Slip control system for torque converter of automatic transmission

Abstract

A slip control system for a torque converter of an automatic transmission includes lock-up clutch device provided in a torque converter for connecting an input and output members of the torque converter directly. A torque detecting device detects a transmitted torque introduced into the output member of the torque converter, a speed difference setting device sets a target value of a rotation speed difference between the input and output members, a pressure difference control device controls a pressure difference between a releasing chamber and an engaging chamber of the lock-up clutch device, based on a predetermined relationship between the input torque and the speed difference so as to accomplish the target value of the speed difference, and a speed difference detecting device detects an actual speed difference between the input and output members. In a preferred embodiment of the invention, a compensatng device compensates the target value of the speed difference set by the speed difference setting device based on a deviation between the actual and target speed difference. A responsive slip control, therefore, can be accomplished.