Study On Parameters Matching And Control Strategy Of Transmission Of Pure Electric Vehicle

In recent years,with the rapid development of pure electric vehicle(PEV)industry,the requirements from the consumers of pure electric vehicle performance requirements are more and more high,As the core part of the pure electric vehicle,the powertrain system has great influence on the economy and dynamic of the whole vehicle.This dissertation made research on the pure electric vehicle motor-transmission powertrain based on the project of an original equipment manufacture.The main research contents are as follows:This dissertation analyzed the differences between the pure electric vehicle and the traditional fuel vehicle with regard to the driving system,made comparison of the advantages and disadvantages of the six currently dominant structure.This dissertation designed the driving system of pure electric vehicle on the basis of the structure of the original car,designed the motor parameters and transmission parameters according to the requirements of maximum speed,maximum climbing degree,acceleration performance and the size of powertrain.This dissertation introduced the composition and control process of powertrain.Based on the output characteristic curve of motor and pedal map,the dynamic shift control strategy was formulated.And the economic control strategy was formulated based on the map of motor efficiency map and pedal map.The comprehensive shift control strategy was developed according to the dynamic shift curve and economic shift curve.For the problem that the transmission change gears frequently under complicated working conditions.This dissertation analyzed the changes of vehicle speed,acceleration and acceleration pedal opening.The flexible shift control strategy was developed to reduce the shifting times under complicated working conditions.Through the analysis of the energy flow of pure electric vehicle,the dynamic model was built in MATLAB by Simulink.The simulation results verified that the vehicle endurance mileage,the vehicle acceleration performance,climbing performance,maximum speed meet the requirements.The shift times of transmission under FTPcondition was simulated,the simulation results show that the flexible shift control strategy can significantly reduce the number of shifting times under FTP condition.Finally,the bench experiment and on-road experiment were made to test the prototype.The bench experiment results show that the transmission can change gears smoothly with a good stability.The on-road experiment results show that the real vehicle endurance mileage,the acceleration performance,the climbing performance and the maximum speed meet the design requirements.