Patent ID: 8332109

Claim:
Method for responding to a rapid change in engine torque in a powertrain comprising an engine, a transmission, a torque converter located between the engine and the transmission, and a torque converter clutch, the torque converter clutch being responsive to a torque converter clutch pressure command including a slip-based feedback control controlling a torque converter slip, the method comprising: monitoring a change in engine torque; monitoring engine speed; determining a rapid change in engine torque when the change in engine torque exceeds a threshold change in engine torque; subsequent to determining the rapid change in engine torque: providing an increase in the torque converter slip by reducing the torque converter clutch pressure command by a selected value and thereafter deactivating the feedback control for a predetermined duration; determining a local maximum engine speed based upon the monitoring the engine speed; and controlling the engine speed to the local maximum engine speed until the feedback control is reactivated; subsequent to the predetermined duration, reactivating the feedback control to decrease the torque converter slip toward a desired torque converter slip value; and reducing the engine speed to decrease the torque converter slip toward the desired torque converter slip value subsequent to feedback control being reactivated; wherein engine speed is reduced according to a desired slope.