Abstract
Keywords: Hybrid powertrain, Energy conversion efficiency, simulation, transient cycle
This paper presents a simulation and analytical analysis of the energy conversion efficiency in parallel and series hybrid powertrains. Analytical approach is based on the energy balance equations, whereas simulation approach is based on an accurate and fast forward-facing simulation model for simulating parallel and series hybrid powertrains. The analysis covers a broad range of parallel hybrid powertrain configurations spreading from mild- to full-hybrids, and series hybrid powertrains with different control strategies. Combined simulation and analytical analysis enables deep insight into energy conversion phenomena in hybrid powertrains and reveals advantages and disadvantages of both hybrid concepts running under different operating conditions. Very good agreement between simulation and analytical results gives confidence in the accuracy of the performed analysis and confirms the validity of the analytical framework. It is obvious from the presented results that parallel hybrid powertrain features better fuel economy than the series one for the applied test cycles, whereas both hybrid powertrain concepts feature the best fuel economy at light duty application.