Research On DCT Shift Control Technology Of Plug-in Single-shaft Parallel Hybrid Electric Vehicle

With the shortage of energy and the deterioration of environment,the hybrid electric vehicle is becoming the research focus of the automotive field.As a multi-power system,it's difficult to get the full potential play by manual shift,so automatic transmission is needful for the hybrid electric vehicle.Shift schedule is one of the core technologies of automatic transmission and it has a direct influence on the power and fuel economy of the vehicle.Therefore,it is very important to study the method of making the shift schedule of the hybrid electric vehicle.In addition,for the dual clutch transmission studied in this paper,the switching control of the dual clutch during the shift has an important influence on the drive comfort.This paper mainly focuses on the shift control technology of the plug-in single-shaft parallel hybrid electric vehicle with double clutch transmission.Firstly,based on the vehicle system and the parameters of the components,the vehicle physical model is built by using AVL CRUISE.A rule-based energy management strategy is proposed,and the mode switching strategy and torque distribution strategy are discussed.On this basis,vehicle controller model is built by MATLAB / Simulink and the CRUISE-MATLAB joint simulation platform is completed by the MATLAB DLL,which lays the foundation for the study of shift control technology.Then,the velocity and accelerator pedal angle are chosen as the shift control parameters.Based on the torque output characteristics of the hybrid vehicle power source and the vehicle driving equation,the optimal dynamic shift rule is determined with the shortest acceleration time.The working points of the engine and the motor are determined based on the energy management strategy.Then,the vehicle driving efficiency model is established,and the optimal economic shift rule is determined with the highest efficiency.The shift law calculation software is programmed by using Matlab / GUI tools.Based on the CRUISE-MATLAB co-simulation platform,the 0-100km/h acceleration time and maximum velocity are taken as the dynamic index and the NEDC balance fuel consumption is taken as the economic index.The results shows that the optimal dynamic shift schedule and the optimal economic shift schedule respectively improve the vehicle power and fuel economy.The global optimization of the shift schedule based on the working conditions can further improve the fuel economy of the hybrid system.Based on the analysis of the power characteristics of a variety of typical cycle conditions,the classification and switching conditions are determined and a method of making the optimal economic shift rule based on statistical analysis is proposed.The simulation results show that the fuel economy of the vehicle is further improved.Finally,the clutch switching control characteristics of the shift process are analyzed,and the Isight-Cruise-Matlab joint optimization simulation platform is built.Then the change rate of the compression force of the switching control in the inertia phase is optimized and the results show that the degree of jerk is improved by 30% compared to original switching control characteristics,which proves the rationality and feasibility of the optimization method of the clutch switching control characteristics proposed in this paper.