To appropriately learn timing of switching fom pressure increase control to feedback control of a lock-up clutch so that learning accuracy is not lowered even if transmitted torque is significantly fluctuated in a predetermined time before and after a lock-up command.
When a vehicle speed exceeds a lock-up ON vehicle speed, the transmitted torque of the lock-up clutch is computed, the pressure increase control for increasing the connecting pressure of the lock-up clutch is executed, and after the pressure increase control, the feedback control is executed. The maximum value and the amplitude of the transmitted torque in a predetermined time period before and after the lock-up command are computed and the time at which the transmitted torque in the pressure increase control exceeds the maximum value by a predetermined value is set as the timing of switching the mode from the pressure increase control to the feedback control. A time period from the lock-up command to the switching timing is computed to learn the time, thereby correcting the hydraulic pressure of the pressure increase control. According to gain characteristics in which the larger the amplitude of the transmitted torque becomes, the smaller the learning gain becomes, the learning gain conforming to the amplitude is determined and learning corrections are executed using the gain.
KISHI DAISUKE
HATAUCHI SHINYA
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