United States
Environmental Protection
Agency
Clean Automotive Technology Program
Developing Cleaner and More Efficient \
Vehicles and Engines for Tomorrow I
2006 Progress Report
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Contents
Introduction 2
Background 2
What Is the Clean Automotive Technology Program? 3
Summary of Recent Key Accomplishments 5
Program Activities 6
Advancing Promising Technologies 6
Pursuing the Next Generation of Clean Engines 13
HCCI—Diesel Fuel Efficiency with Gasoline Emissions ... 13
FPE—A Simpler, More Efficient Engine 15
Looking Ahead 16
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Introduction
Background
Transportation and mobility are central to the
American economy and way of life. While the
world's desire for personal mobility and commer-
cial transportation has evolved, so have the geopolitical
and environmental landscapes. Global demand for oil is
at an all-time high, driving up the price of gasoline and
diesel fuel, and the environmental consequences of
mobile source emissions have become more and more
apparent. More than 100 million Americans live in coun-
ties that do not attain federal clean air standards for
ozone (03), sulfur dioxide (S02), particulate matter (PM),
or other air pollutants, mostly because of emissions
from the transportation sector.1 Transportation sources
are also responsible for emitting prodigious amounts of
carbon dioxide (C02), a greenhouse gas that is acceler-
ating global climate change. In fact, transportation was
the second largest source of C02 in the United States
in 2004, accounting for approximately 30 percent of
national C02 emissions.2
In response, the U.S. Environmental Protection
Agency's (EPA's) Office of Transportation and Air Quality
(OTAQ) is spearheading a range of programs to reduce
mobile source emissions. Among them, the Clean
Automotive Technology Program is especially equipped
to meet the environmental and fuel supply challenges
of tomorrow. The Clean Automotive Technology Program
leverages American industrial and academic ingenuity
in automotive engineering to develop cost-effective
advances for cleaner, more fuel-efficient engine and
vehicle designs. The program's end products—
prototypes that spur changes in automotive design and
manufacturing—help America's fleet improve fuel
efficiency and reduce C02 emissions while maintaining
the superior vehicle performance that American drivers
have come to expect.
1 Toward a Cleaner Future, Office of Transportation and Air Quality Progress Report 2005, EPA 420-R-05-011, November 2005
2 Inventory of US Greenhouse Gas Emissions and Sinks. 1990-2004, EPA 430-R-06-002, April 2006.
Clean Automotive Technology Program — 2006 Progress Report
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What Is the Clean Automotive
Technology Program?
The goal of the Clean Automotive Technology
Program is to research, evaluate, and develop
advanced technologies that help vehicles increase fuel
efficiency, reduce regulated emissions such as nitrogen
oxides (NOx) and PM, and cut greenhouse gas emis-
sions. With technological breakthroughs and engineer-
ing innovations, the program produces clean, efficient
vehicle and engine prototypes and encourages manu-
facturers to incorporate these cost-effective designs
into cars and trucks developed for the marketplace.
The Clean Automotive Technology Program focuses on
both drivetrain and engine design. EPAs research on
drivetrain design focuses on hydraulic hybrid technology
to achieve significant increases in fuel efficiency. EPAs
recent research on engine design focuses on clean
diesel combustion technology, homogeneous charge
compression ignition, and free piston engines, all of
which promise to reduce air pollutants.
EPA works cooperatively with industry and university
partners throughout the United States to bring
advanced automotive technologies from EPAs laborato-
ry to market. Public-private partnerships with industry
and university research facilities benefit all parties:
• Automotive manufacturers benefit from cost-
effective use and leverage of government resources
to research and evaluate environmentally friendly
technologies. They also help accelerate develop-
ment of new technologies with commercial value
and gain a competitive edge in a highly competitive
global market.
