Allison Transmission

EPA Meeting

May 19, 2011

Ann Arbor, MI

May 19, 2011 1
Agenda

• Introductions – Debbie Gordon

• Update on Rulemaking – EPA

• Allison Summary Points – Debbie Gordon

• Transmission Spec’ing for Fuel Economy – Debbie Gordon

• Hybrid Discussion – George Pelton

• Drive Cycle Weighting – Debbie Gordon

• Allison Test Experience and Lessons Learned – Curt Vapor

• EPA Test of 2000 SeriesTM – EPA

• Wrap-up

May 19, 2011 2
Allison Transmission - EPA Meeting

Purpose: 

1. Discuss EPA/NHTSA intent for upcoming Fuel Efficiency 

Regulations for MD/HD Vehicles

2. Discuss Allison views on various topics

Process:

Presentation with open discussion

Product:

1. EPA have a better understanding of Allison views

2. Allison have a better understanding of EPA/NHTSA 

direction

3. Follow-up items if required

May 19, 2011 3
May 19, 2011 Attendees

Allison

Debbie Gordon

Bob Leopold

Kevin Rodgers

Curt Vapor

Mark Janson

George Pelton

Crowell & Moring

Bob Meyers 

May 19, 2011 4
President Obama Visits Allison: May 6, 2011 

“What you’re doing here at Allison 

Transmission is really important. Today 

there are more than 3,800 buses using 

(your) hybrid technology all over the 

world...... soon, you’ll be expanding 

this technology to trucks as well..... 

That means more jobs here at 

Allison. Last month, you added 50 jobs 

at this company and I hear that you 

plan to add another 200 over the next 

two years. So we are very proud of 

that. ”

“I don't want the new 

breakthrough technologies and 

the new manufacturing taking 

place in China and India. I 

want all those new jobs right 

here in Indiana, right here in 

the United States of America, 

with American workers, 

American know-how, American 

ingenuity.” 5
Agenda

• Introductions – Debbie Gordon

• Update on Rulemaking – EPA

• Allison Summary Points – Debbie Gordon

• Transmission Spec’ing for Fuel Economy – Debbie Gordon

• Hybrid Discussion – George Pelton

• Drive Cycle Weighting – Debbie Gordon

• Allison Test Experience and Lessons Learned – Curt Vapor

• EPA Test of 2000 SeriesTM – EPA

• Wrap-up

May 19, 2011 6
Allison Summary Points

May 19, 2011 7
Allison Summary Points

Vehicle Testing

• The effect of transmission on the emission of GHGs and FE cannot 

be accurately assessed in isolation, but can only be assessed with 

respect to the entire vehicle system.

– Work done must represent net calculation of work, not just positive work

– Testing must be tightly controlled to ensure integrity of results; tests 

must produce results that are actually representative of real-world 

vehicle configurations and performance.

– Powerpack testing may not represent a realistic integrated vehicle 

system unless special care is taken to account for system level effects 

to achieve real world results.

• EPA must take the necessary time to “get it right.” EPA should not finalize 

any overly simplistic testing protocol for transmissions, but instead exclude 

transmissions as originally proposed.

May 19, 2011 8
Allison Summary Points

May 19, 2011 9

Drive Cycle

• EPA received numerous comments on drive cycles, particularly for 

vocational vehicles. Most comments agreed that the cycles did not reflect 

real world operation of the vehicles and that steady-state cruise was overrepresented in drive cycles and transient operation was under-represented.

• Final rule can be improved by:

– Ensuring that drive cycles are weighted based on time – not distance.

– Measuring vehicle impact on GHGs/FE through assessment of the actual 

distance traveled on the drive cycle in the time prescribed in the drive cycle

– Including grades within drive cycles

– Include vocational subgroups (Allison-suggested approach)

– NOT including straight line acceleration in GEM drive cycles. Straight line 

acceleration does not reflect “natural acceleration” curves. Straight line 

acceleration is not “technology neutral” but contains bias towards AMTs.

– Utilizing European-type approach for drive cycles.
Allison Summary Points

Hybrid Testing/Innovative Technology Program

• Any “A to B” testing must use common vehicle configurations, as 

actually built by OEMs for the “A” vehicle. The “B” configuration 

must be the exact configuration of the hybrid or innovative 

technology intended to be produced. Vehicle system must include:

1. Engine, engine calibration, and after-treatment system but no regen during 

testing.

2. Automatic transmission system must replicate the actual, integrated vehicle 

system including torque converter, gear set, shift schedule, axle, cooling system 

load, electrical system/accessory loads.

3. Manual/AMT transmissions must include the clutch, gear set, 

controls/calibration, axle, cooling system load, electrical system/accessory 

loads.

4. Hybrid system representative hybrid components, energy storage, powertrain, 

drivetrain, calibrations, axle, cooling system load, electrical system/accessory 

loads.

May 19, 2011 10
Allison Summary Points

Hybrid Testing/Innovative Technology Program

• Hybrid Drive Cycles need to be substantially revised from those 

contemplated in proposed rule; need to include additional transient 

operation and account for grades.

– Hybrid PTO cycles should be available in combination with the most 

representative drive cycle for either refuse or utility drive cycles.

