Research On Matching Of Power System And Shifting Strategy For Parallel Hybrid Electric Vehicle

With the continuous acceleration of the automobile industry,automobiles have played an increasingly important role in people’s lives.The ensuing environmental pollution has prompted the emergence of hybrid electric vehicles.Compared with traditional fuel vehicles,hybrid electric vehicles can increase fuel consumption.The utilization rate of the vehicle has good prospects and is an important direction for future automobile development.Nowadays,people’s research on hybrid electric vehicles is mostly focused on mode division and torque distribution,and there is little research on shifting strategy.Shifting strategy is one of the most important key technologies of automated mechanical transmission(AMT).A reasonable shift strategy can greatly improve the power and economy of the vehicle.Most of the current hybrid vehicles use the traditional two-parameter shift strategy.Compared with traditional fuel vehicles,hybrid vehicles can provide more the driving force of the motor,so the traditional two-parameter shift strategy is unreasonable.According to the parallel hybrid electric vehicle studied in this paper,the following research work has been carried out around the problems of power matching,mode division,torque distribution,formulation of shift strategies and verification of strategies:(1)Discusses the development history of hybrid electric vehicles at home and abroad,analyzes the working principles of hybrid electric vehicles with different structures and the structure of AMT,and makes reasonable arrangements for the subsequent drive system matching and formulation;(2)Based on the power-related indicators of the vehicle design,the performance parameters of each component of the vehicle power system are solved through theoretical calculations and empirical formulas,the vehicle powertrain is matched,and the speed ratio of each gear of the AMT is calculated;(3)According to the matched power system,combined with the driving characteristics of the research model and the component state parameters,the working mode is divided,and then combined with the driver’s required braking torque,the energy recovery torque and the braking torque are determined,and the engine and the braking torque are determined.The torque of the motor is also distributed;(4)The theoretical knowledge of the shifting rule is studied,and the traditional twoparameter shifting rule is solved for the parallel hybrid electric vehicle studied in this article.On the basis of the two-parameter shifting rule,the representative electric motor of the hybrid electric vehicle is added.The effective throttle opening is the parameter,and then the three-parameter shifting law is solved by the analytical method;(5)The physical model of the vehicle was built using the simulation software AVLCruise,and the vehicle control strategy model and the shift control strategy model were built using MATLAB/Simulink.The co-simulation method was used to verify that the threeparameter shift strategy developed in this article was compared with the traditional two parameters.The superiority of the shift strategy.