What is the thermodynamic efficiency of a typical automobile?

The thermodynamic efficiency of a typical automobile is around 20% to 30%, with more modern and efficient gasoline engines reaching efficiencies of about 30% to 40%. In this context, selecting an efficiency of 38% is plausible, as it falls within the range of performance observed in newer vehicles that utilize advanced engineering and technology to maximize fuel efficiency.

Efficiency is determined by the amount of useful work output relative to the energy input, which in the case of automobiles, translates to how much of the fuel's energy is converted into actual movement as opposed to being lost as heat. Factors that contribute to this include the internal combustion process, energy losses due to friction, and other mechanical inefficiencies inherent in vehicle operation.

The other values, such as 62%, 32%, and 18%, do not align with realistic automotive efficiencies when taking into consideration the operations of conventional gasoline engines or even hybrid systems, thus highlighting 38% as a more reasonable approximation for the thermodynamic efficiency of a typical automobile.