[Federal Register Volume 77, Number 3 (Thursday, January 5, 2012)]
[Notices]
[Pages 488-497]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-33842]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-9616-1]


Control of Emissions From New Highway Vehicles and Engines; 
Approval of New Scheduled Maintenance for Selective Catalytic Reduction 
Technologies

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of approval.

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SUMMARY: This notice announces that EPA has granted certain diesel 
vehicle and engine manufacturers' requests for approval of emission-
related maintenance and scheduled maintenance intervals for 
replenishment of reducing agent in connection with their use of 
selective catalytic reduction (SCR) technologies. EPA's approval 
pertains to the use of SCR with 2011 and later model year (MY) diesel-
fueled light-duty vehicles and light-duty trucks along with medium-duty 
passenger vehicles and chassis-certified diesel vehicles up to 14,000 
pounds gross vehicle weight (GVW) and 2012 and later MY heavy-duty 
diesel engines.

FOR FURTHER INFORMATION CONTACT: David Dickinson, Compliance Division, 
Office of Transportation and Air Quality, U.S. Environmental Protection 
Agency, 1200 Pennsylvania Avenue (6405J), NW., Washington, DC 20460. 
Telephone: (202) 343-9256. Fax: (202) 343-2800. Email: 
[email protected].

SUPPLEMENTARY INFORMATION: 

I. Background

    EPA adopted new emission standards for light-duty vehicles on 
February 10, 2000.\1\ At that time, EPA established an emission 
standard of 0.07 grams per mile for each manufacturer's average full 
life NOX emissions of its vehicles in each model year. For 
heavy-duty vehicles and engines, EPA published a rule setting stringent 
new requirements on January 18, 2001.\2\ Among other requirements, the 
diesel engine NOX emission standard was set at 0.20 grams 
per brake horsepower-hour (g/bhp-hr), to be phased-in between the 2007 
and 2010 model years.
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    \1\ 65 FR 6734 (February 10, 2000).
    \2\ 66 FR 5002 (January 18, 2001).
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    Diesel vehicle and engine manufacturers began planning to meet 
those requirements by optimizing engine designs for low emissions and 
adding high-efficiency aftertreatment systems. Manufacturers examined 
the use of several different types of NOX reduction 
technologies, including NOX absorbers, exhaust gas 
recirculation, and selective catalytic reduction (SCR). SCR systems use 
a nitrogen-containing reducing agent that usually contains urea and is 
known as diesel exhaust fluid (DEF). The DEF is injected into the 
exhaust gas upstream of a catalyst. For continued functioning of the 
systems, the reducing agent needs to be replenished periodically by 
refilling the DEF tank.
    Maintenance performed on vehicles, engines, subsystems, or 
components used to determine exhaust, evaporative, or refueling 
emission deterioration factors is classified as either emission-related 
or non-emission-related and scheduled or un-scheduled. Any emission-
related scheduled maintenance must be technologically necessary to 
ensure in-use compliance with the emission standards. Manufacturers 
must demonstrate to EPA that all of the emission-related maintenance to 
be performed is technologically necessary and must be approved prior to 
being performed or being included in maintenance instructions provided 
to purchasers. 40 CFR 86.094-25(b)(3), 86.094-25(b)(4), 86.1834-
01(b)(3) and 86.1834-01(b)(4) establish minimum allowable maintenance 
intervals for various emission-related technologies. EPA determined 
that emission-related maintenance for the specified technologies at 
intervals shorter than those listed in paragraphs (b)(3) and (b)(4) are 
not technologically necessary, except as provided for in paragraphs 
(b)(7). Paragraphs (b)(7) of those regulatory sections allows 
manufacturers to request new scheduled maintenance and maintenance 
intervals or a change to existing scheduled maintenance interval, 
including an interval shorter than that prescribed in paragraphs (b)(3) 
and (b)(4). For light-duty, medium-duty, and heavy-duty diesel-cycle 
engines, emission-related maintenance for certain emission-related 
components cannot occur before 100,000 miles of use.\3\ Thereafter, 
emission-related maintenance cannot again occur before 100,000 mile 
intervals for light heavy-duty engines, or before 150,000 mile 
intervals for medium and heavy heavy-duty engines.\4\
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    \3\ 40 CFR 86.1834-01(b)(4)(ii) and 40 CFR 86.004-25(b)(4)(iii).
    \4\ Id.
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    Pursuant to 40 CFR 86.1834-01(b)(7), a manufacturer must submit a 
request to EPA for approval of any new scheduled maintenance that it 
wishes to perform during durability determination and recommend to 
purchasers. New scheduled maintenance is maintenance that did not exist 
prior to the 1980 model year (such as DEF refills), including that 
which is the direct result of the implementation of new technology not 
found in production prior to the 1980 model year (such as SCR 
technology). In their approval requests to EPA, manufacturers are 
required to submit a variety of information, including a recommendation 
as to the maintenance category (i.e., emission-related or non-emission-
related, and critical or non-critical). If the suggested maintenance is 
emission-related, manufacturers must indicate the maximum feasible 
maintenance interval. Manufacturers must also provide detailed 
evidence, data, or other substantiation supporting the need for the new 
scheduled maintenance, the categorization of such maintenance, and the 
suggested interval, if the maintenance is emission-related.
    If EPA approves a request for new scheduled maintenance, the Agency 
then designates that maintenance as emission-related or non-emission-
related. For emission-related maintenance, EPA will further designate 
that maintenance as critical or non-critical. A designation of critical 
maintenance will be made if the component receiving the maintenance 
meets the regulatory definition of critical emission-related component 
in 40 CFR 86.1834-01(b)(6). Critical emission-related components 
include catalytic converters. 40 CFR 86.1834-01(b)(6) requires that 
critical emission-related maintenance must have a reasonable likelihood 
of being performed in use, as shown by the manufacturer.\5\ Examples of

[[Page 489]]

