Rising fuel price and stringent regulations on CO₂ make vehicle's fuel efficiency the main marketable quality. To make more efficient car, there were efforts on high efficiency engine and transmission. But, the races for the efficient vehicle make u...
Rising fuel price and stringent regulations on CO₂ make vehicle's fuel efficiency the main marketable quality. To make more efficient car, there were efforts on high efficiency engine and transmission. But, the races for the efficient vehicle make us turn the eye on vehicle's road-load again. Therefore, in this paper we systematically studied on vehicle's road load and reviewed. Fist, road-load divided into three parts; aerodynamic drag, rolling resistance, and internal resistance. And then, the aerodynamic drag differences between real load drag and wind-tunnel results (include the influence of ride height) were studied. The rolling resistance was studied in view of warm-up transient characteristic and inflation pressure effect. And on-board measuring method of internal resistance (ex. differential gear drag) and brake drag was developed.