of less than 1.5 seconds.
* * * * *
    86. A new section 86.1213-94 is added to subpart M to read as 
follows:


Sec. 86.1213-94  Fuel specifications.

    (a) Gasoline fuel. (1) Gasoline having the following specifications 
will be used in emissions testing for gasoline-fueled vehicles. 

------------------------------------------------------------------------
                                     ASTM test method                   
               Item                        No.               Value      
------------------------------------------------------------------------
Octane, research, min..............  D2699                            93
Sensitivity, min...................  ................                7.5
Lead (organic) g/U.S. gal..........  D3237                      \1\0.050
    (g/liter)......................  ................         \1\(0.013)
Distillation range:                                                     
    IBP  deg.F.....................  D86                           75-95
         ( deg.C)..................  ................          (23.9-35)
    10 pct. point  deg.F...........  D86                         120-135
        ( deg.C)...................  ................        (48.9-57.2)
    50 pct. point  deg.F...........  D86                         200-230
        ( deg.C)...................  ................         (93.3-110)
    90 pct. point  deg.F...........  D86                         300-325
        ( deg.C)...................  ................      (148.9-162.8)
    EP, max.  deg.F................  D86                             415
        ( deg.C)...................  ................            (212.8)
Sulphur, max. wt. pct..............  D1266                          0.10
Phosphorous, max. g/U.S. gal.......  D3231                         0.005
    (g/liter)......................  ................           (0.0013)
RVP, psi...........................  D323                        8.7-9.2
    (kPa)..........................  ................        (60.0-63.4)
Hydrocarbon composition:                                                
    Olefins, max. pct..............  D1319                            10
    Aromatics, max. pct............  D1319                            35
    Saturates......................  D1319                        (\2\) 
------------------------------------------------------------------------
\1\Maximum.                                                             
\2\Remainder.                                                           

    (2) (i) Unleaded gasoline representative of commercial gasoline 
which will be generally available through retail outlets shall be used 
in service accumulation.
    (ii) The octane rating of the gasoline used shall be no higher than 
1.0 Research octane number above the minimum recommended by the 
manufacturer and have a minimum sensitivity of 7.5 octane numbers, 
where sensitivity is defined as the Research octane number minus the 
Motor octane number.
    (iii) The Reid Vapor Pressure of the gasoline used shall be 
characteristic of the motor fuel used during the season in which the 
service accumulation takes place.
    (3) The specification range of the gasoline to be used under 
paragraphs (a)(1) and (a)(2) of this section shall be reported in 
accordance with Sec. 86.094-21(b)(3).
    (b) Methanol fuel. (1) Methanol fuel used in evaporative emission 
testing and in service accumulation of methanol-fueled vehicles shall 
be representative of commercially available methanol fuel and shall 
consist of at least 50 percent methanol (CH3OH) by volume.
    (i) Manufacturers shall recommend the methanol fuel to be used for 
testing and service accumulation.
    (ii) The Administrator shall determine the methanol fuel to be used 
for testing and service accumulation.
    (2) Other methanol fuels may be used for testing and service 
accumulation provided:
    (i) They are commercially available;
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Use of a fuel listed under paragraph (b)(1) of this section 
would have a detrimental effect on emissions or durability; and
    (iv) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (3) The specification range of the methanol fuels to be used under 
paragraphs (b)(1) and (b)(2) of this section shall be reported in 
accordance with Sec. 86.094-21(b)(3).
    (c) Mixtures of petroleum and methanol fuels for flexible fuel 
vehicles. (1) Mixtures of petroleum and methanol fuels used for exhaust 
and evaporative emission testing and service accumulation for flexible 
fuel vehicles shall be within the range of fuel mixtures for which the 
vehicle was designed.
    (2) Manufacturer testing and service accumulation may be performed 
using only those mixtures (mixtures may be different for exhaust 
testing, evaporative testing and service accumulation) expected to 
result in the highest emissions, provided:
    (i) The fuels which constitute the mixture will be used in customer 
service;
    (ii) Information, acceptable to the Administrator, is provided by 
the manufacturer to show that the designated fuel mixtures would result 
in the highest emissions; and
    (iii) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (3) The specification range of the fuels to be used under 
paragraphs (c)(1) and (c)(2) of this section shall be reported in 
accordance with Sec. 86.094-21(b)(3).
    (d) Natural gas fuel. (1) Natural gas fuel having the following 
specifications will be used in evaporative emission testing and in 
service accumulation of natural gas-fueled vehicles shall be 
commercially available natural gas fuel.

              Natural Gas Certification Fuel Specifications             
------------------------------------------------------------------------
                                                 ASTM test              
            Item                                method No.       Value  
------------------------------------------------------------------------
Methane....................  min. mole pct...  D1945                89.0
Ethane.....................  max. mole pct...  D1945                 4.5
C3 and higher..............  max. mole pct...  D1945                 2.3
C6 and higher..............  max. mole pct...  D1945                 0.2
Oxygen.....................  max. mole pct...  D1945                 0.6
Inert gases:                                                            
    Sum of CO2 and N2......  max. mole pct...  D1945                 4.0
Odorant\1\                                                              
------------------------------------------------------------------------
\1\The natural gas at ambient conditions must have a distinctive odor   
  potent enough for its presence to be detected down to a concentration 
  in air of not over \1/5\ (one-fifth) of the lower limit of            
  flammability.                                                         

    (2) Natural gas fuel representative of commercial natural gas which 
will be generally available through retail outlets shall be used in 
service accumulation.
    (3) Other natural gas fuels may be used for emission testing and 
service accumulation provided:
    (i) They are commercially available;
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (4) The specification range of the fuels to be used under 
paragraphs (d)(1), (d)(2) and (d)(3) of this section shall be reported 
in accordance with Sec. 86.094-21(b)(3).
    (e) Liquefied petroleum gas-fuel. (1) Liquefied petroleum gas-fuel 
used in evaporative emission testing and in service accumulation of 
liquefied petroleum gas-fueled vehicles shall be commercially available 
liquefied petroleum gas-fuel.
    (i) Manufacturers shall recommend the liquefied petroleum gas-fuel 
to be used for testing and service accumulation.
    (ii) The Administrator shall determine the liquefied petroleum gas-
fuel to be used for testing and service accumulation.
    (2) Other liquefied petroleum gas fuels may be used for testing and 
service accumulation provided:
    (i) They are commercially available;
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (3) The specification range of the fuels to be used under 
paragraphs (e)(1) and (e)(2) of this section shall be measured in 
accordance with ASTM D2163-91 and reported in accordance with 
Sec. 86.094-21(b)(3).
    87. Section 86.1221-90 of subpart M is amended by revising 
paragraphs (a) introductory text, (a)(2) and (b)(3), and adding 
paragraph (e) to read as follows:


Sec. 86.1221-90  Hydrocarbon analyzer calibration.

* * * * *
    (a) Initial and periodic optimization of detector response. Prior 
to its introduction into service and at least annually thereafter, the 
FID hydrocarbon analyzer shall be adjusted for optimum hydrocarbon 
response. (The HFID used with methanol-fueled vehicles shall be 
operated at 235 deg. 15 deg.F (113 deg. 
8 deg.C)). Analyzers used with gasoline-fuel and liquefied 
petroleum gas-fuel shall be optimized using propane. Analyzers used 
with natural gas-fuel may be optimized using methane, or if calibrated 
using propane the FID response to methane shall be determined and 
applied to the FID hydrocarbon reading. Alternate methods yielding 
equivalent results may be used, if approved in advance by the 
Administrator.
* * * * *
    (2) Optimize on the most common operating range. Introduce into the 
analyzer a propane (or methane as appropriate) in air mixture with a 
propane (or methane as appropriate) concentration equal to 
approximately 90 percent of the most common operating range.
* * * * *
    (b) * * *
    (3) Calibrate on each normally used operating range with propane in 
air (or methane in air as appropriate) calibration gases having nominal 
concentrations of 15, 30, 45, 60, 75 and 90 percent of that range. For 
each range calibrated, if the deviation from a least squares best-fit 
straight line is two percent or less of the value at each data point, 
concentration values may be calculated by use of a single calibration 
factor for that range. If the deviation exceeds two percent at any 
point, the best-fit non-linear equation which represents the data to 
within two percent of each test point shall be used to determine 
concentration.
* * * * *
    (e) FID response factor to methane. When the FID analyzer to be 
used for the analysis of natural gas-fueled vehicle hydrocarbon samples 
has been calibrated using propane, the methane response factor of the 
analyzer shall be established. To determine the total hydrocarbon FID 
response to methane, known methane in air concentrations traceable to 
National Institute of Standards and Technology (NIST) shall be analyzed 
by the FID. Several methane concentrations shall be analyzed by the FID 
in the range of concentrations in the exhaust sample. The total 
hydrocarbon FID response to methane is calculated as follows:
rCH4 = FIDppm/SAMppm

Where:

(1) rCH4 = FID response factor to methane.
(2) FIDppm = FID reading in ppmC.
(3) SAMppm = the known methane concentration in ppmC.
    88. Section 86.1227-96 of subpart M is amended by revising the 
section heading and paragraphs (b) introductory text and (b)(2) to read 
as follows:


Sec. 86.1227-96  Test procedures; overview.

* * * * *
    (b) The evaporative emission test (gasoline-fueled, natural gas-
fueled, liquefied petroleum gas-fueled, and methanol-fueled vehicles) 
is designed to determine hydrocarbon and/or methanol evaporative 
emissions as a consequence of diurnal temperature fluctuation urban 
driving and hot soaks during engine-off periods. It is associated with 
a series of events representative of heavy-duty vehicle operation, 
which result in hydrocarbon and/or methanol vapor losses. The test 
procedure is designed to measure:
* * * * *
    (2) Running losses resulting from a simulated trip on a chassis 
dynamometer, measured by the enclosure or point-source technique (see 
Sec. 86.1234; this test is not required for gaseous-fueled vehicles); 
and
* * * * *
    89. Section 86.1230-96 of subpart M is amended by revising 
paragraphs (a) and (b), to read as follows:


Sec. 86.1230-96  Test sequence; general requirements.

    (a)(1) Gasoline- and methanol-fueled vehicles. The test sequence 
shown in figure M96-1 of this section shows the steps encountered as 
the test vehicle undergoes the procedures subsequently described to 
determine conformity with the standards set forth. The full three-
diurnal sequence depicted in figure M96-1 tests vehicles for all 
sources of evaporative emissions. The supplemental two-diurnal test 
sequence is designed to verify that vehicles sufficiently purge their 
evaporative canisters during the dynamometer run. Sections 86.1232-96, 
86.1233-96 and 86.1238-96 describe the separate specifications of the 
supplemental two-diurnal test sequence.
    (2) Gaseous-fueled vehicles. The test sequence shown in figure M96-
1 of this section shows the steps encountered as the test vehicle 
undergoes the procedures subsequently described to determine conformity 
with the standards set forth, with the exception that the fuel drain 
and fill and precondition canister steps are not required for gaseous-
fueled vehicles. In addition, the supplemental two-diurnal test and the 
running loss test are not required.
    (b) The vehicle test for fuel spitback during fuel dispensing is 
conducted as a stand-alone test (see Sec. 86.1246). This test is not 
required for gaseous-fueled vehicles.
* * * * *
    90. Section 86.1232-96 of subpart M is amended by revising 
paragraphs (b) and (f), to read as follows:


Sec. 86.1232-96  Vehicle preconditioning.