demonstrations that maintenance will have a reasonable likelihood of 
being performed in use include: Data establishing that a vehicle's 
engine performance will deteriorate to an unacceptable point due to 
poor emissions performance, survey data demonstrating an eighty percent 
confidence level that maintenance is in fact performed in use, and 
installation of a clearly displayed signal system to alert drivers that 
maintenance is required. When approving a new scheduled maintenance 
request, EPA also establishes a technologically necessary maintenance 
interval, based on the evidence submitted by industry and any other 
information available to the Agency.
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    \5\ 40 CFR 86.094(b)(6)(ii) and 86.1834-01(b)(6)(ii). Both 
sections present the following conditions as acceptable of having a 
reasonable likelihood that the maintenance item will be performed 
in-use:
    (A) Data are presented which establish for the Administrator a 
connection between emissions and vehicle performance such that as 
emissions increase due to lack of maintenance, vehicle performance 
will simultaneously deteriorate to a point unacceptable for typical 
driving.
    (B) Survey data are submitted which adequately demonstrate to 
the Administrator that, at an 80 percent confidence level, 80 
percent of such engines already have this critical maintenance item 
performed in-use at the recommended interval(s)
    (C) A clearly displayed visible signal system approved by the 
Administrator is installed to alert the vehicle driver that 
maintenance is due. A signal bearing the message ``maintenance 
needed'' or ``check engine,'', or a similar message approved by the 
Administrator, shall be actuated at the appropriate mileage point or 
by component failure. This signal must be continuous while the 
engine is in operation and not be easily eliminated without 
performance of the required maintenance. Resetting the signal shall 
be a required step in the maintenance operation. The method for 
resetting the signal system shall be approved by the Administrator.
    (D) A manufacturer may desire to demonstrate through a survey 
that a critical maintenance item is likely to be performed without a 
visible signal on a maintenance item for which there is no prior in-
use experience without the signal. To that end, the manufacturer may 
in a given model year market up to 200 randomly selected vehicles 
per critical emission-related maintenance item without such visible 
signals, and monitor the performance of the critical maintenance 
item by the owners to show compliance with paragraph (b)(6)(ii)(B) 
of this section. This option is restricted to two consecutive model 
years and may not be repeated until any previous survey has been 
completed. If the critical maintenance involves more than one engine 
family, the sample will be sales weighted to ensure that it is 
representative of all the families in question.
    (E) The manufacturer provides the maintenance free of charge, 
and clearly informs the customer that the maintenance is free in the 
instructions provided under Sec.  86.087-38.
    (F) Any other method which the Administrator approves as 
establishing a reasonable likelihood that the critical maintenance 
will be performed in-use.
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    In 2007, EPA issued guidance indicating how the above-described 
regulatory requirements for allowable maintenance could impact EPA 
certification decisions regarding implementation of SCR technologies 
for light-duty and heavy-duty diesel vehicles and engines.\6\ That 
guidance announced that EPA would consider service operations performed 
on SCR systems to be critical emission-related scheduled maintenance. 
We stated our belief that because catalysts are listed in the (b)(3) 
and (b)(4) provisions as critical emission-related components, and lack 
of replenishing agent renders SCR catalysts inoperative, SCR system 
maintenance would meet the definition of critical emission-related 
maintenance. Therefore, allowable maintenance requirements would apply 
to SCR systems, including SCR catalysts, reducing agent, reducing agent 
storage tanks, dosing valves, and all lines and hoses. Additionally, 
because manufacturers indicated that packaging constraints would 
prevent them from being able to equip their vehicles with reducing 
agent storage tanks of sufficient size to allow reducing agent 
replenishment to comply with the general maintenance intervals of 
100,000 or 150,000 miles, EPA clarified that manufacturers would likely 
need to request a change to the scheduled maintenance interval pursuant 
to the (b)(7) provision.
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    \6\ U.S. Environmental Protection Agency, CISD 07-07, ``Dear 
Manufacturer Letter Regarding Certification Procedure for Light-Duty 
and Heavy-Duty Diesel Vehicles and Heavy-Duty Diesel Engines Using 
Selective Catalytic Reduction (SCR) Technologies,'' March 27, 2007, 
available at: http://iaspub.epa.gov/otaqpub/display_file.jsp?docid=16677&flag=1.
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    In that same 2007 guidance, EPA also stated that an SCR system 
utilizing a reducing agent that needs to be periodically replenished 
could be an adjustable parameter as set forth in 40 CFR 86.094-22(e)(1) 
and 86.1833-01(a)(1). Those regulatory provisions establish the 
requirements for determining the physically adjustable ranges of 
parameters, and EPA's 2007 guidance addressed its determination under 
the regulations that operation without DEF is within the scope of such 
ranges. EPA's 2007 guidance also provided industry-wide notice that SCR 
system designs and information submitted by manufacturers during 
certification could be used to provide EPA with assurance that DEF 
levels will remain at proper ranges during the operation of their 
vehicles and engines while in use.\7\
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    \7\ EPA issued guidance on December 30, 2009. U.S. Environmental 
Protection Agency, Dear Manufacturer Letter regarding ``Revised 
Guidance for Certification of Heavy-Duty Diesel Engines Using 
Selective Catalyst Reduction (SCR)Technologies,'' December 30, 2009, 
reference number CISD-09-04 (HDDE), available at http://iaspub.epa.gov/otaqpub/display_file.jsp?docid=20532&flag=1.
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II. Previous Model Year Approval of New Scheduled Maintenance for SCR 
Systems

    In 2009, EPA approved manufacturer-specific and industry-wide new 
scheduled maintenance interval requests for diesel-cycle motor vehicles 
and motor vehicle engines equipped with SCR systems.\8\ At that time, 
EPA stated that:

    \8\ 74 FR 57672 (November 9, 2009).
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    * * * SCR systems are a new type of technology designed to meet 
the newest emission standards and the DEF refill intervals represent 
a new type of scheduled maintenance; therefore, EPA believes that 
manufacturers may request from EPA the ability to perform the new 
scheduled maintenance of DEF refills. Requests from manufacturers 
for new scheduled maintenance intervals must include: (1) Detailed 
evidence supporting the need for the maintenance requested and (2) 
supporting data or other substantiation for the recommended 
maintenance category and for the interval suggested for the emission 
maintenance. Any emission-related maintenance must be 
technologically necessary to assure in-use compliance with the 
emission standards since minimum service intervals are established 
in part to ensure that the control of emissions is not compromised 
by a manufacturer's overly frequent scheduling of emission-related 
maintenance.

    Upon review of industry-wide and manufacturer-specific evidence and 
supporting data, EPA approved new scheduled maintenance intervals for 
DEF equal to the scheduled oil change interval for light-duty vehicles 
and trucks for the 2009 and 2010 model years. For heavy-duty vehicles 
and engines through the 2011 model year, EPA approved new scheduled 
maintenance intervals for DEF tanks based on ratios to a given 
vehicle's fuel capacity. Vocational heavy-duty vehicles (e.g., dump 
trucks, concrete mixers, refuse trucks, and other centrally-fueled 
vehicles) were permitted a DEF tank maintenance interval no less than 
the vehicle's fuel capacity (i.e., a 1:1 ratio of DEF refill to fuel 
refill). For other heavy-duty vehicles, a longer interval was approved 
depending upon whether the vehicle was equipped with a DEF level 
indicator that would be constantly viewable by the operator. For those 
heavy-duty vehicles with a DEF level indicator, EPA approved a DEF tank 
refill interval no less than twice the range of the vehicle's fuel 
capacity (i.e., a 2:1 ratio). For those heavy-duty vehicles without a 
DEF level indicator, EPA approved a DEF tank refill interval no less 
than three times the range of the vehicle's fuel capacity (i.e., a 3:1 
ratio).
    When evaluating the evidence, data, and justifications presented by 
manufacturers to support their requested intervals, EPA identified as 
significant the impact a larger sized DEF tank would have on vehicle 
design and vehicle weight. To merely accommodate the inclusion of a DEF 
tank into vehicle design, heavy-duty vehicle manufacturers had to 
redesign their configurations by taking such measures as reducing the 
number of batteries, designing space-saver configurations,

[[Page 490]]

lengthening frame rails, moving compressed air tanks inside the frame 
rails, and redesigning fuel tank configurations. Light-duty car and 
truck manufacturers had similar vehicle design issues related to their 
inherently space constrained vehicles: they had to choose whether to 
reduce interior vehicle space or find a place to accommodate a DEF tank 
in the engine compartment of vehicle's undercarriage. Aside from 
vehicle design issues, the addition of a large DEF tank onto any given 
vehicle represents a significant addition of weight to the vehicle. The 
addition of a significant amount of weight to a given vehicle, in turn, 
presents its own concerns: added vehicle weight more quickly 
deteriorates engine performance, and added vehicle weight decreases 
fuel economy. With those considerations in mind, EPA announced its 
approval of the requested maintenance intervals:

    After reviewing this data and information, EPA believes that 
longer refill intervals than those noted above would require larger 
and heavier DEF tanks, and the design and engineering work performed 
by manufacturers thus far indicate that the recommended DEF refill 
intervals noted above approximate the maximum feasible maintenance 
intervals associated with reasonable DEF tank sizes. The maintenance 
intervals recommended ensure that the functions and operational 
efficiency of such vehicles are not overly compromised. Based on 
this information we believe the intervals noted above are 
warranted.\9\
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    \9\ 74 FR 57671, 57674 (November 9, 2009).

