Gm Global Technolgoy Operations, Inc.

Edward J Jensen

Kenneth J Buslepp

Kenneth J Cinpinski

James H Currie

LeRoy E Medendorp

Douglas K Mehaffey

An ignition timing control for an internal combustion engine subjects a combustion pressure signal to multiple switched capacitor bandpass filters with frequencies controlled in phase lock loop from engine speed to generate harmonic wave signals at frequencies which are constant multiples of the varying firing frequency. The phase difference between the peaks of two harmonics such as the second and fourth is used to control ignition timing to a phase difference of zero, in some cases with ignition pulses referenced to the detected peak of the first harmonic (fundamental) rather than a detected crankshaft position. The ratio of peak amplitudes between two harmonics such as the first and fourth is used to control dilution by EGR or variable valve lift to a predetermined ratio and may also be used to retard ignition timing from the normal timing to reduce knock. The ratio of the peak amplitude of subharmonics to the fundamental may be used as a roughness or driveability sensor.

Engine ignition timing with knock control by combustion pressure

A dilution control adjusts an EGR valve, variable valve lift mechanism or similar dilution control device in an internal combustion engine in response to the relationship between ignition timing and the timing of peak combustion pressure (LPP) in the vicinity of a desired timing of peak combustion pressure (DLPP). The relationship is derived in the process of controlling ignition timing in response to LPP, wherein LPP is controlled to DLPP or as close to it as possible. In this process, LPP varies slightly back and forth through DLPP or through a maximum retard value, if LPP is not attainable. The apparatus detects whether LPP is retarded with respect to DLPP as it reverses from retard to advance, increases dilution if it is so retarded and decreases dilution if it is not. The engine thus operates with maximum EGR consistent with LPP being equal to the desired value DLPP.

Adaptive dilution control for IC engine responsive to LPP

A charge dilution control for an internal combustion engine subjects a combustion pressure signal to multiple switched capacitor bandpass filters with frequencies controlled in phase lock loop from engine speed to generate harmonic wave signals at frequencies which are constant multiples of the varying firing frequency. The amplitude ratio between the peaks of two harmonics, with one preferably the fundamental firing frequency, is used to control charge dilution apparatus such as EGR or variable valve lift to maintain a predetermined ratio. The harmonic compared to the fundamental may be a higher harmonic or a subharmonic. Ignition timing for the engine may be controlled to maintain a phase difference of zero between two of the higher harmonics such as the second and fourth.

Engine dilution control by combustion pressure harmonic amplitude ratio

An ignition timing control for an internal combustion engine subjects a combustion pressure signal to multiple switched capacitor bandpass filters with frequencies controlled in phase lock loop from engine speed to generate harmonic wave signals at frequencies which are constant multiples of the varying firing frequency. The phase difference between the peaks of two harmonics such as the second and fourth is used to control ignition timing to a phase difference of zero, in some cases with ignition pulses referenced to the detected peak of the first harmonic (fundamental) rather than a detected crankshaft position. The ratio of peak amplitudes between two harmonics such as the first and fourth is used to control dilution by EGR or variable valve lift to a predetermined ratio. The ratio of the peak amplitude of subharmonics to the fundamental may be used as a roughness or driveability sensor.

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Rochester, MI, United States of America

Edward J Jensen