Simulation analysis of the dynamics characteristics of battery electric vehicle transmission system under impact condition

This paper analyzes the dynamic characteristics of transmission system of battery electric vehicle through simulations. The research method and conclusions can serve as a theoretical basis and reference for the design of vehicle system architecture. To accurately describe the torsional vibration characteristics of battery electric vehicle’s transmission system, it is necessary to reasonably simplify the system. Furthermore, when subjected to short-wave uneven road surface excitation, the connection between the rigid ring in the SWIFT (Short Wavelength Intermediate Frequency Tire model) tire model and the ground belongs to single-point contact and cannot represent the tire enveloping properties. Around the above issues, a method has been proposed to simplify the gearbox model into a force-coupled model with centralized damping, stiffness, and mass, along with an equivalent road surface model consisting of series-connected elliptical cam that can represent tire enveloping properties. Correspondingly, an evaluation criterion has been established, which utilizes the ratio of the peak torque of the impact force at the rear wheel hub after encountering a step to the maximum output torque of the gearbox as the impact coefficient. In four-wheel-drive vehicle models, the impact coefficient of the front axle is greater than that of the rear axle when going uphill, and when going downhill, the impact coefficient of the rear axle is greater than that of the front axle, for another, in both uphill and downhill scenarios. The impact coefficient of the four-wheel-drive vehicle model is greater than that of the front-wheel-drive and rear-wheel-drive models for both the uphill and downhill scenarios.