* * * * *
    (b)(1) Gasoline- and methanol-fueled vehicles. Drain the fuel 
tank(s) and fill with test fuel, as specified in Sec. 86.1213, to the 
``tank fuel volume'' defined in Sec. 86.082-2. The fuel cap(s) shall be 
installed within one minute after refueling.
    (2) Gaseous-fueled vehicles. Vehicle fuel tanks are to be filled 
with fuel that meets the specifications in Sec. 86.113. Fuel tanks 
shall be filled to a minimum of 75% of service pressure for natural 
gas-fueled vehicles or a minimum of 75% of available fill volume for 
liquefied petroleum gas-fueled vehicles. Prior draining of the fuel 
tanks is not called for if the fuel in the tanks already meets the 
specifications in Sec. 86.113.
* * * * *
    (f)(1) Gasoline- and methanol-fueled vehicles. Within five minutes 
of completion of the preconditioning drive, the vehicle shall be driven 
off the dynamometer and parked. For gasoline- and methanol-fueled 
vehicles, drain the fuel tank(s) and fill with test fuel, as specified 
in Sec. 86.1213, to the ``tank fuel volume'' defined in Sec. 86.082-2. 
The vehicle shall be refueled within one hour of completion of the 
preconditioning drive. The fuel cap(s) shall be installed within one 
minute after refueling.
    (2) Gaseous-fueled vehicles. Within five minutes of completion of 
the preconditioning drive, the vehicle shall be driven off the 
dynamometer and parked. Vehicle fuel tanks shall be refilled with fuel 
that meets the specifications in Sec. 86.113. Fuel tanks shall be 
filled to a minimum of 75% of service pressure for natural gas-fueled 
vehicles or a minimum of 75% of available fill volume for liquefied 
petroleum gas-fueled vehicles. Prior draining of the fuel tanks is not 
called for if the fuel in the tanks already meets the specifications in 
Sec. 86.113.
* * * * *
    91. Section 86.1233-96 of subpart M is amended by revising 
paragraphs (a)(1) and (a)(3) to read as follows:


Sec. 86.1233-96  Diurnal emission test.

    (a)(1) The diurnal emission test for gasoline-, methanol- and 
gaseous-fueled vehicles consists of three 24-hour test cycles following 
the hot soak test. Emissions are measured for each 24-hour cycle, with 
the highest emission level used to determine compliance with the 
standards specified in subpart A of this part. The Administrator may 
truncate a test after any 24-hour cycle without affecting the validity 
of the collected data. Sampling of emissions from the running loss and 
hot soak tests is not required as preparation for the diurnal emission 
test. The diurnal emission test may be conducted as part of either the 
three-diurnal test sequence or the supplemental two-diurnal test 
sequence, as described in Sec. 86.1230-96.
* * * * *
    (3) For the supplemental two-diurnal test sequence, the diurnal 
emission test outlined in paragraph (p) of this section follows the 
alternate hot soak test specified in Sec. 86.1238-96(k). This test is 
not required for gaseous-fueled vehicles.
* * * * *
    92. Section 86.1234-96 of subpart M is amended by revising 
paragraph (a) to read as follows:


Sec. 86.1234-96  Running loss test.

    (a) Overview. Gasoline- and methanol-fueled vehicles are to be 
tested for running loss emissions during simulated high-temperature 
urban driving; this test is not required for gaseous-fueled vehicles. 
During operation, tank temperatures are controlled according to a 
prescribed profile to simulate in-use conditions. If the vehicle is 
determined to have exceeded the standard before the end of the running 
loss test, the test may be terminated without invalidating the data. 
The test can be run either in a sealed enclosure or with the point-
source method, as specified in paragraph (g) of this section.
* * * * *
    93. Section 86.1238-96 of subpart M is amended by revising 
paragraph (a) to read as follows:


Sec. 86.1238-96  Hot soak test.

    (a)(1) Gasoline- and methanol-fueled vehicles. For gasoline- and 
methanol-fueled vehicles, the hot soak test shall be conducted 
immediately following the running loss test. However, sampling of 
emissions from the running loss test is not required as preparation for 
the hot soak test.
    (2) Gaseous-fueled vehicles. Since gaseous-fueled vehicles are not 
required to perform a running loss test, the hot soak test shall be 
conducted within five minutes of the hot start exhaust test.
* * * * *
    94. Section 86.1242-90 of subpart M is amended by adding new 
paragraphs (m) and (n) to read as follows:


Sec. 86.1242-90  Records required.

* * * * *
    (m) For natural gas-fueled vehicles. Composition, including all 
carbon containing compounds; e.g. CO2, of the natural gas-fuel 
used during the test. C1 and C2 compounds shall be 
individually reported. C3 and heavier hydrocarbons, and C6 
and heavier hydrocarbons may be reported as a group.
    (n) For liquefied petroleum gas-fueled vehicles. Composition of the 
liquefied petroleum gas-fuel used during the test. Each hydrocarbon 
compound present, through C4 compounds, shall be individually 
reported. C5 and heavier hydrocarbons may be reported as a group.
    95. Section 86.1243-96 of subpart M is amended by revising 
paragraphs (a) and (b)(1)(ii)(B) to read as follows:


Sec. 86.1243-90  Calculations; evaporative emissions.

    (a) The following equations are used to calculate the evaporative 
emissions from gasoline- and methanol-fueled vehicles, and for gaseous-
fueled vehicles.
    (b) * * *
    (1) * * *
    (ii) * * *
    (B) CHC=FID hydrocarbon concentration as ppm carbon including 
FID response to methanol (or methane, as applicable) in the sample.
* * * * *
    96. Section 86.1306-90 of subpart N is amended by revising 
paragraph (a) to read as follows:


Sec. 86.1306-90  Equipment required and specifications; overview.

    (a) Exhaust emission tests. All engines subject to this subpart are 
tested for exhaust emissions. Petroleum-fueled, natural gas-fueled, 
liquefied petroleum gas-fueled and methanol-fueled, Otto-cycle and 
diesel engines are tested identically with the exception of the systems 
used to measure hydrocarbon, nitrogen oxide, methanol, formaldehyde and 
particulate; petroleum-fueled diesel engines require a heated, 
continuous hydrocarbon detector and a continuous nitrogen oxide 
detector (Sec. 86.1310); methanol-fueled engines require a heated 
hydrocarbon detector, a methanol detector and a formaldehyde detector; 
either a heated or a non-heated continuous hydrocarbon detector may be 
used with natural gas-fueled and liquefied petroleum gas-fueled diesel 
engines; gasoline-fueled, natural gas-fueled, liquefied petroleum gas-
fueled and methanol-fueled Otto-cycle engines are not tested for 
particulate emissions (Sec. 86.1309). Necessary equipment and 
specifications appear in Secs. 86.1308, 86.1309, 86.1310 and 86.1311.
* * * * *
    97. Section 86.1306-96 of subpart N is amended by revising 
paragraph (a) to read as follows:


Sec. 86.1306-96  Equipment required and specifications; overview.

    (a) Exhaust emission tests. All engines subject to this subpart are 
tested for exhaust emissions. Petroleum-, natural gas-, liquefied 
petroleum gas-, and methanol-fueled Otto-cycle and diesel engines are 
tested identically with two exceptions. First, the systems used to 
measure hydrocarbon, nitrogen oxide, methanol, formaldehyde and 
particulate depend on the type of engine being tested; petroleum-fueled 
diesel engines require a heated, continuous hydrocarbon detector and a 
heated, continuous nitrogen oxide detector (see Sec. 86.1310); 
methanol-fueled engines require a heated hydrocarbon detector, a 
methanol detector and a formaldehyde detector; either a heated or non-
heated continuous hydrocarbon detector may be used with natural gas-
fueled and liquefied petroleum gas-fueled diesel engines; gasoline-
fueled, natural gas- fueled, liquefied petroleum gas-fueled and 
methanol-fueled Otto-cycle engines are not tested for particulate 
emissions (see Sec. 86.1309). Second, if a gasoline-fueled and 
methanol-fueled engine is to be used in a vehicle equipped with an 
evaporative canister, the test engine must have a loaded evaporative 
canister attached for the exhaust emission test. Necessary equipment 
and specifications appear in Secs. 86.1308, 86.1309, 86.1310 and 
86.1311.
* * * * *
    98. Section 86.1309-90 of subpart N is amended by revising the 
section heading and paragraphs (a)(1) and (b)(4) to read as follows:


Sec. 86.1309-90  Exhaust gas sampling system; Otto-cycle engines.

    (a)(1) General. The exhaust gas sampling system described in this 
paragraph is designed to measure the true mass of gaseous emissions in 
the exhaust of either gasoline-fueled, natural gas-fueled, liquefied 
petroleum gas-fueled or methanol-fueled Otto-cycle engines. In the CVS 
concept of measuring mass emissions, two conditions must be satisfied; 
the total volume of the mixture of exhaust and dilution air must be 
measured, and a continuously proportioned volume of sample must be 
collected for analysis. Mass emissions are determined from the sample 
concentration and total flow over the test period.
* * * * *
    (b) * * *
    (4) The flow capacity of the CVS shall be large enough to eliminate 
water condensation in the system. This is especially critical in the 
case of methanol-fueled engines and may also be of concern with natural 
gas- and liquefied petroleum gas-fueled engines; see ``Calculation of 
Emissions and Fuel Economy When Using Alternative Fuels,'' EPA 460/3-
83-009.
* * * * *
    99. Section 86.1310-90 of subpart N is amended by revising the 
section heading and paragraphs (a) introductory text and (a)(2) to read 
as follows:


Sec. 86.1310-90  Exhaust gas sampling and analytical system; and 
methanol-fueled diesel engines.

