CREEP TORQUE AND LOCK-UP CONTROL FOR AUTOMATIC TRANSMISSION

摘要

A control device for an automatic transmission comprises an electromagnetic valve that is subject to pulse duty factor control and generates an adjustment pressure variable in a first pattern after a rod of a shift operation mechanism has moved into an overstroke range beyond a maximum reduction ratio position. The adjustment pressure is variable in a second pattern when the rod fails to move into the overstroke range. An adjustment pressure change-over valve is formed integral with the rod and applies the adjustment pressure to a servo actuating pressure regulator valve (i.e., a throttle valve) when the motor vehicle is at a standstill and the engine idles so as to effect a creep torque control. When the motor vehicle starts moving at a speed above a certain vehicle speed, the adjustment pressure change-over valve applies the adjustment pressure to a lock-up control valve, thereby to effect a lock-up control.