Clean Automotive Automotive Technology Technology

Cost‐Effective Solutions

For a Petroleum and Carbon Constrained World

John J. Kargul

Director of Technology Transfer

Office of Transportation and Air Quality

U.S. Environmental Protection Agency

Clean Automotive Technology

www.epa.gov/otaq/technology

NAS Review of 21st Century Truck Program – September 8, 2010

 Lower emissions emissions

 Increased fuel efficiency

 Reduced greenhouse gases

 Cost‐effective technology

Clean Automotive Technology ‐ US EPA 2

2005 2010

EPA’s Hydraulic Hydraulic Hybrid Program Program

Series HHV Medium Car

Series HHV UPS Package Car

Urban

Vehicles

Series HHV SUV (pickup)

Series HHV Kalmar Yard Hostler

Series HHV FedEx Ground Truck

Series HHV Navistar IC Shuttle Bus

Technology Technology Transfer Transfer Partnerships Partnerships

Parallel HHV Work Truck

Concept Concept Demonstration Demonstration Vehicles Vehicles
Clean Automotive Technology ‐ US EPA 3

EPA Technology Technology Transfer Transfer Partners Partners

Clean Automotive Technology ‐ US EPA 4

Industry is Active!

Moving to Full Production

2008      2009      2010     2011

fleet testing of

pilot vehicles

Purchases of

early/pre‐

production

vehicles

~20

refuse

~6

delivery 46* delivery

89* refuse

* Purchases which have been announced 

(specific deployment dates are not known)

Please note that there are also other companies that 

are developing original equipment and retrofit HHV 

systems for on-road, non-road, and military applications.
Clean Automotive Technology ‐ US EPA 5

Parallel Parallel HHV Configuration Configuration

Benefits

 Fuel savings

 Reduced emissions

 Reduced brake and 

engine wear

 Represents easiest opportunity to start getting fuel savings.

 As with HEV systems, first HHV systems will be parallel with good benefits.

Clean Automotive Technology ‐ US EPA 6

R&D / Proof‐of‐Concept Concept Series HHVs

Using Prototype Components

EPA UDV1 Chassis EPA UDV2 Chassis
Clean Automotive Technology ‐ US EPA 7

Power Capacity Capacity of Hydraulics Hydraulics Enables Enables

Series Hybrid Vehicles Vehicles

1. Hydraulic accumulator’s capacity to receive and discharge

power is not a constraint for any HHV.

– It is a design parameter, set to correspond to the performance needs of the

particular vehicle’s vocation (duty cycle, operational weight).

2. Accumulator capacity in UPS hydraulic hybrid vehicle has

been set to handle in excess of 200kw of power.

– Since the engine in this vehicle can deliver 130kw, the power capacity of the

accumulator does not need to be more than 200kw.  

– In addition, there is a flow fuse which serves as a safety feature.   It is

calibrated to shut the flow off if the fluid discharge is above the maximum

power level (approximately 180 gallons per minute in the UPS truck).

Clean Automotive Technology ‐ US EPA 8

Why Series Hydraulic Hybrid Vehicles?

 Maximizes regenerative braking

 Engine operates at best efficiency

 Engine can shutoff at idle

 Engine can shutoff at all times when not needed (e.g. while

braking and during low power cruising)

• Highest possible hybrid fuel economy

• Lowest incremental cost

o Shortest payback to owner

o Highest lifetime‐savings

• Enables unique high‐efficiency engines

• Ultra‐low emissions

• Greater reductions in greenhouse gases

• Greater reductions in imported oil
Clean Automotive Technology ‐ US EPA 9

Efficiencies Efficiencies While Braking/Accelerating Braking/Accelerating ...

Overall Regenerative Efficiency

Hydraulic Hybrids > 70%   versus   Electric Hybrids < 25%

Friction Braking & Drag and 

Driveline Losses

Braking Event 

35-0 mph, 0.1g

Acceleration Event 

0-35 mph, 0.1g

Clean Automotive Technology ‐ US EPA 10

Series HHVs do not need the

engine to respond to transient

road‐load changes

 Engine is de‐coupled from the

wheels, enabling it to be operated

at “best efficiency”

 Very high “diesel‐like” driving

torque characteristics are delivered

by the series hybrid drivetrain, not

the engine

 Buffering by the HHV accumulator

system eliminates the need for

quick engine transients

 Use of advanced engines is possible

(e.g., gasoline HCCI)

Engine Operation Operation for Series HHVs

Engine is de-coupled from the wheels
Clean Automotive Technology ‐ US EPA 11

Bent‐Axis Pump‐Motors

110cc pump-motor assembly

Yoke

Barrel

Pumping or motoring power increases 

as yoke angle increases.

