Abstract
To reduce the fuel consumption of passenger cars,hybrid propulsion systems (i.e.,combinations of IC engines with electric motors,classical and novel long and short range energy storage devices,fuel cells,etc.)have been proposed by many research groups,and first vehicles are now entering the market.The design of such propulsion systems requires adequate software tools which must have a clear,underlying theoretical foundation in order to manage its complexity.In this survey paper such models and methods will be presented and several examples of powertrain optimizations (structural, parametric and control)will be given.