1



### TO: Byron Bunker

FROM: Deb o r a h Gordon

RE: Follow

- Up Items 5/19/2011

DATE: 6/2/2011

Attached please find follow

- up information to the 5/19/2011 meeting concerning EPA’s proposed medium

- and heavy

- duty rulemaking. This information provides further explanation of comments filed by Allison Transmission, Inc.

If you have any questions concerning this information, please do not hesitate

to contact me.2

I. Drive Cycle Equivalency During “A” to “B” Testing

EPA has proposed utilizing “A” to “B” testing in several areas of its proposed

Medium

- and Heavy

- Duty (“MD/HD”) Greenhouse Gas (“GHG”) and Fuel Efficiency (“FE”) Standards. For example, this testing protocol may be utilized in Part 1036, Subpart F for cer tain hybrid engines with PTO capability when the engine is coupled with

a transmission ; Part 1037 ; Subpart G for hybrid powertrains ; Part 1037 , Subpart F section 1037.525 for hybrid vehicles with PTO ; and Subpart F section 1037.610 for hybrid vehicles and other advanced technologies

.

In comments filed on January 31, 2011 , A llison Transmission, Inc. (“A TI ”) outlined several issues concerning the drive cycle testing of MD/HD vehicles, including the ability of vehicles to follow a “trace,” the proposed criteria for determining compliance, the proposed “A” to “B” testing of hybrid technologies and other issues

. 1 A TI also submitted numerous questions on the proposed definitions of hybrid systems, testing syste ms for hybrids, the configuration of test vehicles, how “real world” comparison vehicles would

be determined and other matters. 2

A. Further Specification of “A” to “B” Testing

I n light of these filed comments and A TI ’s current understanding of EPA’s

Novem ber 30, 2010 proposed regulations, EPA has the opportunity to clarify and provide further specification of “A” to “B” testing. Specifically, this could be done by :

1. Adopt the EPA criteria that the speed trace is followed within 2 mph within a 1

second win dow unless at maximum effort (reference “maximum effort” criteria), but add the following requirement:

a. Total distance traveled has to be within 1% of theoretical

. 2. Clarify that i f condition specified in 1 a. is not met , the test must be re

- run until the req uirement is met. This w ould insure that both time and distance are equivalent (within 1%) for configuration A and B.

3. If 1 a

. still cannot be met due to vehicle not being able to follow the trace, then the speed trace could be increased by a factor ( for ex ample: theoretical distance / actual distance) and the cycle would be rerun. This process could continue until item 1 a. (referenced to the original speed trace) is met.

4. Do not use data from tests that have a DPF regeneration event. If a DPF regeneration event occurs, re

- run the test.

5. In the long term, comparison of the number of DPF regeneration cycles/1000

mi les , for different technologies would capture the real world effect of different engine and transmission technologies on GHG emissions and gal lons / 1000 ton

miles.

6. Whenever vehicle speed is below the target speed, continue Wide Open Throttle (“WOT”) accel eration until speed target is met, instead of starting dyne braking/torque control for the next deceleration event.

7. Update test procedures to account for new technologies as they are introduced, such as the need for warm up of DPF and SCR systems.

1 See e.g., Allison Comments, Sections XI and XII

2 Id. at XII, B.3

E xample trace s for which the above

- described procedure number 3 could be implemented

are shown below :45 B. Alternative Procedure

Alternatively, the average speed ratio could be used to adjust the Raw Gallons/1000 ton

miles data as follows:

Adjusted Gallons/1000 ton

- miles = Raw Gallons/1000 ton

- miles X (average speed reference /average speed actual )

II. Definition of “A” and “B” Vehicle s

“A” to “B” te sting that is contemplated for the generation of credits (i.e., whether with respect to hybrid testing or otherwise) utilizes the concept of an “equivalent

conventional vehicle” in order to assess relative GHG and FE “gains

. ” Under the current regulatory concepts that are employed , the “ equivalent conventional vehicle ” would be defined with respect to utilizing the same footprint, intended service class, aerodynamic drag and other factors.

