Modeling and Simulation of Continuously Variable Transmission for Passenger Car

Abstract

In order to implement the demand of minimum fuel consumption and good power performance for continuously variable transmission (CVT) car, aiming at the whole vehicle model including the engine, the clutch, the CVT and load, the dynamics model of CVT system is established according to different stage of clutch engaging, based on that the dynamic integrated simulation model is developed. Aiming at the running situation of car being complex and variable frequently and the input and output of transmission system being strong coupling, a PD speed ratio controller of self-adjusting parameter and a clutch torque fuzzy controller are devised respectively. Finally three typical running situations are simulated and analyzed, including starting-accelerating, starting-decelerating and encountering resistance disturbance. The steady car speeds of three simulation situations are 109.40 Km/h, 39.93 Km/h and 74.48 Km/h respectively, on the other hand, the theoretical values of that are 109.97 Km/h,39.90 Km/h and 74.49 Km/h respectively. The dynamical curves of simulation demonstrates that the simulation model established is correct, the controllers devised have good control effect and implement reasonable match between engine and CVT.