| 摘要 |
PROBLEM TO BE SOLVED: To control the transmission torque capacity of a release side frictional engagement element in the initial period of gear shift with high accuracy in an automatic transmission capable of switching the frictional engagement elements for simultaneously executing the fastening control and the releasing control of the different frictional engagement elements. SOLUTION: The critical transmission torque capacity is determined on the basis of a ratio of the input shaft torque and the critical torque, the critical transmission torque capacity is corrected with the margin to be reduced in accompany with a lapse of time to determine the transmission torque capacity at release side, and the engagement oil pressure at release side is gradually reduced on the basis of the transmission torque capacity. The control for the reduction of the transmission torque capacity is temporarily stopped in a state that the transmission torque capacity at a time when a gear ratio of a transmission mechanism starts its change, is regarded as a value corresponding to the critical transmission torque capacity, and the release side oil pressure is reduced to 0 while waiting the increase of the transmission torque capacity of the fastening side frictional engagement element. |
