At a news conference inside a wind tunnel at NASA's Ames Research Center at Moffett Field, scientists explained how reducing the aerodynamic drag of a semi-truck can increase the truck's fuel efficiency, saving $10 billion in diesel fuel costs annually.
Aerodynamic drag is caused by pressure differences around the vehicle, and at highway speeds semi-trucks use more than 50 percent of the energy produced by the vehicle engine to overcome that drag, according to scientists.
About three weeks ago, scientists brought a semi truck to the wind tunnel, owned by the U.S. Air Force and located at Ames. There, the truck has been undergoing tests, according to Kambiz Salari, a senior scientist at the Lawrence Livermore National Laboratory.
Scientists have learned that inserting a gap-seal plate between the truck and the trailer, base flaps on the side of the trailer in the rear, and an underbody device on the base of the trailer that blocks air flow beneath the truck can increase fuel efficiency by up to 12 percent, Salari said.
The technology to reduce the aerodynamic drag still needs about 2.5 to three years to complete before it can be put on the market, Salari said, but testing the truck in a wind tunnel helps move the process forward.
"This is a significant step toward reducing the United States' dependency on fossil fuels," Lawrence Livermore National Laboratory director George Miller said.
The wind tunnel, which is large enough to fit a Boeing 737 plane, became operational in 1987 and functions as a test zone for parachutes, helicopters, planes and other vehicles, according to David Duesterhaus of the Ames Research Center.
Wind blows up to 100 knots in the tunnel and can simulate whatever speed is needed, Duesterhaus said.