The National Vehicle and Fuel Emissions
Laboratory: Home to the Clean Automotive
Technology Program
EPA established the National Vehicle and Fuel Emissions
Laboratory in 1971 in Ann Arbor, Michigan—near the birth-
place of the automobile industry and home to some of the
world's most advanced vehicle manufacturing, testing, and
research facilities. Since its founding, the lab has been at
the forefront of developing clean automotive technology
and designing programs to reduce and prevent air pollu-
tion. It is now recognized as a leader in advanced emission
testing services and automotive technology to reduce con-
ventional pollutants and greenhouse gas emissions. This
185,000-square foot facility houses 400 experts in a variety
of technical and public policy fields, including auto
mechanics, engineering, chemistry, economics, natural
resources management, and law.
Universities benefit by being involved in cutting-
edge research and supplementing students' educa-
tion with training in advanced automotive
technologies at EPAs world-class labs and testing
facilities.
EPA benefits from the shared expertise of its part-
ners and through sharing the high upfront costs of
technology development.
Most importantly, the public benefits when clean,
efficient technologies are incorporated quickly into
vehicles, resulting in more fuel-efficient vehicles
and cleaner air.
Clean Automotive Technology Program — 2006 Progress Report
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EPA's industry partnerships are formalized through
Cooperative Research and Development Agreements
(CRADAs). In signing a CRADA, EPA's partners commit to
supporting the development of advanced technologies by
assisting in one or more of the following activities:
• Sharing development costs
• Providing components and parts
• Performing research and development
• Evaluating technology
• Sharing information and expertise
• Facilitating commercialization
As of 2006, six different companies were working
with EPA to promote the development and commercial-
ization of advanced technologies. In addition, four
university partners had collaborated actively with EPA—
performing tests on clean engine components at
EPA's Ann Arbor, Michigan, laboratory or at their own
testing facilities and sharing a variety of resources.
EPA Technology Transfer Industry Partners
ORGANIZATION
Eaton Corporation — Fluid Power
Ford Motor Company
International Truck and Engine Corp.
Parker-Hannafin Corporation
UPS
U.S. Army National Automotive Center
CLEAN ENGINES
/
/
HYDRAULIC DRIVETRAINS
/
/
/
/
/
EPA Technology Transfer University Partners
ORGANIZATION
Michigan State University
University of Michigan
University of Toledo
University of Wisconsin
CLEAN ENGINES
/
HYDRAULIC DRIVETRAINS
/
/
/
/
Clean Automotive Technology Program — 2006 Progress Report
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Summary of Recent Key
Accomplishments
Innovations and breakthroughs from the Clean
Automotive Technology Program are the result of
decades of work pioneered by scientists, engineers,
and manufacturers that have collectively invested signif-
icant capital and time in pursuit of improved systems.
Technical advances such as these require hundreds of
tests and thousands of hours to advance to the state of
commercial viability.
For 2004 through 2006, the program's most significant
accomplishments include the following:
• As of October 2006, filed for five new patent
applications, adding to the 18 applications already
pending and 42 patents issued. These patents will
enable clean technologies to be more quickly
adopted into vehicles destined for sale and use
in the United States.
• Working on six CRADAs with industry partners and
four cooperative agreements with institutions of
higher education.
EPA Inventions
The Clean Automotive Technology Program applies for
patents on a regular basis to secure rights to its innova-
tions and enable them to be shared with commercial part-
ners. These patents encompass a range of hydraulic
components, hydraulic hybrid vehicle configurations and
control methods, clean diesel combustion technologies,
homogeneous charge compression ignition, and other
advanced alternative engines. A total of 29 advanced tech-
nology patents have already been issued to EPA.
Demonstrated prototypes at 15 major conferences,
competitions, and other forums around the nation.
As a result, EPA estimates that several thousand
influential industry stakeholders learned directly
about the program's emerging technologies.
Developing breakthroughs to create clean diesel
combustion engines that meet NOX levels estab-
lished by Tier 2 standards.
Clean Automotive Technology Program — 2006 Progress Report
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Program Activities
Advancing Promising Technologies
EPA's clean automotive technology research is
focused on hydraulic hybrid vehicles and clean
engines. Incorporating hydraulic hybrid technolo-
gy and cleaner engines into an SUV or delivery truck
could cut C02 emissions by more than 40 percent and
increase fuel economy by more than 70 percent above
current models. If EPA's prototypes were incorporated
into today's fleet of cars and light trucks, the air quality
and oil consumption improvements and greenhouse gas
emissions reductions would be impressive.