300 HP @

5000 psi

Clean Automotive Technology ‐ US EPA 12

Types of Accumulators Accumulators

“Bladder” “Piston”

CHARGED (full of fluid)

UNCHARGED (empty of fluid)

Cut‐away of a piston carbon‐fiber high‐pressure

accumulator used in some EPA demonstration HHVs.

UNCHARGED (empty of fluid)

CHARGED (full of fluid)

Adding hydraulic fluid to the accumulator 

compresses the nitrogen filled bladder.

High pressure accumulators operate 

between 2000 and 7000 psi.

Low pressure accumulators typically 

operate between 50 and 200 psi.

Adding hydraulic fluid to the accumulator 

compresses the piston into the nitrogen filled shell.
Clean Automotive Technology ‐ US EPA 13

Relative Relative Performance Performance of Energy‐Storage Storage

1

2

4

6

10

2

4

6

100

2

4

6

1000 Specific Energy (Wh/kg)

100 101 102 103 104

Specific Power (W/kg)

Lead-acid

Capacitors

Fuel Cells

IC Engine

HEV goal

1 h 0.1 h 36 s 3.6 s

10 h

100 h

Ni-MH

Li-ion

1 h 0.1 h 36 s 3.6 s

10 h

100 h

Acceleration

Range

EV goal

1 h 0.1 h 36 s 3.6 s

10 h

100 h

Source: Product data sheets

Venkat Srinivasan and John Newman; Environmental Energy Technologies Division; Lawrence Berkeley National Laboratory; Berkeley, CA

The HHV 

UPS truck 

operates 

here. 0.1h 36 s

Hydraulic Accumulators

Accumulators 

can operate 

anywhere in 

the green box 

with infinite 

life.

Clean Automotive Technology ‐ US EPA 14

Example Example 22‐Gallon Carbon‐Fiber

HHV Accumulator Accumulator

View looking at driver’s side of the vehicle

Rear 

Wheel

* Energy‐wise a smaller accumulator would be large enough to handle only the regenerative braking,

however, the rest of the capacity is used so the hybrid truck can drive further with the engine‐off and

for improved engine buffering (i.e., reduced engine on/off cycling).

Class 6 ‐ 23,400 GVW ‐ urban delivery vehicle

A hydraulic hybrid urban delivery vehicle containing a

44‐gallon accumulator system* with a stored energy capacity of:

.4 kW‐hr @5000 psi to .52 kW‐hr @6500 psi
Clean Automotive Technology ‐ US EPA 15

Technologies Technologies Needed for Engine‐Off Operation Operation

Engine‐off power steering steering unit* Engine‐off power brake unit*

 In HHVs, these technologies use energy from the high pressure accumulator to provide the

“power assist” including when the engine is not operating.

 By adding a small accumulator to store pressure from the power steering pump, these systems

could easily be used in HEVs and conventional trucks to enable engine‐off operation.

 Various strategies exist to maximize engine “off” time when HVAC systems must be used

(heat in the winter, AC in the summer).

* available from R.H. Sheppard

Clean Automotive Technology ‐ US EPA 16

HWFET

HD Veh UDDS

FTP-bag3

CILCC

FTP

CSHRV

FTP-bag2

WVU City

NYC Truck

CBD Truck

Mahattan Bus

36% 32% 49% 46% 49% 31% 33%

19% 21%

6%

-25% -12%

0%

25%

50%

75%

100%

125%

150%

175%

% Improvement over Vehicle's Baseline MPG 

. Drive Cycle

Initial MPG Testing of EPA's UDV1

HWFET

HD Veh UDDS

FTP-bag3

CILCC

FTP

CSHRV

FTP-bag2

WVU City

NYC Truck

CBD Truck

Mahattan Bus

36% 32% 49% 46% 49% 31% 33%

19% 21%

6%

-25% -12%

0%

25%

50%

75%

100%

125%

150%

175%

% Improvement over Vehicle's Baseline MPG 

. Drive Cycle

Initial MPG Testing of EPA's UDV1

HWFET

HD Veh UDDS

FTP-bag3

CILCC

FTP

CSHRV

FTP-bag2

WVU City

NYC Truck

CBD Truck

Mahattan Bus

36% 32% 49% 46% 49% 31% 33%

19% 21%

6%

-25% -12%

0%

25%

50%

75%

100%

125%

150%

175%

% Improvement over Vehicle's Baseline MPG 

. Drive Cycle

Initial MPG Testing of EPA's UDV1

Fuel Efficiency Efficiency of EPA’s Series HHV with

Prototype Prototype Hydraulic Hydraulic Components Components

This prototype prototype system (UDV1) achieved achieved 45‐50% mpg improvement improvement when field tested

in real‐world package package delivery delivery by UPS.
Clean Automotive Technology ‐ US EPA 17

HWFET

HD Veh UDDS

FTP-bag3

CILC

FTP

C

CSHRV

FTP-bag2

WVU City

NYC Truck

CBD Truck

Mahattan Bus

119 %

113 %

9 1%

84 %

71%

61%

5 1%

44 %

3 3% 33%

1%

3 6% 3 2% 49 % 46 % 4 9%

3 1% 3 3%

19 % 2 1%

6%

- 12 % -25%

0%

25%

50%

75%

100%

125%

150%

175%

% Improvement over Vehicle's Baseline MPG .

Driv e Cycle

Initial MPG Testing of EPA's UDV1 & Pilot UDV

UDV1 @ 19,994 lbs

Pilot @ 20,000 lbs 

HWFET

HD Veh UDDS

FTP-bag3

CILC

FTP

C

CSHRV

FTP-bag2

WVU City

NYC Truck

CBD Truck

Mahattan Bus

119 %

113 %

9 1%

84 %

71%

61%

5 1%

44 %

3 3% 33%

1%

3 6% 3 2% 49 % 46 % 4 9%

3 1% 3 3%

19 % 2 1%

6%

- 12 % -25%

0%

25%

50%

75%

100%

125%

150%

175%

% Improvement over Vehicle's Baseline MPG .

Driv e Cycle

Initial MPG Testing of EPA's UDV1 & Pilot UDV

UDV1 @ 19,994 lbs

Pilot @ 20,000 lbs 

HWFET

HD Veh UDDS

FTP-bag3

CILC

FTP

C

CSHRV

FTP-bag2

WVU City

NYC Truck

CBD Truck

Mahattan Bus

119 %

113 %

9 1%

84 %

71%

61%

5 1%

44 %

3 3% 33%

1%

3 6% 3 2% 49 % 46 % 4 9%

3 1% 3 3%

19 % 2 1%

6%

- 12 % -25%

0%

25%

50%

75%

100%

125%

150%

175%

% Improvement over Vehicle's Baseline MPG .

Driv e Cycle

Initial MPG Testing of EPA's UDV1 & Pilot UDV

UDV1 @ 19,994 lbs

Pilot @ 20,000 lbs 

Fuel Efficiency Efficiency of EPA’s Series HHV with

Right‐Sized Hydraulic Hydraulic Components Components

EPA’s newest  

”Pilot” series HHV chassis

Clean Automotive Technology ‐ US EPA 18

HWFET

HD Veh UDDS

FTP-bag3

CILCC

FTP

CSHRV

FTP-bag2

WVU City

NYC Truck

CBD Truck

Mahattan Bus

15 1%

79 %

58%

34%

119 %

113%

9 1%

8 4%

7 1%

61%

51%

44 %

33% 3 3%

1%

3 6% 32 % 49 % 46 % 49% 3 1% 3 3%

19 % 21%

6 %

-25% - 12 %

0%

25%

50%

75%

100%

125%

150%

175%

% Improvement over Vehicle's Baseline MPG .

