Featured Research

from universities, journals, and other organizations

Low-Drag Trucks: Aerodynamic Improvements & Flow Control System Boost Fuel Efficiency In Heavy Trucks

Date:
January 10, 2005
Source:
Georgia Institute Of Technology
Summary:
Flow control techniques and aerodynamic improvements developed at the Georgia Institute of Technology could save the U.S. trucking industry hundreds of millions of gallons of fuel per year. Recent tests done using a full-size tractor-trailer truck show the techniques – which are based on systems originally developed for jet aircraft wings – could increase fuel economy by as much as 11-12 percent.

Aerodynamic improvements on truck trailers -- such as rounded corners -- coupled with pneumatic controls for blowing air from slots, help reduce drag and improve fuel economy for heavy trucks. (Georgia Tech Photo)

Flow control techniques and aerodynamic improvements developed at the Georgia Institute of Technology could save the U.S. trucking industry hundreds of millions of gallons of fuel per year.

Recent tests done using a full-size tractor-trailer truck show the techniques – which are based on systems originally developed for jet aircraft wings – could increase fuel economy by as much as 11-12 percent. The improvements could also enhance braking and directional control, potentially improving safety for the big vehicles.

“Aerodynamically, we have resolved unknowns raised in earlier testing, and the next step is to get this into a fleet of trucks for more extensive testing,” said Robert Englar, principal research engineer in the Aerospace, Transportation and Advanced Systems Laboratory of the Georgia Tech Research Institute (GTRI).

“We have shown that this technology now works quite successfully, and we expect that the industry will find a potential 12 percent fuel economy improvement worth pursuing," he added. "At highway speeds, each one percent improvement in fuel economy results in saving of about 200 million gallons of fuel for the U.S. heavy truck fleet.”

The aerodynamic improvements produced by geometry changes – which generate fuel savings of as much as six to seven percent -- involve rounding aft trailer corners, installing fairings and making other changes that smooth air flow over the boxy trailers. Fuel savings of an additional five percent come from pneumatic devices that blow air from slots at the rear of the trailer to further improve and prevent separation of air flow.

Supported by the U.S. Department of Energy, the project began in the late 1990s with tests of simple scale model tractor-trailers in GTRI’s low-speed wind tunnel. Those studies suggested the possibility of dramatic fuel savings based on these simple models, but in the first tests on a full-scale truck, the results fell short of expectations.

So researchers went back to their wind tunnel with more realistic truck models to study lessons learned from the first test.

Working with Volvo Trucks of North America and Great Dane Trailers – manufacturers of the basic tractor and trailer respectively – Englar’s research team and Smyrna prototype shop Novatek installed a new set of aerodynamic features and revised the blowing system at the rear of the trailer. A series of higher-speed test runs at the Transportation Research Center’s Ohio fuel-economy test track in September then demonstrated the real fuel savings that had been expected.

The tests involved operating a blowing-equipped test tractor-trailer for several different 45-mile runs around a 7.5-mile oval at highway speeds of 65 and 75 miles per hour. A control truck that did not have the aerodynamic improvements or pneumatic control system was operated under the same conditions to provide a comparison. For additional comparisons, the test truck was also run without the experimental blowing equipment.

Before the pneumatic control system can be widely used in trucks, however, researchers will have to choose the best source of compressed air for the blowing system, Englar notes. Options include a diesel-powered motor installed in the trailer like current refrigeration units, bleeding pressurized air from the truck’s supercharger, or a simple chain drive to turn air blowers from the trailer’s wheels.

Aerodynamic drag becomes dominant only at higher speeds, so the blowing would be turned off when the trucks were idling or operating at low speeds, Englar said.

To fully assess the energy savings, the researchers will have to accurately account for the power needed by the blowing system, which will cut into the fuel savings. And other practical issues – such as protecting the pneumatic surfaces from damage during docking – still must be resolved, though that effort is already underway.

Beyond boosting fuel efficiency, the pneumatic system can also provide a form of aerodynamic braking to assist the mechanical brakes. “Using the pneumatic systems, you can turn a low-drag configuration into a high-drag configuration in a very rapidly, giving you a lot more braking power,” Englar said.

Differential blowing could also improve control of trailers in crosswinds by helping compensate for the wind direction. “This would allow you to have the blown equivalent of an airplane rudder on the trailer, without any physical additions,” he explained. “Beyond increasing fuel efficiency, the pneumatic system could be a drag reducer, drag increaser, safety factor and a stabilizing device.”

Both the improved braking and directional control could be part of an automated system that would not require special attention from drivers.

Further energy savings could come using a pulsed pneumatic system, which preliminary wind-tunnel studies on wings have shown could produce the same aerodynamic efficiency with less energy consumed by the blowing system. Englar hopes to get further funding to study how this might affect the truck aerodynamics – as well as fuel consumption.

“Our suspicion is that by using pulsed blowing, you could reduce the blowing system’s fuel requirements by about half to three-quarters,” he said. “This would reduce the penalty for running this kind of a blown system.”


Story Source:

The above story is based on materials provided by Georgia Institute Of Technology. Note: Materials may be edited for content and length.


Cite This Page:

Share This



More Matter & Energy News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

US Police Put Body Cameras to the Test

US Police Put Body Cameras to the Test

AFP (Oct. 1, 2014) Police body cameras are gradually being rolled out across the US, with interest surging after the fatal police shooting in August of an unarmed black teenager. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com
Raw: Japan Celebrates 'bullet Train' Anniversary

Raw: Japan Celebrates 'bullet Train' Anniversary

AP (Oct. 1, 2014) A ceremony marking 50 years since Japan launched its Shinkansen bullet train was held on Wednesday in Tokyo. The latest model can travel from Tokyo to Osaka, a distance of 319 miles, in two hours and 25 minutes. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Robotic Hair Restoration

Robotic Hair Restoration

Ivanhoe (Oct. 1, 2014) A new robotic procedure is changing the way we transplant hair. The ARTAS robot leaves no linear scarring and provides more natural results. Video provided by Ivanhoe
Powered by NewsLook.com
Argentina's Tax Evaders Detected, Hunted Down by Drones

Argentina's Tax Evaders Detected, Hunted Down by Drones

AFP (Sep. 30, 2014) Argentina doesn't only have Lionel Messi the footballer, it has now also acquired "Mesi" the drone system which monitors undeclared mansions, swimming pools and soy fields to curb tax evasion in the country. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins