Southwest Research Institute® (SwRI®) News
Printer Friendly VersionSwRI, EPA evaluate fuel, air quality gains from big-rig modifications
San Antonio — March 22, 2006 — In a project with the U.S. Environmental Protection Agency (EPA), Southwest Research Institute® (SwRI®) is evaluating low-drag tires and trailers on Class 8 trucks for improvements in fuel efficiency and pollutant emissions.
The project, which began in September 2005 and continues through March 2006, involves measuring reductions in oxides of nitrogen (NOx) and improvements in fuel economy for trucks hauling specially modified Class 8, 53-foot box van trailers. The project is led by the EPA Office of Transportation and Air Quality's SmartWay™ Transportation Partnership, a voluntary program aimed at reducing pollution and greenhouse gas emissions from motor vehicles.
Burning fossil fuels in an internal combustion engine produces exhaust gases containing NOx and other emissions. In preliminary tests in 2005 using a line-haul Class 8 truck with a cooled exhaust gas recirculation system installed on its engine, the EPA demonstrated that there is significant opportunity for innovative technologies to reduce engine load and thereby reduce the amount of carbon dioxide and other exhaust emissions on a per-mile basis. This also would reduce greenhouse gases and other emissions, leading to new and innovative strategies to improve air quality.
Highway line-haul trucks are integral to the nation's freight delivery system, accounting for a significant portion of all freight-truck fuel usage because they typically travel more miles than other types. Most of these miles are driven at highway speeds, where the fuel demand to overcome aerodynamic and rolling resistance drag is the greatest. A number of fleets already equip their trucks with low-rolling-resistance tires and aerodynamic roof fairings over the cab. More recent technologies, such as aerodynamic trailer fairings and single-wide tires to replace dual tires, offer additional opportunities to reduce drag and save fuel.
Preliminary tests last year indicated that reducing aerodynamic drag helped reduce engine loads, which in turn led to lower NOx emissions and higher fuel economy. In the current test, SwRI is helping the EPA to further research the link between saving fuel and reducing pollutant emissions.
"With rising fuel costs, the pay-back period for rig modifications that improve fuel economy becomes shorter and thus more attractive," said Steven D. Marty, director of SwRI's Fuels and Driveline Lubricants Research Department.
SwRI and EPA will compare pairs of trucks typical of highway line-haul operation, including trucks with electronically controlled engines and with engines that feature advanced emission-reduction technology. These trucks will be tested on a track over a number of drive cycles to simulate a wide range of highway operation. The trucks will perform the standard SAE J1321 fuel economy test procedure and will be equipped with portable emissions monitoring systems to measure NOx. Fuel economy and NOx emissions will be measured for a number of fuel-saving retrofit configurations, over several drive cycles, using different engine types.
Results so far are promising and support earlier findings. Completion of this and any subsequent tests will produce data that could lead to EPA guidance for states that want to achieve air quality improvements with innovative truck retrofit projects that would pay for themselves through fuel savings.
Editors: High-resolution image for download is available at http://www.swri.org/press/2006/EPA.htm .
For more information, contact Joe Fohn, Communications Department, (210) 522-4630, Southwest Research Institute, PO Drawer 28510, San Antonio, TX 78228-0510.