Driv e Cycle

Initial MPG Testing of EPA's UDV1, Pilot UDV, and Shuttle Bus

UDV1 @ 19,994 lbs

Pilot @ 20,000 lbs 

Shuttle @ 18,500 lbs 

HWFET

HD Veh UDDS

FTP-bag3

CILCC

FTP

CSHRV

FTP-bag2

WVU City

NYC Truck

CBD Truck

Mahattan Bus

15 1%

79 %

58%

34%

119 %

113%

9 1%

8 4%

7 1%

61%

51%

44 %

33% 3 3%

1%

3 6% 32 % 49 % 46 % 49% 3 1% 3 3%

19 % 21%

6 %

-25% - 12 %

0%

25%

50%

75%

100%

125%

150%

175%

% Improvement over Vehicle's Baseline MPG .

Driv e Cycle

Initial MPG Testing of EPA's UDV1, Pilot UDV, and Shuttle Bus

UDV1 @ 19,994 lbs

Pilot @ 20,000 lbs 

Shuttle @ 18,500 lbs 

HWFET

HD Veh UDDS

FTP-bag3

CILCC

FTP

CSHRV

FTP-bag2

WVU City

NYC Truck

CBD Truck

Mahattan Bus

15 1%

79 %

58%

34%

119 %

113%

9 1%

8 4%

7 1%

61%

51%

44 %

33% 3 3%

1%

3 6% 32 % 49 % 46 % 49% 3 1% 3 3%

19 % 21%

6 %

-25% - 12 %

0%

25%

50%

75%

100%

125%

150%

175%

% Improvement over Vehicle's Baseline MPG .

Driv e Cycle

Initial MPG Testing of EPA's UDV1, Pilot UDV, and Shuttle Bus

UDV1 @ 19,994 lbs

Pilot @ 20,000 lbs 

Shuttle @ 18,500 lbs 

Fuel Efficiency Efficiency of EPA’s Series HHV Shuttle Shuttle

with Right‐Sized Hydraulic Hydraulic Components Components

EPA’s newest  

”Shuttle Bus” series HHV chassis
Clean Automotive Technology ‐ US EPA 19

HWFET

HD Veh UDDS

FTP-bag3

C

FTP

ILCC

CSHRV

FTP-bag2

WVU City

NYC Truck

CBD Truck

Mahattan Bus

151%

79%

58 %

3 4%

119 %

113 %

9 1%

8 4%

7 1%

6 1%

5 1%

44 %

3 3% 33 %

1%

3 4% 37%

3 2%

-25%

0%

25%

50%

75%

100%

125%

150%

175%

% Improvement over Vehicle's Baseline MPG .

Driv e Cycle

Initial MPG Testing of EPA's Pilot UDV, and Shuttle Bus

Comparing to HEV Re sults from NREL

HEV @ 17,500 lbs

Pilot @ 20,000 lbs 

Shuttle @ 18,500 lbs 

HWFET

HD Veh UDDS

FTP-bag3

C

FTP

ILCC

CSHRV

FTP-bag2

WVU City

NYC Truck

CBD Truck

Mahattan Bus

151%

79%

58 %

3 4%

119 %

113 %

9 1%

8 4%

7 1%

6 1%

5 1%

44 %

3 3% 33 %

1%

3 4% 37%

3 2%

-25%

0%

25%

50%

75%

100%

125%

150%

175%

% Improvement over Vehicle's Baseline MPG .

Driv e Cycle

Initial MPG Testing of EPA's Pilot UDV, and Shuttle Bus

Comparing to HEV Re sults from NREL

HEV @ 17,500 lbs

Pilot @ 20,000 lbs 

Shuttle @ 18,500 lbs 

HWFET

HD Veh UDDS

FTP-bag3

C

FTP

ILCC

CSHRV

FTP-bag2

WVU City

NYC Truck

CBD Truck

Mahattan Bus

151%

79%

58 %

3 4%

119 %

113 %

9 1%

8 4%

7 1%

6 1%

5 1%

44 %

3 3% 33 %

1%

3 4% 37%

3 2%

-25%

0%

25%

50%

75%

100%

125%

150%

175%

% Improvement over Vehicle's Baseline MPG .

