Date: 27/02/2011

Petrol driven hybrid electric truck is more fuel-efficient than diesel truck

The U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) recently completed a year long technology evaluation of gasoline (petrol) hybrid electric (gHEV) trucks compared with conventional diesel vehicles.
NRELfinds gHEV trucks produced substantially reduced tailpipe emissions during all drive cycles tested in the laboratory when compared to conventional diesel vehicles. On a drive cycle representing routes with frequent stops and accelerations, the gHEV trucks exhibited a 20 percent improvement in fuel economy while drive cycles representing routes with fewer stops and accelerations demonstrated similar fuel economy to the diesels.

"We conducted this study to show how a gasoline hybrid might perform compared to a conventional diesel truck given that gasoline engines are less efficient than diesel engines and generally not used in heavier vehicles," said Lee Slezak, program manager for DOE's Advanced Vehicle Testing Activity.

NREL's Fleet Test and Evaluation Team collected and analyzed fuel economy, maintenance, and other vehicle performance data on three gHEV trucks and three conventional diesel trucks used for FedEx parcel delivery service in the Los Angeles area. The team also tested a hybrid and conventional truck at NREL's Renewable Fuels and Lubricants Research Laboratory in Denver, Colo.

"Southern California continues to experience the worst air quality in the nation, and transitioning heavy-duty vehicle fleets to cleaner-burning vehicle technology is an important element of our overall clean air goals," said Barry R. Wallerstein, executive officer of the South Coast Air Quality Management District.

Manufactured by Ford, the gHEV trucks feature 5.4L gasoline engines and hybrid propulsion systems produced by Azure Dynamics with 100kW electric motors, regenerative braking, and nickel-metal-hydride batteries.
FedEx Express operates more than 32,000 motorized vehicles in the United States, including 20 gHEVs on parcel delivery routes in Los Angeles and Sacramento, Calif. The FedEx Express hybrid fleet, which has driven more than 8 million miles in revenue service, includes an all-hybrid station in Bronx, N.Y., where nearly half of the vehicles are gHEVs.

This research is a boon to hybrid automotive designers who may not have complete test figures of fuel efficiency. The hybrid electric cars can replace diesel cars for the sake of efficiency and good vehicle acceleration. But what about the total cost of the vehicle!

To provide more info to electric car and vehicle developers NREL has released a convenient online collection of case studies in electric vehicle deployment. The case studies detail the early experiences of four U.S. locations on the leading edge of home-charging implementation.
The newly compiled information is housed in Clean Cities Alternative Fuels and Advanced Vehicles Data Center (AFDC) at www.afdc.energy.gov/plugin_case_studies.