[Federal Register Volume 63, Number 93 (Thursday, May 14, 1998)]
[Notices]
[Pages 26798-26806]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-12850]
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ENVIRONMENTAL PROTECTION AGENCY
[FRL-6013-8]
Retrofit/Rebuild Requirements for 1993 and Earlier Model Year
Urban Buses; Certification of Equipment
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of EPA certification of equipment provided by Detroit
Diesel Corporation.
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SUMMARY: Today's Federal Register notice announces EPA's decision to
certify equipment to the 0.10 g/bhp-hr standard for the Urban Bus
Retrofit/Rebuild Program. The equipment is provided by the Detroit
Diesel Corporation (DDC).
DDC submitted to EPA a notification of intent to certify equipment,
in materials signed July 16, 1997, pursuant to the program regulations
at 40 CFR Part 85, Subpart O. On November 6, 1997, EPA published a
notice in the Federal Register that the DDC notification had been
received and made the notification available for public review and
comment for a period of 45 days (62 FR 60077). EPA has completed its
review and the Director of the Engine Programs and Compliance Division
has determined that it meets all requirements for certification.
Therefore, EPA certified this equipment in a letter to DDC dated April
6, 1998.
The equipment consists of the base engine components used on the
25% reduction retrofit/rebuild kit certified by DDC, components from
the 25% retrofit catalyst kit certified by Engine Control Systems, Ltd.
(ECS) and a TurboPac supercharger system supplied by Turbodyne Systems,
Inc. that supplies additional air for combustion during engine
acceleration.
The kit is applicable to 6V92TA urban bus engine models made by
Detroit Diesel Corporation (DDC) from model years 1979 to 1989 and
equipped with mechanical unit injectors (MUI), and may be used
immediately by transit operators in compliance with program
requirements. The kit would be available in three horsepower levels
(253, 277, and 294).
EPA has determined that this DDC kit complies with the 0.10 gram
per brake horsepower-hour (g/bhp-hr) particulate matter (PM) standard
for the applicable engines. EPA has not determined that DDC's
notification complies with the life cycle cost requirements of the
program regulations because no life cycle costs were supplied with the
application.
Today's Federal Register notice does not trigger any additional
program requirements for transit operators. The 0.10 g/bhp-hr PM level
has already been triggered for all engines covered by this
notification.
The notification of intent to certify, as well as other materials
specifically relevant to it, are contained in Category XX-A of Public
Docket A-93-42, entitled ``Certification of Urban Bus Retrofit/Rebuild
Equipment.'' This docket is located at the address listed below.
Additional details concerning this certification, the DDC's kit,
and responsibilities of transit operators, are provided below.
DATES: EPA certified this equipment in a letter to DDC dated April 6,
1998. Today's Federal Register notice announces this certification. The
0.10 g/bhp-hr standard was triggered on March 14, 1997 (62 FR 12166)
for all engines covered by this certification.
ADDRESSES: The DDC notification, as well as other material specifically
relevant to it, are contained at the U.S. Environmental Protection
Agency's Public Air Docket A-93-42 (Category XX-A), Room M-1500, 401
``M'' Street SW, Washington, DC 20460.
The DDC notification of intent to certify, as well as other
materials specifically relevant to it, are contained in the public
docket indicated above. Docket items may be inspected from 8:00 a.m.
until 5:30 p.m., Monday through Friday. As provided in 40 CFR Part 2, a
reasonable fee may be charged by EPA for copying docket materials.
FOR FURTHER INFORMATION CONTACT: Anthony Erb, Engine Programs and
Compliance Division (6403J), U.S. Environmental Protection Agency, 401
``M'' St. SW, Washington, D.C. 20460. Telephone: (202) 564-9259.
SUPPLEMENTARY INFORMATION:
I. Description of the Certified Kit
The certified kit described in today's Federal Register notice is
provided by DDC. It is certified to the 0.10 g/bhp-hr standard but does
not comply with the applicable life cycle cost requirements of the
program. No cost data was provided in the notification.
The certification described in today's notice applies to 1979
through 1989 model year DDC 6V92TA engines that are equipped with
mechanical unit injectors (MUI) and certified to federal emissions
standards. It does not apply to engines certified to California
emissions standards. The impact of this decision on transit operators
is discussed in more detail in the ``Transit Operator Requirements''
section below.
[[Page 26799]]
The kit, described further below, consists of base engine
components used on the 25% reduction kit certified by DDC earlier, a
catalytic exhaust muffler supplied by Engine Control Systems, Ltd.
(ECS), and a TurboPac supercharger system supplied by Turbodyne
Systems, Inc. that supplies additional combustion air during
acceleration. The kit is available in three horsepower (hp) ratings
(253, 277, and 294 hp).
For retrofit with the DDC kit, an engine is rebuilt in accordance
with standard DDC rebuild procedures, using specified engine
components. This component set essentially includes the equipment
certified by EPA to provide a 25% particulate reduction on October 2,
1995, at 60 FR 51472. These components are provided in two separate
sets of parts. The first set of components is comprised of newly
manufactured parts, including a gasket kit, air inlet hose, cylinder
kits (piston assemblies and cylinder liners) a by-pass valve and a
truck type throttle delay. The second set of components includes
Reliabilt TM remanufactured parts, including the fuel
injectors, camshafts, blower assembly, turbocharger, and head
assemblies. Kit usage is based on engine rotation (righthand (RH) or
lefthand (LH)), engine orientation, right bank cam gear mounting (bolt
or nut), and engine power output based on injector size. The only
difference from the previously certified equipment according to DDC is
the inclusion of a truck-style throttle delay, adjustment of the
throttle delay and injector timing settings to improve driveability.
Additionally, the cylinder kit components have been modified to improve
durability.
The converter is the same size and shape as the catalytic converter
muffler certified by ECS for the Urban Bus Program as described in the
Federal Register on January 6, 1997 (61 FR 746), is a direct
replacement for the original equipment muffler, and is designed to fit
the specific bus/engine combination. The use of diesel fuel that has
been mixed with crankcase oil is prohibited by DDC.