May 19, 2011 11
Transmission Spec’ing for 

Fuel Economy

May 19, 2011 12
Automatic Transmission Spec’ing Approach

• General perception of Truck Use

– Highway speed majority of time

– “Line Haul” type applications

– Average speed is typically tied to highway speed

– General outlook is time spent at 55+ MPH

• Often concerned with a “top speed” when spec’ing

driveline

• Based on years of data logs of a variety of in-service duty 

cycles

– Data suggests majority of operational time is spent 

at far less MPH than thought

May 19, 2011 13
May 19, 2011 14

US Total Freight ton-miles per year by Mode

(1992 - 2013)

(FTR Associates, 24 April 2009)

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

1990 1995 2000 2005 2010 2015

Calendar Year Ton-miles (millions) per year

Total Truck

Rail

Pipeline

Water

Air
May 19, 2011 15

US Truck Freight by Haul Length

(FTR Associates, 24 April 2009)

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

1,800,000

1990 1995 2000 2005 2010 2015

Calendar Year Ton-miles (millions) per year

Short + Med. (< 300 mi)

Long Haul (300+ mi.)
May 19, 2011 16

US Total Freight ton-miles per year by Mode

(1992 - 2013)

(FTR Associates, 24 April 2009)

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

1990 1995 2000 2005 2010 2015

Calendar Year Ton-miles (millions) per year

Total Truck

Rail

Pipeline

Water

Air

US Total Truck Freight by Haul Length

(FTR Associates, 24 April 2009)

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

1,800,000

1990 1995 2000 2005 2010 2015

Calendar Year Ton-miles (millions) per year

Long Haul (300+ mi.)

Medium Haul (125 - 299 mi)

Short Haul (< 125 mi)
Freight Trends are Significant to 

Transmission Selection

•Many like to think in terms of “steady state”

– Cruising at highway speeds

− Average speed is associated with cruise speed

BUT

• With more ton/miles in short and medium haul

– There is much more stop & go, which translates into more:

• Shifting

• Acceleration & Deceleration

– Acceleration is critical to 

• Average speed (miles per day)

• Productivity

• Fuel efficiency

May 19, 2011 17
Transmission Spec Decisions

• The transmission must be considered to be part of the vehicle 

system.

– Engine

– Vehicle application

– Drive cycle

– Startability requirements

– Highway cruise speed 

– Top Gear Speed

– Durability

– Tires (size and rolling resistance)

• Vehicle system requirements drive the transmission and axle ratio 

selection

– Torque Converter (for automatics)

– Ratio coverage

– Shift schedule

– Axle ratio

May 19, 2011 18
The transmission spec has significant influence on 

relative fuel economy/efficiency performance

• Simulation study done to show relative influence of spec 

decisions

Common specifications: 

• Straight truck-On-Highway

• Cummins 2010 ISC 300 hp/860 lb ft

• Allison 3000 HS 6-speed automatic transmission

• 6 x 4 drive configuration

• 500 rev/mile tires (standard radials)

• Smooth concrete road surface

• 96 square feet frontal area

• 0.700 aero drag coefficient

Variation in specs:

• Axle Ratios 4.63 4.88 5.29 5.86 6.14 6.43

• Torque converters: 7 different ones available w. 3000HS

• Shift Schedules: 7 different ones (more are available)

May 19, 2011 19
Axle Ratio has the Largest 

Impact on Fuel Economy 

• Going from a 6.43 to 4.63 axle ratio meets performance 

requirements and results in a 19% increase in MPG at 55 MPH 

cruise.

• Cruise is completely insensitive to shift calibration and torque 

converter.

May 19, 2011 20
Torque Converter 

• TC418 and TC419 are the only two (of seven) TCs to match the 

engine

• Input torque

• Smoke control

• Turbo lag

• By holding all variables common except the torque converter running 

the ARB transient cycle, the fuel economy range is 4.6%

May 19, 2011 21
Shift Schedule Considerations 

• Many shift schedules are available and are selected based on 

engine performance and vocational requirements.

• Load Based Shift Schedule (LBSS) 

• Combines Performance/Economy when loaded/unloaded

• Optimize shift schedules to align with engine sweet spot

• Impact will be more apparent in real-world operation than 

a fixed cycle

May 19, 2011 22
Simulation Conclusions

• Drive cycle is the most important factor in spec’ing a 

transmission for fuel economy

• Axle ratio has the largest impact on spec’ing an automatic 

transmission for fuel economy

• Torque converter selection must be matched to the 

engine

• Shift schedule can be optimized to balance vehicle 

performance and fuel economy

• Vehicle weight impacts actual fuel economy 

May 19, 2011 23
Overview of Allison Transmission’s New 

Technology for Commercial Trucks –

H 3000TM Hybrid System

• Demonstration vehicle built

• Used for promotional activities

May 19, 2011 24
H 3000TM System Overview

High Voltage / High Current AC Cables

High Voltage / High Current DC Cables

DC-DC Converter

3000 SeriesTM Transmission

Inverter

ESS

Motor/Generator

May 19, 2011 25
H 40/50 EPTM Bus Hybrid System

May 19, 2011 26
Current H 40/50 EPTM Applications

North America

27

May 19, 2011
May 19, 2011 28

 Buses Delivered Worldwide with H 40/50 EP Hybrids 4206 (4022 NAFTA)

 Cities Worldwide with H 40/50 EP Hybrid Buses 189 (167 NAFTA)

