SYSTEM AND METHOD OF EXECUTING A DOUBLE TRANSITION SHIFT IN A TRANSMISSION WITH TRANSITIONING CLUTCH HAVING OPPOSITE CLUTCH SLIP AND TORQUE CARRYING DIRECTIONS

摘要

A method of executing a double transition shift in a transmission includes determining via a controller that one of four clutches involved in the shift has a clutch slip direction relative to input member rotation direction in one of the current gear and the commanded gear and an opposite clutch torque direction relative to input member torque direction in the other of the current gear and the commanded gear. The controller then calculates clutch torques for at least some of the offgoing clutches and at least some of the oncoming clutches, and controls torque at the offgoing clutches and the oncoming clutches during the shift according to the calculated clutch torques to ensure that the clutch with the opposite slip and torque directions does not provide reaction torque during the shift unless clutch slip across said one of the four clutches is zero or in the clutch torque direction.

主权项

1. A method of executing a double transition shift in a transmission having a plurality of selectively engageable clutches engageable in different combinations to establish multiple different gears with gear ratios of torque of an output member to torque of an input member, the method comprising:
receiving a command for a double transmission shift from a current gear to a commanded gear; wherein the double transition shift requires at least four clutches including a first offgoing clutch and a second offgoing clutch that are engaged in the current gear and not engaged in the commanded gear, and a first oncoming clutch and a second oncoming clutch that are not engaged in the current gear and are engaged in the commanded gear; determining via a controller that one of the four clutches has a clutch slip direction relative to input member rotation direction in one of the current gear and the commanded gear and an opposite clutch torque direction relative to input member torque direction in the other of the current gear and the commanded gear; calculating clutch torques for at least some of the offgoing clutches and at least some of the oncoming clutches; and controlling torque at the offgoing clutches and the oncoming clutches during the shift according to said calculated clutch torques to ensure that said one of the four clutches does not provide reaction torque during the shift unless slip across said one of the four clutches is zero or in the clutch torque direction relative to input member torque direction in the other of the current gear and the commanded gear.