Hydraulic Hybrid Vehicles
Hydraulic hybrid drivetrains are a priority for EPA
because they yield higher fuel efficiency, lower emis-
sions, reduced operating costs, and better acceleration
performance than traditional drivetrains. EPA has devel-
oped two types of hydraulic hybrid vehicles—mild
hydraulic hybrids and full hydraulic hybrids.
Clean Automotive Technology Program — 2006 Progress Report
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How Hydraulic Hybrids Work
Hydraulic hybrid technology uses a hydraulic energy
storage and propulsion system in the vehicle. A major
benefit of a hydraulic hybrid vehicle is fuel economy
improvement due to the vehicle's ability to capture ener-
gy normally lost in vehicle braking. The hydraulic system
can capture and store more than 80 percent of the
energy normally wasted in vehicle braking and use this
energy to help propel the vehicle during the next vehicle
acceleration. The hydraulic system also enables the
engine to operate more efficiently when the engine
is needed.
Because the business of medium- and some heavy-
duty vehicles—such as urban delivery trucks, shuttle
buses, and waste disposal vehicles—involves stop-and-
go driving, hydraulic hybrid technology could provide
significant benefits to these types of vehicles, saving
money in fuel costs and reducing emissions.
In urban stop-and-go driving, as much as
one-half of all of the energy available at the
vehicle wheels is lost in braking.
Mild hydraulic hybrids draw from two sources of power
to operate the vehicle—the gasoline or diesel engine
and the hydraulic components. Because both power
sources work together, a typical diesel-powered or
gasoline-powered vehicle can be fitted with hydraulic
components as a secondary energy storage system to
help it run more efficiently.
The central hydraulic components in any hydraulic
hybrid drivetrain are two hydraulic accumulator vessels
(a high-pressure tank capable of storing hydraulic fluid
that compresses inert nitrogen gas and a low-pressure
accumulator) and one or more hydraulic pump/motor
units. When the vehicle brakes, the hydraulic
EPA/UPS Demonstration Truck
Delivers Results
In June 2006, EPA and UPS introduced the world's first full
hydraulic hybrid delivery truck to a crowd of auto industry
representatives, environmentalists, and reporters in
Washington, D.C. Laboratory tests show that this EPA-
patented technology can increase fuel efficiency by 60 to
70 percent in urban driving conditions and reduce C02 by
40 percent compared to conventional UPS diesel delivery
trucks. EPA estimates the upfront costs for the hybrid com-
ponents (when produced in volume) for a typical delivery
vehicle could be recouped in fewer than three years, and
net savings over a vehicle's lifespan could exceed $50,000."*
EPA and UPS showcased the truck throughout the
Northeast and Southwest to demonstrate its performance.
* Assuming diesel fuel price of $2 75 per gallon
pump/motor uses the kinetic energy of the braking to
move hydraulic fluid from a low-pressure accumulator
into a high-pressure accumulator, increasing the pres-
sure of nitrogen gas in the high-pressure accumulator.
Clean Automotive Technology Program — 2006 Progress Report
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EPA's Mild Hydraulic Hybrid Truck in a Medium Duty Delivery Truck Chassis
During the next vehicle acceleration, the hydraulic pump/motor
unit uses the high-pressure hydraulic fluid to generate torque,
sending the fluid back to the low-pressure accumulator, which is
transferred to the driveshaft. Because the vehicle is being pro-
pelled by the hydraulic fluid transfer rather than fuel combustion,
this method of acceleration reduces emissions.