The third constituent of the kit consists of an electrically
powered supercharger system which is supplied by Turbodyne Systems,
Inc. This component set, referred to as the TurboPac TM
supplies additional intake air during engine acceleration from low
engine speeds. DDC states that in addition to decreasing PM emissions
and visible smoke during engine acceleration, the supercharger also
improves engine response and vehicle driveability by reducing the fuel
modulation during acceleration. The basic system consists of a
supercharger blower, a diverter valve, a boost pressure sensor, an
electrical control box and power cables, and a throttle switch for
detecting the start of the engine acceleration mode, and will be
supplied in two kits. One includes those components common to all
installations and a second kit to accommodate the installation
requirements of the various engine and vehicle configurations.
To complete an engine rebuild two (2) base engine component kits,
one (1) converter muffler kit, and two (2) supercharger kits are
required. The specific kits used will depend on the engine/vehicle
combination.
DDC states there are no differences in the service intervals or
maintenance practices for the base engine associated with the
installation of the upgrade kit. The converter/muffler requires no
regularly scheduled maintenance, only an occasional cleaning if the
maximum back pressure of the exhaust system is exceeded. The
supercharger does not require scheduled maintenance; however, a visual
inspection for air leaks is recommended whenever the engine is
serviced.
Standard procedures as described in the service manual for 92
Series engines are to be used when rebuilding the base engines using
the candidate equipment. No unique rebuild procedures are required.
Use of the candidate kit is restricted to 6V92TA Detroit Diesel
Corporation engines manufactured from January 1979 through December
1989, equipped with mechanical unit fuel injectors (MUI), and
originally certified to meet Federal emission standards. The required
fuel is low sulphur (0.05% max by weight) diesel fuel, either number 1
or number 2. Complete rebuild kits will be sold by DDC through normal
distribution channels.
All of the testing presented by DDC for this certification was
conducted using original equipment (OE) parts, except for the converter
muffler and the TurboPac components. EPA has no assurance that engines
rebuilt using parts that are not (OE) would comply with the 0.10 g/bhp-
hr standard. Therefore, use of engine parts that are not the specified
OE parts are not covered by the certification described in today's
Federal Register notice.
Pursuant to 40 CFR 85.1409, DDC will provide a 100,000-mile defect
warranty and a 150,000-mile emissions performance warranty for the kit,
and all of its components.
EPA's certification of the Engelhard Corporation's ETX
TM kit (62 FR 12166; March 14, 1997) triggered the 0.10 g/
bhp-hr standard for 1979-1989 6V92TA MUI engines. That kit provided the
three power ratings: 253, 277, and 294 hp that are included in this
certification. Consequently, the certification of the DDC kit described
in today's Federal Register notice, does not trigger the 0.10 g/bhp-hr
standard for engines included in the certification.
II. Background and Basis for Certification
In a notification of intent to certify equipment, composed of an
initial document signed July 16, 1997 and subsequent documents, DDC
applied for certification of the kit under the Environmental Protection
Agency's (EPA) Urban Bus Retrofit/Rebuild Program. Engines applicable
to the certified kit are 6V92TA urban bus engine models made by Detroit
Diesel Corporation (DDC) from model years 1979 to 1989 that are
equipped with mechanical unit injectors (MUI) and certified to, or
rebuilt to, comply with federal emissions standards. The certifier's
principal place of business is: Detroit Diesel Corporation, 13400 Outer
Drive, West, Detroit, Michigan 48329-4001.
Using engine dynamometer (transient) testing in accordance with the
Federal Test Procedure for heavy-duty diesel engines, DDC demonstrated
compliance with the 0.10 g/bhp-hr particulate matter (PM) emissions
standard. Engine dynamometer data, shown below in Table A, is the basis
for the certification approval of the kit when used on applicable
engines. The emissions test data is part of DDC's notification of
intent to certify, which is available in the public docket located at
the above-mentioned address. All testing was conducted using #2 low-
sulfur diesel fuel.
Table A.--Exhaust Emissions Summary
------------------------------------------------------------------------
g/bhp-hr
---------------------------------
Gaseous and particulate test 6V92TA
1989 HDDE standards MUI with
DDC kit
------------------------------------------------------------------------
HC.................................... 1.3................... 0.1
CO.................................... 15.5.................. 0.4
NOX................................... 10.7.................. 9.8
PM.................................... 0.60.................. 0.091
BSFC \1\.............................. ...................... 0.464
Smoke Test: Standards............. ........
ACCEL............................... 20%................... 3.3%
LUG................................. 15%................... 2.5%
PEAK................................ 50%................... 4.2%
------------------------------------------------------------------------
\1\ Brake Specific Fuel Consumption (BSFC) is measured in units of lb/
bhp-hr.
[[Page 26800]]
The exhaust emissions data presented by DDC is from testing a
Detroit Diesel Corporation (DDC) engine model 6V92TA, in accordance
with procedures set forth at 40 CFR Part 86, Subparts N and I. The
engine model was tested after being equipped with the DDC kit. The 6V92
engine was tested in one horsepower (hp) rating: 277hp.
The data of Table A demonstrates that the test engine, when rebuilt
with the DDC kit, PM emissions are less than 0.10 g/bhp-hr and,
emissions of hydrocarbon (HC), carbon monoxide (CO), NOX and
smoke opacity are within applicable federal standards.
This action applies a PM emissions level of 0.10 g/bhp-hr to all
1979 through 1989 DDC 6V92TA MUI urban bus engines, when properly
equipped with the DDC kit and when using either diesel fuel #1 or #2.
Table B lists the applicable engine models and certification levels
associated with the certification announced in today's Federal
Register.
Table B.--Certification Level of DDC Kit
------------------------------------------------------------------------
Certification PM
Engine models Engine codes level
------------------------------------------------------------------------
1979-1989 DDC 6V92TA MUI........ All certified to 0.10 g/bhp-hr.
meet federal
emissions
standards.
------------------------------------------------------------------------
All engines for which the DDC kit is intended to apply are expected
to meet the 0.10 g/bhp-hr PM standard because the kit instructs the
rebuilder to replace all emissions-related parts during the rebuild
with DDC specified parts included in the kit, install the converter
muffler and install the TurboPac system. The engine-out emissions level
(upstream of the catalyst) is expected to be predictable because all
emission-related parts are replaced using the DDC specified emissions-
related parts and settings of the kit. As demonstrated by the test
engine, the combination of the specified parts, the specified settings
of the kit, the converter muffler and the TurboPac system, result in a
PM level less than 0.10 g/bhp-hr.