    (a) General. The exhaust gas sampling system described in this 
paragraph is designed to measure the true mass of both gaseous and 
particulate emissions in the exhaust of petroleum-fueled, natural gas-
fueled, liquefied petroleum gas-fueled and methanol-fueled heavy-duty 
diesel engines. This system utilizes the CVS concept (described in 
Sec. 86.1309) of measuring mass emissions of HC, CH3OH and HCHO 
(methanol-fueled engines), CO, CO2, and particulate from all fuel 
types. A continuously integrated system is required for HC (petroleum-
fueled, natural gas-fueled and liquefied petroleum gas-fueled engines) 
and NOX (petroleum-fueled, natural gas-fueled, liquefied petroleum 
gas-fueled and methanol-fueled engines) measurement, and is allowed for 
all CO and CO2 measurements plus CH3OH, HCHO and HC from 
methanol-fueled engines. The mass of gaseous emissions is determined 
from the sample concentration and total flow over the test period. The 
mass of particulate emissions is determined from a proportional mass 
sample collected on a filter and from the sample flow and total flow 
over the test period. As an option, the measurement of total fuel mass 
consumed over a cycle may be substituted for the exhaust measurement of 
CO2. General requirements are as follows:
* * * * * *
    (2) The HC analytical system for petroleum-fueled diesel engines 
requires a heated flame ionization detector (HFID) and heated sample 
system (375 20 deg.F (191 11 deg.C)). For 
natural gas-fueled and liquefied petroleum gas-fueled diesel engines 
either a heated flame ionization detector and heated sample system as 
required for petroleum fuel or a non-heated flame ionization detector 
may be used.
* * * * * *
    100. A new section 86.1311-94 is added to subpart N to read as 
follows:


Sec. 86.1311-94  Exhaust gas analytical system; CVS bag sample.

    (a) Schematic drawings. Figure N94-1 is a schematic drawing of the 
exhaust gas analytical system used for analyzing CVS bag samples from 
either Otto-cycle or diesel engines. Since various configurations can 
produce accurate results, exact conformance with the drawing is not 
required. Additional components such as instruments, valves, solenoids, 
pumps and switches may be used to provide additional information and 
coordinate the functions of the component systems. Other components 
such as snubbers, which are not needed to maintain accuracy in some 
systems, may be excluded if their exclusion is based upon good 
engineering judgment.
    (b) Major component description. The analytical system, Figure N94-
1, consists of a flame ionization detector (FID) (heated for methanol-
fueled (235 15 deg.F (113 8 deg.C)) and for 
petroleum-fueled diesel (375 10 deg.F (191 
6 deg.C) engines) for the measurement of hydrocarbons, a 
methane analyzer (consisting of a gas chromatograph combined with a 
FID) for the determination of CH4 (for engines subject to NMHC 
standards, where applicable), nondispersive infrared analyzers (NDIR) 
for the measurement of carbon monoxide and carbon dioxide, and a 
chemiluminescence analyzer (CL) for the measurement of oxides of 
nitrogen. The analytical system for methanol consists of a gas 
chromatograph (GC), equipped with a flame ionization detector. The 
analysis for formaldehyde is performed using high pressure liquid 
chromatography (HPLC) of 2,4-dinitrophenylhydrazine (DNPH) derivatives 
using ultraviolet (UV) detection. The exhaust gas analytical system 
shall conform to the following requirements:
    (1) The CL requires that the nitrogen dioxide present in the sample 
be converted to nitric oxide before analysis. Other types of analyzers 
may be used if shown to yield equivalent results and if approved in 
advance by the Administrator.
    (2) The carbon monoxide (NDIR) analyzer may require a sample 
conditioning column containing CaSO4, or desiccating silica gel to 
remove water vapor, and containing ascarite to remove carbon dioxide 
from the CO analysis stream.
    (i) If CO instruments are used which are essentially free of 
CO2 and water vapor interference, the use of the conditioning 
column may be deleted (see Secs. 86.1322 and 86.1342).
    (ii) A CO instrument will be considered to be essentially free of 
CO2 and water vapor interference if its response to a mixture of 
three percent CO2 in N2, which has been bubbled through water 
at room temperature, produces an equivalent CO response, as measured on 
the most sensitive CO range, which is less than one percent of full 
scale CO concentration on ranges above 300 ppm full scale or less than 
3 ppm on ranges below 300 ppm full scale (see Sec. 86.1322).

BILLING CODE 6560-50-P

TR21SE94.000

BILLING CODE 6560-50-C
    (c) Alternate analytical systems. Analysis systems meeting the 
specifications of subpart D of this part may be used for testing 
required under this subpart, with the exception of Secs. 86.346 and 
86.347, provided that the systems in subpart D of this part meet the 
specifications of this subpart. Heated analyzers may be used in their 
heated configuration.
    (d) Other analyzers and equipment. Other types of analyzers and 
equipment may be used if shown to yield equivalent results and if 
approved in advance by the Administrator.
    102. Section 86.1313-94 of subpart N is revised to read as follows:


Sec. 86.1313-94  Fuel specifications.

    (a) Gasoline fuel. (1) Gasoline having the specifications listed in 
Table N94-1 will be used by the Administrator in exhaust emission 
testing. Gasoline having these specifications or substantially 
equivalent specifications approved by the Administrator, shall be used 
by the manufacturer in exhaust emission testing, except that the octane 
specification does not apply.

                               Table N94-1                              
------------------------------------------------------------------------
                  Item                        ASTM            Value     
------------------------------------------------------------------------
Octane, research, min..................  D2699                        93
Sensitivity, min.......................  .............               7.5
Lead (organic), g/U.S. gal. (g/liter)..  D3237                \1\(0.050)
                                                              \1\(0.013)
Distillation range:                                                     
    IBP,  deg.F ( deg.C)...............  D86                       75-95
                                                               (23.9-35)
    10 pct. point,  deg.F ( deg.C).....  D86                     120-135
                                                             (48.9-57.2)
    50 pct. point,  deg.F ( deg.C).....  D86                     200-230
                                                              (93.3-110)
    90 pct. point,  deg.F ( deg.C).....  D86                     300-325
                                                           (148.9-162.8)
    EP, max.  deg.F ( deg.C)...........  D86                         415
                                                                 (212.8)
    Sulphur, Max., wt. pct.............  D1266                      0.10
    Phosphorus, max., g/U.S. gal. (g/    D3231                     0.005
     liter).                                                    (0.0013)
    RVP, psi (kPa).....................  D323                    8.0-9.2
                                                             (60.0-63.4)
Hydrocarbon composition:                                                
    Olefins, max. pct..................  D1319                        10
    Aromatics, max. pct................  D1319                        35
    Saturates..........................  D1319                     (\2\)
------------------------------------------------------------------------
\1\Maximum.                                                             
\2\Remainder.                                                           

    (2)(i) Unleaded gasoline representative of commercial gasoline 
which will be generally available through retail outlets shall be used 
in service accumulation.
    (ii) The octane rating of the gasoline used shall not be higher 
than one Research octane number above the minimum recommended by the 
manufacturer and have a minimum sensitivity of 7.5 octane numbers, 
where sensitivity is defined as the Research octane number minus the 
Motor octane number.
    (iii) The Reid Vapor Pressure of the gasoline used shall be 
characteristic of the motor fuel used during the season in which the 
service accumulation takes place.
    (3) The specification range of the gasoline to be used under 
paragraph (a) of this section shall be reported in accordance with 
Sec. 86.094-21(b)(3).
    (b) Petroleum diesel test fuel. (1) The petroleum fuels for testing 
diesel engines employed for testing shall be clean and bright, with 
pour and cloud points adequate for operability. The petroleum diesel 
fuel may contain nonmetallic additives as follows: Cetane improver, 
metal deactivator, antioxidant, dehazer, antirust, pour depressant, 
dye, dispersant and biocide. Fuels specified for emissions testing are 
intended to be representative of commercially available in-use fuels.
    (2) Petroleum diesel fuel for diesel engines meeting the 
specifications in Table N94-2, or substantially equivalent 
specifications approved by the Administrator, shall be used in exhaust 
emissions testing. The grade of petroleum diesel fuel used shall be 
commercially designated as ``Type 2-D'' grade diesel fuel except that 
fuel commercially designated as ``Type 1-D'' grade diesel fuel may be 
substituted provided that the manufacturer has submitted evidence to 
the Administrator demonstrating to the Administrator's satisfaction 
that this fuel will be the predominant in-use fuel. Such evidence could 
include such things as copies of signed contracts from customers 
indicating the intent to purchase and use ``Type 1-D'' grade diesel 
fuel as the primary fuel for use in the engines or other evidence 
acceptable to the Administrator.

                                                   Table N94-2                                                  
----------------------------------------------------------------------------------------------------------------
                          Item                                 ASTM            Type 1-D            Type 2-D     
----------------------------------------------------------------------------------------------------------------
Cetane Number............................................  D613                        40-54               40-48
Cetane Index.............................................  D976                        40-54               40-48
Distillation range:                                                                                             
    IBP  deg.F ( deg.C)..................................  D86                       330-390             340-400
                                                                               (165.6-198.9)       (171.1-204.4)
    10 pct. point  deg.F ( deg.C)........................  D86                       370-430             400-460
                                                                               (187.8-221.1)       (204.4-237.8)
    50 pct. point  deg.F ( deg.C)........................  D86                       410-480             470-540
                                                                                 (210-248.9)       (243.3-282.2)
    90 pct. point  deg.F ( deg.C)........................  D86                       460-520             560-630
                                                                               (237.8-271.1)       (293.3-332.2)
    EP  deg.F ( deg.C)...................................  D86                       500-560             610-690
                                                                               (260.0-293.3)       (321.1-365.6)
    Gravity  deg.API.....................................  D287                        40-44               32-37
    Total sulfur pct.....................................  D2622                   0.03-0.05           0.03-0.05
Hydrocarbon composition:                                                                                        
    Aromatics, pct.......................................  D1319                        \1\8               \1\27
    Paraffins, Naphthenes, Olefins.......................  D1319                       (\2\)               (\2\)
    Flashpoint, min.,  deg.F ( deg.C)....................  D93                           120                 130
                                                                                      (48.9)              (54.4)
    Viscosity, centistokes...............................  D445                      1.6-2.0             2.0-3.2
----------------------------------------------------------------------------------------------------------------
\1\Maximum.                                                                                                     
\2\Remainder.                                                                                                   

    (3) Petroleum diesel fuel for diesel engines meeting the 
specifications in Table N94-3, or substantially equivalent 
specifications approved by the Administrator, shall be used in service 
accumulation. The grade of petroleum diesel fuel used shall be 
commercially designated as ``Type 2-D'' grade diesel fuel except that 
fuel commercially designated as ``Type 1-D'' grade diesel fuel may be 
substituted provided that the manufacturer has submitted evidence to 
the Administrator demonstrating to the Administrator's satisfaction 
that this fuel will be the predominant in-use fuel. Such evidence could 
include such things as copies of signed contracts from customers 
indicating the intent to purchase and use ``Type 1-D'' grade diesel 
fuel as the primary fuel for use in the engines or other evidence 
acceptable to the Administrator.