    EPA's 2009 approval also noted that, ``while not a specific 
criterion under paragraph (b)(7) of the regulations, because DEF refill 
maintenance is considered `critical emission-related maintenance,' 
paragraph (b)(6) requires that there be a reasonable likelihood that 
the DEF maintenance refill will be performed in use.'' \10\ EPA then 
noted the number of means available to make such a showing, including a 
clearly displayed visible signal system or the presentation of 
supporting data.
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    \10\ See 40 CFR 86.1834-01(b)(6)(ii) and 86.094-25(b)(6)(ii).
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III. Current Requests for New Scheduled Maintenance for SCR Systems

A. Light-Duty Requests

1. Alliance of Automobile Manufacturers Request
    EPA has received information from the Alliance of Automobile 
Manufacturers (the ``Alliance''), that requested re-approval of new 
scheduled maintenance for DEF refilling at service intervals (i.e., oil 
change intervals) for light-duty vehicles and light-duty trucks (and 
heavy-duty engines that are chassis-certified for NOX) 
equipped with SCR systems.\11\ The Alliance presented several reasons 
why the SCR maintenance interval should be equivalent to the service 
interval, including: ``vehicles will be designed and equipped to ensure 
vehicle compliance with emission standards; DEF will be readily 
available and accessible to drivers; maintenance is likely to be 
performed; there are engineering constraints on packaging a large DEF 
tank on light duty vehicles; and there is a significant penalty on fuel 
economy and performance associated with carrying both a larger DEF tank 
and the weight of a large amount of DEF.''
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    \11\ The Alliance represents BMW Group, Chrysler LLC, Ford Motor 
Company, General Motors, Jaguar Land Rover, Mazda, Mercedes-Benz, 
Mitsubishi Motors, Porsche, Toyota, and Volkswagen. EPA also 
received similar information from Mahindra.
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    With regard to the engineering constraints associated with 
packaging a large quantity of DEF on light duty vehicles, the Alliance 
notes that it is impractical to install a DEF tank of sufficient size 
to achieve a 100,000 mile scheduled maintenance interval. ``Light duty 
vehicles are constrained in the amount of space that can be dedicated 
to a DEF tank. In addition to the DEF tank, SCR vehicles must package 
an SCR catalyst, SCR mixer and DEF dosing and heating mechanisms.'' The 
Alliance cites an example of a current production vehicle that provides 
a 6.1 gallon DEF tank to achieve a 10,000 mile change interval ratio 
tied to the oil change interval. To accommodate a 100,000 mile 
maintenance requirement would require 60 gallons of DEF and would take 
approximately 8 cubic feet of space--and would also be almost 
equivalent to installing 4 extra fuel tanks. ``To reduce the existing 
usable volume to such an extent would result in an uncompetitive 
vehicle in terms of usable passenger or cargo volume.''
    With regard to the Alliance's concerns regarding the potential for 
a significant penalty on fuel economy and performance associated with 
carrying both a larger DEF tank and the weight of a large amount of 
DEF, they note the simple impracticability for light duty vehicles to 
carry the weight of a DEF tank sufficient in size to achieve a 100,000 
mile maintenance interval. Noting that such a tank could weigh as much 
as 540 lbs it could affect fuel economy almost as much as 10% on a 3800 
lb curb weight vehicle. The Alliance also notes similar handling 
performance (acceleration, braking, and turning) along with passenger 
space, cargo carrying and/or towing capacity.
2. Ford Request
    EPA has received information from Ford (regarding its chassis-
certified vehicles) that is similar to the concerns raised by the 
Alliance. In addition, Ford notes that by attempting to go to a longer 
service interval, for example a 16-20 gallon DEF tank to meet a two oil 
change interval, would not be feasible with the space limitations and 
performance requirements that are necessary for typical medium-duty 
vehicle (chassis-certified) design. In addition to the market concerns 
associated with a loss in fuel capacity, cargo or truck bed space due 
to a larger DEF tank not being acceptable to its customers, Ford also 
notes the ``hard-point'' packaging issues with attempting to place a 
large DEF tank in the engine compartment or in the vehicles 
undercarriage.\12\
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    \12\ Ford notes the undercarriage is already fully utilized with 
the engine, exhaust system, catalytic converters, mufflers, fuel 
tank, etc severely limiting any available space for a DEF tank. Ford 
also notes that DEF tanks represent a significant weight challenge 
which affects performance and fuel efficiency. To increase a DEF 
tank for every 2 oil change interval would increase a tank weight by 
72 lbs as one example.
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3. Isuzu Request
    EPA also received information from Isuzu for its medium-duty 
vehicle (chassis-certified vehicles with GVW of 8,501 to 10,000 pounds) 
engine families. Isuzu requested a maintenance interval based on the 
rate of DEF consumption. Isuzu presented that the DEF consumption rate 
of 2% the rate of diesel fuel consumption renders it ``impossible'' to 
equip a vehicle with a DEF tank large enough to operate for the full 
120,000 mile maintenance interval without DEF. Isuzu requested its 
interval based on reasons of technological necessity, including 
maintenance is likely to be performed on schedule, there is limited 
space available on vehicles for a large DEF tank, the physical 
properties of DEF present limitations, and DEF is publicly and readily 
available to drivers.

B. Heavy-Duty Requests

1. Engine Manufacturers Association Request
    The Engine Manufacturers Association (``EMA'') renewed its previous 
request for maintenance intervals for DEF refill for heavy-duty on-
highway diesel fueled engines and vehicles.\13\ EMA presents that the

[[Page 491]]

