Simulation And Evaluation On Shifting Performance Of Transmission For Hybrid Electric Vehicle In Pure Electric Drive Mode

Since transmission is one of the core components of vehicle power-train, the character in kinematics and dynamics of transmission influence the efficiency of power-train and the performance of vehicle. The shift performance is a physical characteristic of transmission which is shown during the shift process, and the study on transmission shift performance is of great significance to improve design efficiency and product quality.In order to build China’s self-owned brand cars in a real sense, our country’s major car manufacturers to strengthen self-development for the key parts. This transmission for hybrid electric vehicle we researched is in design stage, and we expect to use simulation method to research shift performance of transmission for hybrid electric vehicle in pure electric drive mode so as to achieve the aim of improving its shift comfort.This dissertation uses existing transmission to be the contrast model, which is simplified and only contains low gear group,a combination of ADAMS and Pro/E is used to build the multi-body dynamics model of the transmission, and that whether the motor actively participates in the regulating speed under shifting process condition is analyzed. Then a transmission test bench is built to conduct shifting test under corresponding conditions. The consistency of simulation results and the corresponding test results of the transmission’s shift performance are compared to verify the feasibility of this simulation method, moreover, a conclusion that the motor must participate actively in speed regulation and the goal rpm should meet the active part of synchronizer’s speed is higher than the passive part of synchronizer’s is reached.A multi-body dynamics model of designing transmission for hybrid electric vehicle is built by using the same simulation method. The shift performance of its shifting process between the two working gears in the condition that motor participates actively in speed regulation and the two ends of the synchronizer have a speed difference after the control of motor speed is analyzed, and the shift performance is evaluated by using shift time and shift impulse as the evaluation indexes, which can provide basis for the establishment of shifting control strategy.Finally, the finite element analysis of two working synchronizers based on ABAQUS is performed, and the stress distribution states of synchronizers in synchronizing process are obtained at a certain speed difference. The FEA results are input into FEMFAT software, and taking the pulsation cycle impact into consideration, the fatigue analysis is performed. The fatigue life of synchronizers is evaluated by using the fatigue cycles as the evaluation index.This dissertation provides effective simulation method to analyze the shift performance of a transmission for hybrid electric vehicle in pure electric drive mode. That is mean that the shift performance of transmission for hybrid electric vehicle can be predicted and evaluated through simulation analysis method in the design stage of the transmission for hybrid electric vehicle in different working condition.