Patent ID: 7264570

Claim:
A method of establishing a reserve of electric motor torque in a vehicle powertrain system comprising a plurality of electric motors and a transmission, each of the plurality of electric motors operably and selectively coupled to the transmission through a corresponding plurality of coupling means and adapted to provide an output torque contribution thereto, each electric motor having a predetermined maximum motor output torque and a predetermined minimum motor output torque which are used to determine a range of permissible control points for at least one transmission control parameter, comprising, for each of the electric motors, the steps of: determining a static maximum torque reserve value; determining a static minimum torque reserve value calculating a dynamic maximum torque reserve value; calculating a dynamic minimum torque reserve value; calculating a maximum reserved motor output torque using the predetermined maximum motor output torque, the static maximum torque reserve value and the dynamic maximum torque reserve value; and calculating a minimum reserved motor output torque using the predetermined minimum motor output torque, the static minimum torque reserve value and the dynamic minimum torque reserve value.