Reducing Tire Rolling Resistance to Save Fuel and Lower Emissions

In a context of a renewable and sustainable progress in the automotive industry where fuel and respect for the environment are in the middle of all concerns, energy efficient tires could play a significant role in saving money, limiting greenhouse gases and contributing to reduced local pollution. Using simulation, this paper establishes a simple law to predict fuel savings between two tire configurations, which appear to be almost independent of the usage and which depend on the difference of rolling resistance coefficients, the actual weight of the vehicle and the fuel type. This approach has been evaluated in practice for passenger car tires fitted on one gasoline and one Diesel Midsize car by performing rolling resistance tests, coast down tests, fuel consumption tests at constant speed and emissions recorded on a test bench. Even more than just validating the fuel savings prediction law, the test results also show how low rolling resistance tires can help to decrease CO₂ emissions and local pollutants such as CO emissions for gasoline engines and NO_x emissions for Diesel engines. This conclusion of simultaneous CO₂ and NO_x reduction has also been proven at constant speed on a heavy duty vehicle equipped with a gas analyzer.