determinations of technological necessity that EPA made in 2009 still 
apply today for DEF refill intervals.\14\ Specifically, EMA believes 
that ``while the SCR-related urea infrastructure has continued to 
develop, the space and weight constraints that are inherent to the 
design and operation of [heavy-duty on-highway] vehicles, and the 
underlying DEF consumption rate, have not changed. As a result, the 
need and justification for the previously-approved reduced DEF 
maintenance intervals also have not changed.'' EMA requests that EPA's 
previously approved new scheduled maintenance intervals for DEF be 
extended for the 2012 and later model years.\15\
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    \13\ EMA members include AGCO Corporation, American Honda Motor 
Company, Inc., Briggs & Stratton Corporation, Caterpillar Inc., 
Chrysler Group LLC, Cummins Inc., Daimler Trucks North America LLC, 
Deere & Company, DEUTZ Corporation, Dresser Waukesha, Fiat 
Powertrain Technologies S.p.A., Ford Motor Company, Hino Motors, 
Ltd., Isuzu Manufacturing Services of America, Inc., Kohler Company, 
Komatsu Ltd., Kubota Engine America Corporation, Navistar, Inc., 
Onan--Cummins Power Generation, PACCAR Inc., Scania CV AB, Tognum 
America, Inc., Volkswagen of America, Inc., Volvo Powertrain 
Corporation, W[auml]rtsil[auml] North America, Inc., Yamaha Motor 
Corporation, and Yanmar America Corporation.
    \14\ EMA cites from EPA's 2009 FR Notice: ``EPA believes that in 
light of the existing tight space constraints and the overall desire 
to maximize cargo-carrying capacity, minimize emissions and meet 
consumer operation demands, and the built-in DEF tank size buffer to 
insure DEF refills, that the DEF tank sizes associated with the 2:1 
refill and 3:1 intervals are technologically necessary. EPA believes 
that requiring tank sizes above these ratios will cause increases in 
space constraints and weight that would not be appropriate for these 
[HDOH] vehicles. * * * After reviewing this data and information, 
EPA believes that longer refill intervals than those noted above 
would require larger and heavier DEF tanks. And the design and 
engineering work performed by manufacturers thus far indicate that 
the recommended DEF refill intervals noted above approximate the 
maximum feasible maintenance interval associated with reasonable DEF 
tank sizes. The maintenance intervals recommended ensure that the 
functions and operational efficiency of such vehicles are not overly 
compromised. Based on this information we believe the intervals 
noted above are warranted.'' See 74 FR at 57674.
    \15\ EMA expressly states that one of its members--Navistar, 
Inc.--does not support EMA's request.
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2. Volvo Request
    By letter dated April 28, 2011, Volvo Powertrain North America and 
Volvo Powertrain Japan (collectively, ``Volvo'') submitted a request 
that EPA extend its previous approval of alternative scheduled 
maintenance intervals for DEF tanks used in SCR systems. Volvo believes 
that the intervals EPA previously approved remain technologically 
necessary, ``as nothing about the design, constraints or functionality 
of Volvo vehicles and engines has changed so as to permit the use of 
larger tanks.'' Volvo further states that ``The inherent nature of 
vehicle space and weight constraints makes significantly larger DEF 
tanks infeasible on a practical basis. That said, larger DEF tanks also 
are not necessary in light of systems Volvo has developed to ensure 
that vehicle operators refill DEF tanks.'' Volvo states that to ensure 
efficient and practical operation its trucks are designed in such a way 
that they necessarily have space and weight constraints. Thus, there 
are inherent limits on the size of add-on components, such as DEF 
tanks, that can be installed on the vehicles and such limits are 
unavoidable. In this context Volvo states that its trucks are designed 
to operate using DEF at all times and that the size of the DEF tanks, 
like the vehicle's fuel tank, dictates the vehicle's range of 
operation. Volvo maintains that the 2:1 ratio remains technologically 
necessary for model year 2012 engines and vehicles as nothing about the 
design, constraints or functionality of Volvo vehicles and engines has 
changed (since the 2009 approval) so as to permit the use of larger 
tanks. Volvo also presents that it has implemented controls to assure 
that there is ``more than a `reasonable likelihood' that the 
recommended DEF refill intervals will be complied with in-use. Volvo 
asserts that it has equipped its SCR-based systems with visible warning 
systems and driver inducements such that vehicle performance will 
deteriorate to an unacceptable point, in order to compel vehicle 
operators to refill the DEF tank. Volvo initially developed these 
strategies in consultation with EPA staff in order to ensure its 
engines met EPA certification requirements, and has since improved its 
strategies for current and future model year engines. In its request, 
Volvo further describes the specific steps it has taken to design its 
SCR systems to protect against operation of its vehicles without DEF 
and to prevent SCR system tampering. In addition, Volvo seeks the 
flexibility to utilize a 1:1 ratio in light of its 40% power reduction 
(see further clarification below in the SCR Engine Manufacturers 
request submitted after the Volvo request--EPA assumes this is the 
flexibility that Volvo is seeking).
3. SCR Engine Manufacturers Request
    EPA has also received requests for scheduled maintenance intervals 
for 2012 and later model years from a group of SCR engine manufacturers 
(collectively the ``SCR Engine Manufacturers'' \16\) that specifically 
ask for EPA to approve the use of a 1:1 DEF to fuel ratio for vehicles 
with a DEF level indicator, in addition to vocational vehicles. The SCR 
Engine Manufacturers state that such approval is necessary and 
appropriate to reflect current and anticipated changes in vehicle 
designs, significant changes in inducement strategies, and the 
increased availability of DEF since EPA's last approval in 2009.
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    \16\ This group includes Chrysler Group, LLC, Cummins Inc., 
Daimler Trucks North America LLC, Detroit Diesel Corporation, Ford 
Motor Company, Mack Trucks Inc., PACCAR Inc., UD Trucks Corporation, 
and Volvo Group North America.
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    The SCR Engine Manufacturers note that much of the information 
required in a (b)(7) petition was confirmed by EPA in its 2009 notice 
and thus needs no further elaboration. EPA has already concluded that 
replenishment of DEF is ``technologically necessary'' critical 
emission-related maintenance, and that the 1:1, 2:1, and 3:1 ratios 
were ``maximum feasible'' maintenance intervals based on information 
available in 2009. There has been no change in the need for DEF 
replenishment or designation of the category of maintenance since 2009. 
The SCR Engine Manufacturers new petition for a 1:1 DEF interval 
reflects what is believed to be the ``maximum feasible interval'' based 
on reasonable tank sizes, given the latest information regarding SCR 
systems and DEF availability.
    Included in the SCR Engine Manufacturers' petition is their 
position regarding the threshold criteria that EPA should follow for 
setting a ``technologically necessary maintenance interval.'' They 
claim that the general maintenance regulations, including the 
introductory paragraph of (b)(2) which helps frame the established 
intervals in (b)(3) and (b)(4), provides guidance on what 
``technologically necessary'' means when it states that any emission-
related maintenance ``must be technologically necessary to assure in-
use compliance with the emission standards.'' Thus EPA must first 
determine whether an interval shorter than the regulatory default is 
necessary in order to assure in-use compliance. They note that in the 
2009 notice EPA specifically addressed the unique nature of liquid DEF 
replenishment and the need to strike a reasonable balance between 
conflicting design goals.
    Thus, the SCR Engine Manufacturers maintain that the words 
``technologically necessary'' are used in two contexts. First, as noted 
above, (b)(2) requires all maintenance that meets the definition of 
``emission-related maintenance'' ``must be technologically necessary to 
assure in-use compliance with the emission standards.'' Consistent with 
this provision is (b)(7)(ii) which requires that any alternative 
interval set by EPA be ``a technologically necessary maintenance 
interval'' (emphasis added). Thus the term ``technologically 
necessary'' merely describes the

[[Page 492]]

category of maintenance that is allowable but not what the specific 
interval must be. Subsequently, the SCR Engine Manufacturers note that 
once EPA makes this threshold determination (as required in (b)(7)) 
then the Agency, with a level of discretion, examines the information 
submitted by the petitioner. Such information includes the petitioner's 
position on what is the ``maximum feasible maintenance'' including any 
supporting data or other substantiation for the interval suggested. 
Rather than looking at the ``maximum level'' that is technologically 
feasible, the term ``feasible'' requires EPA to look at the overall 
practicality and reasonableness of a particular proposed interval. The 
maximum feasible interval is used as a point of reference for EPA to 
evaluate the reasonableness of the manufacturers' recommended interval. 
According to the SCR Engine Manufacturers, ``The maximum possible 
interval for DEF replenishment is established in each case by the total 
load capacity of the vehicle in question, the space available for a 
given DEF tank size, the fuel efficiency and greenhouse gas impact of 
various DEF dosing rates, the desired operating range of the vehicle 
between fuel and DEF refills, and the impact of extra weight on vehicle 
performance, safety, and compliance with U.S. Department of 
Transportation regulatory requirements. DEF tank size must also be 
balanced against the need to carry cargo, or to enable the vehicle to 
meet the purpose for which it was built, to determine what is feasible 
in the most economical way possible while achieving compliance.''
    The SCR Engine Manufacturers suggest that as EPA performs its case-
by-case analysis, the likelihood of the maintenance being performed in-
use is the most important factor in establishing the precise 
maintenance interval. EPA explained that ``minimum service intervals 
are established in part to ensure that the control of emissions is not 
compromised by a manufacturer's overly frequent scheduling of emission-
related maintenance.'' \17\ They also state that EPA explained in its 
2009 notice that while the likelihood of maintenance being performed 
in-use was a specific criteria under (b)(6), it was also a factor that 
was ``important to note'' with regard to EPA's (b)(7) findings. 
Further, EPA then concluded that it was reasonable to base the DEF 
refilling event on diesel refueling intervals due to DEF infrastructure 
developed at diesel refueling stations.
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    \17\ EPA made this statement in its 2009 Notice, see 74 FR at 
57673.
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    EPA has also received information from the SCR Engine Manufacturers 
indicating that EPA should set the minimum required DEF refill interval 
at an interval equal to the vehicle's fuel capacity (i.e., a 1:1 ratio) 
for all heavy duty engines.\18\ They claim that this shorter 
maintenance interval is ``necessary and appropriate to reflect current 
and anticipated changes in vehicle designs, significant changes in 
inducement strategies, and the increased availability of DEF.'' They 
note that certification practices of the EPA regarding inducement 
practices for SCR-equipped engines make it ``essentially impossible for 
an SCR vehicle to operate without regular DEF replenishment.'' They 
state that the severity of inducements related to DEF levels (e.g. 
severe reduction in engine power and/or vehicle speed) is 
``extraordinary and must be taken into account'' when EPA is 
determining appropriate maintenance intervals. They state that ``in 
light of these severe inducements, it is reasonable to expect that a 
driver with a 1:1 tank ratio will operate under a firm discipline that 
the DEF tank must be refilled every time the fuel tanks are filled, as 
opposed to a driver with a 2:1 or greater tank ratio who may become 
accustomed to filling the DEF tank only when necessary, and is 
therefore more likely to rely on gauge levels, warnings, and 
inducements to trigger refills.''
---------------------------------------------------------------------------

    \18\ Letters dated August 18, 2011 and September 27, 2011 to 
Karl Simon, EPA, Director, Compliance and Innovative Strategies 
Division from R. Latane Montague, Hogan Lovells.
---------------------------------------------------------------------------

    The SCR Engine Manufacturers also state that EPA's promulgation of 
new standards regulating greenhouse gases increase the size and weight 
restraints associated with DEF tank size.

