The work described here is part of an ongoing program

sponsored by the U.S. Department of Energy (DOE), and

managed by the National Renewable Energy Laboratory (NREL),

a DOE national laboratory. NREL is cooperating with the 

U.S. General Services Administration, West Virginia University

(WVU), fleet operators, and several private laboratories to

perform this work. 
Laboratory staff have tested a wide variety of original

equipment manufacturer alternative fuel vehicle models, and

a limited sample of aftermarket conversions. The vehicles

have been tested on methanol (M85, 85% methanol and 15%

gasoline), ethanol (E85, 85% ethanol and 15% gasoline)

compressed natural gas (CNG), propane, and reformulated

gasoline (RFG).

To stay current with the changing marketplace, testing of the

latest qualified vehicle modifier (QVM) CNG and liquefied

petroleum gas (LPG) vehicles has been scheduled. 

1,3butadiene were much lower from the alternative fuels,

but the alcohol fuels had increased aldehyde emissions.

Hydrocarbon emissions from CNG vehicles were primarily

methane. Also, the hydrocarbon compounds from the

alternative fuels had consistently lower ozone-forming

potential than reformulated gasoline.

Emissions results from CNG and LPG aftermarket conversio

were not as promising as the original equipment manufacturer’s models. This highlights the need to consider both th

fuel and the vehicle technology when evaluating options fo

reducing air pollution. 

Number of Carbon Atoms

Hydrocarbon Emissions (mg/mi)

0

50

100

150

200

250

1 2 3 4 5 6 7 8 9 10 11 1

Hydrocarbon Emission Profile

B250 van RFG

B250 van CNG

Taurus RFG

Taurus E85

Intrepid RFG

Intrepid M85

0 50

66

76

18

25

25

25

25

100

Number of Vehicles Tested

150 200 250

Dodge B250 van

Dodge Spirit

Ford Econoline van

Chevrolet Lumina

Dodge Caravan

Ford Taurus

Dodge Intrepid

Control Vehicles* 243

*Standard gasoline vehicles

for each model 

RFG

E85

M85

CNG

Fuel

Fuels, Vehicle Models, and Number of Vehicles Tested
Alternative fuel heavy vehicle engine technology is evolving

rapidly. Several engine manufacturers are releasing new

alternative fuel models or enhanced versions of the older

engines. Testing and evaluation of these latest engines is a

high priority for the program. 

Emissions Test Laboratory

Transit Buses

Light-Duty Vehicles

Heavy Trucks

Source: DOE Alternative Fuel Data Center

Southwest Research

Institute (SwRI)

EPA – Researc

Triangle Park

Environm

Research 

Developm

(ERD)

ManTech

Environmental

Denver

EPA-Ann Arbor

West Virginia

University

Automotive Testing

Laboratories (ATL)

Emissions Testing Locations

Tacoma, WA Transit Buses

LNG Portland, OR Transit Buses

BD35 Sheldon, IA Line-Haul

Trucks

Detroit 6V92 Ethanol Peoria, IL Line-Haul

Diesel Trucks/Buses

Minneapolis, Snowplows/

MN Buses

Methanol Miami, FL Transit Buses

BD20 St. Louis, MO Transit Buses

Series 60 CNG NYC Garbage Trucks

BD35 Sheldon, IA Line-Haul

Trucks

Caterpillar 3306 BD35 Sheldon, IA Line-Haul

Trucks
paper number 961092

• Alternative Fuel Trucks Case Studies: Running Refuse

Haulers on Compressed Natural Gas, and Running LineHaul Trucks on Ethanol, October 1996

NREL/BR-425-21498

DE96014324

October 1996

Prepared by the National Renewable Energy Laboratory for the 

U.S. Department of Energy’s Office of Transportation Technologies

Printed with a biodegradable ink on paper containing at least 50% wastepaper,

including 20% postconsumer waste