ATI comments and other comments rec eived by EPA have reflected the importance

of drivetrains and transmissions to affect G HG emissions and improve FE generally. Specifically with respect to “A” to “B” testing, however, it is important to incorporate such concepts within the definition of t he “A” vehicle or the “equivalent conventional vehicle” to which assessment of improved GHG or FE performance is measured. In this respect, important variables which should be the same for the “A” vehicle and the “B” vehicle (except where such variables t hemselves are designed to directly produce improved GHG or FE performance) are:

 Transmission and Torque Converter

 Shift Calibration

 Engine

 Gross Vehicle Weight

 Axle Ratio

That is, EPA should hold the above vehicle components constant when “A” to “B” testing is performed to the greatest extent possible as determined by the advanced/innovative technology in order to assess any improvement in GHGs emitted or FE gained due solely to the use of hybrid systems or other advanced or innovative technologies. Failure to hold such components constant could increase the potential for gaming of “A” to “B” comparisons and the probability that improvements in GHGs or FE due to the hybrid systems o r advanced or innovative technology will not be realized.

A conceptual chart as to how such components could be specified for different types

of vehicles is represented below . Vehicles in a class would first be subdivided as to

vocation. Foll owing this classification, a standard configuration for transmission and drivetrain components , gross vehicle weight and engine type would be specified

. Configurations would be determined on the basis of “normal and customary” practices in the industry fo r the type of vehicle involved.6 

### Class 8 HD Vehicle

Vocation Transmission

& Torque

Converter Shift

Calibration Engines Gross

Vehicle Weight Axle Ratio

Straight Truck (on

highway) Cummins

DDC

Navistar

Mack/Volvo Straight Truck (on /

off

highway)

Short Haul

Tractor

Trailer

Line Haul

Tractor

Trailer City Bus

Coach

III. Transient Drive Cycles/Weighting

A TI submitted comments with regard to GEM modeling and the steady state operating periods at 55 mph and 65 mph incorporated into the model

. 3 We currently understand that the GEM model will include both steady state operations and transient cycle operation . As ATI also cited with respect to the compliance cycles for Class 7/8 Tractor Cabs, 4 the underlying assumptions and relative weighting of steady

- state and transient operation of all MD/HD vehicles remains a crucial issue. Thus, any final

decisions on the GEM should increas e transient operation of vehicles, especially vocational vehicles, to better reflect real world vehicle utilization and traffic conditions. EPA has received multiple comments on this issue and thus has a sufficient basis on which to reweigh its proposed approaches to include a more accurate assessment of the transient operations of vocational and Class 7/8 tractor cabs , whether modeled or directly tested for compliance.

3 Id. at III. A. and B.

4 Id. at VI. 

# N o t i o n a l

- Data

to be Inserted7

IV. Straight Line Acceleration

ATI previously provided comments on the straight line acceleration utilized in the

GEM , noting the obvious differen ce between such assumed acceleration and the real world acceleration experience d by many different MD/HD vehicles

. 5 While we would

understand that in the GEM

, straight line acceleration is not i ntended to be used for determining vehicle compliance with GHG/FE standards, questions remain with respect

to the acceleration “curves” or drive cycle traces that may be utilized ( either within the GEM or otherwise as part of compliance testing for the MD/ HD GHG and FE program )

.

As noted below in Section VII, acceleration rates utilized in American Public Transit Association (“APTA”) guidelines provide a publicly accepted method to measure acceleration broadly across different vehicle classes and types

. That is, transit buses represent a ubiquitous commercial vehicle that is well

- defined in the marketplace. Like other MD/HD vehicles, the relative fuel efficiency of such vehicles is a main factor affecting vehicle purchasing decisions. While MD/HD vehicl es subject to regulation under EPA’s proposed standards are obviously diverse, when selecting acceleration rates and drive cycle traces that will be utilized in compliance testing, the APTA transit bus cycle should be considered as providing a reasonably a ccurate and available methodology for assessing relative GHG emissions and FE associated with different MD/HD vehicles. Certainly, acceleration traces utilized in the APTA guidelines are far more accurate than “defaulting” to straight

- line acceleration or utilizing acceleration rates that are unreasonably slow in the commercial marketplace.

V. Methods to insure the vehicle at least makes “best effort” if it cannot meet the drive cycle

Implicit in the concepts outlined above is the need to ensure that a veh icle being tested exerts the maximum effort in order meet the vehicle speed trace. We would understand that section 1066.330(c)(4) require s a vehicle to “operate at maximum available power” but that section 1066.330(e)(4)(iii) appears to not count insuffi cient acceleration as being outside of specified limits. As noted in previous comments, clarification of EPA’s proposed regulations may be desirable on these matters. In specific :

1) Accelerator Pedal Position A) The accelerator pedal can be monitored with a position sensor. For vehicles that use

the J1939 CAN data link, m onitoring the J1939 APP parameter being used by the engine or hybrid system is also acceptable. B) Most engines use the APP parameter contained in the EEC2 message from one of the following source addresses: 17, 49, 33, or 00. C) Most engines use one of the following APP parameters in the EEC2 message: a) Accelerator Pedal Position 1

- SPN91 b) Accelerator Pedal Position 2

- SPN29 c) Remote Accelerator Pedal Position

- SPN974 2) Kickdown switch activation (if equipped) 3) Performance/Economy Mode Selection (if equipped) 4) Gear selected provides maximum performance . This would include requiring the driver to override automatic gear selection if that would improve performance to t he speed trace.

