TORQUE POINT LEARNING METHOD FOR CLUTCH

摘要

PROBLEM TO BE SOLVED: To prevent a learning error in learning a torque point for a wet multiple disc clutch. SOLUTION: A power transmission device for a vehicle has a fluid joint and a wet friction clutch provided in series on a midway between an engine and a transmission for changing an operating fluid pressure to be supplied to the wet friction clutch with a duty pulse to be output from an ECU and thereby controlling the disconnected condition of the clutch. When the torque point for serving first transmission of predetermined torque during the transition of the clutch from the disconnected condition to a connected condition is learned by the ECU, the clutch is put in gradual contact therewith while detecting an input-side rotating speed Nt of the clutch and an engine speed Ne, and when the input-side rotating speed Nt of the clutch falls a preset rotating speed Nm down in terms of the engine speed Ne in this process, a value Dm for a duty ratio at this time is learned as the torque point. The learning is performed after a preset timeΔt1 passes since detecting the fall-down of the rotating speed.