 States in United States with H 40/50 EP Hybrid Buses 39 of 50

 Countries Worldwide 9

 World's Largest Producer of HD Transit Hybrids YES

 Offered by all North American bus manufacturers YES

 Total Accumulated Miles > 323,030,875

 Total Accumulated Kilometers > 519,853,587

 Achieved 100,000,000 Fleet Miles without any

 "End-of-Life" Hybrid Battery Failures (Since SOP YES

 of H 40/50 EPs in October 2003

 Gallons Fuel Saved* > 17,171,076

 Liters Fuel Saved* > 64,992,524

 Metric Tons CO2 Eliminated* > 169,930

 Data updated April 22, 2011 / * Indicates Estimated Savings
(i) EPA and NHTSA have not precisely specified what the agencies will 

consider to be a “complete hybrid system.” For example, the Draft RIA 

appears to indicate that pre-transmission systems constitute such a 

“complete hybrid system.” 67 yet there is not an accepted industry view 

of this term or what does and does not constitute a complete system. 

Transmissions are integral to many hybrids and hybrid vehicle systems 

and cannot be arbitrarily excluded. 

(ii) EPA and NHTSA propose different testing systems for hybrid vehicles: 

testing of a complete vehicle and “powertrain test cell” testing without 

adequate explanation or justification for this proposal.68 On what 

informational basis is this proposal made and would the use of such 

differential testing protocols be decided by EPA, NHTSA or those 

manufacturers seeking to test hybrid systems?

(iii) It is unclear as to how the proposed testing protocols for hybrids will 

account for expected aging of the systems and how such expected 

aging would affect the end crediting of the hybrid system.

May 19, 2011 29
(iv) EPA and NHTSA must give greater consideration to the baseline 

configuration of hybrids in “A to B” testing. Within both the 

preamble and the draft RIA, it is not clear as to whether the 

agencies will require that the baseline vehicle be of the same 

model year and configuration as normally specified by vehicle 

purchasers and supplied by equipment manufacturers.

v) The “value” of hybrids relative to conventional vehicles can only be 

assessed with respect to a real world non-hybrid vehicle of 

substantially similar type. Given that the transmission/rear axle 

combination determines the engine torque/speed map for a brake 

power cycle, EPA should specify how “pre transmission” drivetrain 

components will taken into account in the intended testing protocol.

(vi) It is unclear as to whether hybrid manufacturers are to submit A vs. 

B test cycles for each vehicle or a family of hybrid vehicles, or 

whether some other methodology is intended in the proposed rules.

(vii) It is unclear how accessory/hotel loads will be specified or 

considered in the A vs. B testing.

May 19, 2011 30
(viii) It is unclear whether the test methods are focused specifically on 

sandwich hybrid and engine hybrid configurations and/or whether 

the test methods would be limited to such a configurapower take-off 

tion.

(iv) Engine certifications have traditionally involved criteria pollutant 

standards. Since the proposed rules address FE and GHG 

standards, in the case of A vs. B hybrid testing, will criteria pollutants 

be considered with respect to the certification of a hybrid system or 

considered separately with respect to engine certification?

(x) It is unclear how EPA and NHTSA contemplate that hybrid vehicles 

will be certified and by whom. The proposed regulations generally 

provide that engine manufacturers must comply with Subpart A 

regulations Subpart G regulations, however, refer not only to engine 

and vehicle manufacturers but “all other persons.” Given the nonengine components that are necessary for the testing, EPA needs to 

clarify whether a certification can be required from or held by an 

engine manufacturer, an OEM or a hybrid component manufacturer. 

May 19, 2011 31
Weighting of Drive Cycles

May 19, 2011 32
33

• Current EPA weighting proposals tend to:

– Over-represent steady-state highway cruising

– Under-represent transient operation 

(i.e., stop & go traffic, uphill & downhill)

– Underestimate Hybrid benefits

Goal of any hybrid is to exploit vehicle transients:

o Capture vehicle kinetic energy (1⁄2mv2) during braking

o Capture vehicle potential energy (mgh) during downhill

o Re-use the energy for propulsion

Drive Cycle Weighting 

May 19, 2011
Common Highway Cruise Cycles

-1 0

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

0 100 200 300 400 500 600 700 800 900

Vehicle Speed (MPH)

Time (seconds)

65 MPH Steady State

-1 0

0

1 0

2 0

3 0

4 0

5 0

6 0

0 100 200 300 400 500 600 700 800

Vehicle Speed (MPH)

Time (seconds)

55 MPH Steady State

GEM: 55 mph & 65 mph Cruise Cycles

A-to-B Testing: 55 mph & 65 mph Cruise Cycles

300 seconds @ 55 mph and 65 mph (+/- 1.0 mph)

May 19, 2011 34
Common Highway Cruise Cycles

In order to be able to 

• Maintain commonality between testing and simulation

•drive cycles

•weighting percentages

• Avoid confusion among like-named cycles

Allison recommends using the same cycles in GEM and Ato-B testing to represent cruise.

May 19, 2011 35
Weighting by Time (not distance)

Current EPA Proposal:

• 3 basic sub-cycles: Transient, 55 mph Cruise, 65 mph Cruise

• All vehicles will be tested on same 3 basic sub-cycles

• Differences in overall drive cycle according to vehicle operation

to be accommodated by mathematical “weighting” of each sub-cycle

Allison Comment:

• This approach is reasonable in principle

• Seeks to comprehend a broad variation in actual vehicle operation

without placing a huge burden of test/simulation on OEMs

However, there are some areas of confusion... 