During the past few years, EPA has focused its hydraulic hybrid
technology research on creating a full hydraulic hybrid drivetrain,
which operates even more efficiently by replacing the transmis-
sion and enabling operation of the vehicle's engine near its peak
efficiency. In fact, EPA unveiled the world's first full hydraulic
hybrid SUV at the 2004 Society of Automotive Engineers (SAE)
World Congress in Detroit, Michigan. This vehicle had outstanding
performance in the laboratory. Dynamometer tests showed that
the full hydraulic hybrid SUV offered an estimated 35 to 55 per-
cent fuel economy improvement over a comparable, commercially
available SUV and a 25 to 35 percent reduction in C02 emissions
due to the hydraulic technology.
While this hydraulic hybrid technology is projected to
increase the cost of a large SUV by about $600, consumers
Conventional vs. Mild Hydraulic
Hybrid Drivetrain
Conventional Drivetrain
Mild (Parallel) Hydraulic Hybrid
High Pressure Accumulator II ,
1 Drive
Shaft
^
Pump
Motor
i r
Low Pressure Accumulator
Conventional vs. Full Hydraulic
Hybrid Drivetrain
Conventional Drivetrain
Clean Automotive Technology Program — 2006 Progress Report
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Full Hydraulic Hybrid SUV
could expect to recoup this cost in fewer than three years
through fuel savings and maintenance savings due to
reduced brake wear.
In 2005, EPA developed a full hydraulic hybrid package deliv-
ery truck with UPS (see page 7 for an update on this project).
The delivery truck expanded on previous demonstrations and
evaluations of the technology through a partnership arrange-
ment with UPS, Eaton Corporation (hydraulic supplier),
International Truck and Engine Corporation (urban truck and
engine manufacturer), and the U.S. Army's National Auto-
motive Center. In laboratory tests, EPA achieved a 60 to 70
percent improvement in fuel economy and a 38 to 41 percent
reduction in C02 emissions for the demonstration truck.
Chassis View
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EPA's engine research focuses on developing engines
that are simultaneously clean, efficient, and cost effec-
tive and that have a high potential to produce real-world
benefits. Current research in the Clean Automotive
Technology Program has focused primarily on clean
diesel combustion (CDC) engines, which can help vehi-
cles meet EPA's Tier 2 vehicle emissions standards
cost-effectively.
EPA focuses research efforts on CDC technology
because it reduces the costs of complying with emis-
sions standards. In addition, it significantly reduces NOX
emissions below what is currently achievable without
the need for exhaust treatment systems, and it can be
applied to either light-duty or heavy-duty diesel engines.
Tier 2 and Clean Engine Development
EPA's Tier 2 vehicle emissions standards require new cars,
SUVs, pickup trucks, and vans to meet NOX, carbon
monoxide, PM, and non-methane hydrocarbon emissions
standards, which will make vehicles 77 to 95 percent
cleaner than 2003 models.
Comparably, large trucks must meet the new 2007/2010
heavy-duty (HD) standard of less than 0.2 grams per brake-
horsepower hour (g/BHP-hr) NOX. EPA's 2007 HD standard
requires that 50 percent of heavy-duty engines sold
achieve NOX emissions of 0.2 g/BHP-hr. The 2010 HD stan-
dard requires 100 percent of heavy-duty engines to achieve
the same emissions level.
How CDC Technology Works
CDC technology keeps NOX emissions from forming
when the diesel fuel is burned in the engine. Through a
series of engine improvements—to increase the per-
formance of the diesel fuel injection system, reoptimize
and refine air management/turbocharging systems, and
improve the combustion system—CDC technology main-
tains consistent diesel engine combustion while main-
taining peak temperatures below 1700° Celsius (°C) or
about 25 percent lower temperature than conventional
diesel engines. NOX pollution is formed in an engine only
at temperatures exceeding approximately 1700°C.
Conventional diesel engine combustion typically reaches
temperatures of 2300°C and higher. At these high
temperatures in the engine's combustion chamber, the
nitrogen and oxygen in air combine to form NOX.
NOX Formation During Diesel Combustion
30
to 20
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> >
+J 0
03 _l
0 X
QC O 1°
•z.
