Patent ID: 7273439

Claim:
A hybrid electric vehicle powertrain including an engine, a motor/generator and battery sub-system and a controller; the engine defining in part a mechanical power flow path to a driveshaft for a traction wheel-and-axle assembly; the sub-system defining in part an electro-mechanical power flow path to the traction wheel-and-axle assembly driveshaft whereby engine power is complemented by electrical power; the sub-system having an electric motor drivably connected to the driveshaft; the controller responding to a drive torque demand by determining engine power required to satisfy the driver demand for driver torque; the engine power determined by the controller being a function of actual motor speed and torque at motor speeds greater than a predetermined value; and the engine power determined by the controller being a function of a calibrated motor speed of non-zero value at actual motor speeds less than the predetermined value.