Pure Electric Vehicle Shifting Rules And Transmission System Speed Ratio Optimization

At present,we are facing serious environmental pollution and energy security issues,so energy conservation and emission reduction is imperative.In this context,pure electric vehicles have quickly become the focus of attention due to their zero emissions and easy control.However,due to the short charging time and short driving range,pure electric vehicles have seriously affected the user experience.Therefore,under the existing conditions,how to improve the economy,power and comfort of pure electric vehicles has become a problem to be solved.This paper first introduces the transmission mode of pure electric vehicles,and then chooses to drive the motor,the final drive,the automatic transmission as the main body of the transmission,and then to improve the power and economy of the whole vehicle,for pure electric vehicles.The key components of the drive motor,power battery pack and automatic transmission of the powertrain are selected and matched with the initial parameters.The current automatic transmission shift law is studied and analyzed.Finally,the accelerator opening and the speed are selected.The shift control parameters have been formulated to take into account the shifting laws of the vehicle's power and economy.In the advanced automotive software ADVISOR,the model of the pure electric vehicle powertrain system was established,and then the parameters of the preliminary matching were simulated and verified,and the accuracy of the model was verified.Finally,the acceleration time of the vehicle was 0~80km/h and the NEDC work.The energy consumption establishes the objective function,and the setting requirements of the whole vehicle are taken as the constraint conditions.The particle swarm optimization algorithm based on simulated annealing is used to optimize the transmission ratio of the main reducer and the automatic transmission of the transmission system,and then the optimized results are simulated and analyzed.The simulation results show that the acceleration time of the vehicle at 0~50km/h is shortened by 5.8% compared with that before optimization;the acceleration time of50~80km/h is shortened by 9.3% compared with that before optimization;the maximum grade is increased by 7.9%.The 60 km/h constant speed driving range increased by 5.9%.The correctness of the gear ratio optimization in this paper is verified.