While diesel is approaching $5 a gallon, researchers become more interested in finding a way to reduce fuel consumption on the heavy trucks at highway speeds. Now they have come up with an interesting idea: while there’s little point in firstly modifying the engines to consume less, and spending a lot of money on upgrading them, the focus went on making the existing heavy weight trucks more aerodynamic.
The technology is not new. It has been developed during the past decade at the Georgia Tech Research Institute (GTRI).
They use an “air flow control” pressurizing technique, combined with conventional aerodynamic streamlining. If installed throughout the U.S. trucking fleet, these technologies for reducing aerodynamic drag could save between 1.6 and 2.4 billion gallons of fuel per year.
“The dramatic increase in diesel prices has led the trucking industry to reconsider aerodynamic fuel efficiency improvements that might not have been cost effective only a few years ago,” said Robert Englar, a GTRI principal research engineer and principal investigator for the project. “Though there are technical challenges ahead, we believe our techniques for improving fuel efficiency offer significant potential to reduce the impact of these fuel cost increases. Beyond the trucking industry, that would help consumers who see the effects of fuel costs in everything they buy.”
The active air flow control technique has been used in the 1980’s by the army to develop military aircrafts. In addition of making the vehicles more aerodynamic, they can make them the opposite: that means more efficient braking and stability control for the truck: “The pneumatic systems can turn a low-drag configuration into a high-drag configuration very rapidly, providing a lot more braking power,” Englar said.
The tests showed that the techniques could reduce drag coefficients up to 31 percent, which means 11 to 12 percent less fuel used. When the energy required by the air compressor installed on the truck to provide the compressed air for these prototype tests was subtracted from those savings, those tests showed that the low-drag techniques could produce an overall fuel efficiency increase of 8 to 9 percent.
Further energy savings could come using a pulsed pneumatic system, which preliminary wind-tunnel studies show could produce the same aerodynamic efficiency with 40 to 50 percent less energy consumed by the blowing system. Englar hopes to receive additional funding to study how this might affect the truck aerodynamics – as well as fuel consumption.
“The ultimate proof would be to apply this overall aerodynamic system to a small fleet of heavy trucks and run them on their normal cross-country routes for a month or so to measure the operational increases in fuel efficiency and safety,” Englar said.