Driv e Cycle

Initial MPG Testing of EPA's Pilot UDV, and Shuttle Bus

Comparing to HEV Re sults from NREL

HEV @ 17,500 lbs

Pilot @ 20,000 lbs 

Shuttle @ 18,500 lbs 

Comparison Comparison to HEV Fuel Efficiency Efficiency

Dynamometer Tests

Performed by NREL

Clean Automotive Technology ‐ US EPA 20

Series HHV, Gasoline Gasoline‐HCCI Engine

Demonstration Demonstration Shuttle Shuttle Bus

Goal  World’s Cleanest Cleanest and Most‐Efficient Efficient

Shuttle Bus

Demonstrate real‐world emission emission and fuel economy economy

benefits benefits which can be obtained obtained by combining combining series

hydraulic hydraulic hybrid drivetrain drivetrain technology technology with advanced advanced high‐

efficiency efficiency gasoline gasoline HCCI engine technology technology in an urban

delivery delivery vehicle vehicle such as a shuttle shuttle bus.

Project Status:

• Tested HHV w/diesel engine

• Gas‐HCCI engine installed and being calibrated

• Waiting for body installation

• Field testing will be in California

EPA Shuttle Bus Chassis

Powertrain very suitable for a “midi‐bus”.

IC‐Bus demonstration chassis
Clean Automotive Technology ‐ US EPA 21

1 50

2 00

2 50

3 00

3 50

4 00

4 50

5 00

5 50

6 00

20 kW

30 kW

40 kW

50 kW

120 kW

1 50

2 00

2 50

3 00

3 50

4 00

4 50

5 00

5 50

6 00

20 kW

30 kW

40 kW

50 kW

120 kW

Gasoline Gasoline‐HCCI, Series HHV

1. Opportunity for high‐efficiency and lower GHG emissions

 Higher efficiency than conventional gasoline engines

 High compression ratio  more efficient operation (thermodynamically)

 No throttle  no unnecessary pumping losses

 Lean burn combustion  improves efficiency

 Low temperature combustion  low engine out NOx emissions

 Exhaust coming from engine meets 2010 HDE limits (eliminating

need for LNT or SCR aftertreatment to get diesel‐like efficiency)

 Ultra low particulate matter emissions

(no diesel PM – eliminating need for PM filter)

 Homogeneous fuel mixing prevents local “rich spots”,

which enables clean burning combustion

 Avoids distillate shortages (adding to today’s higher diesel prices)

2. Opportunity for lower engine costs

 Attractive for achieving diesel‐like high efficiency and

low emissions at near gas‐engine costs

 No diesel type fuel system

 No diesel type aftertreatment necessary

 Would likely be produced from a diesel “ base engine”

 Better‐than‐diesel efficiency

6.4L Gasoline-HCCI Efficiency Map

Series HHV Drive Unit

Gasoline‐HCCI Engine

Clean Automotive Technology ‐ US EPA 22

 Demonstrated a cost‐effective, high‐efficiency alcohol (E85 & M85)

engine technology suitable for both conventional and hybrid vehicles

for the medium‐duty fleet truck market.  

 Achieved diesel levels of energy efficiency with E85 fuel using simple

TWC to meet 2010 emission standards.

 Currently calibrating the engine in a series HHV chassis, field testing

planned for later this year.  

High‐Efficiency Efficiency Alcohol Alcohol‐fuel Engine, Engine, Series

HHV

Navistar 

VT-275 engine

High-Efficiency E85 Engine versus Diesel Engine

30

32

34

36

38

40

42

30 40 50 60 70 80 90 100 110

Average Engine Power (kW)

Average BTE (%)

Diesel

E85

Poly. (E85)

Poly. (Diesel)
Clean Automotive Technology ‐ US EPA 23

Hydraulics Hydraulics Could Extend Battery Battery

Range for All‐Electric Electric Vehicles Vehicles

• Much of a vehicle’s energy is needed for acceleration

in congested urban operation.

• More than 50% of energy supplied to the wheels is

available for recovery.

• Early modeling suggest that high efficiency energy

recovery could significantly improve the range of

all‐electric vehicles (or significantly reduce the

battery size for the same range).

Navistar all‐electric class 4 truck

 A small hydraulic pump‐motor and accumulator can efficiently capture

all of braking energy and reuse it for next vehicle acceleration.

 The electric drive system and battery could be right‐sized for cruising

and light acceleration.

 Cost of cooling batteries and power electronics would be significantly

reduced since they would not be used during high power braking and

acceleration.