Research On Integrated Fuzzy Control Of Continuously Variable Transmission For Passenger Car

Continuously variable transmission (CVT) technology has revolutionary significance in development history of automobile transmission. In recent years, more and more countries begin to adopt CVT as automatic speed-adjusting device of automobile. CVT will hold a dominant status in the future of transmission development. Metal pushing V-belt type continuously variable transmission (CVT) has obvious technology predominance comparing with other transmission. It can realize the optimum matching between engine and load, and can improve fuel economy performance remarkably. CVT is an ideal transmission mode for vehicle, and it can increase power performance and stabilization of vehicle. However, control strategy of CVT's control system is still one difficulty, and now it is not mature completely in theory, as well as in practice. In this dissertation, theoretical and emulational experiment researches of transmission mechanism and control strategy of CVT system have been carried out profoundly under the project (2003BA435C) financed by National Science & Technology Project foundation. The researches in this dissertation have both important theoretical significance and engineering value.The development history and current technology status of Metal pushing V-belt type CVT about domestic and overseas are reviewed in this dissertation. The structure and work principle of the metal pushing V-belt type CVT are analyzed. Aim at the special structure of Metal pushing V-belt type, the under stress instance of metal V-belt and the relation between speed ratio and work radius of belt pulley are studied. The calculating formula for clamping force of belt pulley is given, based on that, the relation between oil pressure of pulley cylinder and input torque is obtained. The mathematic modle of oil pressure equilibrium of active cylinder and passive cylinder under different speed ratio and load condition is established. For the importance of speed ratio changing rate in CVT control, the affection of speed ratio changing rate to accelerating and smooth performance of passenger car is discussed.