May 19, 2011 36
Weighting by Time (not distance)

Issue: Are the % weightings based on time or distance? 

• PTO operation in “Vocational, with PTO” must be time based

(PTO operates with vehicle standing still)

• Other weightings in the table may be distance based

• The RIA uses conflicting terminology in the same sentence (page 3-25):

“... the line haul trucks spent 5% of the miles at speeds less than 50 mph,

17% between 50 and 60 mph, and 78% of the time at speeds greater than

60 mph”.

May 19, 2011 37
Weighting by Time (not distance)

Allison Recommendations: 

• Always use “% weighting” based upon time

• Make time-weighting very clear in the regulations

Reasoning:

• To avoid confusion, either time or distance must be used

• If stationary PTO is involved, time must be used

• Time-based weighting is very common in the industry

• Time-based weightings can reflect the same distance-based prescription

May 19, 2011 38
Weighting of Current Vehicle Types

General Trends:

• EPA 2010 weightings (vs. EPA 2007 Draft Protocol) show:

– less transient operation

– more operation > 60 mph

– higher average speed 

• Allison weightings (vs. EPA 2010) reflect 

– more transient operation

– less operation > 60 mph

– lower average speed

– operation on grades

Note: Allison measured & analyzed 185 in-service drive cycles:

- - 6 Sleeper Cab

- - 21 Day Cab

- - 158 Vocational 

May 19, 2011 39
Notes: 

• EPA 2007 data included speed vs. time traces, so % time was available

• % time ratings can be adjusted to accord with a % distance rating

• Allison data includes grades

2010 EPA

% Time % Distance % Distance % Time % Distance

55.2% 8.9% 5% 24.1% 6.7%

10.1% 4.2% 9% 14.7% 15.6%

34.7% 86.9% 86% 61.2% 77.7%

61.6

SLEEPER CABS

2007 EPA Allison Data

60.2 56.8

Duty Cycle

Transient (<50 MPH)

50 MPH - 60 MPH

>60 MPH

Avg MPH

Sleeper Cabs

Weighting of Current Vehicle Types

May 19, 2011 40
Notes: 

• Strong disparity in weighting & average speeds between EPA & Allison

• Allison data includes grades

Duty Cycle

Transient (<50 MPH)

50 MPH - 60 MPH

>60 MPH

Avg MPH

2010 EPA

% Time % Distance % Distance % Time % Distance

41.7% 19.6% 19% 61.3% 23.2%

35.6% 47.5% 17% 12.1% 22.8%

22.7% 32.9% 64% 26.6% 54.0%

53.9

DAY CABS

2007 EPA Allison Data

50.5 33.8

Day Cabs

Weighting of Current Vehicle Types

May 19, 2011 41
Duty Cycle

Transient (<50 MPH)

50 MPH - 60 MPH

>60 MPH

Avg MPH

2010 EPA

% Time % Distance % Distance % Time % Distance

87.5% 66.6% 42% 83.1% 65.8%

12.5% 33.4% 21% 6.5% 13.8%

0.0% 0.0% 37% 10.3% 20.4%

42.0

VOCATIONAL VEHICLES

2007 EPA Allison Data

28.6 18.1

Allison Data for Vocational Vehicles summary includes all data from duty cycles that are included in 

the EPA's definition of Vocational Vehicles - Refuse, Dump, Mixer, Transit, School Bus, P&D, etc.

• EPA 2007 was somewhat close to the Allison Data

• But EPA 2010 shows an enormous disparity, shift from EPA 2007

• Allison data includes grades

Vocational Vehicles

Weighting of Current Vehicle Types

May 19, 2011 42
Weighting of Vocational Sub-Groups

General:

• Current EPA proposal uses 1 weighting for all Vocational vehicles

– Actual cycles vary significantly among Vocational sub-groups

– Establishing a few sub-groups may be helpful

– Could accommodate vocations which lend themselves to hybrids

• EPA’s suggested vocational sub-groups:

– Urban (City Bus)

– Mixed Urban/Freeway (P&D, delivery)

– Refuse Packer

– Utility Truck with Boom

May 19, 2011 43
Allison Experience Base

Vocational vehicles per EPA definition

Count Vehicle Class

VOCATIONAL VEHICLES % Time % Distance % Time % Distance % Time % Distance

EPA Defined Vocational - Allison Data 83.1% 65.8% 6.5% 13.8% 10.3% 20.4% 158

Oil Field, Dual Mode, Straight Truck 68.3% 60.0% 12.3% 16.1% 19.3% 23.9% 5 8

Refuse, Front Loader, Straight Truck 92.2% 78.9% 7.5% 20.1% 0.4% 1.0% 1 1 8

Refuse, Rear Loader, Straight Truck 91.7% 75.5% 6.2% 17.9% 2.1% 6.6% 1 6 8

Refuse, Recycling Roll Off, Straight Truck 86.2% 63.6% 7.9% 20.2% 5.9% 16.3% 1 8

Refuse, Side Loader, Straight Truck 99.1% 96.5% 0.9% 3.5% 0.0% 0.0% 2 8

Dock Spotter, Tractor Trailer 100.0% 100.0% 0.0% 0.0% 0.0% 0.0% 3 8

Concrete Mixer, Front Discharge, Straight Truck 80.9% 67.0% 10.9% 24.5% 8.2% 8.5% 1 4 8

