Analysis of Fuel Consumption Reduction Due to Powertrain Hybridization and Downsizing of ICE

This paper presents an extensive simulation and analytical analysis of the energy conversion efficiency in parallel and series hybrid powertrains. The simulation approach is based on an accurate and fast forward-facing simulation model, whereas the analytical approach is based on the energy balance equations. Analysis covers broad range of parallel and series hybrid powertrain configurations. Very good coincidence of simulation and analytical results gives confidence in the accuracy of the performed analysis and confirms the validity of the analytical framework. Combined simulation and analytical analysis enables deep insight into energy conversion efficiency phenomena in hybrid powertrains and reveals advantages and disadvantages of both hybrid configurations running under different operating conditions. It is shown that parallel hybrid powertrain features better fuel economy than the series one, whereas both hybrid powertrain concepts allow for the highest fuel economy enhancements at light duty application.