| abstract |
In an adaptive shift control system for regulating the operation of a fluid-operated torque-establishing device (28, 30, 32, 34) associated with a specified speed ratio in a motor vehicle automatic transmission (10), shifting from a currently engaged speed ratio to the specified speed ratio includes a completion phase during which fluid is supplied to the torque-establishing device (28, 30, 32, 34) in accordance with a predetermined pressure schedule to initiate and progressively increase the transmission of torque therethrough. The time required to complete a specified portion of the speed ratio progression is identified and compared with a reference time representative of the time required to complete the progression when the shift quality is not degraded. The predetermined pressure schedule is adjusted based on such comparison so as to adaptively compensate for sources of error which affect the increase of torque transmission through the torque-establishing device (28, 30, 32, 34) during the completion phase and cause the shift quality to be degraded. |