Design And Simulational Research On Two Speeds Automatic Transmission Of Electric Vehicle

Along with people all over the world pay more and more attention to environment pollution and the problem of energy shortage, as a convenient conveyance without pollution, electric vehicles have a great development. Many domestic and foreign automobile manufactures pumped much money into the development of electric vehicles. Transmission is the core component of power transmission system for electric vehicle. It’s function has a great impact on the power and economy performance, and also affects the feelings of the driver and passengers. Therefore, the study of electric vehicle transmission has realistic significance. In this paper,a two speeds automatic transmission for the electric vehicle of JAC will be researched.Based on the electric vehicle driving performance standard,the parameters of the vehicle transmission system are matched. The gear ratios needed are achieved. The structure of two speeds automatic transmission, the planetary gear sets and the clutches are designed, according to the characteristics of planetary gear sets. Three-dimensional model of the transmission is established to verify the design of rationality by using CATIA. The model of wet multi-disc clutch is established, by studying the structure and torque transfer characteristics of wet multi-disc clutch. A mathematical model of the transmission shift switch is established. The simulation models in the vehicle launch and gearshift process were built by using Simulink software.The two performance indicators of the slipping friction work and jerk are analyzed. Linear quadratic optimizing control theory is used to get the pressure curves of the clutch for automatic transmission shift process. Based on the simulation models built, the curves of friction work and shifting jerks are achieved.According to the analysis results,the jerk and slipping friction work in the vehicle launch and gearshift process are all reasonable. The results show that based on the linear quadratic optimizing control theory, t he clutch pressure achieved can control the transmission in good shifting quality. It can be apply to the two speeds automatic transmission of electric vehicle in this paper.