The Optimizing Clamping Force Control For Metal Pushing V-belt Continuously Variable Transmission Based On The Slipping

The metal pushing V-belt Continuously Variable Transmission(CVT) is an ideal transmission for vehicle. It can realize the optimum matching between the engine and the vehicle, so it can improve the vehicle's fuel economy and dynamic performance, and lower air pollution. The control for the metal pushing V-belt CVT including the clamping force control, the ratio control and the clutch control. The traditional clamping force control system set force as the control target, the clamping force was calculated according to the engine torque and the ratio. The fixed pump was propelled by the engine to supply oil for the secondary pulley, in order to prevent any slipping between the pulley and the metal belt the control system would multiply the safety margin to provide much clamping force, but this would increase the energy loss in the hydraulic system and mechanism, and lower the transmission's efficiency.This paper aims at proposing a new clamping force control method, the method allows a certain amount of slipping between the pulley and the metal belt. The slip value is estimated by the axial displacement of the primary movable pulley and compare with the optimization slip value. The fuzzy self-adaptive PID control method will be employed to control the slip, and restrict the slip in a certain range in order to realize the optimization control for the clamping force of the secondary pulley. Establish the simulation model based on the model CVT, the simulation results show that the new strategy will increase the friction coefficient between the pulley and the metal belt, lower the clamping force applied on the secondary pulley, reduce the energy loss and improve the efficiency of the transmission. The new clamping force control method will improve the vehicle's fuel economy and dynamic performance, and prompt the CVT's widely application on the vehicle.The paper is based on the"Continuously Variable Transmission (CVT) electronic and hydraulic control system research"project. It's one of the important research plans of Hunan province, the number is 05GK2007.