The Energetic Performance of Vehicles

Various methods of determining the energetic performance of vehicles were described and compared. Earlier work emphasized maximum vehicle power and theoretical performance limits, and characterized the vehicle or payload in terms of weight. Energetic efficiency was calculated here as the payload mass times distance moved divided by thermal energy used. This efficiency was multiplied by average speed to yield an energetic performance parameter that was expressed in seconds, using SI units. The differential form of this parameter was twice the useful payload kinetic energy divided by thermal power expenditure. A transportation matrix was developed, describing how vehicles are most commonly used in terms of speed, efficiency, GHG emissions, payload mass and energetic performance. Vehicles with the highest level of energetic performance have efficient powerplants, high payload to gross mass ratios, or reduced friction with the surrounding environment.