US Patent 7722499 Launch control of a hybrid electric vehicle

A method for controlling a vehicle launch using a transmission having an input, a current gear, an input clutch associated with a target gear and an output, an engine and an electric machine for driving the input, includes the steps of using the engine and the first electric machine to drive the transmission input at a desired magnitude of torque, determining a desired magnitude of torque capacity of the input clutch, determining a crankshaft speed error, determining a magnitude of a change in torque capacity of the input clutch that will reduce the crankshaft speed error, and increasing the torque capacity of the input clutch to a desired torque capacity whose magnitude is determined by adding the current magnitude of torque capacity of the input clutch and said change in torque capacity of the input clutch.