Development of an electronically controlled four wheel drive system for FR vehicle with AT

Abstract

A high-performance electronically controlled four wheel drive system was developed for a Front engine Rear drive (FR) vehicle with automatic transmission. This system consists of a center differential (torque split ratio is front: rear = 30:70 ), a linear solenoid valve, a hydraulic multi-disk clutch and a hydraulic control circuit. By regulating the hydraulic pressure on the clutch, the driving force distribution can be continously varied to the optimum ratio for the running condition of the vehicle, which is determined by wheel speed, yaw velocity and the steering wheel angle.