Slip control system for lock-up clutch of a torque converter

摘要

A controller of a slip control system of a torque converter with a lock-up clutch is configured to carry out calculating a target slip rotation speed of the converter based on a vehicle speed and an open degree of a throttle valve; calculating a running condition of the vehicle, which includes drive and coast conditions, based on the operation condition of the throttle valve; calculating a torque converter characteristic with reference to a speed of a turbine of the converter and the running condition of the vehicle; calculating a target converter torque based on the torque converter characteristic; calculating a target lock-up clutch engaging torque based on the target converter torque and an engine torque; and outputting an instruction signal to an actuator to provide the lock-up clutch with the target lock-up clutch engaging torque. The torque converter characteristic is represented by two groups of maps, one being for the drive running condition and other being for the coast running condition.