    EPA has announced new [greenhouse gas] standards for HDOH 
trucks, and manufacturers have moved to voluntarily increase the 
fuel efficiency of their vehicles in advance of the effective dates 
of those regulations. Within these regulations, EPA recognizes the 
impact of weight savings on fuel efficiency and GHG emissions. In 
addition, manufacturers have developed innovative new DEF dosing 
strategies to reduce CO2 emissions. These new strategies may involve 
increasing the DEF dosing rate. Increasing the DEF dosing rate also 
makes it more and more difficult to satisfy a 2:1 tank size ratio 
without increasing the size of the DEF tank above the size EPA 
previously considered the maximum reasonable size. For this reason, 
if the application of the 1:1 tank ratio is not expanded, EPA will 
effectively be mandating larger DEF tanks, with their accompanying 
weight increase, in order to accommodate technology advancements 
developed to reduce CO2 emissions--tanks that are larger than the 
tanks EPA determined to be the maximum reasonably required in 2009. 
In addition, this could inadvertently cause manufacturers to 
restrict application of the most fuel efficient engines to vehicles 
that have reduced range between fuel and DEF refills, such that they 
will be unattractive to the line-haul fleets that consume the most 
fuel.

    The commenters elaborated that:

    To meet the next round of GHG reduction requirements, some 
manufacturers expect to increase DEF dosing by as much as 100% over 
current levels. These increased levels of dosing will require a 
corresponding increase in DEF tank capacity and size to meet the 
existing 2:1 tank ratio requirements. For example, increasing DEF 
dosing by 40% on average would require an increase in DEF tank size 
of approximately 40% (depending on how much extra capacity was 
included in the tanks used in previous model years). The shape, size 
and location of DEF tanks on a truck frame are constrained by a 
number of factors including: the need to place the tank below the 
filler-neck; the need for clearance from other components such as 
fuel tanks, battery boxes, air tanks, diesel particulate filters, 
and the drive axle and wheels; the need for gravity feed; body 
installation requirements; clear-back-of-cab requirements; weight 
distribution requirements; bridge formula and related axle placement 
issues; and fuel capacity/driving range demands.

    They state that another consequence of the greenhouse gas 
regulations is more attention to improved aerodynamics and weight 
reduction, which are harmed by the need for a 2:1 DEF tank size 
requirement. They claim that EPA should allow manufacturers to use all 
available options to increase fuel economy and meet greenhouse gas 
standards. They state the possible harm of allowing shorter maintenance 
intervals is minimal, given the severe negative inducements associated 
with failure to replenish the DEF tank.
4. Navistar's Opposition to Renewed Requests
    EPA has received information from Navistar expressing its 
opposition to any extension of EPA's previously approved DEF refill 
intervals. Navistar maintains that the touchstone of allowable 
maintenance is whether it is reasonably likely that the maintenance 
will be performed. To this point, it states that EPA's own 
certification guidance ensures that maintenance will not occur, or at 
least not for lengthy periods of time. It also states that EPA's 
inducements to cause drivers to replenish DEF do not work and, and by 
definition, ensure that maintenance will not occur.\19\ Separately, 
Navistar

[[Page 493]]

contends that the previously approved intervals are not 
``technologically necessary'' under EPA's regulations. The purpose of 
EPA's maintenance regulations is to reduce the amount of driver 
attention emissions systems require in order to ensure that certified 
engines comply with emission standards on the road. Navistar claims 
that the Clean Air Act (CAA) and EPA's regulations require that SCR 
engine manufacturers make efforts to improve the durability of their 
driver-dependent emission control systems after MY 2009. Navistar 
points to EPA's statement from the 2009 approval (``expectation that 
SCR-related technologies and the urea infrastructure will continue to 
develop and mature.''), as evidence that EPA must require continuous 
improvement.\20\ Navistar states that ``other SCR technology is now 
available that offers exponentially longer maintenance ranges, weighs 
less and conserves fuel more.'' Navistar maintains that EPA's approved 
maintenance for liquid, urea-based SCR is not about ``technological 
necessity''. SCR engine manufacturers can easily quadruple the refill 
interval with little or no effort. They also suggest that EPA cannot 
legally accept SCR engine manufacturers' lack of effort and extend the 
same illegal DEF-replacement maintenance intervals for future model 
years. ``Because other SCR technology is proven to be available with a 
maintenance interval in the range of 35,000 to 45,000 miles, EPA's own 
allowable maintenance regulations require that liquid, urea-based SCR 
meet that same benchmark.''
---------------------------------------------------------------------------

    \19\ Navistar throughout its comments returns to its theme that 
EPA's certification scheme allows DEF refills to be deferred for 
lengthy periods of time. As such, Navistar maintains that EPA has 
illegally amended its allowable maintenance regulations to eliminate 
the requirement that maintenance be shown as likely to occur. 
Similarly, Navistar points to EPA's 2001 rulemaking and maintains 
that EPA ``concluded its maintenance inducements do not create a 
reasonable likelihood that the maintenance will be performed. (See 
2011 Rule at 5053 (finding no ``adequate safeguards in place to 
ensure the [DEF] is used throughout the life of the vehicle.'')
    \20\ Navistar maintains that SCR engine makers could have 
substantially increased the 2009-2011 DEF replacement intervals by 
doubling the size of the DEF tank and decreasing urea consumption by 
half.
---------------------------------------------------------------------------

    Navistar also chooses to contrast liquid, urea-based SCR systems 
with other emission control technologies to suggest that the 
maintenance interval tied with DEF refills is unnecessarily short They 
note EPA's approval of new scheduled maintenance for exhaust 
recirculation valves at 67,500 miles.\21\ Navistar states that EPA's 
basis for defining ``technologically necessary'' has always been ``the 
longest interval that any manufacturer recommend(s).'' \22\ Lastly, 
Navistar notes that EPA is well aware that they have developed for 
production and introduced other SCR technology (i.e. EGNR) that 
provides a maintenance interval in the range of 35,000 to upwards of 
45,000 miles.
---------------------------------------------------------------------------

    \21\ 73 FR 79089 (December 24, 2008).
    \22\ 45 FR 4136, 4141 (January 21, 1980).
---------------------------------------------------------------------------

IV. Discussion

    As set forth above, EPA in its 2007 guidance states that SCR system 
maintenance meets the regulatory definition of critical emission-
related maintenance. EPA has further clarified that allowable 
maintenance requirements apply to SCR systems, including SCR catalysts, 
reducing agent, reducing agent storage tanks, dosing valves, and all 
lines and hoses. Additionally, because manufacturers indicated that 
packaging constraints would prevent them from being able to equip their 
vehicles with reducing agent storage tanks of sufficient size to allow 
reducing agent replenishment to comply with required maintenance 
intervals of 100,000 or 150,000 miles, EPA clarified that manufacturers 
would likely need to request a change to the scheduled maintenance 
interval pursuant to the (b)(7) provision.
    Also set forth above, manufacturers have in fact requested such 
changes for more frequent scheduled maintenance to accommodate DEF 
refilling events for previous, current, and future model years. When 
EPA reviewed those manufacturer requests in 2009, it determined that 
maintenance associated with refill of DEF tanks was new scheduled 
maintenance and that the manufacturer-requested maintenance request and 
scheduled maintenance intervals were appropriate and announced that 
determination in the Federal Register.\23\ The broad-level 
considerations EPA evaluated when considering the maintenance interval 
requests were the space and weight constraints presented by 
incorporating a DEF tank into vehicle design, as well as the impact a 
DEF tank's inclusion could have on engine performance. In our 2009 
Federal Register notice, we concluded that the requested intervals were 
appropriate because we determined that manufacturer-recommended DEF 
refill intervals approximated the maximum feasible maintenance 
intervals associated with reasonable DEF tank sizes. We also concluded 
that the maintenance intervals recommended ensure that the functions 
and operational efficiency of such vehicles are not overly compromised.
---------------------------------------------------------------------------

    \23\ 74 FR 57671 (November 9, 2009).
---------------------------------------------------------------------------

