LOCK-UP CLUTCH CONTROLLER OF AUTOMATIC TRANSMISSION

PROBLEM TO BE SOLVED: To properly control the slipping amount of a lock-up clutch in lock-up clutch control performed when a vehicle in a deceleration state is re-accelerated.SOLUTION: When lock-up clutch command oil pressure which is instructed in accordance with the shift-up transmission control of an automatic transmission is learned, a reaching time from a shift control completion point of a time until a real slip ratio reaches a prescribed target value or a prescribed value close thereto is measured and the learned value of the command oil pressure is updated on the basis of the length of the reaching time. Original inertia phase control command pressure is corrected on the basis of the learned value and the control of the lock-up clutch accompanied by transition from the torque phase of shift control to an inertia phase is performed according to the corrected inertia phase control command pressure. Thereby, the slipping amount of the lock-up clutch upon shift-up under vehicle acceleration can be properly controlled and heat generation, the lowering of fuel efficiency, the generation of a shock and vibration or the like accompanied by the excessive generation of clutch slippage can be prevented.