5 Id. at III. A.8

5 ) Other driver selectable methods to increase vehicle acceleration and speed capability, such as selectable input to vehicle acceleration rate management control (if equipped). 6) Monitor the J1939 TSC1 message for torque or speed limit s (or control) from external devices

for all tests. 7) Require 100% APP, kickdown engaged, performance mode selected, etc. whenever the vehicle (or powerpack, or engine) cannot meet the speed trace.

VI. Pre

- transmission “A” to “B” testing for advanced tec hnologies, such as hybrids

EPA’s proposed metric and testing protocols are based on the concept of measuring the work performed by vehicles. To further EPA’s objective , there is a need to ensure that interactions between the vehicle, engine, and hybrid system components are
accounted for

– in a similar fashion

– in both pre

- and post

- trans mission test methods.

P re

- trans mission “ A ” to “B” testing for hybrids should not get an unrealistic advantage compared to hybrids that use post

- trans mission or vehicle test ing

. This could be ensured by requiring that :

 Energy Storage System (“ESS”) usage be equivalent to usage in a real world hybrid system. For this, the hybrid system and E SS production controls would need to be used for the testing. Otherwi se, the ESS could be used more than in a production vehicle which would skew the results.

 The accessory configuration for the vehicle must b e replicated for the pre

trans mission and post

- trans mission test cell test setup s

. It should at least simulate

a re al world vehicle

. This is important since accessory loads will reduce the amount of regen erative energy captured

.

 The amount of regenerative braking captured for the pre

- trans mission test cycle

must not be more than the post

- trans mission test or vehicle t est would provide.

VII. “A” to “B” test gaming by chan ging engine accessory loads, including PTO operation

In general, “ A ” to “ B ” tests should include realistic accessory loads regardless if they consist

of a pre

- trans mission test, post

- trans mission test, or complete vehicle test

. Accessory loads

would include a 12/24 v olt alternator and the loads that it drives on the vehicle, air or hydraulic service brake power booster, power steering, engine radiator fan, engine water pump, and air conditioning compressor.

Accessory l oads should also be the same for both A and B tests. If both A and B configurations use accessories that are mechanically driven by the engine, the parasitic torque vs. engine speed should be the same for both A and B tests.

If electrically driven accessories are used for the B configuration , the output of the accessory

should be the same for both A and B tests. For example:

 T he 12/24 v olt electrical system loading should be set at a realistic level (or duty cycle)

and be the same regardless of whether an alternator or a DC

- DC converter is used to

service the 12/24 v olt load.

 Engine r adi at or fan output shall remain adequate to cool the engine for both engine driven and electrically driven fans

. Likewise for electrically driven engine water pump s.9

 Power steering hydraulic output power vs. time duty cycle shall be realistic, and the same

for both engine driven and electrically driven power steering systems.

 Air conditioning output should remain adequate to control cabin temperatu re under standard conditions for both engine driven and electrically driven compressors

.

Additional electrical load needed to drive the electrically driven accessories should be

included in the “ A ” to “ B ” tests. This could be on the 12/24 v olt system or the high voltage system, depending on the accessory. Otherwise, EPA should only us e the Refuse part of the PTO cycle for the duty cycle weighting for Refuse trucks and only us e the Utility part of the PTO cycle for the duty cycle weighting for Utility trucks. T he proposed Utility and Refuse PTO cycles should also be compared with the broad range of duty cycles in actual use to see if adjustments to the cycles are needed.

