Gm Global Technolgoy Operations, Inc.

LeRoy E Medendorp

Kenneth J Buslepp

Kenneth J Cinpinski

James H Currie

Alan F Chiesa

Edward J Jensen

John F Schweikert

Douglas K Mehaffey

Edward C Perry

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 system is described for diagnosing the operation of an exhaust gas recirculation system of an internal combustion engine having a speed density fuel delivery system and having a closed loop fuel adjustment. The EGR system operation is determined by disabling the EGR system and observing the magnitude of change of the integral adjustment of the closed loop system.

EGR diagnostic system

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Romeo, MI, United States of America

LeRoy E Medendorp