Tractor Feature Article

Blowin' in the wind - research on tractor-trailer fuel consumption - Brief Article

Author: Fleet Owner

The answer, my friend, is compressed air

This is the strangest idea I've heard in a number of years. And stranger still, it may also be one of the best I've heard in a number of years.

A magazine is fair game for any crackpot or snake-oil salesman with a "revolutionary" invention, and normally a recent email would have had my credibility alarm ringing loud and long. A team of researchers claimed that it's come up with a way to cut tractor-trailer fuel consumption a whopping 12% by blowing compressed air through slots spread around the trailer.

If the fuel savings isn't outlandish enough, the researchers say this "pneumatic system" can also help control jack-knifing and trailer sway, improve vehicle stability in ice and rain, shorten stopping distances, increase tire life and reduce wheel spray. Does it also make coffee and unload the freight?

I probably wouldn't have given the note a second glance if it wasn't for the source -- it's the highly reputable Georgia Tech Research Institute (GTRI), which received funding for this particular project from the equally reputable Dept. of Energy's (DOE) Office of Heavy Vehicle Technologies. Even more impressive was the email's attachment, a formal paper presenting the group's research, experimental results and conclusions in great detail to their peers at SAE.

Borrowing from patented pneumatic systems developed in the 1970s to boost lift for airplanes, the GTRI team used a wind tunnel to test the concept on a tractor-trailer model. They found that blowing lightly compressed air over a curved surface on top of the trailer decreases drag by 35 to 50%, while also decreasing rolling resistance by lifting a portion of the vehicle's weight off the tires. A 35% drag reduction would translate into a 12% fuel savings by their calculations, or about 1.2 billion gallons of diesel a year in the U.S. The 50% number would raise the annual savings to 1.7 billion gallons.