Construction, Dump Truck, Straight Truck 89.0% 70.0% 8.1% 21.2% 2.9% 8.9% 4 8

Equipment Hauler, Tractor Trailer 100.0% 100.0% 0.0% 0.0% 0.0% 0.0% 2 8

Transit, Articulated Bus 99.4% 97.4% 0.4% 1.6% 0.2% 1.1% 5 8

Transit, 40 Foot Bus 98.0% 93.7% 1.5% 2.0% 0.5% 4.3% 3 2 7

Shuttle Bus 91.2% 71.7% 5.3% 16.0% 3.5% 12.3% 8 6

Intercity Transit Coach 86.8% 81.9% 10.8% 8.8% 2.4% 9.3% 4 8

Tour Coach 18.1% 10.7% 14.8% 14.8% 67.2% 74.5% 7 8

School Bus 93.3% 87.6% 6.4% 12.2% 0.3% 0.2% 8 5

Beverage Delivery, Straight Truck 87.6% 73.2% 8.2% 17.5% 4.1% 9.3% 2 5/6

Beverage Delivery, Tractor Trailer 81.9% 63.7% 7.5% 13.3% 10.6% 23.0% 4 6/7

City Delivery, Straight Truck 69.6% 58.0% 8.1% 17.8% 22.3% 24.2% 1 1 5/6

City Delivery, Walk-In Van 84.5% 60.9% 6.1% 17.2% 9.4% 22.0% 1 9 4/5

Transient (<50 MPH) 50 MPH - 60 MPH >60 MPH

Weighting of Vocational Sub-Groups

Allison data includes grades

May 19, 2011 44
The separate Vocational Sub-Groups are justified:

• Large variation between cycles, even in propulsion mode alone

• PTO loadings in Refuse and Utility add to the variation

Summary of Allison Recommendations

Refuse & Utility do not break out PTO operation separately 

Weighting of Vocational Sub-Groups

Count Vehicle Class

% Time % Distance % Time % Distance % Time % Distance

Urban 98.0% 93.7% 1.5% 2.0% 0.5% 4.3% 3 2 7

Mixed Urban 69.6% 58.0% 8.1% 17.8% 22.3% 24.2% 1 1 5/6

Refuse Packer 92.2% 78.9% 7.5% 20.1% 0.4% 1.0% 1 1 8

Utility Truck 69.6% 58.0% 8.1% 17.8% 22.3% 24.2% 1 1 5/6

Transient (<50 MPH) 50 MPH - 60 MPH >60 MPH

May 19, 2011 45
Situation

– Allison cycle data reflect grades

– EPA cycles may not

– Grades are a part of real-life operations

– Grades are well-suited to capture hybrid advantages

Allison General Suggestion

– Either include grades in the cycles

(Can typical dynamometers/test stands accommodate them?)

(Uphill means just added load, downhill means a “powering” dyno)

– Or increase the “% transient” time when weighting all cycles

Accounting for Road Gradients

May 19, 2011 46
Accounting for Road Gradients

Complications

– Allison cycle data does not include measured grade data 

– Difficult to measure until recently (even GPS is not accurate)

– Broad variation in grades across the USA

– So, how can grades be quantified? 

(either directly or in additional % transient time)

Allison Specific Suggestions

Allison can only show that road gradient is highly significant: 

• Importance of an Inclinometer: 

– Allison’s next generation controls will include an inclinometer

– Competitive automated transmissions also use an inclinometer

• Show quantitative relationship between grade and vehicle speed:

– Important to hybrid operation

– Compares Energy from grade to energy from vehicle speed

May 19, 2011 47
Accounting for Road Gradients

Grade Elevation vs. Vehicle Speed

Kinetic Energy = 1⁄2mv2

Grade Energy = mgh mgh = 1⁄2mv2 h =

v

2

2g

Example: Stop from 60 mph involves the same energy as a drop of 120 feet. 

(less than a half-mile on a 5% grade) 

May 19, 2011 48
49

May 19, 2011

Allison Test Experience and 

Lessons Learned 
Allison Test Experience and Lessons Learned 

• Purpose of this discussion:

• Identify & communicate key Fuel Economy Test 

Factors

– Identify differences between engine test cell & vehicle roll 

dyne testing

• Discuss key fuel economy testing measures

• Discuss lessons & observations from initial EPA 

testing with Allison’s 2000 SeriesTM transmission

May 19, 2011 50
•Test Factors influencing Fuel Economy & differences 

between these factors in engine test cells & vehicle roll 

dynes 

•Engine test factors

•Transmission test factors

•Environmental, Duty Cycle & Use factors

•Vehicle factors

•Test methodology, accuracy & repeatability factors

Allison Test Experience and Lessons Learned 

May 19, 2011 51
Test factors influencing fuel economy Level of engine test cell to 

vehicle roll dyne difference

Level of difficulty to eliminate or reduce 

difference between engine test cell & 

vehicle roll dyne testing

Engine Torque curve (various pedal 

positions)

No difference with same Engine 

Cal 

Idle Speed No difference with same Engine 

Cal 

Maximum (governed) speed No difference with same Engine 

Cal 

Brake Specific Fuel Consumption Curve No difference with same Engine 

Cal 

Recent EPA / ATI fuel economy test results

indicate a difference in fuel maps even though 

engines were intended to be the same

Throttle to Torque Relationship Curves 

(pedal progression)