A. Light-Duty Requests

    As EPA explained in its 2009 notice, automobile manufacturers have 
stated it takes approximately an 8 gallon DEF tank to ensure that DEF 
will last for the length of a typical oil change interval. Assuming an 
oil change interval of 10,000 miles, a DEF tank size of approximately 
80 gallons would be required to meet a 100,000 mile DEF refill 
maintenance interval. Even a 16-20 gallon DEF tank (to meet a 2 oil 
change interval) would interfere with the space that is necessary for 
typical light-duty vehicle design and transportation needs of the 
consumer. Interior cabin volume and cargo space are highly valued 
attributes in light-duty vehicles and trucks. Manufacturers have 
historically strived to optimize these attributes, even to the point of 
switching a vehicle from rear-wheel drive to front-wheel drive to gain 
the extra interior cabin space taken up by where the drive shaft tunnel 
existed, or switching the size of the spare tire from a conventional 
sized tire to a small temporary tire to gain additional trunk space. 
Thus any significant interior, cargo or trunk space used to store a DEF 
tank would be unacceptable to customers. There are also packaging 
concerns with placing a large DEF tank in the engine compartment or in 
the vehicles undercarriage. Most vehicle undercarriages are already 
crowded with the engine, exhaust system, including catalytic converters 
and mufflers, fuel tank, etc. limiting any available space for a DEF 
tank.
    In addition to the inherently space constrained areas on the 
vehicle to place both fuel tanks and DEF tanks (an additional 8 gallon 
tank represents a very significant demand for space) the addition of 
the weight associated with the DEF represents significant concerns 
(e.g. performance and efficient operation) on the operation of the 
vehicle. For example, assuming a density of 9 lb/gallon, an 8 gallon 
DEF tank represents an additional 72 lbs on a vehicle already looking 
to optimize performance. Adding additional DEF tank size to even 
accommodate a two-oil change interval is not feasible or practical 
given these weight constraints. A requirement for a larger DEF tank may 
also have an adverse effect on the ability of a manufacturer to meet 
greenhouse gas emission standards and fuel economy standards.
    Presently, no manufacturer has presented any indication that things 
have changed in any material fashion that would allow for the 
installation of

[[Page 494]]

larger DEF tanks and/or less frequent DEF refilling intervals on light 
duty vehicles and trucks. More importantly, EPA is aware of no 
technological advances in this area and believes that none are likely 
to occur in the near future. The space and weight constraints presented 
by inclusion of a DEF tank into vehicle design are inherent. Forcing 
manufacturers to install larger DEF tanks would not only be impractical 
for manufacturers, it would also present utility constraints for 
consumers, drivers, and operators. Therefore, alternative maintenance 
intervals remain technologically necessary for refilling DEF tanks used 
on SCR systems.
    EPA notes that the DEF refill maintenance interval being equivalent 
to and occurring with the oil change interval is a fairly long interval 
(e.g. 7,500 to 12,500 miles) for light-duty vehicles and trucks and is 
not likely to result in overly frequent maintenance under typical 
vehicle driving. EPA also believes that an adequate DEF supply will be 
available to perform the DEF refills at the stated intervals. EPA 
believes it important to also consider when, where and how often 
vehicle owners or operators are most likely to perform the DEF refill 
maintenance. For light-duty vehicles and light-duty trucks, EPA 
believes the requested DEF refill interval's association with the oil 
change interval is appropriate given the likelihood of DEF availability 
at service stations and the likelihood that DEF refill would occur 
during such service.
    Recognizing that alternative maintenance intervals for DEF 
refilling remain technologically necessary due to space and weight 
constraints, EPA believes that the above-described alternative 
maintenance intervals requested by light-duty vehicle manufacturers are 
appropriate.

B. Heavy-Duty Requests

    EPA continues to believe it is reasonable to base the DEF refilling 
event on diesel refueling intervals given that it is likely that the 
DEF refill maintenance would be undertaken at the time of fuel refill 
due to DEF infrastructure developed at diesel refueling stations. EPA 
agrees with manufacturers that the DEF refilling intervals requested by 
EMA, as a threshold matter, are ``technologically necessary.'' EPA 
knows of no SCR technology that is currently available that is yet 
capable of attaining higher mileage without a DEF refill. Although 
Navistar maintains that EPA is aware of its ``EGNR'' technology that it 
has ``developed for production and introduced'' that provides a 
maintenance interval in the range of 35,000 to upwards of 45,000 miles, 
Navistar presents no further evidence regarding this technology. 
Navistar has presented no evidence that such technology is currently 
available in the marketplace and can meet all requirements of the Clean 
Air Act and the regulations promulgated thereunder. EPA knows of no 
application for certification of engines using such technology; nor 
have any engines using such technology on heavy-duty engines been 
introduced within the United States. In any case, such technology would 
be different technology than the DEF-based SCR technology being used by 
current SCR manufacturers. If engine families using such EGNR 
technology become established in the marketplace and can meet all of 
the requirements in EPA's regulations, then it might be appropriate to 
revisit this issue, although the fact that such technology is 
substantially different from DEF-based SCR would be relevant for 
determining whether the establishment of this technology is relevant to 
the establishment of maintenance intervals for DEF-based SCR.
    For vocational vehicles such as dump trucks, concrete mixers, 
refuse trucks and similar typically centrally-fueled applications, EPA 
believes the DEF tank refill interval should equal the range (in miles 
or hours) of the vehicle operation that is no less that the vehicle's 
fuel capacity (i.e., a 1:1 ratio). For all other vehicles, EPA believes 
the DEF tank refill interval must provide a range of vehicle operation 
that is no less than twice the range of vehicle's fuel capacity (i.e., 
a 2:1 ratio).\24\ As EPA has noted previously, assuming that 25,000 
gallons of diesel fuel were consumed to reach a 150,000 mile interval 
(the interval applicable to catalyst maintenance for heavy-duty 
engines), and assuming a 3% DEF consumption rate, 750 gallons of DEF 
weighing approximately 6,750 pounds would be required to meet a 150,000 
mile maintenance interval for DEF refill. A line-haul truck is allowed 
a maximum gross vehicle weight of 85,000 pounds of which approximately 
45,000 pounds is for cargo carrying. A DEF tank of this size would 
reduce the cargo-carrying capacity by 15%. Another example from the 
line-haul industry suggests that a DEF tank size of over 900 gallons 
would be needed to reach the 150,000 mile interval for a common highway 
vehicle with a diesel fuel capacity of 200 gallons and achieving 6.5 
miles per gallon fuel efficiency. Similarly, a medium heavy-duty engine 
would require 375 gallons of DEF weighing 3,275 lbs to meet a 150,000 
mile interval. EPA believes that such tank sizes are clearly not 
reasonably feasible in light of the weight and space demands and 
constraints on heavy-duty trucks and the consumer demand for as much 
cargo-carrying capacity as possible.\25\
---------------------------------------------------------------------------

    \24\ As SCR-equipped vehicles uniformly have a constantly 
viewable DEF level indicator, EPA is not including a DEF tank refill 
interval equal to no less than three times the range of the 
vehicle's fuel capacity (i.e., a 3:1 ratio) for vehicles without 
such an indicator.
    \25\ Navistar states, at page 5 of its comments, that 
``[d]eviation from `minimum' maintenance is rare and intended * * * 
to be temporary. As noted above, EPA has found that DEF refill is a 
new type of maintenance and is not fairly considered as part of the 
maintenance of the catalyst covered under (b)(4). In any case, it is 
clearly of a different type than normal physical maintenance of an 
emission-related part and EPA must make its determination of 
maintenance interval based on the particular maintenance being 
applied. Even Navistar's comments do not suggest that 150,000 miles 
would be an appropriate maintenance interval for DEF refill.
---------------------------------------------------------------------------

