Patent ID: 7361120

Claim:
A lock-up clutch control device which controls a lock-up clutch provided in a torque converter interposed between an engine and a transmission used with a vehicle, comprising: a differential pressure generating device which engages, causes a slip of or disengages the lock-up clutch by adjusting the differential pressure supplied to the lock-up clutch, a vehicle speed sensor which detects a vehicle speed, a throttle valve opening sensor which detects an opening of a throttle valve which adjusts an air flowrate supplied to the engine, an input shaft rotation speed sensor which detects an input shaft rotation speed of the transmission, torque detection means which detects an engine torque of the engine, and a controller programmed to: determine, based on the detected vehicle speed and the detected throttle valve opening, whether or not a control region of a torque converter is a converter region wherein control is performed to disengage the lock-up clutch, when the control region of the torque converter is not the converter region, determine whether or not the control region of the torque converter is a first slip control region, based on the detected vehicle speed, when the control region of the torque converter is not the converter region, determine whether or not the control region of the torque converter is a second slip control region wherein control is performed to make the lock-up clutch slip, based on the detected input shaft rotation speed of the transmission and the detection engine torque, when the torque converter is in the first slip control region, and the second slip control region, command the differential pressure generating device to cause a slip of the lock-up clutch.