Mechanistic Excess Fuel Consumption of a 3D Passenger Vehicle on Rough Pavements

A passenger vehicle's fuel-powered engine compensates for its dissipated energy, which is caused by road roughness. This paper presents an integrated vehicle-pavement approach and investigates the excess fuel consumption of a seven-degree-of-freedom (DOF) full-car model on rough pavements. In the approach, a nonstationary Laplace process is used to artificially generate road roughness profiles with consideration of local roughness variance and parallel roughness correlation. The proposed mechanistic approach quantifies the impact of road roughness and vehicle dynamic characteristics on excess fuel consumption. The study concluded that overlooking local roughness variance, an indicator of road roughness nonstationarity, may underestimate excess fuel consumption by 30%. Compared with a two-dimensional (2D) half-car model, a three-dimensional (3D) full-car model reduces computation error of excess fuel consumption by approximately 11%. For practical implementation, the extended roughness-speed-impact (ERSI) model (R2=98%) is developed to estimate roughness-induced energy dissipation of five two-axle vehicles.