Image Number 3 for United States Patent #6453864.
A method of controlling engine crankshaft motion in a hybrid electric drive system having an internal combustion engine and a motor-generator operatively connected to a crankshaft of the engine is disclosed. The steps include monitoring the crankshaft position, forecasting a crankshaft stall position; comparing the forecast stall position with a target range; and if the forecast crankshaft stall position is outside the target range, operating the motor-generator to modify the forecast stall position to be within the target range. These steps properly position the crankshaft for re-initiating engine start-up. The method further includes the steps of calculating an effective lube interval time once the crankshaft speed is zero; comparing the effective lube interval time to a critical time; and if the effective lube interval time is greater than the critical time, pulsing the motor-generator to rock the crankshaft for a pulse time to redistribute a lubricant film.