                                                  Table N94-3                                                   
----------------------------------------------------------------------------------------------------------------
                          Item                                 ASTM            Type 1-D            Type 2-D     
----------------------------------------------------------------------------------------------------------------
Cetane Number............................................  D613                        40-56               30-58
Cetane Index.............................................  D976                      Min. 40             Min. 40
Distillation range:                                                                                             
    90 pct. point  deg.F ( deg.C)........................  D86                       440-530             540-630
                                                                               (226.7-276.7)       (282.2-332.2)
Gravity  deg.API.........................................  D287                        39-45               30-42
Total sulfur, min. pct...................................  D2622                   0.03-0.05           0.03-0.05
Flashpoint, min.  deg.F ( deg.C).........................  D93                           120                 130
                                                                                      (48.9)                54.4
Viscosity, centistokes...................................  D445                      1.2-2.2             1.5-4.5
----------------------------------------------------------------------------------------------------------------

    (4) Other petroleum distillate fuels may be used for testing and 
service accumulation provided:
    (i) They are commercially available; and
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Use of a fuel listed under paragraphs (b)(2) and (b)(3) of 
this section would have a detrimental effect on emissions or 
durability; and
    (iv) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (5) The specification range of the fuels to be used under paragraph 
(b) of this section shall be reported in accordance with Sec. 86.094-
21(b)(3).
    (c) Methanol-fuel. (1) Methanol fuel used for exhaust and 
evaporative emission testing and in service accumulation of methanol-
fueled engines shall be representative of commercially available 
methanol fuel and shall consist of at least 50 percent methanol by 
volume.
    (i) Manufacturers shall recommend the methanol fuel to be used for 
testing and service accumulation.
    (ii) The Administrator shall determine the methanol fuel to be used 
for testing and service accumulation.
    (2) Other methanol fuels may be used for testing and service 
accumulation provided:
    (i) They are commercially available; and
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Use of a fuel listed under paragraph (b)(4)(c)(1) of this 
section would have a detrimental effect on emissions or durability; and
    (iv) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (3) The specification range of the fuels to be used under 
paragraphs (c)(1) and (c)(2) of this section shall be reported in 
accordance with Sec. 86.094-21(b)(3).
    (d) Mixtures of petroleum and methanol fuels for flexible fuel 
vehicles. (1) Mixtures of petroleum and methanol fuels used for exhaust 
and evaporative emission testing and service accumulation for flexible 
fuel vehicles shall be within the range of fuel mixtures for which the 
vehicle was designed.
    (2) Manufacturer testing and service accumulation may be performed 
using only those mixtures (mixtures may be different for exhaust 
testing, evaporative testing and service accumulation) expected to 
result in the highest emissions, provided:
    (i) The fuels which constitute the mixture will be used in customer 
service;
    (ii) Information, acceptable to the Administrator, is provided by 
the manufacturer to show that the designated fuel mixtures would result 
in the highest emissions; and
    (iii) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (3) The specification range of the fuels to be used under paragraph 
(d)(2) of this section shall be reported in accordance with 
Sec. 86.090-21(b)(3).
    (e) Natural gas-fuel. (1) Natural gas-fuel having the following 
specifications will be used by the Administrator for exhaust and 
evaporative emission testing of natural gas-fueled engines:

                                 Natural Gas Certification Fuel Specifications                                  
----------------------------------------------------------------------------------------------------------------
                                                                                  ASTM test method              
                 Item                                                                   No.             Value   
----------------------------------------------------------------------------------------------------------------
Methane................................  min. mole pct.........................  D1945                      89.0
Ethane.................................  max. mole pct.........................  D1945                       4.5
C3 and higher..........................  max. mole pct.........................  D1945                       2.3
C6 and higher..........................  max. mole pct.........................  D1945                       0.2
Oxygen.................................  max. mole pct.........................  D1945                       0.6
Inert gases:                                                                                                    
  Sum of CO2 and N2....................  max. mole pct.........................  D1945                       4.0
Odorant1                                                                                                        
----------------------------------------------------------------------------------------------------------------
\1\The natural gas at ambient conditions must have a distinctive odor potent enough for its presence to be      
  detected down to a concentration in air of not over \1/5\ (one-fifth) of the lower limit of flammability.     

    (2) Natural gas-fuel representative of commercial natural gas-fuel 
and which will be generally available through retail outlets shall be 
used in service accumulation.
    (3) Other natural gas-fuels may be used for testing and service 
accumulation provided:
    (i) They are commercially available;
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (4) The specification range of the fuels to be used under 
paragraphs (e)(1) and (e)(2) of this section shall be reported in 
accordance with Sec. 86.094-21(b)(3).
    (f) Liquified petroleum gas-fuel. (1) Liquified petroleum gas-fuel 
used for exhaust and evaporative emission testing and in service 
accumulation shall be commercially available liquefied petroleum gas-
fuel.
    (i) Manufacturers shall recommend the liquefied petroleum gas-fuel 
to be used for testing and service accumulation.
    (ii) The Administrator shall determine the liquefied petroleum gas-
fuel to be used for testing and service accumulation.
    (2) Other liquefied petroleum gas-fuels may be used for testing and 
service accumulation provided:
    (i) They are commercially available;
    (ii) Information, acceptable to the Administrator, is provided to 
show that only the designated fuel would be used in customer service; 
and
    (iii) Written approval from the Administrator of the fuel 
specifications must be provided prior to the start of testing.
    (3) The specification range of the fuels to be used under 
paragraphs (f)(1) and (f)(2) of this section shall be measured in 
accordance with ASTM D2163-91 and reported in accordance with 
Sec. 86.094-21(b)(3).
    (g) Fuels not meeting the specifications set forth in this section 
may be used only with the advance approval of the Administrator.
    102. A new section 86.1314-94 is added to subpart N to read as 
follows:


Sec. 86.1314-94  Analytical gases.

    (a) Gases for the CO and CO2 analyzers shall be single blends 
of CO and CO2, respectively, using nitrogen as the diluent.
    (b) Gases for the hydrocarbon analyzer shall be single blends of 
propane using air as the diluent.
    (c) Gases for the methane analyzer shall be single blends of 
methane using air as the diluent.
    (d) Gases for the NOX analyzer shall be single blends of NO 
named as NOX with a maximum NO2 concentration of five percent 
of the nominal value using nitrogen as the diluent.
    (e) Fuel for the FID and the methane analyzer shall be a blend of 
40 2 percent hydrogen with the balance being helium. The 
mixture shall contain less than 1 ppm equivalent carbon response; 98 to 
100 percent hydrogen fuel may be used with advance approval of the 
Administrator.
    (f) The allowable zero gas (air or nitrogen) impurity 
concentrations shall not exceed 1 ppm equivalent carbon response, 1 ppm 
carbon monoxide, 0.04 percent (400 ppm) carbon dioxide and 0.1 ppm 
nitric oxide.
    (g)(1) ``Zero-grade air'' includes artificial ``air'' consisting of 
a blend of nitrogen and oxygen with oxygen concentrations between 18 
and 21 mole percent.
    (2) Calibration gases shall be accurate to within 1 
percent of NBS gas standards, or other gas standards which have been 
approved by the Administrator.
    (3) Span gases shall be accurate to within 2 percent of 
NBS gas standards, or other gas standards which have been approved by 
the Administrator.
    (h) The use of precision blending devices (gas dividers) to obtain 
the required calibration gas concentrations is acceptable, provided 
that the blended gases are accurate to within 1.5 percent 
of NBS gas standards, or other gas standards which have been approved 
by the Administrator. This accuracy implies that primary gases used for 
blending must be ``named'' to an accuracy of at least 1 
percent, traceable to NBS or other approved gas standards.
    103. A new section 86.1316-94 is added to subpart N to read as 
follows:


Sec. 86.1316-94  Calibrations; frequency and overview.

    (a) Calibrations shall be performed as specified in Secs. 86.1318 
through 86.1326.
    (b) At least monthly or after any maintenance which could alter 
calibration, the following calibrations and checks shall be performed:
    (1) Calibrate the hydrocarbon analyzer, methane analyzer, carbon 
dioxide analyzer, carbon monoxide analyzer, oxides of nitrogen 
analyzer, methanol analyzer and formaldehyde analyzer (certain 
analyzers may require more frequent calibration depending on the 
equipment and use).
    (2) Calibrate the engine dynamometer flywheel torque and speed 
measurement transducers, and calculate the feedback signals to the 
cycle verification equipment.
    (3) Check the oxides of nitrogen converter efficiency.
    (c) At least weekly or after any maintenance which could alter 
calibration, the following checks shall be performed:
    (1) Perform a CVS system verification.
    (2) Check the shaft torque feedback signal at steady-state 
conditions by comparing:
    (i) Shaft torque feedback to dynamometer beam load; or
    (ii) By comparing in-line torque to armature current; or
    (iii) By checking the in-line torque meter with a dead weight per 
Sec. 86.1308(e).
    (d) The CVS positive displacement pump or critical flow venturi 
shall be calibrated following initial installation, major maintenance 
or as necessary when indicated by the CVS system verification 
(described in Sec. 86.1319).
    (e) Sample conditioning columns, if used in the CO analyzer train, 
should be checked at a frequency consistent with observed column life 
or when the indicator of the column packing begins to show 
deterioration.
    104. A new section 86.1321-94 is added to subpart N to read as 
follows:


Sec. 86.1321-94  Hydrocarbon analyzer calibration.

    The FID hydrocarbon analyzer shall receive the following initial 
and periodic calibration. The HFID used with petroleum-fueled, natural 
gas-fueled and liquefied petroleum gas-fueled diesel engines shall be 
operated to a set point 10  deg.F (5.5  deg.C) 
between 365 and 385  deg.F (185 and 197  deg.C). The HFID used with 
methanol-fueled engines shall be operated at 235 15  deg.F 
(113 8  deg.C).
    (a) Initial and periodic optimization of detector response. Prior 
to introduction into service and at least annually thereafter, the FID 
hydrocarbon analyzer shall be adjusted for optimum hydrocarbon 
response. Alternate methods yielding equivalent results may be used, if 
approved in advance by the Administrator.
    (1) Follow good engineering practices for initial instrument start-
up and basic operating adjustment using the appropriate fuel (see 
Sec. 86.1314) and zero-grade air.
    (2) Optimize on the most common operating range. Introduce into the 
analyzer a propane-in-air mixture with a propane concentration equal to 
approximately 90 percent of the most common operating range.
    (3) One of the following procedures is required for FID or HFID 
optimization:
    (i) The procedures outlined in Society of Automotive Engineers 
(SAE) paper number 770141, ``Optimization of Flame Ionization Detector 
for Determination of Hydrocarbons in Diluted Automobile Exhaust''; 
author, Glenn D. Reschke. Available from Society of Automotive 
Engineers International, 400 Commonwealth Dr., Warrendale, PA 15096-
0001.
    (ii) The HFID optimization procedures outlined in subpart D of this 
part.
    (iii) Alternative procedures may be used if approved in advance by 
the Administrator.
    (4) After the optimum flow rates have been determined, they are 
recorded for future reference.
    (b) Initial and periodic calibration. Prior to introduction into 
service and monthly thereafter, the FID or HFID hydrocarbon analyzer 
shall be calibrated on all normally used instrument ranges. Use the 
same flow rate and pressures as when analyzing samples. Calibration 
gases shall be introduced directly at the analyzer, unless the 
``overflow'' calibration option of Sec. 86.1310(b)(3)(i) for the HFID 
is taken.
    (1) Adjust analyzer to optimize performance.
    (2) Zero the hydrocarbon analyzer with zero-grade air.
    (3) Calibrate on each used operating range with propane-in-air 
calibration gases having nominal concentrations of 15, 30, 45, 60, 75 
and 90 percent of that range. For each range calibrated, if the 
deviation from a least-squares best-fit straight line is two percent or 
less of the value at each data point, concentration values may be 
calculated by use of a single calibration factor for that range. If the 
deviation exceeds two percent at any point, the best-fit non-linear 
equation which represents the data to within two percent of each test 
point shall be used to determine concentration.
    (c) FID response factor to methanol. When the FID analyzer is to be 
used for the analysis of hydrocarbon samples containing methanol, the 
methanol response factor of the analyzer shall be established. The 
methanol response factor shall be determined at several concentrations 
in the range of concentrations in the exhaust sample.
    (1) The bag sample of methanol for analysis in the FID shall be 
prepared using the apparatus shown in Figure N90-10. A known volume of 
methanol is injected, using a microliter syringe, into the heated 
mixing zone (250  deg.F (121  deg.C)) of the apparatus. The methanol is 
vaporized and swept into the sample bag with a known volume of zero-
grade air measured by a dry gas meter.
    (2) The bag sample is analyzed using the FID.
    (3) The FID response factor, r, is calculated as follows:

