Patent ID: 8137236

Claim:
In a powertrain for motor vehicle that includes an engine, an electric machine able to function alternately as a motor and a generator, a transmission having an input driveably connected to the engine and a transmission output driveably connected to the electric machine, and a powertrain output driveably connected to the electric machine and wheels of the vehicle, a method for controlling torque during an upshift comprising the steps of: (a) using the engine to produce torque that is transmitted to the powertrain output through the transmission; (b) determining whether a battery state of charge is less than a reference maximum state of charge; (c) if the battery state of charge is less than the reference maximum state of charge, operating the electric machine as a generator to reduce the torque transmitted to the powertrain output during a ratio change phase of the upshift; and (d) if the battery state of charge is equal to or greater than the reference maximum state of charge, discontinuing use of the electric machine.