Modeling Tools for Predicting the Impact of Rolling Resistance on Energy Usage and Fuel Efficiency for Realistic Driving Cycles

Currently, in the United States there is a growing gap between domestic oil production and consumption. The Department of Energy has developed a modeling tool (known as VISION) that projects future consumption by the transportation sector through the year 2050. This paper uses the VISION model to show that an energy savings of 3.8 billion gallons per year can be achieved with a 2.5% improvement in fleet fuel economy, and proposes that this improvement can be made through lower rolling resistance tires and improved tire pressure maintenance. Additionally, the National Renewable Energy Lab has developed a vehicle systems analysis tool known as Advanced Vehicle Simulator (ADVISOR) that models vehicle performance over any predefined driving cycle. In this paper ADVISOR is used to compute the effect of rolling resistance on fuel efficiency for two classes of vehicles (passenger car and sport utility vehicle) and several realistic driving cycles (city, highway, aggressive driving). ADVISOR is used to compute the dynamic vehicle forces, fuel economy, and emissions for the various combinations of vehicles, cycles and tire rolling resistance. Using industry-supplied tire rolling resistance data, the ADVISOR simulations showed fuel economy between 2% and 6.5% lower for a light duty passenger car equipped with low rolling resistance tires, and between 1.0% and 3.4% for a sport utility vehicle over the three different drive cycles.