    The Agency also believes that intervals that are not as long as 
150,000 miles but are longer than 2:1 would require DEF tanks that are 
too large or too heavy to be feasibly incorporated into vehicles. 
Available data show that heavy-duty engines equipped with SCR-based 
systems will consume DEF at a rate that is approximately 2%-4% of the 
rate of diesel fuel consumption. Because of inherent space and weight 
constraints in the configuration and efficient operation of heavy-duty 
vehicles, there are size limits on the DEF tanks. Currently, there are 
truck weight limits that manufacturers must address when making adding 
or modifying truck designs. EPA expects and believes that manufacturers 
are taking significant and appropriate steps in order to install 
reasonably sized DEF tanks to achieve the DEF refills intervals noted. 
For example, manufacturers are taking such steps as reducing the number 
of batteries on vehicles despite customer demands or designing space 
saver configurations, in some instances extending an already very 
limited frame rail distance to incorporate the DEF tanks and SCR 
systems, moving compressed air tanks inside the frame rails, 
redesigning fuel tank configurations at significant costs, and 
otherwise working with significant size and weight constraints to 
incorporate DEF tanks. EPA was provided with examples of the 
consequences of requiring heavy-duty vehicles to accommodate a DEF 
refill interval of 5:1, and the information provided to the Agency 
strongly suggested that great compromises would be required in cost, 
weight and utility of vehicles. Increased

[[Page 495]]

tank sizes and weights on the magnitude of 150 to 325 lbs. would be 
required and in some cases diesel fuel volumes would need to be 
reduced. The extra weight associated with the DEF required to meet the 
2:1 refill intervals represents a significant challenge to 
manufacturers seeking to meet both weight and size requirements for 
their vehicle designs. In addition, requiring a longer DEF refill 
interval may result in increased greenhouse gases and decreased fuel 
economy. EPA believes that in light of the existing tight space 
constraints and the overall desire to maximize cargo-carrying capacity 
to minimize emissions and meet consumer operational demands, and the 
built-in DEF tank size buffer to ensure DEF refills, that the proposed 
DEF tank sizes are technologically necessary and are also reasonable 
and appropriate. EPA believes that requiring tank sizes above these 
ratios will cause increases in space constraints and weight that would 
not be appropriate for these vehicles. Similarly, EMA notes that under 
its request, manufacturers would employ the 1:1 refilling ratio for 
only a small number of vocational applications and those vehicle 
applications have very limited vehicle space available to house surplus 
DEF. Such applications (e.g., a garbage truck, concrete mixer, beverage 
truck, or airport refueler) will also be refueled daily at central 
locations. At approximately 0.134 ft\3\ per gallon, any extra DEF would 
displace significant space available to vehicle components and 
subsystems on both the vocational trucks at the 1:1 refill interval as 
well as the 2:1 vehicles.
    In its comments, Navistar suggests that a longer DEF refill 
maintenance interval in the range of 35,000 to 45,000 miles should be 
approved. As noted above, one of Navistar's justifications for this 
longer interval is the claim that other technology is available that 
would need a maintenance interval no shorter than this. However, as 
discussed, EPA has no evidence that such technology is actually 
available at this time, nor does EPA believe that the availability of 
this other technology would necessarily impact the maintenance interval 
needed for DEF-based SCR.
    Navistar also argues that engine manufacturers using SCR should 
have made efforts to increase DEF-refill intervals since 2009 and that 
it is ``certainly feasible'' for SCR systems to meet such a range. 
Although Navistar maintains that SCR engine makers can easily quadruple 
the refill interval with little or no effort, Navistar suggests one way 
to reach this interval is to double DEF tank size, and Navistar makes 
no effort to present evidence depicting where such enlarged DEF tanks 
can reasonably be located or the effects on such tanks on operational 
efficiency. In addition, in determining the minimum maintenance 
interval for DEF, Navistar suggests that manufacturers can double 
maintenance intervals by lowering engine-out emissions, which would 
reduce the DEF dosing frequency and in turn extend the refill interval 
for a fixed DEF tank size. The Agency reviewed the potential for engine 
manufacturers to lower engine-out NOx through in-cylinder control 
techniques such as injection timing retard and exhaust gas 
recirculation (EGR). It is clear that lowering engine-out NOx will 
directly lower the quantity of DEF that is needed to meet the NOx 
standard and hence conceptually might extend the DEF refill interval. 
However, as documented in the EPA rulemaking that set a Nonconformance 
Penalty (NCP) for the 2004 NOx standards, for the relevant range of NOx 
control (around 2 g/bhp-hr NOx engine out) and these specific in-
cylinder NOx control technologies, each one gram of NOx reduction is 
expected to result in a 5 percent increase in fuel consumption.\26\ It 
can also be estimated that the DEF consumption rate is approximately 
one percent of fuel consumption per one gram of NOx reduction. Since 
the increase in fuel consumption to reduce NOx by one gram is 
approximately five times higher than the increase in DEF consumption to 
treat that same one gram of NOx, it is clear that reducing engine-out 
NOx in order to extend the DEF refill interval would require an 
increase in the fuel tank size five times that of the volume savings in 
the DEF tank size in order to keep the same refueling interval. In 
other words, reducing engine-out NOx in order to extend the DEF refill 
interval while keeping the same diesel refueling interval would cause 
the fuel tank to grow larger necessitating a reduction in the DEF tank 
volume at a ratio of 5:1. Since that increased fuel tank size would 
then necessitate a smaller DEF tank, the resulting service interval 
would be shortened not lengthened.
---------------------------------------------------------------------------

    \26\ ``Final Technical Support Document: Nonconformance 
Penalties for 2004 Highway Heavy Duty Diesel Engines'', EPA420-R-02-
021, August 2002.
---------------------------------------------------------------------------

    It could be argued that there's no need to increase fuel tank size 
in response to higher fuel consumption rates because operators can 
simply refuel at greater frequencies. To this point, it is important to 
note that the effective operating range of a vehicle on a single tank 
of fuel is a key design parameter that determines the mission 
capability of a vehicle. For example, refuse trucks are designed with 
appropriate fuel capacity to operate over residential and commercial 
customer routes and have enough reserve driving range to then allow 
delivery of payload to a landfill often in remote locations. If a 
manufacturer maintained fuel tank size and increased the frequency at 
which the trucks must refuel, these trucks may not be able to 
accomplish their intended mission without making additional stops for 
fuel. Fueling stations may not be directly located along the remote 
route to some landfills, necessitating unplanned trip deviations. At 
the very least, these trucks would be impaired in the ability to 
accomplish their mission. Similarly, line-haul trucks are designed with 
necessary fuel capacity to deliver freight over significant interstate 
distances while minimizing the need for refueling stops. Increasing the 
frequency at which the trucks must refuel compromises the ability to 
accomplish their mission. Increasing the frequency of refueling stops 
poses a serious negative consequence to the end user of these trucks 
given their use in commercial applications where the time to accomplish 
a mission is business critical. EPA does not believe its allowable 
maintenance provisions are intended to drive this type of impact.
    Navistar also suggests that SCR engine makers are legally required 
to make efforts to improve the time between maintenance for their SCR 
systems. However, the regulations do not require this, and EPA must 
review the technological necessity of maintenance intervals based on 
the existing factual circumstances. Current circumstances do not 
indicate that a larger maintenance interval is appropriate. While EPA's 
statement made in the 2009 notice indicates that EPA will continue to 
monitor the evolution of SCR systems along with urea infrastructure to 
determine whether the frequency of DEF refills can be adjusted, this 
does not imply that adjustment is necessary or appropriate, or in which 
direction such adjustment would go. In addition, regarding Navistar's 
reference to a 1980 EPA rulemaking regarding EPA's consideration of the 
longest interval that any manufacturer recommends, while EPA does look 
at such information, that interval does not necessarily become the 
interval determined under (b)(7). In some instances EPA may set an even 
more frequent interval and in others the Agency may set a less frequent 
interval; EPA's determination of what is a feasible interval for an 
engine family or an industry is based on a number of