r=FIDppm/SAMppm

Where:

(i) r=FID response factor.
(ii) FIDppm=FID reading in ppmC.
(iii) SAMppm=methanol concentration in the sample bag in ppmC.

0.02406 x fuel injected x fuel density=Air volume  x  mol. wt. 
CH3OH

Where:

(iv) 0.02406=volume of one mole at 29.92 in Hg and 68  deg.F, m\3\.
(v) Fuel injected = volume of methanol injected, ml.
(vi) Fuel density=density of methanol, 0.7914 g/ml.
(vii) Air volume=volume of zero-grade air, m3.
(viii) Mol. Wt. CH3OH=32.04.

    (d) FID response factor to methane. When the FID analyzer is to be 
used for the analysis of natural gas-fueled vehicle hydrocarbon 
samples, the methane response factor of the analyzer shall be 
established. To determine the total hydrocarbon FID response to 
methane, known methane in air concentrations traceable to National 
Institute of Standards and Technology (NIST) shall be analyzed by the 
FID. Several methane concentrations shall be analyzed by the FID in the 
range of concentrations in the exhaust sample. The total hydrocarbon 
FID response to methane is calculated as follows:

rCH4=FIDppm/SAMppm

 Where:

(1) rCH4=FID response factor to methane.
(2) FIDppm=FID reading in ppmC.
(3) SAMppm=the known methane concentration in ppmC.

    105. A new section 86.1325-94 is added to subpart N to read as 
follows:


Sec. 86.1325-94  Methane analyzer calibration.

    Prior to introduction into service and monthly thereafter, the 
methane analyzer shall be calibrated:
    (a) Follow the manufacturer's instructions for instrument startup 
and operation. Adjust the analyzer to optimize performance.
    (b) Zero the methane analyzer with zero-grade air.
    (c) Calibrate on each normally used operating range with CH4 
in air with nominal concentrations of 15, 30, 45, 60, 75 and 90 percent 
of that range. Additional calibration points may be generated. For each 
range calibrated, if the deviation from a least-squares best-fit 
straight line is two percent or less of the value at each data point, 
concentration values may be calculated by use of a single calibration 
factor for that range. If the deviation exceeds two percent at any 
point, the best-fit non-linear equation which represents the data to 
within two percent of each test point shall be used to determine 
concentration.
    106. A new section 86.1327-94 is added to subpart N to read as 
follows:


Sec. 86.1327-94  Engine dynamometer test procedures; overview.

     (a) The engine dynamometer test procedure is designed to determine 
the brake specific emissions of hydrocarbons, nonmethane hydrocarbons 
(for natural gas-fueled engines only), carbon monoxide, oxides of 
nitrogen, particulate (petroleum-fueled, natural gas-fueled, liquefied 
petroleum gas-fueled and methanol-fueled diesel engines), and methanol 
and formaldehyde (for methanol-fueled diesel engines). The test 
procedure consists of a ``cold'' start test following either natural or 
forced cool-down periods described in Secs. 86.1334 and 86.1335, 
respectively. A ``hot'' start test follows the ``cold'' start test 
after a hot soak of 20 minutes. The idle test of Subpart P may be run 
after the ``hot'' start test. The exhaust emissions are diluted with 
ambient air and a continuous proportional sample is collected for 
analysis during both the cold- and hot-start tests. The composite 
samples collected are analyzed either in bags or continuously for 
hydrocarbons (HC), methane (CH4--for natural gas-fueled engines 
only), carbon monoxide (CO), carbon dioxide (CO2), and oxides of 
nitrogen (NOX), or in sample collection impingers for methanol 
(CH3OH) and sample collection impingers (or capsules) for 
formaldehyde (HCHO). Measurement of CH3OH and HCHO may be omitted 
for 1990 through 1994 model year methanol-fueled engines when a FID 
calibrated on methanol is used. A bag or continuous sample of the 
dilution air is similarly analyzed for background levels of 
hydrocarbon, methane, carbon monoxide, carbon dioxide and oxides of 
nitrogen and, if appropriate, methanol and formaldehyde. In addition, 
for petroleum-fueled, natural gas-fueled, liquefied petroleum gas-
fueled and methanol-fueled diesel engines, particulates are collected 
on fluorocarbon-coated glass fiber filters or fluorocarbon-based 
(membrane) filters, and the dilution air may be prefiltered.
    (b) Engine torque and rpm shall be recorded continuously during 
both the cold- and hot-start tests. Data points shall be recorded at 
least once every second.
    (c) Using the torque and rpm feedback signals the brake horsepower 
is integrated with respect to time for the cold and hot cycles. This 
produces a brake horsepower-hour value that enables the brake-specific 
emissions to be determined (see Sec. 86.1342, Calculations, gaseous 
exhaust emissions; and Sec. 86.1343, Calculations, particulate exhaust 
emissions).
    (d)(1) When an engine is tested for exhaust emissions or is 
operated for service accumulation on an engine dynamometer, the 
complete engine shall be tested, with all emission control devices 
installed and functioning.
    (2) Evaporative emission controls need not be connected if data are 
provided to show that normal operating conditions are maintained in the 
engine induction system.
    (3) On air-cooled engines, the fan shall be installed.
    (4) Additional accessories (e.g., oil cooler, alternators, air 
compressors, etc.) may be installed or their loading simulated if 
typical of the in-use application.
    (5) The engine may be equipped with a production type starter.
    (e) Means of engine cooling which will maintain the engine 
operating temperatures (e.g., temperatures of intake air, oil, water, 
etc.) at approximately the same temperature as specified by the 
manufacturer shall be used. Auxiliary fan(s) may be used to maintain 
engine cooling during operation on the dynamometer. Rust inhibitors and 
lubrication additives may be used, up to the levels recommended by the 
additive manufacturer. Antifreeze mixtures and other coolants typical 
of those approved for use by the manufacturer may be used.
    (f) Exhaust system. The exhaust system shall meet the following 
requirements:
    (1) Otto-cycle engines. A chassis-type exhaust system shall be 
used. For all catalyst systems, the distance from the exhaust manifold 
flange(s) to the catalyst shall be the same as in the vehicle 
configuration unless the manufacturer provides data showing equivalent 
performance at another location.
    (2) Diesel engines. Either a chassis-type or a facility-type 
exhaust system or both systems simultaneously may be used. The exhaust 
backpressure or restriction shall be typical of those seen in the 
actual average vehicle exhaust system configuration and may be set with 
a valve (muffler omitted).
    (i) The engine exhaust system shall meet the following 
requirements:
    (A) The total length of the tubing from the exit of the engine 
exhaust manifold or turbocharger outlet to the primary dilution tunnel 
should not exceed 32 feet (9.8 m).
    (B) The initial portion of the exhaust system may consist of a 
typical in-use (i.e., length, diameter, material, etc.) chassis-type 
exhaust system.
    (C) The distance from the exhaust manifold flange(s) to any exhaust 
aftertreatment device shall be the same as in the vehicle configuration 
unless the manufacturer is able to demonstrate equivalent performance 
at another location.
    (D) If the exhaust system tubing from the exit of the engine 
exhaust manifold or turbocharger outlet to the primary dilution tunnel 
exceeds 12 feet (3.7 m) in length, then all tubing in excess of 12 feet 
(3.7 m) (chassis and/or facility type) shall be insulated.
    (E) If the tubing is required to be insulated, the radial thickness 
of the insulation must be at least 1.0 inch. The thermal conductivity 
of the insulating material must have a value no greater than 0.75 BTU--
in/hr/ft2/ deg.F measured at 700 deg.F.
    (F) A smoke meter or other instrumentation may be inserted into the 
exhaust system tubing. If this option is exercised in the insulated 
portion of the tubing, then a minimal amount of tubing not to exceed 18 
inches may be left uninsulated. However, no more than 12 feet of tubing 
can be left uninsulated in total, including the length at the smoke 
meter.
    (ii) The facility-type exhaust system shall meet the following 
requirements:
    (A) It must be composed of smooth tubing made of typical in-use 
steel or stainless steel. This tubing shall have a maximum inside 
diameter of 6.0 in (15 cm).
    (B) Short sections (altogether not to exceed 20 percent of the 
entire tube length) of flexible tubing at connection points are 
allowed.
    107. Section 86.1327-96 of subpart N is amended by revising 
paragraphs (a), (f)(1) and (f)(2) introductory text to read as follows:


Sec. 86.1327-96  Engine dynamometer test procedures; overview.