No difference with same Engine 

Cal 

Turbocharger / Smoke Control Lag 

Characteristics

No difference with same Engine 

Cal 

Accessory Losses as a function of engine 

speed

Test cells may not have fans or 

alternators & typically do not run 

compressors or AC

Significant impact if these differences must be 

eliminated

Engine Inertia No difference if engine is the 

same

Fuel type, density & temperature No difference if these factors are 

controlled

Equipment & facilities to control these factors 

is expensive & not common

No or small difference Some difference Significant difference

Test Factors influencing Fuel Economy & differences between these factors in engine test cells & 

vehicle rolls dynes (Engine Factors)

May 19, 2011 52
Test factors influencing fuel economy Level of engine test cell 

to vehicle roll dyne 

difference

Level of difficulty to eliminate or 

reduce difference between engine 

test cell & vehicle roll dyne testing

Transmission mechanical factors

No difference if the same configuration transmission is used for 

engine test cell or vehicle roll dyne testing (see note 1)

Model

Gear ratios

Torque converter

Spin losses

Pump losses

(Gear) Range inertia

Transmission control capabilities

No difference if the same transmission calibration is used for engine 

test cell or vehicle roll dyne testing (see note 1)

automatic load based shift pattern selection

Automatic shift to neutral when stopped

Optimized shift pattern

Rate of acceleration management

No or small difference Some difference Significant difference

Test Factors influencing Fuel Economy & differences between these factors in engine test cells & 

vehicle rolls dynes (Transmission Factors)

Note 1: changes in test duty cycle may require changes in transmission 

mechanical & controls configuration

May 19, 2011 53
Test factors influencing fuel economy Level of engine test cell to 

vehicle roll dyne difference

Level of difficulty to eliminate or reduce 

difference between engine test cell & 

vehicle roll dyne testing

Ambient temperature

Both test cells & vehicle roll dynes require environmental test capability to control 

these factors (see note 1)

Hot & cold temperature extremes

Humidity & air density

Terrain; flat, hilly, mountains etc

Both test cells & vehicle roll dynes can manage these factors via duty cycle 

definition (ref note 2)

Road conditions; smooth, bumpy etc

Driving conditions; congested, city, hi-way 

etc

Application; pickup & delivery, 

construction, garbage, over the road etc

Driver; passive, aggressive, nervous etc Drivers in roll dynes will add 

variation not seen in test cells 

using automated test cycles

automated drivers in roll dynes needed to 

eliminate variation

Reasonable duty cycles & use of 

accelerator pedal & brake

Test cells with automated cycles 

can make unrealistic accelerator 

pedal & brake commands

Assure all duty cycles are representative of 

typical vehicle use & are not too slow, too 

abrupt or too transient.

No or small difference Some difference Significant difference

Test Factors influencing Fuel Economy & differences between these factors in engine test cells & 

vehicle rolls dynes (Environmental, Duty Cycles & Use Factors)

Note 1: Environmental test cells for BIG trucks are very expensive & very uncommon

Note 2: Different duty cycles require different transmission & vehicle configurations 

May 19, 2011 54
Test factors influencing fuel economy Level of engine test cell to 

vehicle roll dyne difference

Level of difficulty to eliminate or reduce the 

difference between engine test cell & 

vehicle roll dyne testing

Vehicle mass

Differences in these factors are 

a function of differences 

between engine test cell & roll 

dyne control & measurement 

equipment. 

The level of difficulty to reduce or eliminate 

these differences is a function of the test cell 

changes / equipment needed to obtain 

accurate FE test results

Vehicle rolling resistance

Vehicle aerodynamic drag

Number, age & design of tires

Axle ratio

No or small difference Some difference Significant difference

Test Factors influencing Fuel Economy & differences between these factors in engine test cells & 

vehicle rolls dynes (Vehicle Factors)

Note 1: The EPA agreed to change the axle in initial testing with the ATI 2000 

SeriesTM transmission. This change was appreciated & necessary for the 2000 

SeriesTM transmission to demonstrate representative FE test results

Note 2: test cells able to perform high accuracy fuel economy & emissions testing on 

complete powertrain systems are rare & expensive

May 19, 2011 55
Test factors influencing fuel economy Level of engine test cell to vehicle 

roll dyne difference

Level of difficulty to eliminate or 

reduce the difference between engine 

test cell & vehicle roll dyne testing

First time test accuracy

Both engine test cells & vehicle roll 

dynes are subject to these test 

Quality & methodology factors. 

Test methodology will need to include 

“sanity” checks, use of test “masters” 

should be considered & comparison of 

test results to prior data may not be 

possible. (in other words, all tests may 

need to include a new baseline)

Time to time variation in test results (for 

example: tests are run months apart)

Part to part variation (for example: a 

transmission or engine is changed / 

updated

Test cell equipment change variation (for 

example: a dyne or torque meter is 

changed)

Test cell to test cell variation (for

example: differences between the EPAs 

& ATIs test cell)

No or small difference Some difference Significant difference

Test Factors influencing Fuel Economy & differences between these factors in engine test cells & 

vehicle rolls dynes (Test methodology, accuracy & repeatability)

Note: During initial EPA testing with the ATI 2000 SeriesTM transmission, an EPA 

torque measurement problem was identified via a “sanity” check.

May 19, 2011 56
Testing accuracy, repeatability & the price of the last 1% – 2%

Indy cars are rare & very expensive to buy & operate:

•The price of a race track ready Indy Car is over $500k.

