Modeling and simulation of hydraulic control system for vehicle continuously variable transmission

Continuously variable transmission (CVT) is an advanced transmission device. The metal V-belt type CVT introduced in this paper is a mechano-hydraulic servo system, which can realize auto optimum power matching control continuously. In this paper, the structure and operating principle of the metal V-belt type CVT were introduced. The relations between the rotating speed of the engine and the running speed of the vehicle were analyzed. The mathematical model of the system was established in the style of state equation using bond graph method. The hydraulic control system of the metal V-belt type CVT was simulated. It was found that, the metal V-belt type CVT makes the vehicle's velocity respond to changes of external environment rapidly and excellently, and then changes the vehicle's speed ratio continuously. The study of this project provides academic bases for further studying on dynamic characteristics of continuously variable transmission and vehicle.