    (a) The engine dynamometer test procedure is designed to determine 
the brake-specific emissions of hydrocarbons, nonmethane hydrocarbons 
(for natural gas-fueled engines only), carbon monoxide, oxides of 
nitrogen, particulate (petroleum-fueled and methanol-fueled diesel 
engines), and methanol and formaldehyde (for methanol-fueled diesel 
engines). The test procedure consists of a ``cold'' start test 
following either natural or forced cool-down periods described in 
Secs. 86.1334 and 86.1335, respectively. A ``hot'' start test follows 
the ``cold'' start test after a hot soak of 20 minutes. The idle test 
of subpart P of this part may be run after the ``hot'' start test. The 
exhaust emissions are diluted with ambient air and a continuous 
proportional sample is collected for analysis during both the cold- and 
hot-start tests. The composite samples collected are analyzed either in 
bags or continuously for hydrocarbons (HC), methane (CH4--natural 
gas-fueled engines only), carbon monoxide (CO), carbon dioxide 
(CO2), and oxides of nitrogen (NOX), or in sample collection 
impingers for methanol (CH3OH) and sample collection impingers (or 
capsules) for formaldehyde (HCHO). A bag or continuous sample of the 
dilution air is similarly analyzed for background levels of 
hydrocarbon, carbon monoxide, carbon dioxide and oxides of nitrogen 
and, if appropriate, methane, or methanol and formaldehyde. In 
addition, for petroleum-fueled, natural gas-fueled, liquefied petroleum 
gas-fueled and methanol-fueled diesel engines, particulates are 
collected on fluorocarbon-coated glass fiber filters or fluorocarbon-
based (membrane) filters, and the dilution air may be prefiltered.
* * * * *
    (f) * * *
    (1) Otto-cycle engines. A chassis-type exhaust system shall be 
used. For all catalyst systems, the distance from the exhaust manifold 
flange(s) to the catalyst shall be the same as in the vehicle 
configuration unless the manufacturer provides data showing equivalent 
performance at another location.
    (2) Diesel engines. Either a chassis-type or a facility-type 
exhaust system or both systems simultaneously may be used. The exhaust 
back pressure or restriction shall be typical of those seen in the 
actual average vehicle exhaust system configuration and may be set with 
a valve (muffler omitted).
* * * * *
    108. Section 86.1332-90 of subpart N is amended by revising 
paragraphs (c)(1) heading, (c)(2) heading, (d)(2) heading, (d)(3) 
heading, (e)(1) heading and (e)(2) heading to read as follows:


Sec. 86.1332-90  Engine mapping procedures.

* * * * *
    (c) * * *
    (1) Otto-cycle engines.
* * * * *
    (2) Diesel engines.
* * * * *
    (d) * * *
    (2) Otto-cycle engines.
* * * * *
    (3) Diesel engines.
* * * * *
    (e) * * *
    (1) Otto-cycle engines.
* * * * *
    (2) Diesel engines.
* * * * *
    109. Section 86.1336-84 of subpart N is amended by revising 
paragraph (e)(2) heading to read as follows:


Sec. 86.1336-84  Engine starting, restarting, and shutdown.

* * * * *
    (e) * * *
    (2) Diesel-fueled, natural gas-fueled and liquefied petroleum gas-
fueled engines.
* * * * *
    110. Section 86.1337-90 of subpart N is amended by revising 
paragraphs (a)(7), (a)(8), (a)(13), (a)(20) and (a)(26) to read as 
follows:


Sec. 86.1337-90  Engine dynamometer test run.

    (a) * * *
    (7) For diesel engines tested for particulate emissions, carefully 
install a clean particulate sample filter into each of the filter 
holders and install the assembled filter holders in the sample flow 
line (filter holders may be preassembled).
    (8) Follow the manufacturers choke and throttle instructions for 
cold starting. Simultaneously start the engine and begin exhaust and 
dilution air sampling. For petroleum-fueled diesel engines (and natural 
gas-fueled, liquified petroleum gas-fueled or methanol-fueled diesels, 
if used), turn on the hydrocarbon and NOX (and CO and CO2, if 
continuous) analyzer system integrators (if used), and turn on the 
particulate sample pumps and indicate the start of the test on the data 
collection medium.
* * * * *
    (13) Immediately after the engine is turned off, turn off the 
engine cooling fan(s) if used, and the CVS blower (or disconnect the 
exhaust system from the CVS). As soon as possible, transfer the ``cold 
start cycle'' exhaust and dilution air bag samples according to 
Sec. 86.1340. A stabilized reading of the exhaust sample on all 
analyzers shall be obtained within 20 minutes of the end of the sample 
collection phase of the test. Analysis of the methanol and formaldehyde 
samples shall be obtained within 24 hours of the end of the sample 
collection period. For diesel engines tested for particulate, carefully 
remove the filter holder from the sample flow apparatus, remove each 
particulate sample filter from its holder and place each in a petri 
dish and cover.
* * * * *
    (20) For diesel engines tested for particulate, carefully install a 
clean particulate filter in each of the filter holders and install 
assembled filter holders in the sample flow line (filter holders may be 
preassembled).
* * * * *
    (26) As soon as possible, transfer the ``hot start cycle'' exhaust 
and dilution air bag samples to the analytical system and process the 
samples according to Sec. 86.1340. A stabilized reading of the exhaust 
sample on all analyzers shall be obtained within 20 minutes of the end 
of the sample collection phase of the test. Analyze the methanol and 
formaldehyde samples within 24 hours. (If it is not possible to perform 
analysis within 24 hours, the samples should be stored in a cold 
(approximately 0 deg.C) dark environment until analysis can be 
performed). For diesel engines tested for particulate, carefully remove 
the assembled filter holder from the sample flow lines and remove each 
particulate sample filter from its holder and place in a clean petri 
dish and cover as soon as possible. Within one hour after the end of 
the hot start phase of the test, transfer the four particulate filters 
to the weighing chamber for post-test conditioning.
* * * * *
    111. Section 86.1337-96 of subpart N is amended by revising 
paragraphs (a)(7), (a)(8), (a)(13), (a)(20) and (a)(26) to read as 
follows:


Sec. 86.1337-96  Engine dynamometer test run.

    (a) * * *
    (7) For diesel engines tested for particulate emissions, carefully 
install a clean particulate sample filter into each of the filter 
holders and install the assembled filter holders in the sample flow 
line (filter holders may be preassembled).
    (8) Follow the manufacturer's choke and throttle instructions for 
cold starting. Simultaneously start the engine and begin exhaust and 
dilution air sampling. For petroleum-fueled diesel engines (and natural 
gas-fueled, liquified petroleum gas-fueled or methanol-fueled diesels, 
if used) turn on the hydrocarbon and NOX (and CO and CO2, if 
continuous) analyzer system integrators (if used), and turn on the 
particulate sample pumps and indicate the start of the test on the data 
collection medium.
* * * * *
    (13) Immediately after the engine is turned off, turn off the 
engine cooling fan(s) if used, and the CVS blower (or disconnect the 
exhaust system from the CVS). As soon as possible, transfer the ``cold 
start cycle'' exhaust and dilution air bag samples according to 
Sec. 86.1340. A stabilized reading of the exhaust sample on all 
analyzers shall be obtained within 20 minutes of the end of the sample 
collection phase of the test. Analysis of the methanol and formaldehyde 
samples shall be obtained within 24 hours of the end of the sample 
collection period. For diesel engines tested for particulate, carefully 
remove the filter holder from the sample flow apparatus, remove each 
particulate sample filter from its holder and place each in a petri 
dish and cover.
* * * * *
    (20) For diesel engines tested for particulate, carefully install a 
clean particulate filter in each of the filter holders and install 
assembled filter holders in the sample flow line (filter holders may be 
preassembled).
* * * * *
    (26) As soon as possible, transfer the ``hot start cycle'' exhaust 
and dilution air bag samples to the analytical system and process the 
samples according to Sec. 86.1340. A stabilized reading of the exhaust 
sample on all analyzers shall be obtained within 20 minutes of the end 
of the sample collection phase of the test. Analyze the methanol and 
formaldehyde samples within 24 hours. (If it is not possible to perform 
analysis within 24 hours, the samples should be stored in a cold 
(approximately 0 deg.C) dark environment until analysis can be 
performed). For diesel engines tested for particulate, carefully remove 
the assembled filter holder from the sample flow lines, remove each 
particulate sample filter from its holder, place in a clean petri dish 
and cover as soon as possible. Within one hour after the end of the hot 
start phase of the test, transfer the four particulate filters to the 
weighing chamber for post-test conditioning.
* * * * *
    112. A new section 86.1340-94 is added to subpart N to read as 
follows:


Sec. 86.1340-94  Exhaust sample analysis.

    Section 86.1340-94 includes text that specifies requirements that 
differ from Sec. 86.1340-90. Where a paragraph in Sec. 86.1340-90 is 
identical and applicable to Sec. 86.1340-94, this may be indicated by 
specifying the corresponding paragraph and the statement ``[Reserved]. 
For guidance see Sec. 86.1340-90.''
    (a) through (d)(6) [Reserved]. For guidance see Sec. 86.1340-90.
    (d)(7) Measure HC (except diesels), CH4 (natural gas-fueled 
engines only), CO, CO2, and NOX sample bag(s) with 
approximately the same flow rates and pressures used in Sec. 86.1340-
90(d)(3). (Constituents measured continuously do not require bag 
analysis.)
    (d)(8) through (h)(2) [Reserved]. For guidance see Sec. 86.1340-90.
    113. A new section 86.1342-94 is added to subpart N to read as 
follows:


Sec. 86.1342-94  Calculations; exhaust emissions.

    Section 86.1342-94 includes text that specifies requirements that 
differ from Sec. 86.1342-90. Where a paragraph in Sec. 86.1342-90 is 
identical and applicable to Sec. 86.1342-94, this may be indicated by 
specifying the corresponding paragraph and the statement ``[Reserved]. 
For guidance see Sec. 86.1342-90.''
    (a) introductory text [Reserved]. For guidance see Sec. 86.1342-90.
    (a)(1) AWM = Weighted mass emission level (HC, CO, CO2 or 
NOX) in grams per brake horsepower-hour and, if appropriate, the 
weighted mass organic material hydrocarbon equivalent or non-methane 
hydrocarbon, in grams per brake horsepower-hour.
    (a)(2) through (b)(7) [Reserved]. For guidance see Sec. 86.1342-90.
    (b)(8) Non-methane hydrocarbon mass:

NMHCmass = Vmix  x  DensityNMHC  x  (NMHCconc/
1,000,000)

    (c) through (d)(1)(i) [Reserved]. For guidance see Sec. 86.1342-90.
    (d)(1)(ii) DensityHC = Density of hydrocarbons.
    (A) For gasoline and the gasoline fraction of methanol-fuel, and 
may be used for petroleum and the petroleum fraction of methanol diesel 
fuel if desired; 16.33 g/ft\3\-carbon atom (0.5768 kg/m\3\-carbon 
atom).
    (B) For #1 petroleum diesel fuel; 16.42 g/ft\3\-carbon atom (0.5800 
kg/m\3\-carbon atom).
    (C) For #2 diesel 16.27 g/ft\3\-carbon atom (0.5746 kg/m\3\-carbon 
atom). Average carbon to hydrogen ratios of 1:1.85 for gasoline, 1:1.93 
for #1 petroleum diesel fuel and 1:1.80 for #2 petroleum diesel fuel 
are assumed at 68  deg.F (20  deg.C) and 760 mm Hg (101.3 kPa) 
pressure.
    (D) For natural gas and liquified petroleum gas-fuel; 1.1771 
(12.011+H/C (1.008)) g/ft\3\-carbon atom (0.04157 (12.011+H/C (1.008)) 
kg/m\3\-carbon atom) where H/C is hydrogen to carbon ratio of the 
hydrocarbon components of the test fuel, at 68  deg.F (20  deg.C) and 
760 mm Hg (101.3 kPa) pressure.
    (d)(1)(iii) through (d)(1)(iv)(A) [Reserved]. For guidance see 
Sec. 86.1342-90.
    (d)(1)(iv)(B) For petroleum-fueled, natural gas-fueled and 
liquified petroleum gas-fueled engines, HCe is the FID 
measurement.
    (d)(1)(iv)(C) through (d)(3)(v)(A) [Reserved]. For guidance see 
Sec. 86.1342-90.
    (d)(3)(v)(B) COe = [1 - (0.01 + 0.005HCR) CO2e - 
0.000323R] COem for methanol-fuel, natural gas-fuel and liquified 
petroleum gas-fuel where HCR is hydrogen to carbon ratio as measured 
for the fuel used.