[[Page 496]]

factors including manufacturer(s) recommended intervals, any physical 
or technological constraints, burdens that may be placed on the 
operator and what are reasonable expectations of durability from an 
operator's perspective, among other factors.
    After reviewing this data and information, EPA believes that longer 
refill intervals than those noted above would require larger and 
heavier DEF tanks, and the design and engineering work performed by 
manufacturers thus far indicate that the recommended DEF refill 
intervals noted above approximates the maximum feasible maintenance 
intervals associated with reasonable DEF tank sizes, given the 
substantial negative consequences of longer DEF refill interval 
requirements. The maintenance intervals recommended ensure that the 
functions and operational efficiency of such vehicles are not overly 
compromised. Based on this information we believe the intervals noted 
above are warranted.
    EPA is not approving a 1:1 DEF maintenance interval across the 
heavy-duty engine class at this time. EPA notes that manufacturers have 
been meeting a 2:1 ratio for DEF tank size for the past two years and 
the commenters have not yet provided sufficient evidence that this 
ratio will be infeasible in the future. Moreover, the information EPA 
has received to date has not shown that any change in the maintenance 
interval is necessary or appropriate throughout the heavy-duty engine 
category, rather than for particular applications, or that a refill 
interval as low as 1:1, rather than 1.8:1 or 1.5:1, is necessary or 
appropriate. EPA recognizes that the implementation of the future 
standards for greenhouse gases, beginning as early as the 2013 model 
year, may have some implications for this issue, but the SCR Engine 
Manufacturers have not shown that these standards, which are phased in 
and are not applicable in the 2012 model year, will cause the 2:1 
refill interval to be infeasible across the industry, and certainly not 
in the 2012 model year. While EPA agrees that the warnings and 
inducements in place for failure to replenish DEF will restrict the 
ability of operators to run without DEF, and have made operation 
without DEF virtually unheard of, a DEF tank ratio of 1:1 will increase 
the likelihood that operators will need to make more frequent stops to 
replenish DEF, and possibly may need to stop solely to replenish DEF, 
which may place a greater burden on the operator in terms of the 
frequency of DEF refills.
    EPA also notes that the regulations allow any manufacturer to 
petition EPA under the ``paragraph (b)(7) process'' for a shorter 
maintenance interval for a particular engine family or application than 
that approved for the industry if the manufacturer can show that a 
shorter interval is the maximum feasible interval necessary for the 
particular engine or vehicle configuration being certified.
    Navistar and the SCR Engine Manufacturers suggest, respectively, 
that the ``likelihood of the maintenance being performed in-use'' is 
the touchstone of allowable maintenance, or is the most important 
factor in establishing the precise maintenance interval. At the outset, 
EPA believes it is important to note the context of the term 
``reasonable likelihood of being performed in-use'' within paragraph 
(b)(6)(ii). For critical emission-related maintenance (including 
critical emission-related maintenance under paragraph (b)(6)(i), as 
well as such maintenance as determined by EPA under (b)(7)), 
manufacturers are required to show such likelihood prior to performance 
of such maintenance on durability test vehicles. Manufacturers can 
satisfy this requirement by meeting one of the specified conditions in 
paragraphs (b)(6)(ii) (A) through (F). Paragraph (b)(7) does not 
specify any additional showing required of the manufacturer should an 
alternative maintenance interval for emission-related critical 
maintenance be approved. Thus, if a manufacturer can show compliance 
with one of the specified conditions in (b)(6)(ii), the manufacturer 
has met the regulatory requirement to show a ``reasonable likelihood of 
[the maintenance] being performed in-use'' as required under paragraph 
(b)(7). As noted in the 2009 notice, SCR engine manufacturers (or 
vehicle manufacturers) are using a clearly displayed visible signal 
system approved by EPA, meeting the requirements of (b)(6)(ii)(C). In 
addition, SCR engine manufacturers are going beyond the minimum 
requirements of (b)(6)(ii) and are designing, and are expected by EPA 
to design (under the adjustable parameter regulatory provisions) their 
systems to include inducements that will adequately trigger the 
operators to refill the DEF tanks by reducing vehicle performance to a 
point unacceptable for typical driving, which would meet the 
requirements of (b)(6)(ii)(A).\27\ Section (b)(7) does not include an 
affirmative requirement on the petitioner to demonstrate nor on EPA to 
find a likelihood of maintenance being performed beyond that which is 
clearly and specifically prescribe at (b)(6). Indeed, although EPA 
``noted'' the likelihood of performance in its 2009 notice, EPA did so 
in order to provide the regulated community with a complete picture of 
how the allowable maintenance provisions should be read together and 
how they complement each other. In addition, EPA notes that the 
determination of what is maximally feasible under (b)(7) does not 
require, or in fact include, a consideration of the inducements (as 
described above). EPA nevertheless believes that such inducements 
clearly and sufficiently provide the necessary demonstration of 
likelihood of maintenance.
---------------------------------------------------------------------------

    \27\ See EPA's draft guidance at 76 FR 32886 (June 7, 2011).
---------------------------------------------------------------------------

    Conversely, with respect to the arguments from the SCR Engine 
Manufacturers, the fact that maintenance is likely to occur does not 
affect the determination of what is the appropriate ``technologically 
necessary maintenance interval.'' While the likelihood of maintenance 
and the technological necessity of regular maintenance are both 
required elements under (b)(7), and the desire to increase the 
likelihood of maintenance may inform the particular form of the 
maintenance interval (i.e. having DEF refill maintenance be at the same 
time as oil change), the two requirements are separate and distinct. 
The ``technologically necessary maintenance interval'' requirement is 
motivated by a desire to minimize the amount of emission-related 
maintenance, which is distinct from the need to make sure that such 
maintenance is likely to occur. As noted, the SCR Engine Manufacturers 
have not shown that the 1:1 maintenance interval is ``technologically 
necessary.'' Therefore, while EPA agrees that the DEF refill 
maintenance is likely to occur in use, the 1:1 interval does not meet 
the requirements of (b)(7).

V. Approval of New Scheduled Maintenance for SCR Systems

A. Light-Duty Approval

    For the reasons set forth above, EPA finds it appropriate to 
approve new scheduled maintenance intervals for DEF refill equal to the 
scheduled oil change interval for all light-duty vehicles and light-
duty trucks, medium duty vehicles and other chassis certified vehicles 
up to 14,000 pounds for 2011 and later model years.

B. Heavy-Duty Approval

    For the reasons set forth above, EPA again approves new scheduled 
maintenance intervals for DEF based on ratios to a given vehicle's fuel 
capacity for engine certified heavy-duty engines and vehicles for 2012 
and later model years. Vocational heavy-duty vehicles

[[Page 497]]

(e.g., dump trucks, concrete mixers, refuse trucks, and other 
centrally-fueled vehicles) are permitted a DEF tank maintenance 
interval no less than the vehicle's fuel capacity (i.e., a 1:1 ratio of 
DEF refill to fuel refill). For all other heavy-duty vehicles, EPA 
approves a DEF tank refill interval no less than twice the range of the 
vehicle's fuel capacity (i.e., a 2:1 ratio).

C. Reasonable Likelihood of Maintenance Being Performed In Use

    As stated above, because DEF refills are considered ``critical 
emission-related maintenance,'' manufacturers must ``show the 
reasonable likelihood of such maintenance being performed in use.'' 40 
CFR 86.094-25(b)(6)(ii) and 86.1834(b)(6)(ii) provide a number of means 
by which manufacturers may demonstrate such a reasonable likelihood. 
Among those means of demonstration are visible signal systems to alert 
drivers and operators that maintenance is needed, or data demonstrating 
that drivers or operators are induced to perform maintenance. EPA 
intends to review specific manufacturer certification applications in 
order to review whether these regulatory requirements are met.

D. Applicability

    The Agency, as stated above, has approved alternative maintenance 
requests to ensure the proper functioning of SCR systems by allowing an 
appropriately frequent refilling of DEF tanks. We approve these 
requests for all future model years. EPA expressly reserves its ability 
to review this approval at any time in the future, should any 
technological advances be made that would allow for more or less 
frequent DEF refilling or otherwise call this approval into question.

VI. Procedures for Manufacturer Objections

    Any manufacturer may request a hearing on this determination. The 
request must be in writing and include a statement specifying the 
manufacturer's objections to this determination, and data in support of 
such objections. If, after review of the manufacturer's objections and 
supporting data, we find that the request raises a substantial factual 
issue, we shall provide the manufacturer with a hearing in accordance 
with 40 CFR 86.1853-01 with respect to such issue.

    Dated: December 23, 2011.
Gina McCarthy,
Assistant Administrator for Air and Radiation.
[FR Doc. 2011-33842 Filed 1-4-12; 8:45 am]
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