A life cycle cost analysis is necessary only for certification of
equipment that is meant to trigger a program emissions standard.
Certification of Engelhard Corporation's ETXTM kit triggered
the 0.10 g/bhp-hr standard for 6V92TA MUI engines, and made available
kits rated at 253, 277, and 294 hp. The DDC certification does not
include a cost analysis and one is not necessary for this
certification. DDC states that engines equipped with the kit will have
no additional maintenance or service requirements.
III. Summary and Analysis of Comments and Concerns
Comments were received from five parties in response to the Federal
Register notice of November 6, 1997 (62 FR 60077). The commenters are
Johnson Matthey Incorporated (JMI), Engelhard Corporation (Engelhard),
the Washington Metropolitan Area Transit Authority (WMATA), the
Maryland Department of Transportation Mass Transit Administration
(MTA), and the Milwaukee County Transit System (MCTS). JMI and
Engelhard provided extensive comment. JMI is a manufacturer of
equipment certified to meet the 0.10 g/bhp-hr standard for the 1979-
1989 6V92TA MUI engines (see 62 FR 60079; November 6, 1997). Engelhard
is the manufacturer of equipment certified under the urban bus program
that triggered the 0.10 g/bhp-hr standard for the 1979-1989 6V92TA MUI
engines (see 62 FR 12166; March 14, 1997). WMATA, the MTA, and the MCTS
are large transit bus operators in major metropolitan areas, which are
subject to requirements of the urban bus program. The transits provided
generally favorable comments on their experience with the equipment.
Comments or issues fell into the following general categories: (A)
applicability of the kit; (B) description of the kit; (C) testing
demonstration and documentation; (D) life cycle cost analysis; (E)
warranty; (F) durability, and (G) in-use experience. All
correspondence, comments, and other documentation are located in the
public docket at the address above.
(A) Applicability
In the November 6, 1997, Federal Register notice, EPA stated that
the information provided in DDC's notification applied to 6V92TA DDC
engines manufactured from January 1979 to December 1989 equipped with
mechanical unit injectors (MUI) and originally certified to meet
Federal emission standards.
In comments dated December 19, 1997, Engelhard stated that DDC has
failed to provide information demonstrating that this retrofit system
can be applied safely to all vehicles. Engelhard commented that the
electrical charging systems of urban buses can vary by make and design
and asked how can we be sure that this system can be installed in all
urban buses without an assessment of the charging system and
information on the stress that the system that the DDC system will
place on the charging system. Additionally, Engelhard commented that
the Turbodyne system uses a high speed motor that draws over 300 amps
for 8 seconds while the bus is accelerating. This will dramatically
increase the load on the bus' electrical system and will cause
premature wear of the alternator, battery and electrical systems
according to Engelhard. The motor that Turbodyne uses to drive the
compressor can also fail. Engelhard asked if there are any durability
data or effective life data for this motor, and noted that because
urban buses stop and start continuously the Turbodyne system will be
operating during a large portion of the bus operating time.
According to Engelhard this system is not designed to operate
continuously and the urban bus application will require it to operate
much more frequently than it is designed to operate. DDC needs to
provide information, demonstrating that it is reasonable to expect the
Turbodyne system will remain operational for 150,000 miles. Engelhard
commented that it had thoroughly tested the Turbodyne system and found
air leaks and malfunctioning of the controller system occurred
frequently. In its comments of December 19, 1997 JMI states that the
Turbodyne system appears to have two states: on and off. Considering
the performance cycle of a typical urban bus, this system would be
turned on every time a bus would pull away from the curb. Since the
system has a high amperage draw on the bus' electrical system long term
use could prematurely wear out the battery or starter solemoid. What
are the long term impacts on the life to the electrical system? Was a
standard bus battery/starter system used in the test cell? How high is
the amperage and could this require modifications to the bus'
electrical system? Could rewiring be required and are there concerns of
shorts, or fire hazards?
In response to these comments, DDC states that The TurboPac unit is
intended to compensate for the inherent lag in the engine turbocharger
during rapid accelerations from low speed/light load conditions. During
these periods the TurboPac operates at high speed with a current draw
of approximately 300 amps. At all other times when the engine is
operational, the TurboPac runs at low speed in the ``standby''
condition with a current draw of about 10 amps. Accelerations
sufficient to trigger high speed TurboPac operation are expected to
occur quite frequently in urban bus applications. However, the duration
of the high speed TurboPac operation is very short. The system limits
high speed operation to a maximum of eight
[[Page 26801]]
seconds. In most cases the system returns to standby operation in a
shorter period of time after a preset air box pressure has been
achieved. DDC logged data on a pilot bus installation at MATS in
Milwaukee to determine the real-world duty cycle and current draw of
the TurboPac 2500. The bus was run on a city route through downtown
Milwaukee in November 1997. The data logger recorded data for
approximately eight hours in one second intervals. The data analyzed
encompass a 3 hour time period from just before noon to approximately
3:00 p.m. This portion was chosen due to the relatively low idle time
in this sample and the inability of the software to accommodate
additional data. In the evaluation, when off it was assumed to draw 10
amps and when it was on it was assumed to draw 300 amps. The data based
on this evaluation indicates that the TurboPac will be active in the
high speed mode approximately 10% of the time. The time average draw is
about 35 amps.
DDC states that in order to operate on a dedicated electrical
circuit, unit power is taken directly from the battery, so there are no
modification necessary to the bus electrical system. A 500 amp fuse is
installed on the circuit to the controller to protect the system in
case of a short. DDC began field trials of the retrofit system in July
1997. To date, eight complete retrofit units have been installed in
buses and are in regular revenue operation at four major U.S. transit
services. DDC stated that there have been no problems with the
electrical systems or batteries on these buses. These units have almost
40,000 miles of customer service with the high mileage unit having
accrued over 13,000 miles. In addition, TurboPac systems were installed
on two buses operating in transit service. One of these units
experienced an early failure of a hand assembled prototype controller.
