Karen Hanner
Ames Research Center, Moffett Field, Calif.

Anne Stark
Lawrence Livermore National Laboratory, Livermore, Calif.
Feb. 16, 2010
NASA Wind Tunnel Used by LLNL, Navistar to Test Truck Fuel Efficiency
MOFFETT FIELD, Calif. – Saving the nation $10 billion annually in diesel fuel costs may be possible in a few years, thanks to new devices developed at Lawrence Livermore National Laboratory and now being tested at NASA’s Ames Research Center.

In support of the Department of Energy’s mission to reduce the United States’ dependency on fossil fuels, Lawrence Livermore National Laboratory (LLNL) has teamed with Navistar Inc. of Warrenville, Ill., NASA's Ames Research Center, the U.S. Air Force and industry, to develop and test devices for reducing the aerodynamic drag of tractor-trailers. The devices could increase the trucks' fuel efficiency by as much as 12 percent.

Tractor-trailers make up about 12 percent of the United States petroleum consumption or 21 million barrels per day. The average fuel mileage of a tractor-trailer is six miles per gallon. A two percent reduction in the aerodynamic drag of tractor-trailers translates into 285 million gallons of diesel fuel saved per year.

"We are delighted to host this important test that could help our nation save billions of dollars in fuel costs each year," said S. Pete Worden, director of NASA Ames. "This is an excellent example of what can be accomplished through our collaboration with other federal laboratories and industry."

Aerodynamic drag is caused from pressure differences around the vehicle. At highway speeds, a tractor-trailer uses more than 50 percent of the energy produced by the engine to overcome aerodynamic drag, while rolling resistance consumes roughly 30 percent of the usable energy.

Complementing 30 years of tractor-trailer aerodynamic research and development, LLNL computer simulations have identified critical drag producing regions around the trucks, such as the trailer base, the underbody and the gap between tractor and trailer. LLNL scientists estimate that with aerodynamic devices placed in these regions, the trucking industry could see as much as a 20 percent increase in mileage fuel efficiency rate, which saves 4.9 billion gallons of diesel per year, equaling approximately $14.7 billion in diesel fuel savings per year.

"This is a technology that could easily be installed on the tractor trailer trucks that are out on the highway today," said Kambiz Salari, LLNL’s lead scientist on the project. "And its time to market is incredibly quick. In just three years, we could see these devices on the road and realize the real fuel savings."

The lab is conducting a full-scale test in the world’s largest wind tunnel, the National Full-Scale Aerodynamics Complex, also known as the NFAC, which operates under the direction of the Arnold Engineering Development Center at Ames. The goal is to identify drag reduction devices, both commercially available and under development, that show the potential for improving fuel efficiency. The wind tunnel test section's huge size, 80 feet by 120 feet, makes it ideal for testing a full-scale semi with a 53-foot trailer.

"This testing highlights a special opportunity for an Air Force-run facility to participate in research in areas beyond the Department of Defense and work to improve everyday issues such as fuel economy on national roadways," said Christopher Hartley, test engineer for Jacobs Engineering Group Inc., Pasadena, Calif., based at the NFAC.

The commercially available devices to be tested are manufactured by Aerofficient, Aeroindustries, AT Dynamics, Freightwing, Ladyon and Windyne. Prototype devices currently under development will be provided by LLNL and Navistar, which are collaborating to get proven drag reduction devices on the road. Performance will be evaluated under different tractor-trailer combinations.

Livermore's project is funded by the Department of Energy’s Energy Efficiency and Renewable Energy Program’s Freedom Cooperative Automotive Research and fuel partnership.

"Making our trucks more fuel efficient means we can not only travel further using less fuel, but it means we can get our goods to the general public in a more timely, and ultimately, less expensive way," said Ron Schoon, chief engineer of aerodynamics at Navistar.

The lab is collaborating with Navistar to push the state-of-the-art in semi-truck aerodynamics and design the next generation of highly aerodynamic, integrated, energy efficient semi-trucks. Navistar International Corp., formerly International Harvester Company, produces commercial trucks, mid-range diesel engines, and other vehicle products.

For more information about NASA Ames Research Center, visit:

For more information about Lawrence Livermore Labs, visit:

- end -

text-only version of this release

To receive Ames news releases via e-mail, send an e-mail with the word "subscribe" in the subject line to To unsubscribe, send an e-mail to the same address with "unsubscribe" in the subject line.

NASA Image Policies