Vehicle lock-up clutch control device

A lock-up clutch control device of a vehicle, the vehicle comprising an engine, a transmission and a torque converter provided with a lock-up clutch between the engine and the transmission,

• the lock-up clutch control device comprising a coasting capacity learning control section configured to:
• execute control processing of generating a command value for decreasing a lock-up engaging force of the lock-up clutch during accelerator release operation;
• and, when a slip of the lock-up clutch is detected during the decrease of the command value, update the command value at the time of detection of the slip as a lock-up learning value balanced with a coasting torque and update an engine torque value at the time of detection of the slip as an engine torque learning value balanced with coasting torque,
• wherein the coasting capacity learning control section is configured to:
• during the accelerator release operation, decrease the command value to a value obtained by adding a lock-up pressure reference offset value to the lock-up learning value in a coasting open-control state, and then, perform coasting capacity learning control to gradually decrease the command value;
• when an intervention of engine auxiliary equipment load takes place under the coasting capacity learning control, correct the command value by adding thereto a lock-up pressure correction value that corresponds to an increase of input torque to the lock-up clutch;
• and
• when the coasting capacity learning control is completed without detection of a slip of the lock-up clutch during the coasting capacity learning control where learning completion has not been experienced, permit the update of the lock-up learning value and the engine torque learning value on the conditions that:
• the lock-up learning value is lower than or equal to a current lock-up learning value;
• and the engine torque learning value is higher than or equal to a current engine torque learning value.