Analysis of dynamic characteristics of power transmission system of the P2 hybrid vehicle under different power source excitation

ObjectiveThe power sources are important external excitations of the transmission system, so it is necessary to fully explore the influence of different power sources on the dynamic characteristics of the hybrid vehicle power transmission system.MethodsFirstly, the dynamic driving torque of the four-cylinder engine and the permanent magnet synchronous motor was derived and expressed as a function of angular displacement, and the power output model of power source was established. Based on the finite element polycondensation method and the centralized parameter dynamic modeling method, the hybrid dynamic model of the transmission system was established, and the correctness of the modeling method was verified by tests. Finally, the rigid-flexible coupling dynamics model of the power transmission system of hybrid vehicles was established by coupling the power source and the drive system dynamics model, so that the vehicle can operate in pure electric drive mode, engine drive mode and combined drive mode respectively, and the dynamic response characteristics of the system under different drive modes were analyzed. The effects of engine torque fluctuation, motor torque fluctuation and simultaneous operation of engine and motor on the dynamic characteristics of the system were investigated.ResultsThe results show that both engine and motor torque fluctuation will lead to the increase of gear pair meshing torque, bearing force and bearing center trajectory range, as well, the vibration caused by 2 times base frequency of motor and base frequency of four-cylinder engine is the main reason for the increase of the bearing force.