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Idle Reduction Research and Development

The U.S. Department of Energy (DOE) initiated a study of diesel truck engine idle reduction technologies in 2002 through the Advanced Vehicle Testing Activity (AVTA). The study identified several barriers to widespread use of existing idle reduction technologies, including initial cost, driver education and receptiveness, reliability, and maintenance considerations. The study results were used to develop a plan to implement idle reduction technologies.

As part of this study, AVTA sponsored four idle reduction demonstration projects, which consist of teams of a truck fleet, truck manufacturer, and idle reduction technology manufacturer. These projects are described below.

Engine-Off Cab Cooling and Heating

Schneider National Inc. led a project to demonstrate engine-off cab cooling and heating. In cold weather testing, trucks using an auxiliary cab heater averaged 10% idle time (10% of the total operation time was spent idling), versus 27% for comparison trucks (trucks without auxiliary cab heaters), and averaged 2.4% (0.16 miles per gallon) better fuel economy than the comparison trucks. Based on these results, Schneider National is equipping all its new trucks with auxiliary cab heaters. In hot weather testing, trucks using one auxiliary cab cooler technology averaged 20% idle time, versus 23% for comparison trucks. Trucks using another auxiliary cab cooler technology averaged 13% idle time, versus 16% for comparison trucks. Although this reduced idling resulted in modest or no improvement in fuel economy, the results suggest that modifying driver behavior could result in fuel economy improvements of 2% to 3% using the tested technologies. For truck fleets that idle near the industry average of 40% of the time, these savings could provide payback within 2 years.

Engine-Off Accessory Power

Caterpillar Inc. is leading a project to demonstrate Caterpillar's MorElectric technology, which applies electrically driven accessories for cab comfort during engine-off stops and for reducing fuel consumption during on-highway operation. Preliminary results show that the MorElectric trucks idled 13% of the time, versus 27% for control vehicles. This equated to a 0.14 miles per gallon improvement over the control vehicles or approximately 400 gallons of diesel fuel saved per truck per year.

Combined Cab Heating and Cooling

Espar is leading a project to demonstrate combined cab heating and cooling systems. One system combines an air conditioner with a bunk heater. Another system combines an auxiliary power unit, which provides heating, cooling, and accessory power, with a bunk heater. Preliminary results show fuel economy improvements of 3% to 4% (0.23 to 0.27 miles per gallon) compared with benchmark truck fuel economy.

Factory-Installed Idle Reduction System for Sleeper Trucks

International Truck and Engine Corporation is leading a project to develop and integrate onboard idle reduction technology into heavy-duty sleeper trucks as an original-manufacturer, factory-installed equipment option. The idle reduction system consists of an auxiliary power unit, electric air conditioner, cab and engine preheater, and improved cab insulation. In 2006, five trucks equipped with the system began field evaluation in fleets. In addition, production orders for the factory-built system—in hot-climate and cold-climate versions—are already being delivered to customers.

For more information on these projects, see AVTA's Idle Reduction activities and read about the AVTA Idle Reduction Technology Demonstrations: 2005 Status Report (PDF 1 MB), 2004 Status Report (PDF 544 KB).Download Adobe Reader.

Other Government-Sponsored Idle Reduction Activities

DOE's Clean Cities Program sponsors idle reduction projects. Visit State Energy Program Special Projects for Clean Cities to learn about idle reduction projects that have been funded. The U.S. Environmental Protection Agency's SmartWay Transport Partnership also sponsors idle reduction projects. National Idling Reduction Network News is an excellent source of information on idle reduction activities and funding opportunities.