The other bus has operated over 18,000 miles with no failures to the
TurboPac system.
DDC states that the in-use evaluation program has not revealed any
problems with leaks. Consequently, no improvements have been found
necessary to reduce leaks. Since leaks have not been a problem, DDC has
not quantified the size of leak that would be sufficient to impair
performance. With regard to the Engelhard comment concerning system
leaks, DDC commented that the TurboPac system which Engelhard evaluated
in early 1996 was a prototype design. In this design, the TurboPac and
the engine turbocharger compressor were configured in parallel and a
diverter valve was placed downstream where the two flow paths merged.
During TurboPac operation, the valve was positioned to permit flow from
the TurboPac to enter the engine and to block off flow from the
turbocharger. When the TurboPac was not operational, the valve assumed
the opposite position. In some early units, the diverter valve did not
seal adequately and there was backflow through the turbocharger during
TurboPac operation which resulted in reduced system performance. The
current system has been completely redesigned to alleviate this
problem. The TurboPac and engine turbocharger are now in a series
arrangement. A check valve is placed downstream of the TurboPac and
allows the engine to draw its intake air either from the TurboPac or
directly from the engine air cleaner. The check valve has been shown to
seal adequately and prevent backflow during TurboPac operation. DDC
noted that the check valve operates in a relatively low pressure zone
compared to the earlier diverter valve which was exposed to the full
pressure supplied by the turbocharger.
Additional batteries or larger capacity alternators have not been
installed in any of the pilot units and there have been no problems
with the electrical system. DDC states that because the electrical
connections for the TurboPac system are independent of the bus
electrical system, it is not necessary to rewire electrical systems on
buses. No fires or electrical shorts are expected and none have been
reported during the pilot installations. DDC does not expect any
negative impacts on the long term viability and integrity of bus
electrical systems. During emission testing electrical power for the
TurboPac was batter supplied.
DDC has stated that the Delco-Remy 50dn alternator rated at 270 or
300 amps is the standard in the transit industry and is the only
alternator that DDC offered with the 6V-92 transit engines. DDC cannot
state that no other alternator is or could be used on affected transit
buses, but does state that the use of another type alternator would be
extremely rare. Delco-Remy provided a statement that the 50dn
alternator is an approved candidate for use with the DDC kit. It
further states that the 50dn charging system is designed to operate at
full capacity and that electrical demand beyond the alternators
capacity will not adversely affect the alternators performance,
reliability or durability.
Based on the above discussion and the responses provided by DDC
concerning the comments, EPA finds no clear evidence that the DDC
system is inadequately designed to operate on the urban bus engines to
which it applies. Further, the in use evaluation program has
demonstrated the ability to operate without adversely effecting the bus
electrical systems. Therefore, EPA can find no reason based on the
above comments not to grant certification of this kit. EPA further
notes that DDC is required to provide a 100,000 mile defect warranty
and 150,000 mile emissions performance warranty for the DDC kit and all
of its components.
JMI commented that a Turbodyne representative stated publicly at
APTA's Urban Bus Retrofit/Rebuild Program Panel session in Nashville,
TN in August 1997, that Transit buses with routes that would require
the TurboPac to operate more than 30% of the time would not be good
candidates for using this system to reduce PM levels below 0.1 g/bhp-
hr. JMI noted that this was not referenced in the notice of intent to
certify and asked if this statement is still accurate? What data is
available to substantiate DDC/Turbodyne's claim and is industry be
informed of this comment? In response, Turbodyne provided information
in letters dated February 23 and February 27, 1998 that during the
August 1997 APTA Bus Maintenance Workshop in Nashville, a transit
operator commented that the TurboPac on his routes ``would be on all
the time.'' The Turbodyne representative replied that he would not
recommend the TurboPac for applications that exceeded 30% high-speed
duty cycle. The ceiling of a 30% duty cycle was based on the assumption
that the bus alternator would not have sufficient excess capacity for
this type of duty cycle. Excess alternator capacity is a direct
function of the accessory load and alternator rating. In citing an
example, a 270-amp system with a total electrical load including the
accessories of lighting and air conditioning would be 160 amps. The
excess alternator capacity in this situation would be 110 amps.
Assuming a 10% duty cycle, this system would have more than sufficient
excess alternator capacity to meet the average current draw from the
TurboPac of 35 amps.
However, if a hypothetical duty cycle of 40% were to exist, the
TurboPac would require a time-average draw of 140 amps and in this
scenario the alternator would need to be upgraded before the TurboPac
would be appropriate. Turbodyne stated, however, that duty cycles that
exceed 30% are not expected. In practice, Turbodyne stated it would be
very hard to envision a scenario that would demand 30% high speed
operation for more than a few minutes. However,
[[Page 26802]]
DDC/Turbodyne will analyze and make recommendations for any situation
in which the operator believes the vehicle electrical system capacity
may be in question.
(B) Description of the DDC Kit
In its comments Engelhard asked how DDC will ensure that future
rebuilds using this kit will use a new catalyst and not an existing
catalyst. Will all parts be purchased from DDC? What is the price? Will
the catalyst be different from the standard ECS 25% catalyst? Will the
catalyst be labeled as part of the DDC kit? Can DDC ensure catalysts
are not swapped between buses? In response, DDC states that a converter
muffler will be part of each rebuild kit. Complete kits will be sold by
DDC through normal distribution channels. It will not be possible to
purchase a complete rebuild kit without a converter/muffler assembly
included. Swapping of catalysts between buses should not be an issue
since a new catalyst is provided with each kit. The converter muffler
which will be included in the DDC rebuild kits are supplied by Engine
Control Systems, LTD (ECS) and are identical to the ECS converter/
mufflers certified to provide a 25% reduction in PM emissions on DDC
engines on January 6, 1997 as referenced earlier. The catalyst will be
labeled with an ECS serial and model number. Pricing information on the
catalyst was not provided as this kit is not being certified within the
cost ceiling requirements.
In its comments, JMI asked how many superchargers are actually
installed on the engine? What are the physical space requirements for
the supercharger(s)? Will there be adequate space for the
supercharger(s) on all engines and why are two base engine component
kits required?
