CLUTCH-TO-CLUTCH POWER-ON DOWNSHIFTING IN A MOTOR VEHICLE AUTOMATIC TRANSMISSION

摘要

CLUTCH-TO-CLUTCH POWER-ON DOWNSHIFTINGIN A MOTOR VEHICLE AUTOMATIC TRANSMISSIONAbstract of the DisclosureA clutch-to-clutch power-on downshift in amotor vehicle automatic transmission is effected byreducing the torque capacity of the off-going clutchingdevice to permit the transmission input speed toincrease toward a target speed which it will finallyattain subsequent to the shift; increasing the torquecapacity of the off-going clutching device andpreparing the on-coming clutching device when the inputspeed approaches its target speed so that the inputspeed is held near the target speed by the time theon-coming clutching device is prepared to transmittorque; and concurrently applying and releasing theon-coming and off-going clutching device to completethe shift. Since the input speed is substantially atits target value when the exchange of clutching devicesoccurs, a high quality shift with minimal drivelinetorque disruption results.