•The price to operate an Indy Car for a whole race season varies

between $4M & $8M per year

•For $4M you can run an Indy Car that will perform within 2% of the best car on the track.

•The problem is in Indy Car racing the difference between first & last is 2% or less.

•For $8M & the associated process, equipment & labor, you can get the last 2% & 

compete to win.

•To draw from Indy Cars & apply these lessons to commercial vehicle FE testing:

•The equipment needed to test FE accurately is rare & expensive

•The differences between test configurations is small in many cases, 1% - 2%

•The test equipment & process must be capable to “find” these small percentages &, 

like Indy Cars, finding the last couple percent is expensive & takes special process & 

equipment.

May 19, 2011 57
Summary of test factor observations:

•The “same” is not always the “same”

•Several test factors are important & test methodology must allow key factors to be optimized

•Changes in test duty cycle may require changes in transmission mechanical & controls 

configuration and / or changes in the vehicle

•Defining several “core” powertrains & duty cycles is a possibility, however, optimization with 

several FE factors is necessary to assure representative results (ref: EPA allowing ATI’s 

request to change the axle ratio used in initial testing)

•Environmental test capability is needed & is expensive & rare

•To assure FE testing accuracy & repeatability test practices will need to include “sanity” checks. 

Due to time to time & other sources of test variation test “masters” should be considered & 

comparing test results with prior data may not be possible. New “baseline” testing may be required 

for all tests. 

•A lot of test factors are important. There’s a lot to learn & evolve with test methodology, process & 

facilities. There will likely be a shortage of test facilities able to provide accurate & repeatable test 

results. The importance of reducing our environmental risks is extreme. 

Considering these facts, ...................... What to do?

May 19, 2011 58
This coming week end 40 plus drivers & cars will attempt to qualify for the Indy 500; only 33 of them will 

make the field. One of those 33 will win the purse of over $2M! (the prize is large!)

To make the field, the participants must post one of top 33 Qualification speeds. Qualifications consists of 4 

laps where the drivers hold their breath the entire 4 laps due to the extreme risk.

To Qualify the race cars are set up in a fashion not usable on race day. Gears are removed from the 

transmissions to reduce drag, radiators are blocked to reduce drag etc. These set ups produce good results 

for 4 laps; soon afterwards, the cars break down.

With the EPA the heavy truck industry is entering a race. The race is for the long haul, the whole 500 miles 

& not just 4 laps. The race is to lead the way towards heavy trucks working to improve their environmental 

friendliness.

Qualification set ups won’t get this done. We need race set ups; set ups good for the whole 500 miles. 

We do not have race set ups defined yet, but, we clearly must get started; and, we must recognize the need 

to run the race & not just Qualify. We, just like race cars, need to define the key race tracks (duty cycles) & 

key vehicle & powertrain factors to improve fuel efficiency. Then, put the car on the track in a few key 

configurations & learn & evolve the test process with an eye on winning the race rather than just running 4 

laps to Qualify.

Considering these facts, ...................... What to do?

May 19, 2011 59
Allison Test Experience and Lessons Learned 

• Purpose of this discussion:

• Identify & communicate key Fuel Economy 

Test Factors

• Identify differences between engine test cell & 

vehicle roll dyne testing

• Discuss key fuel economy testing measures

• Discuss lessons & observations from initial 

EPA testing with Allison’s 2000 SeriesTM

transmission

May 19, 2011 60
test measures units comment

Distance travelled during 

the test duty cycle

Miles or feet A component of the traditional measure of fuel economy, MPG. This measure 

assures test configurations are providing the same user benefit. 

cycle time seconds used to compare cycle completion time. This measure assures test 

configurations are performing similarly for users (see slide 91)

vehicle speed average miles / 

hour

used to compare vehicle speed over the test cycle. Very low speed cycles are 

not typical.

fuel used grams traditional EPA measures

MPG miles / gallon

work, all (hp hr) (all work) Use of ALL work is required since all work done with the engine influences fuel 

use / efficiency 

work, positive (hp hr) (+)

fuel efficiency (hp s / g) All work per grams of fuel used. The is a key measure of fuel use since it reflects 

work done per unit of fuel.

Fuel Economy testing measures (used in recent EPA / ATI Fuel Economy 

testing)

May 19, 2011 61
For valid FE testing, distance travelled & cycle time must be equal to 

assure tests are similar in terms of user benefit (getting to the terminal)

test measures units comment

Distance travelled during 

the test duty cycle

Miles or feet A component of the traditional measure of fuel economy, MPG. This measure 

assures test configurations are providing the same user benefit. 

cycle time seconds used to compare cycle completion time. In ATI’s view this is a critical measure 

to assure test configurations are performing similarly for users

Distance travelled during test cycle in test cycle time

Distance travelled during test cycle in test cycle time Need more fuel

terminal

Without measures for distance travelled or cycle time, the 

vehicle may not get to the terminal or will need more fuel to 

get there !

The blue bar represents 

the drive cycle

May 19, 2011 62
A comparison of automatic & manual transmission acceleration using 

work done to lift bowling balls as an illustration

•work is represented by lifting bowling balls onto a pile

•This includes re-lifting those bowling balls that fall off the pile during manual trans 

power interrupts (positive work does not include re-lifting, all work does)

•The automatic trans with power shifts drops no bowling balls & completes the same 

acceleration lifting fewer bowling balls . This result represents improved fuel efficiency 

with the automatic trans ............. same work done with less with less lifting.

