The NC Solar Center at NC State University wrapped up a three year $500,000 project funded by the U.S. Environmental Protection Agency that focused on developing mobile idle reduction technology (MIRTs) to reduce idling of long haul trucks. By federal law, truckers are required to “rest” 10 hours after 11 hours of driving. Many idle their truck engines for creature comforts such as heating and air conditioning as well as a power source for on board appliances. NCSU partnered with Volvo Trucks North America to demonstrate the effectiveness of MIRTs in 20 over the road trucks.
In addition to installing an auxiliary power unit (APU) to supply electricity, heating and air conditioning through a small diesel engine, each truck was outfitted by Volvo with sensors that were remotely monitored by NCSU researchers at the College of Engineering’s Department of Civil, Construction and Environmental Engineering to assess the use and performance of the APUs. Conclusions drawn from the twenty trucks participating in the field demonstration which operated for over 2.8 million miles in 42 states during the sixteen-month data collection period were captured in a case study, video and final report posted at http://www.engr.ncsu.edu/ncsc/transportation/MIRTproject.htm .
At mild temperatures, 100% substitution of APU usage instead of the base engine would lead to an 80 to 90 percent reduction in NOx emissions, 36 to 47 percent reduction in CO2 emissions and fuel use, and 10 to 25 percent reduction in PM emissions. However, the field data imply that the APU was used by single drivers for an average of 59% of idling and by team drivers participating in the demonstration for an average of only 25% of idling. With avoided fuel use costs a significant factor in determining the cost effectiveness of MIRTs, these findings underscore the need for careful evaluation of the appropriateness of incorporating APUs to reduce idling and once selected to provide incentives and training to increase drivers use.