The autoignition temperature of a fuel is defined as the temperature at which a fuel–air mixture would self-explode and ignite. Thus, it sets an upper limit on the temperature of the hot reservoir in an automobile engine. The autoignition temperatures for commonly available gasoline and diesel fuel are about 495 oF and 600 oF, respectively. What are the maximum Carnot efficiencies of a gasoline engine and a diesel engine if the cold reservoir temperature is 40oC?