Numerical Simulation of Combination Engine HEV on Fuel Economy

A concept of combination engine is presented, and applied it on Hybrid Electrical Vehicles (HEV). The fuel economy characteristics of the new power system and that of normal power system with conventional engine were compared and analyzed by numerical simulation at different driving cycles. The simulation results show that the maximum fuel economy of vehicle with combination engine is 7% better than vehicle with conventional engine. In addition, the maximum fuel economy improvement is 8% and realizes the mild hybrid system if combination engine is used in HEV. Thus, reduces the cost. The fuel economy characteristics of HEV with combination engine under different state of charge and engine power ratio conditions were simulated. It is concluded that the combination engine with equal power ratio is more reasonable for the design of HEV. At last, the fuel economy sensitivity coefficient concept is introduced and applied in the analysis. Through sensitivity coefficient analysis, it is concluded that motor has the highest sensitivity coefficient. The combination engine HEV has lower motor and battery sensitivity coefficient than conventional engine HEV. Therefore, the dependence on motor and battery is reduced if combination engine is used in HEV.