DDC indicates that one TurboPac Supercharger unit is required for
each installation. However, the equipment will be supplied in two kits,
one containing components required for all installations and a second
which includes those components needed to accommodate the installation
requirements of the various engine and vehicle configurations. With
regard to the space issue, DDC indicates that it has performed pilot
installations on eight different buses which represent five different
configurations and all have had adequate space to install all kit
components. According to DDC, these configurations represent over 60%
of the MUI buses in operation. The remaining designs have been reviewed
by DDC and found to be similar.
JMI and Engelhard commented that the DDC instructions for
installation tell the installer to, ``provide support to the TurboPac
as required.'' JMI asked what support is required and if the TurboPac
is not supported as required does this negate the warranty? Engelhard
asked if this means that additional support of the unit is necessary to
prevent damage to it or to keep it from contacting other engine
components. Engelhard also expressed the concern that the directions
for installation of the Turbodyne TurboPac are insufficient to ensure
proper installation and operation of the system. Engelhard further
noted that the instructions require the assembler to ``mount the
controller in the engine compartment. The location of the controller
must be in a position which will allow connection of the motor leads
directly to the TurboPac. The location should provide easy connection
to the engines starter and in a location which will receive adequate
air circulation.'' Engelhard asked what is adequate air circulation?
Engelhard asked if heat would damage the controller and whether the
unit needs to be shielded?
In regard to the support concerns, DDC states that the motor and
compressor weigh 16.5 pounds and will need to be properly supported.
There are mounting holes on the unit to which the bracket can be
attached. In the pilot installations, either the transit property or
the DDC distributor has fabricated a simple bracket to support the
unit. DDC will provide installation instructions in the assembly and
installation manual provided with each kit to assist maintenance
personnel in selecting appropriate support. DDC states that if the
equipment is not properly installed, damage to the TurboPac due to
faulty support is not warrantable. DDC states that support failure will
not damage the engine because the location of the motor and compressor
is sufficiently away from the engine and does not require contact of
any kind with the engine components. DDC states that extreme heat would
damage the controller. Therefore, the controller will be located away
from exhaust system components, preferably in a area where air can
circulate around it. It is not recommended that the electronic
controller be shielded. DDC will provide guidance on locating the
controller in the installation instructions that are provided with each
kit. EPA finds that based on the pilot installation experience cited by
DDC and its review of remaining designs, the guidance provided by DDC
in its installation instructions should be adequate to properly support
and locate the kit components. EPA further notes that failure of kit
components which are installed according to DDC instructions will be
covered under the warranty provisions.
Engelhard commented that DDC did not provide a component list for
the retrofit engine and stated that the list is necessary for
comparison of the parts used in a standard rebuild to the DDC retrofit
kit. Engelhard asked if the truck check valve was installed on the test
engine and whether it will be included in the DDC retrofit kit? In
response DDC provided information that the build list for the test
engine corresponds to ``new part kit'' number 23522349 and ``reliabilt
kit'' number R3518035 included in Parts List Number 3 of the
notification; TurboPac kits as defined in Parts List Number 5 and
converter muffler part number 6000-005D as shown in Parts List Number 6
also in the notification. The check valve is integral to the throttle
delay assembly and was included in the ``new part kit'' on the test
engine.
JMI commented that the DDC application states that ``the throttle
delay was set for optimum vehicle driveability.'' JMI questioned how
you adjust for optimum vehicle driveability in the engine test cell?
Was the throttle delay changed to account for the faster response of
the engine with the TurboPac? If not, what is the rationale behind this
decision? In response, DDC stated that the throttle delay is a dashpot
device which delays the movement of the injector rack to the full fuel
position. The setting dimension controls the rack position at which
delays are incurred. A higher numerical setting dimension results in
the rack being further from the full fuel position and results in more
delay and poorer driveability. The minimum numeric setting dimension
positions the rack closest to the full fuel position before any delay
is incurred. This results in the minimum delay and the best
driveability. During development testing for the retrofit system, DDC
determined that the 0.10g/bhp-hr PM level and acceptable engine smoke
opacity could be achieved with the minimum throttle delay setting of
0.490 inches. The orifice through which the oil is purged during engine
acceleration is the same for both truck and bus throttle delays. The
truck throttle delay has a smaller fill hole which slows the fill rate
of the oil in the throttle delay body. Bus throttle delays have a
larger fill hole to provide a more rapid fill. The use of the retrofit
system has shown that the more rapid fill of the bus throttle delay is
no longer required to achieve 0.10 g/bhp-hr PM and
[[Page 26803]]
acceptable smoke control. Therefore, a truck type throttle delay was
specified in order to provide improved driveability.
JMI commented that in the notification DDC states that; ``Pursuant
to 40 CFR Section 85.1406(e), * * * does not alter or render
inoperative any feature of the on-board diagnostic system incorporated
by the engine manufacturer.'' JMI asked what type of diagnostic systems
are incorporated on MUI engines? In response, DDC states that MUI
engines are not equipped with a computer which can store problem codes
that can be used later by a service technician to diagnose an engine
problem. The reference statement was provided by DDC as part of the
standard format for notifications of intent to certify under the urban
bus retrofit/rebuild program.
(c) Testing
JMI commented that the notification started that the rebuilt engine
for the test program was originally a 1984 engine but it doesn't state
that the engine was rebuilt to a 1984 configuration prior to testing.
What was the configuration of the baseline engine and is it consistent
with the claims made by DDC? Engelhard commented that DDC has not
included a baseline test for comparison with the proposed retrofit kit
and that this data is necessary to verify that the equipment being
installed on the engine does not affect engine performance or fuel
economy.
EPA notes that DDC did not perform baseline testing for this
notification. Under the urban bus retrofit/rebuild program baseline
testing is required when certification is requested within specified
life cycle cost limitations. In such cases, baseline testing is needed
to demonstrate equipment impact on fuel economy and associated life
cycle costs. EPA does not require baseline testing when demonstrating
compliance with the 0.10 g/bhp-hr PM standard when certification with
life cycle cost requirements is not requested and if all applicable
engines are to be converted to the test engine configuration during
retrofit/rebuild. In view of the fact that this certification is not
being made within life cycle cost limits, and all converted engines
will be retrofit to the test engine configuration, baseline testing is
not required for this certification.
