NASA, LLNL, and Navistar Testing Aerodynamic Devices for Big Trucks
Filed Under: green automotive technology, GreenBigTruck on February 26, 2010
More than half of a big rig’s engine power is used to fight drag, or air resistance. Any driver who’s been across Wyoming in the windy season and seen their fuel efficiency drop by 3-4mpg knows this. The fastest, cheapest, and simplest way to improve fuel efficiency and increase mileage is to overcome as much of that aerodynamic drag as possible. Scientists and experts at the Lawrence Livermore National Laboratory (LLNL) have teamed up with Navistar (makers of International trucks), the NASA Ames Research Center, the U.S. Air Force and others to find better ways to make big trucks more streamlined.
Several devices are being tested and have the potential to decrease drag and thus raise fuel efficiency by 12%. That would mean about $10 billion in fuel saved every year.
LLNL Director George Miller says that “This is a significant step toward reducing the United States’ dependency on fossil fuels.” With the U.S. importing over 70% of its oil, that’s definitely a significant goal. The transportation sector uses about 1/3 of the petroleum used in the U.S.
Aerodynamic drag is caused by pressure differences between one point in the vehicle and another. In a truck, the drag is usually worst at the trailer base, underbody, and the gap between tractor and trailer. A truck’s drag coefficient (measurement of vehicle drag) shows that more than 50% of the engine’s power is being used to move the truck while another 30% is used to overcome rolling resistance (friction with the road).
The LLNL has been studying truck aerodynamics for some time and has used models and computers to get to this point. Now, the lab is teamed with NASA to use the wind tunnel on a full-sized rig. Kambiz Salari, the lead LLNL scientist on the project, says that 12% is just the beginning. “We expect to increase that savings even more during the current series of wind tunnel tests. It’s 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 LLNL project is funded by the Department of Energy’s Energy Efficiency and Renewal Energy Program’s Freedom CAR (Cooperative Automotive Research). The project began in the late 1990s and is responsible for many of the aerodynamic improvements already on the road today.
