Patent ID: 7351183
Filing Date: 2008-04-01
Classification: F16H,Y10T

Abstract:
1. A synchronous gear ratio shift control for a multiple-ratio automatic transmission in a powertrain for an automotive vehicle, the transmission including gearing defining multiple torque flow paths from a transmission input torque source to a transmission torque output member and first and second torque establishing elements for selectively establishing, respectively, a gear configuration with a low speed ratio and a gear configuration with a higher speed ratio during a ratio upshift event; a synchronous ratio upshift event being characterized by a preparatory phase followed by a torque phase; means for maintaining torque capacity of the first torque establishing element against slippage during the preparatory phase and releasing torque capacity of the first torque establishing element during the torque phase; means for increasing torque capacity of the second torque establishing element during the preparatory phase and the torque phase; the torque phase being followed by an inertia phase; means for increasing transmission input torque prior to the inertia phase; and means for reducing transmission input torque during the inertia phase; the synchronous ratio upshift event being completed following the inertia phase by restoring torque from the torque source; torque capacity of the second torque establishing element being increased at a first rate during the preparatory phase and at a second rate during the torque phase as the torque capacity of the first torque establishing element is decreased during the torque phase until the first torque establishing element begins to slip.