Patent ID: 8597158

Claim:
Method to execute a shift in a powertrain comprising a plurality of torque generative devices comprising an engine and an electric motor rotatably connected through a first clutch, the method comprising: operating the powertrain in a continuously variable operating range state; monitoring a command to execute the shift comprising: monitoring a target speed for the electric motor; and monitoring a command to disengage the first clutch; and shifting the first clutch from an engaged state to a disengaged state, comprising: operating a torque phase of the first clutch wherein the first clutch is transitioned from the engaged state to the disengaged state including reducing clamping force between plates of the first clutch while maintaining the first clutch in synchronous operation; simultaneous with the torque phase, operating an inertia speed phase of the first clutch wherein a speed of the electric motor is transitioned from an initial speed to the target speed; and ending operating in the torque phase and continuing operating in the inertia speed phase to transition the electric motor to the target speed; wherein shifting the first clutch further comprises controlling a torque transmitted through the first clutch to exceed a maximum clutch torque capacity for the clutch at the end of the torque phase.