May 19, 2011 63
Summing up measures: The importance of distance travelled, time to cross the 

finish & fuel efficiency

Indy car racing has very good measures. 

•The car crossing the finish with all laps complete in the shortest length of time wins the race

To draw from these measures & apply them to the operation of commercial vehicles:

•Finishing all the laps is important. You cannot just leave the last 3 garbage cans at the end of the 

shift or fail to drop off the last load of milk! Measuring distance travelled is important!

•Whoever completes the race in the shortest amount of time using no more than the prescribed 

amount of fuel wins. Whoever finishes the job in the least time in an expensive / revenue generating 

commercial vehicle can use the vehicle to generate additional revenue. Measuring time to complete 

jobs is important.

•The amount of fuel Indy cars use in a race is legislated & very limited. Those who burn fuel 

inefficiently will not win races. Measuring fuel efficiency is important & reflects the meaningful 

measure of work done per unit of fuel used!

May 19, 2011 64
Allison Test Experience and Lessons Learned 

• Purpose of this discussion:

• Identify & communicate key Fuel Economy 

Test Factors

• Identify differences between engine test cell & 

vehicle roll dyne testing

• Discuss key fuel economy testing measures

• Discuss lessons & observations from initial 

EPA testing with Allison’s 2000 SeriesTM

transmission

May 19, 2011 65
lesson recommendation

Some Duty cycles are not realistically 

aggressive 

Define test cycles representative of 

drivers & vehicles in real world use. 

Assure we do not strive for “one cycle 

fits all” and, in fact, end up with “one 

cycle fits none”.

Some duty cycles' average speed is not 

realistic

Test representative vehicle weights

Straight Line acceleration is not 

representative of real world

A more natural diminishing 

acceleration with a smooth transition 

to cruising is more realistic and will 

eliminate some controls issues. 

Vehicle model should be the same for all 

powertrains

The EPAs “coast down” vehicle test 

disadvantages automatic transmissions 

since the drive line cannot be de-coupled. 

Use of a common vehicle model keeps the 

playing field level.

Other lessons learned & observations from initial EPA testing 

May 19, 2011 66
“Natural” Acceleration

Results in the typical “speed vs. time” graph...

May 19, 2011 67
“Natural” Acceleration

May 19, 2011 68
“Natural” Acceleration

Straight line acceleration is highly “unnatural”...

May 19, 2011 69
70

Straight-line Acceleration

• Throttle must be “jockeyed” to try to fit the straight line

• Introduces transient operations which:

– Are not typical of actual operation

– Reduce ability to put in vehicle energy efficiently 

– Acceleration rate is very slow

– Here’s what happens with straight line cycles in terms of gas 

pedal movement

• keep in mind, this applies to the EPA Transient cycle too

70

May 19, 2011
Straight line acceleration throttle pedal movement

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 140 160 180 200

Throttle %

Time (seconds)

GEM 55 Throttle

GEM 65 Throttle

71

May 19, 2011 These bumps are gas 

pedal movements. 

This is not how people 

drive
72

Standardized on road test (SORT) Process

• SORT is a European standard

• SORT accepts that straight-line acceleration is not realistic

• SORT sets start & end points (i.e, average acceleration);

in-between is flexible

• SORT acceleration is far quicker than EPA cycles 

72

May 19, 2011
lesson Recommendation / observation

Time from engine start to start of 

cycle not closely controlled

The EPA includes an engine start at the beginning of their cycles. There 

does not seem to be a set time to begin the test cycle. Establish a set 

time.

For cruise cycle data, the EPA is 

only using a portion of the cycle 

where they are at cruise speed

For the 55 mph cruise and 65 mph cruise cycles, the EPA only used the 

last 300 seconds of steady-state operation & not the entire cycle to get 

their fuel economy number. This gives MTs an advantage since their

power interrupts during acceleration are excluded from the FE 

measurement.

Powertrain Test Stand Set-up The EPA's use of an AC motoring dyne, no inertia wheel, and an inline 

torque meter for dyne control offers several advantages for fuel testing 

over the ATI test cell set-up of an EC brake, inertia wheel, and load cell 

for dyne control. 

Torque Transducer Specification Torque transducer selection is key. The EPA has standards to determine 

the required accuracy of their torque transducer to insure good data. ATI 

should follow their standards for future testing.

Require that measured torque be 

within certain limits of requested 

(vehicle model) torque.

The EPA has requirements that the measured torque be within certain 

limits of the modeled vehicle torque. This requirement insures that the 

test cell is accurately modeling the vehicle. This is good test practice.

Other lessons learned & observations from initial EPA testing 

May 19, 2011 73
Allison Test Experience and Lessons Learned 

• Purpose of this discussion:

• Identify & communicate key Fuel Economy Test 

Factors

• Identify differences between engine test cell & vehicle 

roll dyne testing

• Discuss key fuel economy testing measures

• Discuss lessons & observations from initial EPA 

testing with Allison’s 2000 SeriesTM transmission

• End of this section of the presentation

May 19, 2011 74
Wrap-up

May 19, 2011 75
Closing Remarks

• Allison, as a leader in transmission 

technology, has made several 

recommendations based on extensive 

experience in the medium and heavy 

duty vehicle market

• Thank you, EPA, for the opportunity to 

share our views for your consideration 

and action.

76 May 19, 2011