Prior to performance of the emissions test, the test engine was
rebuilt using the DDC kit. DDC stated that the test engine was in a
post-rebuild configuration which is not related to a particular model
year. However, DDC noted that the test engine was mechanically similar
to a 1989 configuration.
JMI commented that DDC stated in the notification that the 277 hp
rating was chosen because, ``it represents the engine injector
combination on which the candidate equipment will be used.'' JMI
commented that this statement is understandable if DDC is certifying
only 277 hp engine kits. However, the DDC application also claims 0.10
g/bhp-hr PM levels for 253 hp and 294 hp engine kits. JMI asked what
FTP test date is available to demonstrate that this technology is
effective on 253 hp and 294 hp engine. JMI stated that the EPA should
require DDC to demonstrate that they can attain 0.10 g/bhp-hr level for
these two horsepower ratings before including them in DDC's
application.
Additionally, Engelhard commented that DDC has not tested the worst
case engine for its system. The Turbodyne system is designed to force
additional air into the intake before the standard turbocharger can
spool up. According to Engelhard, it is the amount of air supplied
during aceleration that allows better combustion which reduces the
particulate emissions during acceleration. The amount of air supplied
is critical for obtaining PM reduction. The emissions data supplied by
DDC is for a 277 hp engine. Engelhard states that to meet the 0.10 g/
bhp-hr level, the Turbodyne system will have to supply more air for a
294 hp engine. However, DDC has provided no justification or data
demonstrating that the device is large enough to accommodate the air
flow requirements of the 294 hp engine. This requirement is supported
by the fact that DDC uses a different turbo with a higher A/R ratio for
the 294 hp engine than the 277 hp engine.
DDC stated that it selected the 277 hp engine rating for
certification testing because this is the rating most commonly used in
transit bus operations. DDC agrees that the 294 hp engine will require
more airflow than an engine rated at 277 hp when both engines are
operating at their respective full rated power. DDC also points out
that the TurboPac is not intended to deliver the full airflow
requirements of the engine. The purpose of the TurboPac is to provide
additional air during engine accelerations to compensate for the lag of
the engine turbocharger, and its air supply performance is the same for
all engines regardless of power rating. DDC states that an engine at
the 294 hp rating is capable of injecting more fuel than an engine at
the 277 hp rating, but the difference in fueling is small. The 294 hp
rating has a peak torque of 875 lb-ft at 1200 rpm while the 277 hp
rating has a peak torque of 880lb-ft at 1000 rpm. At 1200 rpm, full
load, under steady state conditions, the 294 hp rating delivers 71.0
lb/hr of fuel vs. 68.5 lb/hr for the 277 hp engine. DDC notes that this
is only a 3.6% difference. DDC has not measured fueling differences for
the two ratings during rapid accelerations, but because the throttle
delay limits fueling to some fraction of the full rack fueling, the
fueling difference during acceleration would be somewhat less than the
steady state difference. Since the fueling difference is small, DDC
believes the TurboPac will provide sufficient supplementary air to
provide adequate particulate control with the 294 hp engine.
EPA's urban bus certification requirements for heavy-duty urban bus
diesel engines, 40 CFR 85.1406 (a)(2)(i) states ``The test engine used
must represent the `worst case' with respect to particulate emissions
of all those engine configurations for which the retrofit/rebuild
equipment is being certified. The worst case engine configuration shall
be the engine configuration having the highest engine-out particulate
matter emission levels, when properly maintained and used, prior to
installation of the retrofit/rebuild equipment.'' Based on available
information, it is not clear whether an engine rated at 253 hp, 277 hp,
or 294 hp would have significantly different exhaust emissions or,
which would represent the worst case for this certification decision.
EPA believes that a comparison with the criteria for selecting test
engines under EPA's new engine certification program is relevant. EPA's
new engine certification requirements for heavy-duty diesel engines, 40
CFR Sec. 86.090-24 (b)(3)(ii) for test engine selection state ``* * *
Within each combination, the engine that features the highest fuel feed
per stroke, primarily at the speed of maximum rated torque and
secondarily at rated speed, will usually be selected'' for a test
engine. In a facsimile dated March 7, 1998, DDC provided information on
the fuel feed rate for each hp at maximum rated torque. That
information shows that the fuel feed per stroke for the 277 hp engine
clearly exceeds the 253 hp at maximum rated torque (88.8 mm/stroke vs.
77.4 mm/stroke). With regard to the 294 hp engine, DDC has provided
information that the fuel feed per stroke for the 277 hp engine is
virtually identical to the fuel feed per stroke of the 294 hp engine at
maximum rated torque (88.8 vs. 88.9 mm/stroke). While a strict
comparison of this data indicates that the 277 hp engine does not meet
the ``highest fuel
[[Page 26804]]
feed per stroke'' criteria as stated, it is within one-tenth of one
percent of the 294 hp rating with regard to this measurement. DDC's
March 27, 1998 submission has been placed in the docket at the above
address.
In conjunction with the discussion above and the following reasons,
EPA believes that the 6V92TA engine equipped with the DDC kit rated at
277hp, is acceptable for compliance at the 253, 277 and 294 hp ratings.
First, the 6V92TA MUI test engine is clearly the engine model for which
DDC is claiming applicability of the DDC kit. Further, the hp rating of
the certification is the most popular power rating. It is therefore the
most representative power rating. Second, it is consistent with the use
of a 277hp test engine by JMI for certification applicable to various
hp ratings applicable to 6V92TA model engines (see 62 FR 60079;
November 6, 1997). In EPA's approval of this JMI certification kit, EPA
allowed the certification test engine at the 277 hp rating to represent
additional hp ratings which were certified. No additional information
was presented by JMI or Engelhard in their respective comments relative
to different emission levels from the various ratings. Lacking such
information EPA can find no reason to change from the decision made in
the JMI certification to allow the 277 hp test engine to represent the
additional ratings. Additionally, it is not clear that an engine of the
DDC rated 253 hp or 294 hp would have significantly different exhaust
emissions from the certified test engine. Because of the above noted
reasons, and consistent with EPA's decision in that JMI certification,
EPA finds that the 277 hp rating is acceptable to represent the 253 hp
and the 294 hp ratings in this certification. EPA retains the authority
to conduct in-use testing of any certified equipment for compliance
with the 150,000 mile performance warranty on all certified equipment.
