Gm Global Technolgoy Operations, Inc.

David P Garrett

Paul Alan Bauerle

David S Mathews

Richard A Marsh

Anthony E Cubr

Michael J Vanek

An ignition timing control method for a vehicle which provides an engine torque output waveform for canceling vibrational disturbances caused by sudden throttle plate movement resulting in engine accelerations and decelerations. The ignition timing is variably advanced and retarded in accordance with a phase-shifted derivative of engine speed to produce an appropriate engine torque output waveform for optimally canceling the vehicle vibrational disturbances. The phase shift is accomplished by applying a time delay to the engine speed derivative. A negative bias is added to the ignition timing for retarding ignition timing by a predetermined amount to permit a full sinusoidal canceling waveform. A blend multiplier is utilized to gradually remove the effects of the canceling waveform and bias, thereby gradually returning the ignition timing to its original setting.

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Sylvan Lake, MI, United States of America

David P Garrett