Gm Global Technolgoy Operations, Inc.

Saturn Corporation

William Joseph Bolander

Robert L Morris

Robert Charles Simon, Jr

Joseph M Tolkacz

Gary Arthur Nichols

Mark De Backer

Jeffrey R Drexel

Automotive internal combustion engine ignition timing control operations for varying timing of engine cylinder combustion chamber ignition events models the lead-lag combustion chamber temperature change profile under a transition from a first to a second engine operating condition and varies ignition timing following the transition in response to the temperature change profile. The lead-lag profile is implemented by applying a step change in ignition timing followed by a more gradual timing change, such as along a first order lag trajectory, toward a final ignition timing following the transition, and is updated in synchronism with engine cylinder events to account for a dependence on engine speed.

Ignition timing control

Control of engine speed responsive to a deviation in engine speed away from a target speed is applied selectively under closed-loop airflow control operating conditions, such as idle and coastdown operating conditions in response to analysis of a cause of an engine intake airflow deviation away from a modeled airflow. If airflow deviations are determined to have resulted from variation in internal engine friction away from a nominal friction level, the control is applied. If airflow deviations are determined to have resulted from change in internal engine airflow restriction, such as due to contaminant build-up over a period of engine use, then the control is not applied under closed-loop airflow control operating conditions to avoid overcompensating for such deviations.

Internal combustion engine control

Synchronization of relative engine angular position information is provided in the absence of an absolute engine position input signal by inducing misfires in a known engine cylinder and then monitoring misfire behavior over a test period. If significant misfire activity does not occur in an engine cylinder assumed, in accord with an assumed engine absolute position, to correspond to the known engine cylinder, then the assumed engine absolute position was not correct and is corrected through application of a position offset to the assumed position. Misfires are induced and the absolute position corrected when the engine is operating at a level assumed to be insensitive to the misfires and the correction.

Engine synchronization

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Ortonville, MI, United States of America

William Joseph Bolander