Researchers Identify Opportunities for Heavy Vehicle Fuel Savings
September 15, 2004
A team of researchers from academia, the Department of Energy's (DOE's) national laboratories, the National Aeronautical and Space Administration (NASA), and industry, working together on DOE's Heavy Vehicle Aerodynamic Drag Project, has identified fuel savings advances that could save the U.S. trucking industry $3 billion per year in operating costs. These advances, discussed at a July working group meeting on Heavy Vehicle Aerodynamic Drag in Portland, Oregon, include devices that address base, gap, and underbody drag reduction.
According to the researchers, using a simple base flap at the trailing edge of the trailer, side extenders or splitter plate at the tractor-trailer gap, and a skirt or a simple short underbody wedge could provide more than 25 percent drag reduction. A California road test with the trailer base flaps demonstrated a 4 percent fuel savings at an optimum base flap angle of 13 degrees. Manufacturers must improve or control engine flow for enhanced cooling, while maintaining or improving aerodynamic drag, in order to balance the effects of upcoming EPA emission requirements that will potentially decrease the fuel efficiency of heavy-duty, over-the-road trucks.
Researchers did a significant amount of experimental modeling work using a 12-foot experimental wind tunnel at NASA's Ames Research Center in California. According to Jim Ross of the Experimental Aero-Physics Branch at Ames, "We achieved these research results by combining the best of academia and government lab capabilities. Better yet, we have leveraged technical developments across programs within DOE and NASA while delivering program milestones."
The Department of Energy established the Heavy Vehicle Aerodynamic Drag Project in 1998 to develop and demonstrate the ability to simulate and analyze aerodynamic flow around heavy truck vehicles using existing and advanced computational fluid dynamics (CFD) tools. The final products are validated CFD tools that can be used to predict reductions of aerodynamic drag of heavy truck vehicles resulting from various innovative devices and thus improve their fuel efficiency. The project is funded primarily by DOE's FreedomCAR and Vehicle Technologies Program.