Where:

    (d)(3)(vi) through (d)(7)(ii) [Reserved]. For guidance see 
Sec. 86.1342-90.

For natural gas-fueled or liquefied petroleum gas-fueled vehicles where 
fuel composition is CxHy as measured for the fuel used.

    (d)(8)(i) [Reserved]. For guidance see Sec. 86.1342-90.
    (d)(8)(ii) Otto-cycle engines: KH = 1/[1-0.0047 (H-75)] (or 
for SI units, KH = 1/[1-0.0329(H-10.71)]).

TR21SE94.005

      
    (iii) For diesel engines: KH = 1/[1-0.0026 (H-75)] (or for SI 
units = 1/[1-0.0182 (H-10.71)]).

Where:

    (d)(8)(iv) through (d)(9)(x) [Reserved]. For guidance see 
Sec. 86.1342-90.
    (d)(10)(i) NMHCconc = HCconc-CH4conc
    (ii) DensityNMHC = The density of non-methane hydrocarbon, is 
1.1771(12.011 + H/C (1.008)) g/ft\3\-carbon atom (0.04157(12.011 + H/C 
(1.008))kg/m\3\-carbon atom), where H/C is the hydrogen to carbon ratio 
of the non-methane hydrocarbon components of the test fuel, at 68 
deg.F (20  deg.C) and 760 mm Hg (101.3 kPa) pressure.
    (iii)(A) CH4conc = Methane concentration of the dilute exhaust 
sample corrected for background, in ppm carbon equivalent.
    (B) CH4conc = rCH4  x  (CH4e-CH4d(1-1/DF))

Where:

    (1) CH4e = Methane exhaust bag concentration in ppm carbon 
equivalent.
    (2) CH4d = Methane concentration of the dilution air in ppm 
carbon equivalent.
    (3) rCH4 = HC FID response to methane for natural gas-fueled 
vehicles as measured in Sec. 86.1321 (d).
    (e) through (h)(2)(vii) [Reserved]. For guidance see Sec. 86.1342-
90.
    114. A new section 86.1344-94 is added to subpart N to read as 
follows:


Sec. 86.1344-94  Required information.

    (a) The required test data shall be grouped into the following 
three general categories:
    (1) Engine set up and descriptive data. These data must be provided 
to the EPA supervisor of engine testing for each engine sent to the 
Administrator for confirmatory testing prior to the initiation of 
engine set-up. These data are necessary to ensure that EPA test 
personnel have the correct data in order to set up and test the engine 
in a timely and proper manner. These data are not required for tests 
performed by the manufacturers.
    (2) Pre-test data. These data are general test data that must be 
recorded for each test. The data are of a more descriptive nature such 
as identification of the test engine, test site number, etc. As such, 
these data can be recorded at any time within 24 hours of the test.
    (3) Test data. These data are physical test data that must be 
recorded at the time of testing.
    (b) When requested, data shall be supplied in the format specified 
by the Administrator.
    (c) Engine set-up data. Because specific test facilities may change 
with time, the specific data parameters and number of items may vary. 
The Application Format for Certification for the applicable model year 
will specify the exact requirements. In general, the following types of 
data will be required:
    (1) Engine manufacturer.
    (2) Engine system combination.
    (3) Engine code and CID.
    (4) Engine identification number.
    (5) Applicable engine model year.
    (6) Engine fuel type.
    (7) Recommended oil type.
    (8) Exhaust pipe configuration, pipe sizes, etc.
    (9) Curb or low idle speed.
    (10) Dynamometer idle speed (automatic transmission engines only).
    (11) Engine parameter specifications such as spark timing, 
operating temperature, advance curves, etc.
    (12) Engine performance data, such as maximum BHP, previously 
measured rated rpm, fuel consumption, governed speed, etc.
    (13) Recommended start-up procedure.
    (14) Maximum safe engine operating speed.
    (15) Number of hours of operation accumulated on engine.
    (16) Manufacturer's recommended inlet depression limit and typical 
in-use inlet depression level.
    (17) Exhaust system:
    (i) Diesel engines:
    (A) Header pipe inside diameter.
    (B) Tailpipe inside diameter.
    (C) Minimum distance in-use between the exhaust manifold flange and 
the exit of the chassis exhaust system.
    (D) Manufacturer's recommended maximum exhaust backpressure limit 
for the engine.
    (E) Typical backpressure, as determined by typical application of 
the engine.
    (F) Minimum backpressure required to meet applicable noise 
regulations.
    (ii) Otto-cycle engines: Typical in-use backpressure in vehicle 
exhaust system.
    (d) Pre-test data. The following data shall be recorded and 
reported to the Administrator for each test conducted for compliance 
with the provisions of subpart A of this part:
    (1) Engine-system combination.
    (2) Engine identification.
    (3) Instrument operator(s).
    (4) Engine operator(s).
    (5) Number of hours of operation accumulated on the engine prior to 
beginning the test sequence (Figure N84-10).
    (6) Identification and specifications of test fuel used.
    (7) Date of most recent analytical assembly calibration.
    (8) All pertinent instrument information such as tuning, gain, 
serial numbers, detector number, calibration curve number, etc. As long 
as this information is traceable, it may be summarized by system or 
analyzer identification numbers.
    (e) Test data. The physical parameters necessary to compute the 
test results and ensure accuracy of the results shall be recorded for 
each test conducted for compliance with the provisions of subpart A of 
this part. Additional test data may be recorded at the discretion of 
the manufacturer. Extreme details of the test measurements such as 
analyzer chart deflections will generally not be required on a routine 
basis to be reported to the Administrator for each test, unless a 
dispute about the accuracy of the data arises. The following types of 
data shall be required to be reported to the Administrator. The 
Application Format for Certification for the applicable model year will 
specify the exact requirements which may change slightly from year to 
year with the addition or deletion of certain items.
    (1) Date and time of day.
    (2) Test number.
    (3) Engine intake air or test cell temperature.
    (4) Barometric pressure. (A central laboratory barometer may be 
used: Provided, that individual test cell barometric pressures are 
shown to be within 0.1 percent of the barometric pressure 
at the central barometer location.)
    (5) Engine intake or test cell and CVS dilution air humidity.
    (6) Maximum torque versus speed curve as determined in 
Sec. 86.1332, with minimum and maximum engine speeds, and a description 
of the mapping technique used.
    (7) Measured maximum horsepower and maximum torque speeds.
    (8) Measured maximum horsepower and torque.
    (9) Measured high idle engine speed (governed diesel engines only).
    (10) Measured fuel consumption at maximum power and torque (diesel 
engines only).
    (11) Cold-soak time interval and cool down procedures.
    (12) Temperature set point of the heated continuous analysis system 
components (if applicable).
    (13) Test cycle validation statistics as specified in Sec. 86.1341 
for each test phase (cold and hot).
    (14) Total CVS flow rate with dilution factor for each test phase 
(cold and hot).
    (15) Temperature of the dilute exhaust mixture and secondary 
dilution air (in the case of a double dilution system) at the inlet to 
the respective gas meter(s) or flow instrumentation used for 
particulate sampling.
    (16) The maximum temperature of the dilute exhaust mixture 
immediately ahead of the particulate filter.
    (17) Sample concentrations (background corrected) for HC, CO, 
CO2 and NOX for each test phase (cold and hot).
    (18) For methanol-fueled engines:
    (i) Volume of sample passed through the methanol sampling system 
and the volume of deionized water in each impinger.
    (ii) The methanol concentration in the reference sample and the 
peak area from the GC analysis of the reference sample.
    (iii) The peak area of the GC analyses of the test samples 
(methanol).
    (iv) Volume of sample passed through the formaldehyde sampling 
system.
    (v) The formaldehyde concentration in the reference sample and the 
peak area from the LC analysis of the reference sample.
    (vi) The peak area of the LC analysis of the test sample 
(formaldehyde).
    (vii) Specification of the methanol-fuel used during testing.
    (19) For natural gas-fueled engines: Composition, including all 
carbon containing compounds; e.g., CO2, of the natural gas-fuel 
used during the test. C1 and C2 compounds shall be 
individually reported. C3 and heavier compounds, and C6 and 
heavier compounds may be reported as a group.
    (20) For liquefied petroleum gas-fueled engines: Composition of the 
liquefied petroleum gas-fuel used during the test. Each hydrocarbon 
compound present, through C4 compounds, shall be individually 
reported. C5 and heavier hydrocarbons may be reported as a group.
    (21) The stabilized pre-test weight and post-test weight of each 
particulate sample and back-up filter or pair of filters.
    (22) Brake specific emissions (g/BHP-hr) for HC, CO, NOX and, 
if applicable, OMHCE, CH3OH and HCHO for methanol-fueled vehicles 
for each test phase (cold and hot).
    (23) The weighted (cold and hot) brake specific emissions (g/BHP-
hr) for the total test.
    (24) The weighted (cold and hot) carbon balance or mass-measured 
brake specific fuel consumption for the total test.
    (25) The number of hours of operation accumulated on the engine 
after completing the test sequences described in Figure N84-10.
    115. The title of subpart P is revised to read as follows:

Subpart P--Emission Regulations for New Gasoline-Fueled, Natural 
Gas-Fueled, Liquefied Petroleum Gas-Fueled and Methanol-Fueled 
Heavy-Duty Engines and New Gasoline-Fueled, Natural Gas-Fueled, 
Liquefied Petroleum Gas-Fueled and Methanol-Fueled Light-Duty 
Trucks; Idle Test Procedures

    116. A new section 86.1501-94 is added to subpart P to read as 
follows:


Sec. 86.1501-94  Scope; applicability.

