Method for active engine stop of a hybrid electric vehicle

A method for providing an active engine stop of the engine of a hybrid electric vehicle. The method utilizes the electric machine to oppose and rapidly stop the rotation of the engine at a controlled rate. The method includes the calculation of an input speed reduction trajectory using the engine speed when the active engine stop request is made and a predetermined speed reduction interval. The speed reduction interval is less than a time from the active stop request to the shutoff command to the electric machine The method provides rapid deceleration of the engine, particularly through the powertrain resonance speed, reducing the amount of vibration energy dissipated through the powertrain and chassis. The method removes the electric machine torques from the engine prior to achieving zero engine speed in order to avoid imparting a negative engine speed or counter-rotation of the engine.