Dynamic Modeling And Performance Simulation Of Car Equipped With Metal Pushing V-belt Type CVT

As the ideal transmission mode for vehicle, metal V-belt type continuously variable transmission (CVT) has been used in the car, it has the feature of simple compaction, convenience operation and good performance, and it has extensive develop foreground and market space, but it is still in research and exploit stage in domestic area. In this thesis, theoretical and emulational researches of transmission mechanism and control strategy of CVT system have been carried out profoundly, and the main contents are as follows:The assorting, structure, control technology and work principle of the metal V-belt type CVT are analyzed. The enduring force 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 equilibrium relationship of oil pressure of active cylinder and that of passive cylinder under different speed ratio and load condition is established.Based on experimental data of engine, torque and oil consumption model of engine are established by method of spline interpolation. The optimum economy and power operation line of engine are obtained. To implement optimal economy and power performance of automobile the optimal matching and control strategy between engine and CVT system is discussed, the affection of speed ratio changing rate to accelerating and smooth performance of passenger car is discussed.From the view of integrated fuzzy control, practical starting control strategy of car equipped with CVT is proposed, the clutch fuzzy controller during vehicle starting is devised and simulated.The dynamic model of the transmission system including the engine, the clutch, the CVT and load is established, and based on the mathematical model, the integrated dynamic simulation system is developed by use of Matlab/Simulink software. The oil fuzzy controller and the parameter self-adjusting ratio fuzzy logical controller are devised, finally, based on the simulation model and the control algorithm, four typical operation conditions of the car are simulated. The simulation result indicates that the self-adjusting ratio fuzzy logical controller can obviously improve the economic, smooth and dynamic of car better than conventional proportion and differential controller, the integrated control algorithm has good control effect, moreover it is easy to be implemented by programming and has good value of utility.