Improvement of battery charging efficiency using 2-clutch system for parallel hybrid electric vehicle

A battery charging control using a driving motor is proposed for an AT based parallel HEV. To charge the battery using the driving motor, a 2-clutch system control is proposed which uses the engine clutch and the clutch inside the transmission. The battery charging efficiency is estimated from the engine fuel consumption and efficiency of the power electronics. To evaluate the performance of the suggested battery charging control, HEV performance simulator is developed and simulations are performed for FTP-72 mode. Simulation results show that battery charging using the driving motor has a higher charging efficiency and faster charging speed compared with the conventional battery charging system using the ISG.