JMI commented that the test data states that the muffler was
installed 6 feet from the turbocharger exit. JMI asked if this is the
way it will be installed in the buses. JMI noted that the converter
muffler is a direct bolt on replacement for the original muffler. With
the extreme variation in diameter from muffler to muffler, how many
different size catalyst elements are used? If more than one, which one
was used during the FTP test? If only one, the EPA should require DDC
to provide assurances that the catalyst was sized to achieve 0.1 g/bhp-
hr PM for the complete range of 6V92TA MUI engines form 1979 to 1989.
DDC stated that the converter muffler was tested at a location of
six feet from the turbocharger outlet. The installation on a particular
urban bus will vary based on the original muffler location. DDC tested
at this distance as most urban bus mufflers are installed within this
distance from the turbocharger and chose this location to represent a
worst case in terms of exhaust temperature. EPA accepts the placement
of the converter at six feet from the turbocharger in this instance and
notes that EPA has accepted this distance in previous certification
approvals.
DDC stated that parts list number six in the notification provides
a listing of the different converter/muffler configurations that will
be used. The particular converter/muffler configuration used to
generate the emission test results in the notification was a 12 inch by
23 inch oval cross section design, 22 inches in length. This unit has
the minimum catalyst volume of the different converter/muffler
configurations that will be used according to DDC and corresponds to
part number 6000-005D of that list.
Engelhard asked how the backpressure was set for emissions testing.
DDC testing was performed at Southwest Research Institute in San
Antonio, Texas. With a standard muffler installed in the test cell
exhaust system, the damper was closed (with the test engine at rated
speed) to adjust the backpressure to 80% of the specified maximum, or 2
inches of mercury. The standard muffler was then removed, and the
catalyst was installed in its place. Certification testing was
conducted without changing the position of the throttling valve. The
resulting backpressure was 2.7 inches of mercury with the catalyst
installed. Engelhard asked where did the original muffler come from and
is it a bus muffler? The muffler was provided by the testing facility
and was selected to represent an urban bus muffler.
(D) Life Cycle Cost Analysis
Engelhard commented that DDC has not provided a life cycle cost
calculation for this retrofit equipment. Engelhard noted that this is
extremely important due to the complexity of the installation required
for the Turbodyne system, the potentially expensive maintenance of the
system, the detrimental effect of the huge electrical demand of the
Turbodyne system on the buses charging system, and the increased fuel
consumption of the Turbodyne system. Engelhard commented that this
information is needed so bus companies can make a valid assessment of
this technology's cost effectiveness. DDC's application also did not
include prices or installation costs for any of the retrofit kits. JMI
also commented on the cost of the DDC/Turbodyne kit. It asked about the
labor costs to install the DDC/Turbodyne system because the addition of
a supercharger is over and above what is done during a standard
rebuild. Are there any periodic maintenance requirements that would
increase the cost of the system? What is the impact of the DDC/
Turbodyne technology on fuel consumption? Should a fuel penalty be
assessed?
As stated earlier, DDC has not provided life cycle cost information
in conjunction with this notification. Such a cost analysis is
necessary for certification of equipment that is meant to trigger a
program emissions standard. Certification of Engelhard Corporation's
ETXTM kit triggered the 0.10 g/bhp-hr standard for 6V92TA
MUI engines, and made available kits rated at 253, 277, and 294 hp. The
DDC certification does not include a cost analysis, and one is not
necessary for this certification. DDC states that engines equipped with
the kit will have no additional maintenance or service requirements and
the system will not have a detrimental impact on the electrical system
as discussed earlier. Based on the field installations to date, DDC
estimates that the installation of the TurboPac unit will average an
additional eight hours of labor beyond the labor associated with a
standard rebuild. However, this figure could vary depending on the
specific installation requirements. No claims have been made by DDC
with regard to the impact of this system on fuel economy and the impact
of this system on fuel economy is undetermined. No specific information
on fuel economy impact was provided in the comments. EPA notes that it
is not appropriate to assess a fuel economy penalty in a certification
that does not contain life cycle cost information. With regard to fuel
consumption, the brake specific fuel consumption (BSFC) measured during
emission testing of the DDC kit was 0.464 lb/bhp-hr. In testing
conducted for the three notifications for 0.1 g/bhp-hr PM certification
for 6V92TA MUI engine models that EPA has received to date, the BSFC
measured during emission testing after the installation of the
retrofit/rebuild kits has been between 0.438 and 0.471 lb/bhp-hr.
JMI asked if there are any components or ancillary parts that are
required in order to install the DDC/Turbodyne system that are not
included on any of the parts lists included with DDC's application? If
so, what are the additional costs associated with these
[[Page 26805]]
parts? In response, DDC states that the parts list in the application
does not include the electrical wire (16 AWG and 00 cable), and some
nuts and bolts. DDC states that it believes these are standard items
commonly available in bus repair facilities. Total cost for all of
these parts is estimated by DDC to be between $20 and $40, depending on
the length of the 00 cable. No additional batteries or other changes
are required to the battery charging system. No rewiring of the bus
electrical system is needed according to DDC.
(E) Warranty
Engelhard commented that DDC does not provide any coverage for
damage resulting to other engine components, such as the charging
system, due to the installation of its retrofit kit. In response, DDC
notes that field evaluations have not resulted in any failures to bus
charging or electrical systems. Neither DDC nor Delco-Remy anticipate
that use of the TurboPac system will increase failure rates of the
vehicle charging and electrical systems. Standard warranty coverages,
if not expired, will remain in effect for any failures which may occur
in these systems. DDC will not provide additional warranty coverage for
these systems. Based on the review of comments and the in-use pilots,
EPA is not award of any damage to other components as a result of the
installation of this equipment and does not see reason not to approve
this certification. If significant in-use problems were to develop, EPA
can take action and, ultimately, has authority to decertify equipment.