    This subpart contains gaseous emission idle test procedures for 
gasoline-fueled, natural gas-fueled, liquefied petroleum gas-fueled and 
methanol-fueled Otto-cycle heavy-duty engines, and for gasoline-fueled, 
natural gas-fueled, liquefied petroleum gas-fueled and methanol-fueled 
Otto-cycle light-duty trucks. It applies to 1994 and later model years. 
The idle test procedures are optionally applicable to 1990 through 1993 
model year natural-gas fueled and liquefied petroleum gas-fueled Otto-
cycle heavy-duty engines and Otto-cycle light-duty trucks.
    117. A new section 86.1504-94 is added to subpart P to read as 
follows:


Sec. 86.1504-94  Section numbering; construction.

    (a) The model year of initial applicability is indicated by the 
section number. The two digits following the hyphen designate the first 
model year for which a section is effective. A section remains 
effective until superseded.

    Example: Section 86.1511-84 applies to the 1984 and subsequent 
model years until superseded. If Sec. 86.1511-85 is promulgated, it 
would take effect beginning with the 1985 model year. Section 
86.1511-83 would apply to model years 1983 and 1984.

    (b) A section reference without a model year suffix refers to the 
section applicable for the appropriate model year.
    (c) All provisions in the subpart apply to gasoline-fueled, natural 
gas-fueled, liquefied petroleum gas-fueled and methanol-fueled Otto-
cycle heavy-duty engines, and to gasoline-fueled, natural gas-fueled, 
liquefied petroleum gas-fueled, and methanol-fueled Otto-cycle light-
duty trucks.
    118. A new section 86.1505-94 is added to subpart P to read as 
follows:


Sec. 86.1505-94  Introduction; structure of subpart.

    (a) This subpart describes the equipment and the procedures 
required to perform idle exhaust emission tests on Otto-cycle heavy-
duty engines and Otto-cycle light-duty trucks. Subpart A sets forth the 
testing requirements, reporting requirements and test intervals 
necessary to comply with EPA certification procedures.
    (b) Four topics are addressed in this subpart. Sections 86.1505 
through 86.1515 set forth specifications and equipment requirements; 
Secs. 86.1516 through 86.1526 discuss calibration methods and 
frequency; test procedures and data requirements are listed in 
Secs. 86.1527 through 86.1542 and calculation formulas are found in 
Sec. 86.1544.
    119. A new section 86.1506-94 is added to subpart P to read as 
follows:


Sec. 86.1506-94  Equipment required and specifications; overview.

    (a) This subpart contains procedures for performing idle exhaust 
emission tests on Otto-cycle heavy-duty engines and Otto-cycle light-
duty trucks. Equipment required and specifications are as follows:
    (1) Exhaust emission tests. All engines and vehicles subject to 
this subpart are tested for exhaust emissions. Necessary equipment and 
specifications appear in Secs. 86.1509 through 86.1511.
    (2) Fuel and analytical tests. Fuel requirements for idle exhaust 
emission testing are specified in Sec. 86.1513. Analytical gases are 
specified in Sec. 86.1514.
    120. A new section 86.1513-94 is added to subpart P to read as 
follows:


Sec. 86.1513-90  Fuel specifications.

    The requirements of this section are set forth in Sec. 86.1313-94 
for heavy-duty engines and in Sec. 86.113-94 for light-duty trucks.

PART 88--[AMENDED]

    121. The authority citation for part 88 continues to read as 
follows:

    Authority: 42 U.S.C. 7410, 7418, 7581, 7582, 7583, 7584, 7586, 
7588, 7589 and 7601(a).

    122. Section 88.311-93 of subpart C is amended by revising 
paragraphs (a)(1)(iii), (c) and (d) to read as follows:


Sec. 88.311-93  Emission standards for Inherently Low-Emission 
Vehicles.

    (a) * * *
    (1) * * *
    (iii) The vehicle must meet other special requirements applicable 
to conventional or clean-fuel vehicles and their fuels as described in 
any other parts of this chapter, including 40 CFR parts 86 and 88.
* * * * *
    (c) Light-duty vehicles and light-duty trucks. ILEVs in LDV and LDT 
classes shall have exhaust emissions standards in grams per mile listed 
in Table C93-6.1, as measure under the applicable Federal Test 
Procedures in 40 CFR part 86, subpart B. An ILEV must be able to 
operate on only one fuel, or must be certified as an ILEV on all fuels 
it can operate on. These vehicles shall also comply with all 
requirements of 40 CFR part 86 which are applicable to conventional 
gasoline-fueled, methanol-fueled, or diesel-fueled, natural gas-fueled 
or liquefied petroleum gas-fueled LDVs/LDTs of the same vehicle class 
and model year.
    (d) Heavy-duty vehicles. ILEVs in the HDV class shall have exhaust 
emissions with combined non-methane hydrocarbon and oxides of nitrogen 
exhaust emissions which do not exceed the exhaust emission standards in 
grams per brake horsepower-hour listed in Table C93-6.2, as measure 
under the applicable Federal Test Procedures in 40 CFR part 86, subpart 
M. An ILEV must be able to operate on only one fuel, or must be 
certified as an ILEV on all fuels it can operate on. These vehicles 
shall also comply with all requirements of 40 CFR part 86 which are 
applicable in the case of conventional gasoline-fueled, methanol-
fueled, or diesel-fueled, natural gas-fueled or liquefied petroleum 
gas-fueled HDVs of the same weight class and model year.
* * * * *

PART 600--[AMENDED]

    123. The authority citation for part 600 continues to read as 
follows:

    Authority: 15 U.S.C. 2001, 2002, 2003, 2005, 2006, and 2013.

    124. Section 600.113-93 of subpart B is amended by revising the 
introductory text and paragraphs (a), (b)(1), (b)(2) and (d), and 
adding new paragraph (c)(3) and (h), to read as follows:


Sec. 600.113-93  Fuel economy calculations.

    The Administrator will use the calculation procedure set forth in 
this paragraph for all official EPA testing of vehicles fueled with 
gasoline, diesel, methanol or natural gas fuel. The calculations of the 
weighted fuel economy values require input of the weighted grams/mile 
values for total hydrocarbons (HC), carbon monoxide (CO), and carbon 
dioxide (CO2); and, additionally for methanol-fueled automobiles, 
methanol (CH3OH) and formaldehyde (HCHO); and additionally for 
natural gas-fueled vehicles non-methane hydrocarbons (NMHC) and methane 
(CH4) for both the city fuel economy test and the highway fuel 
economy test. Additionally, the specific gravity, carbon weight 
fraction and net heating value of the test fuel must be determined. The 
city and highway fuel economy values shall be calculated as specified 
in this section. A sample appears in Appendix II to this part.
    (a) Calculate the weighted grams/mile values for the city fuel 
economy test for HC, CO and CO2; and, additionally for methanol-
fueled automobiles, CH3OH and HCHO; and additionally for natural 
gas-fueled automobiles NMHC and CH4 as specified in Sec. 86.144 of 
this chapter. Measure and record the test fuel's properties as 
specified in paragraph (c) of this section.
    (b)(1) Calculate the mass values for the highway fuel economy test 
for HC, CO and CO2, and where applicable CH3OH, HCHO, NMHC 
and CH4 as specified in Sec. 86.144(b) of this chapter. Measure 
and record the test fuel's properties as specified in paragraph (c) of 
this section.
    (2) Calculate the grams/mile values for the highway fuel economy 
test for HC, CO and CO2, and where applicable CH3OH, HCHO, 
NMHC and CH4 by dividing the mass values obtained in paragraph 
(b)(1) of this section, by the actual distance traveled, measured in 
miles, as specified in Sec. 86.135(h) of this chapter.
    (c) * * *
    (3) Natural gas test fuel shall be analyzed to determine the 
following fuel properties:
    (i) Fuel composition per ASTM D 1945-91, Standard Test Method for 
Analysis of Natural Gas By Gas Chromatography. This incorporation by 
reference was approved by the Director of the Federal Register in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be 
obtained from the American Society for Testing and Materials, 1916 Race 
Street, Philadelphia, PA 19103. Copies may be inspected at U.S. EPA, 
OAR, 401 M Street, SW., Washington, DC 20460, or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, Washington, 
DC.
    (ii) Specific gravity (based on fuel composition per ASTM D 1945).
    (iii) Carbon weight fraction based on the carbon contained only in 
the HC constituents of the fuel=weight of carbon in HC constituents 
divided by the total weight of fuel.
    (iv) Carbon weight fraction of fuel=total weight of carbon in the 
fuel (i.e., includes carbon contained in HC and in CO2) divided by 
total weight of fuel.
    (d) Calculate the city fuel economy and highway fuel economy from 
the grams/mile values for total HC, CO, CO2 and, where applicable, 
CH3OH, HCHO, NMHC and CH4 and, the test fuel's specific 
gravity, carbon weight fraction, net heating value, and additionally 
for natural gas, the test fuel's composition. The emission values 
(obtained per paragraph (a) or (b) of this section, as applicable) used 
in each calculation of this section shall be rounded in accordance with 
Sec. 86.084-26(a)(6)(iii) of this chapter. The CO2 values 
(obtained per paragraph (a) or (b) of this section, as applicable) used 
in each calculation of this section shall be rounded to the nearest 
gram/mile. The specific gravity and the carbon weight fraction 
(obtained per paragraph (c) of this section) shall be recorded using 
three places to the right of the decimal point. The net heating value 
(obtained per paragraph (c) of this section) shall be recorded to the 
nearest whole Btu/lb. These numbers shall be rounded in accordance with 
the ``Rounding Off Method'' specified in ASTM E 29-67.
* * * * *
    (h) For automobiles fueled with natural gas, the fuel economy in 
miles per gallon of natural gas is to be calculated using the following 
equation:


TR21SE94.006


Where:

mpge=miles per equivalent gallon of natural gas.
CWFHC/NG=carbon weight fraction based on the hydrocarbon 
constituents in the natural gas fuel as obtained in paragraph (d) of 
this section.
DNG=density of the natural gas fuel [grams/ft3 at 68  deg.F 
(20  deg.C) and 760 mm Hg (101.3 kPa)] pressure as obtained in 
paragraph (d) of this section.
CH4, NMHC, CO, and CO2=weighted mass exhaust emissions 
[grams/mile] for methane, non-methane HC, carbon monoxide, and carbon 
dioxide as calculated in Sec. 600.113.
CWFNMHC=carbon weight fraction of the non-methane HC constituents 
in the fuel as determined from the speciated fuel composition per 
paragraph (c)(2) of this section.
CO2NG=grams of carbon dioxide in the natural gas fuel consumed per 
mile of travel.
CO2NG=FCNG DNG WFCO2
where:


TR21SE94.007

where:

CWFNG=the carbon weight fraction of the natural gas fuel as 
calculated in paragraph (d) of this section.
WFCO2=weight fraction carbon dioxide of the natural gas fuel 
calculated using the mole fractions and molecular weights of the 
natural gas fuel constituents per ASTM D 1945.

[FR Doc. 94-22131 Filed 9-20-94; 8:45 am]
BILLING CODE 6560-50-P