VIII. Minimum performance criteria for “ A ” to “ B ” tests.

A TI ’s filed comments cited the advantages of hybrid technologies and the need to accurately recognize these advantages within the regulatory system. Items that would accomplish these

ends would include :

1) Allow freedom for hybrid systems to de

- rate the engine or downsize to a sma ller engine family

. 2) A llow change s in tire size and axle ratio to optimize the hybrid system compared to a conventional system

. 3) R equire both vehicles to meet minimum commercially acceptable performance criteria for startability and acceleration , as de fined below. “Commercially acceptable” would generally constitute what is reasonable and normal in the existing market. 4) Use APTA bus acceleration requirement for all vehicles (vocational, day cabs and sleeper cabs). 6

6 See “Standard Bus Procurement Guidelines RFP,” American Public Transportation

Association

, October, 2010 . Reference Section TS 7.3 Acceleration, pages 76 and 77.10

5) For vehicles incorporating automatic transmissions , utilize the minimum startability requir ements 7 represented on the chart below:

6) For manual transmissions and automated manual transmissions , startability should be

calculated in the lowest ( automat ic ) starting gear with the engine at clutch engagement torque (i.e., in lug

- up condition at a maximum of 800 rpm).

IX. Accessory Load Values

As indicated previously in Section III above, it is important to realistically define accessory loads given their ef

fect on testing results. The accessory loads shown below are the typical parasitic losses used by the A TI’s iSCAAN vehicle application and performance evaluation tool for all vehicle classes within each application category. More precise values may also be entered into iSCAAN to better define the losses associated with an individual vehicle’s unique configuration.

For example:

Standard Accessory Power/Percent Typical Value

Urban City Transit

– Class 8

Fan Percent of Peak Power 10

Alt/Generator Percent of Peak Power 5
Air Compressor Percent of Peak Power 4
Steer Pump Percent of Peak Power 1

Air conditioning Percent of Peak Power 7

7 M i n im u m S t a r t a b i l i ty b y A p p l i ca tio n i s d ef in ed w i t h i n A ll i s o n T r a n s m i s s i o n T ec hn ic al

D oc um en t T D 1 8 0

- 3 “ V o c a t i o n a l P e r f o r m a n c e G u i d e l i ne s fo r Al lis on T ra ns mi ss ion s

. ”11

P&D Delivery

– Class 5,6, and 7

Fan Percent of Peak Power 6.5

Alt/Generator Percent of Peak Power 0.5

Air Compressor Percent of Peak Power 0.5
Steer Pump Percent of Peak Power 0.5

Air conditioning Percent of Peak Power 1

Day Cab

– Class 7, 8

Fan Percent of Peak Power 6.5

Alt/Generator Percent of Peak Power 0.5

Air Compressor Percent of Peak Power 0.5

Steer Pump Percent of Peak Power 0.5

Air conditioning Percent of Peak Power 1

Refuse Packer

– Class 7, 8

Fan Percent of Peak Power 6.5

Alt/Generator Percent of Peak Power 0.5

Air Compressor Percent of Peak Power 0.5
Steer Pump Percent of Peak Power 0.5

Air conditioning Percent of Peak Power 1

Line Haul

– Class 8

Fan Percent of Peak Power 6.5

Alt/Generator Percent of Peak Power 0.5
Air Compressor Percent of Peak Power 0.5

Steer Pump Percent of Peak Power 0.5

Air conditioning Percent of Peak Power 1

Utility Truck w/Boom

– Class 6, 7

Fan Percent of Peak Power 6.5

Alt/Generator Percent of Peak Power 0.5

Air Compressor Percent of Peak Power 0.5
Steer Pump Percent of Peak Power 0.5

Air conditioning Percent of Peak Power 112

X. Advanced /Innovative Technology Credits

EPA has received many comments supporting advanced technology credits and innovative technology credits. Both credit programs could offer benefits. EPA has proposed only general criteria with respect to the methodology for obtaining innovative technology credits, but the Agency should be aware that:

 S maller engines can be used with an automatic transmission to achieve the same performance as an AMT or m anual trans mission, enabling significant

reductions in GHG s emitted from a vehicle and improved FE

. In this regard, the use of the term “technologies that were not in common use before 2010” might be interpreted to exclude technologies that may have been in existence

in considerable numbers , but had not been utilized in new or widespread combinations or configurations. It would appear that EPA ’s intention in this

matter would not be to exclude such approaches to obtaining GHG reductions and FE gains where the actual deployment of the technology did not occur, or did not commonly occur in the specific configuration or combination for which credit is sought. Instead, it would be reasonable to interpret the “common use” criteria as “common use, or in common use in a particular combination or configuration.”

 A lternate fuel powertrains, s pecifically those utilizing CNG engines

, could

lower GHG emissions and improve FE . Such powertrains should either meet the applicable definitions to be eligible for credits

, or be made eligible for

credits.