(F) Durability
JMI commented that DDC stated in its notification; ``The cylinder
kit components were modified to improve durability.'' JMI expressed
concerns that changes to any parts of the cylinder kits could result in
increased soot formation in the oil or increased oil consumption. JMI
further questioned what the modifications were, how will they be made,
who will make them, how DDC will control uniformity and quality,
whether the change was made for all 92 series engines or just the
engines with the kit and whether the parts will be made available on a
nationwide basis. Engelhard commented that though durability data is
not a requirement of the Urban Bus regulation, the EPA has required
verification of durability and data supporting the claim that the
system will last 150,000 miles.
In response DDC stated that the primary change in the cylinder kit
is the elimination of a ``J-relief'' groove. The J-relief was a
machining process to the lower side of the bottom compression ring
groove which was designed to relieve any pressure build-up between the
upper and lower compression rights. The change to the piston eliminates
the machining operation. DDC states that this change has no affect on
the combustion process, and will have no affect on generation of soot
during the combustion process. According to DDC the change was made
strictly to improve the durability of the lower compression ring. The
changes have been incorporated in the cylinder kits used to service all
DDC series 92 engines, whether used to service truck, bus, or nonroad
engines. The new piston domes are also used on production engines.
Therefore, the parts are subject to the same quality control as any
other DDC production or service part. The new kits are available
worldwide through DDC's distributor network.
EPA is concerned, in general, with equipment durability, and
believes that certifiers will want to evaluate the durability of their
equipment in order to minimize their liability resulting from the
emissions defect and performance warranties. However, program
regulations do not require a durability demonstration. EPA believes
that DDC's explanation does not indicate a durability concern with the
equipment certified in today's notice, and therefore, does not provide
sufficient basis to deny certification on these grounds. EPA has the
authority to conduct in-use testing of certified equipment to determine
compliance with the requirements of the program. In addition, equipment
certifiers must provide a 100,000 mile defect warranty and a 150,000
miles emissions performance warranty on all certified equipment
(G) In-Use Experience
The Washington Metropolitan Area Transit Authority (WMATA), the
Maryland Department of Transportation Mass Transit Administration
(MTA), and the Milwaukee County Transit System (MCTS) provided
favorable comments on the DDC system. WMATA noted that one DDC kit was
installed on September 17, 1997 and that WMATA has not encountered any
installation or servicing problems with the engine and there have been
no failures. The MTA commented that it has installed the DDC kit and it
has performed ``flawlessly.'' The MCTS commented that it has installed
five DDC kits. The first kit was installed in September 1997. To date,
MCTS has not experienced ``any'' electrical component problems on the
buses. By electrical problems, MCTS stated it meant any alternator,
regulator, battery, or wiring problems. MCTS commented that it
experienced ``one'' TurboPac electrical turbo motor failure early in
the test process. MCTS commented that the DDC kit is reliable but that
it was too early in the process to determine if there are any fuel or
power increases.
IV. Certification
The Agency has reviewed the notification of intent to certify and
other information provided by DDC, along with comments received from
interested parties, and finds that the DDC kit described above:
(1) Complies with the particulate matter exhaust emissions standard
of 0.10 g/bhp-hr, without causing the applicable engine families to
exceed other exhaust emissions standards;
(2) Will not cause an unreasonable risk to the public health,
welfare, or safety;
(3) Will not result in any additional range of parameter
adjustability; and,
(4) Meets other requirements necessary for certification under the
Retrofit/Rebuild Requirements for 1993 and Earlier Model Year Urban
Buses (40 CFR Sections 85.1401 through 85.1415).
Therefore, today's Federal Register notice announces certification
of the above-described DDC kit for use in the urban bus retrofit/
rebuild program as discussed below in section V.
V. Transit Operator Responsibilities
Today's Federal Register notice announces certification of the
above-described DDC kit, when properly applied, as meeting the 0.10 g/
bhp-hr particulate matter standard of the Urban Bus Retrofit/Rebuild
Program.
In a Federal Register notice dated March 14, 1997 (62 FR 12166),
EPA announced certification of a retrofit/rebuild kit produced by the
Engelhard Corporation (the ETXTM kit). That certification
means that urban bus operators using compliance program 1 must use
equipment certified to the 0.10 g/bhp-hr standard when rebuilding or
replacing applicable 1979 through 1989 model year DDC 6V92TA MUI model
engines after September 14, 1997. The certified DDC equipment described
in today's notice may be used by operators in compliance with the 0.10
g/bhp-hr standard. Operators using compliance program 2 having
applicable engines may use the certified DDC kit and claim the
certification PM level from Table B above, when calculating their Fleet
Level Attained (FLA). Under program 2, an operator must use sufficient
certified equipment so that its actual fleet emission level complies
with the target level for its fleet.
[[Page 26806]]
As mentioned above, certification of the Engelhard
ETXTM kit triggered the 0.10 g/bhp-hr standard for
applicable 1979-1989 6V92TA MUI engines. That kit provides three power
ratings: 253, 277, and 294 horsepower. DDC will offer the DDC kit in
these three power ratings as well: 253, 277, and 294hp.
Engines of urban buses certified to meet California emissions
standards are not applicable to the DDC kit discussed in today's
Federal Register notice. Additionally, the 0.10 g/bhp-hr PM standard is
not triggered for engines certified to meet California emission
standards. Operators of such urban buses, who choose to comply with
program 1, are not required to use equipment certified to the 0.10 g/
bhp-hr PM standard until the standard has been triggered for such
engines. Operators of urban buses having engines certified to meet
California emission standards, and who choose to comply with program 2,
may not use the DDC kit described in today's notice to meet program
requirements.
As stated in the program regulations (40 CFR 85.1401 through
85.1415), operators must, beginning January 1, 1995, maintain records
for each engine in their fleet to demonstrate that they are in
compliance with the requirements of the Urban Bus Retrofit/Rebuild
Program. These records include purchase records, receipts, and part
numbers for the parts and components used in the rebuilding or urban
bus engines.
Dated: May 5, 1998.
Richard D. Wilson,
Acting Assistant Administrator for Air and Radiation.
[FR Doc. 98-12850 Filed 5-13-98; 8:45 am]
BILLING CODE 6560-50-M