0
^^
5 msec 1 msec
1 ;
--/--:-
/ j
/
/
/
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1500 1700 1900 2100 2300
Temperature (°C)
10
Clean Automotive Technology Program — 2006 Progress Report
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EPA's Clean Diesel Combustion Minivan
CDC Partnerships
EPA is working closely with industry partners to develop
and prove the promise of CDC technology. For example,
in 2004, EPA and the International Truck and Engine
Corporation announced a partnership to further develop
EPA's CDC technology for cars, SUVs, and light pickup
trucks. The International Truck and Engine Corporation
has begun researching and evaluating CDC effective-
ness in its new SUV-sized V-6 diesel engine.
In 2005, EPA and Ford Motor Company developed a
Ford Galaxy minivan demonstration vehicle to showcase
CDC technology. The diesel minivan gets 30 to 40 per-
cent better mileage than a gasoline minivan, while
meeting EPA's Tier 2 emission standards for NOX of 0.07
grams per mile. The test vehicle showed that CDC tech-
nology can maintain high diesel efficiency and perform-
ance while achieving dramatic emissions reductions.
Clean Automotive Technology Program — 2006 Progress Report
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Building on Successes
In 2005, EPA and Ford Motor Company agreed to
continue research efforts on the development of CDC
technology. This work will build on previous joint
research with the Ford Galaxy minivan, refining and
testing the potential for the commercial application of
CDC technology that meets the stringent Tier 2 emis-
sion standards and is more fuel-efficient than gasoline.
Building on its hydraulic hybrid drivetrain partnership
with UPS, Eaton Corporation, International Truck and
Engine Corporation, and the U.S. Army's National
Automotive Center, EPA is continuing its UPS delivery
truck demonstrations to a second phase. The plans for
the latter phase of this project entail combining the
hydraulic hybrid vehicle research with EPAs innovative
CDC engine demonstrations into one package delivery
truck. With the addition of the CDC engine, the demon-
stration truck is expected to meet EPAs 2010 NOX stan-
dard for heavy duty-trucks without the need for any
diesel exhaust treatment systems.
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Clean Automotive Technology Program — 2006 Progress Report
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Pursuing the Next
Generation of Clean Engines
EPA has recently begun focusing on two clean
engine technologies: clean homogeneous charge
compression ignition (HCCI) and free piston
engine (FPE) technologies. Both HCCI and FPE have
shown tremendous promise in EPA's laboratories and
are ready for field demonstrations. EPA is currently
looking for industry partners to help develop these
exciting new technologies.
HCCI —Diesel Fuel Efficiency
with Gasoline Emissions
HCCI technology has shown tremendous promise in
laboratory testing. Because engine peak temperatures
are cooler in an HCCI engine than in spark-ignited and
diesel engines, HCCI significantly reduces NOX emis-
sions. In addition, premixed combustion in HCCI
engines reduces PM emissions to low levels. Because
Clean Automotive Technology Program — 2006 Progress Report
13
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of these features, an HCCI engine could perform
with the fuel economy of a diesel engine, but
with significantly lower emissions.
An HCCI engine can operate using many fuels as
long as the fuel can be vaporized and mixed with
air before ignition. EPA tested the HCCI engine
concept with a four-cylinder gasoline-fueled
engine that includes the EPA patented HCCI tech-
nology. Initial tests show multiple benefits of
HCCI:
• Diesel-like fuel efficiency with gasoline.
• No exhaust treatment systems needed to
achieve low NOX emissions.
• HCCI possible for full operating range of the
engine.
Under the Clean Automotive Technology Program,
EPA has been working with Michigan State
University to expand the operating range and per-
formance of HCCI. Further, EPA is evaluating HCCI
for use in hybrid vehicles.
How HCCI Engines Work
A HCCI engine combines the principles of a traditional gasoline-
powered engine with those of a traditional diesel-fueled engine.
In an HCCI engine, fuel is homogeneously premixed with air (as in
a spark-ignited gasoline engine) with a high proportion of air to
fuel. As with diesel engine combustion, HCCI combustion is
initiated by compression igniting the homogeneous fuel charge.
Gasoline has primarily been used for initial demonstrations by EPA.
