Comparison Research of Electric Vehicles Equipped with Fixed Ratio Gearbox and Two-Speed Gearbox

Abstract

Parameters of powertrain system directly affect the dynamic performance and economy of electric vehicles (EVs). In order to further explore the impact of the structure of powertrain system on vehicle performance, the parameters of driving motor and automatic transmission are calculated based on the performance requirements of the target vehicle. Gear ratios of transmissions with fixed ratio gearbox and two-speed gearbox are optimized respectively. The EVs with two transmission schemes are simulated under three driving cycles using the optimized gear ratios. The simulation results show that both transmissions can satisfy the requirement of vehicle power performance, while the economy of EV with two-speed gearbox is better than that of EV with fixed ratio gearbox.