The semi-truck looks pretty much like a semi-truck. But take a second look and you'll notice a few add-ons — the kind that researchers say could save 3.4 billion gallons of diesel fuel and $10.2 billion per year.
Researchers from the Lawrence Livermore National Laboratory are working to develop devices to make semi-trucks more aerodynamic. They recently brought some of their trucks across the Bay to test their project in a massive wind tunnel at Moffett Field, and showed off their progress at a media event Tuesday.
A shiny big rig with a red cab sat in the middle of the 80-by-120-foot wind tunnel at the NASA Ames Research Center in Mountain View. It was a standard semi-truck, but with a couple of extra flaps behind the tractor cab, some more flaps hanging straight down from the bottom of the trailers' sides, and a boxy, angled "Trailer Tail" device projecting from the back end.
At highway speeds, semi-trucks have to use more than 50 percent of their energy to overcome the drag they create, laboratory representatives said in a statement. The large trucks account for about 12 percent of the United States' total petroleum consumption, representatives said.
With aerodynamic add-ons like the ones on display Tuesday, researchers say they can reduce drag by 12 percent, preventing 36 million tons of carbon dioxide from being released into the atmosphere annually.
The laboratory has been working on the Department of Energy-funded project for about 15 years and has spent a total of about $3.5 million, including $400,000 in 2009.
Laboratory senior scientist Kambiz Salari, who has been leading the project for three years, said the goal is to work around the inherent box structure of a truck trailer. The flaps that hang down from the bottom, for example, block some of the open space beneath the truck and help reduce drag from crosswinds.
"Somehow, we have to trick the flow (of air) so it thinks it's a more streamlined body," Salari said.
Testing of two tractors and three trailers — which can be used in various combinations— began in Moffett Field's wind tunnels about three weeks ago, Salari said, and likely will continue another few weeks. After those tests, Salari said, researchers will narrow down their choices of devices and then test the trucks on a track and on a road to collect more data and determine the best combination.
Some of the devices are prototypes, while others, such as the Trailer Tail by ATDynamics, are already commercially available. Salari said he hopes the project will result in products for sale in two or three years.
After the initial few weeks in the wind tunnel, Salari said, "it will take us a quite a while to process the data, but the results have been promising."
NASA Ames aerospace engineer James Ross said he has seen many different types of vehicles come through the wind tunnel for testing, including airplanes and spacecraft. He said he worked on two similar tests with semi-trucks, but this one is more extensive.
"They finally got enough government interest to look at a lot of things in this test," Ross said. "We haven't had that luxury before."
Officials from the laboratory, NASA Ames, the Navistar trucking company, the U.S. Air Force and local politicians praised the project at Tuesday's event.
"We really are bringing together the great minds and great aspirations that really give our country a reason to dream that we can have a better place to live," said U.S. Rep. Mike Honda, D-San Jose.
E-mail Diana Samuels at email@example.com.