The technical challenges of HCCI engines involve controlling the
combustion process and expanding the mode of operation to a
larger proportion of an engine's load and speed range.
Homogeneous Charge Compression Ignition
Combines Best Attributes of Gasoline and Diesel Engines
HCCI
(Gasoline or Diesel)
Spark
Ignition
(Gasoline)
Compression
Ignition
(Diesel)
• Homogeneous
Air/Fuel Mix
•Compression
Ignition
• Homogeneous
Air/Fuel Mix
•Spark Ignition
• Heterogeneous
Air/Fuel Mix
• Compression
Ignition
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Clean Automotive Technology Program — 2006 Progress Report
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FPE—A Simpler, More
Efficient Engine
FPEs offer higher fuel efficiency, lower emissions,
and lower initial and maintenance costs than a tra-
ditional combustion engines. In addition, EPA has
developed FPEs that can combust a variety of petrole-
um or renewable fuels and deliver hydraulic energy.
FPE benefits include:
• Higher fuel efficiency. The fuel efficiency of an
FPE is higher than that of a traditional combustion
engine because there are lower friction losses (due
to fewer parts and the pistons not having side
forces exerted on them from a crankshaft).
• Lower emissions. An FPE yields lower NOX
emissions because the products of combustion
remain at high temperatures for shorter periods of
time than in traditional engines, limiting the oppor-
tunity for NOX to form.
• Lower initial cost. Due to the simplicity of FPE
design, the manufacturing cost of an engine is
anticipated to be much lower than the system it
would replace.
• Lower maintenance costs. Maintenance costs
for an FPE are lower due to simpler design and
fewer parts.
EPA has designed two FPEs—a two-stroke engine and
a four-stroke engine. EPAs engine testing indicates that
four-stroke efficiency exceeds that of the best available
diesel engine/hydraulic pump combination. In addition,
EPA has developed a novel and robust control system
for the FPE that could be incorporated into a vehicle
drivetrain.
How FPEs Work
An FPE is a combustion engine in which the piston move-
ment is not limited by any mechanical linkage. There is no
crankshaft or flywheel. FPEs typically deliver their energy in
pneumatic, hydraulic, or electric form.
The EPA FPEs are an integrated combination of an internal
combustion engine and a hydraulic pumping system. The
core of the engine is a combustion piston directly linked to
a hydraulic pumping chamber. The piston assembly is not
connected to any other mechanism and is free to move
within the limitations of the cylinders. In this way, the ener-
gy of the combustion process is almost directly converted
into hydraulic energy.
EPA Free-Piston Engine
Internal combustion engine with no output shaft: direct
conversion to hydraulic power
Dual-piston, opposed cylinder design
Centrally located hydraulic pumping chamber
Low
Pressure
Reservoir
Hydraulic
Pumping
Chamber
Reservoir \
Clean Automotive Technology Program — 2006 Progress Report
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Looking Ahead
EPA has ambitious plans to continue developing
advanced vehicle technologies to help reduce
the impact of vehicles on the environment by
increasing fuel efficiency while reducing greenhouse
gases and regulated emissions.
EPA's goals for the Clean Automotive Technology
Program include:
• Accomplishing further technical advances in drive-
train and clean engine technologies, including meet-
ing EPA's 2010 heavy duty NOX standard with more
than 30 percent fuel economy improvements.
• Continuing to work diligently with industry partners
to bring promising developing technologies to mar-
ket, with the goal of guiding hydraulic hybrid
drivetrain and clean diesel combustion engine
technology to commercial production by 2010.
• Involving new industry and university partners in
groundbreaking new clean engine research includ-
ing HCCI and FPE technologies.
With constraints on the supply of fossil fuels and
increases projected for fuel prices into the foreseeable
future, the work of the Clean Automotive Technology
Program is as important as ever. EPA looks forward
to continuing its efforts to advance innovative new
technologies side-by-side with industry and university
partners, leveraging resources towards making trans-
portation as clean and fuel-efficient as possible.
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Clean Automotive Technology Program — 2006 Progress Report
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