Gm Global Technolgoy Operations, Inc.

Richard A Peden

Frank Ament

David P Sczomak

Pamela I Labuhn

Ronald Paul

James H Currie

Mark Alan Mitchell

John E Ausen

Michael J Brown

Closed-loop control of the quantity of diesel engine exhaust gas that is recirculated to an air intake of the engine responds to a degree of deviation of a sensed air inlet rate away from a desired air inlet rate. A series of dedicated adaptive correction values are selectively updated and stored in memory in response to the degree of deviation for corresponding engine operating ranges. Proportional and integral correction for air inlet rate deviations is thereby provided to an otherwise open-loop desired EGR quantity.

Closed-loop control of a diesel engine

The air/fuel ratio of the combustion mixture in the cylinders of an engine is sensed and the sensed air/fuel ratio is controlled to a predetermined scheduled air/fuel ratio by controlling the amount of exhaust gases recirculated. When the exhaust gas recirculated is substantially zero, the air/fuel ratio is thereafter closed loop adjusted to a predetermined scheduled minimum air/fuel ratio when the sensed air/fuel ratio is less than the minimum and when the sensed air/fuel ratio is greater than the minimum while the operator command is at a maximum to thereby provide precise fuel limiting at a predetermined fuel limit schedule.

Diesel engine closed loop air/fuel ratio control

A simulator for generating simulated crankshaft angle signals during rotation of an internal combustion engine for use as a backup to a sensor sensing the ring gear teeth is described. A number representing the time in terms of the pulses from a clock for the engine crankshaft to rotate through an angle equal to one-half the angular spacing of the teeth on the ring gear is determined based on the current engine speed. This number is continuously counted by a counter whose output comprises simulated crankshaft angle signals.

Engine crankshaft position sensor

A method of accurately determining the location of each cylinder top dead center position of an engine relative to a reference pulse whose location is not precisely known.

Engine top dead center locating method

The timing of the injection of fuel to the cylinders of a diesel engine is normally determined in accordance timing values obtained from an empirically derived steady state timing schedule but is modified during transient engine operation by an amount determined in accordance with the cylinder-to-cylinder change in requested fuel amount. In light to moderate engine acceleration, the steady state timing value is modified by a correction amount which serves to retard the start of injection for effecting a reduction in engine noise and exhaust emissions. In periods of heavy engine acceleration, the steady state timing value is modified by a correction amount which serves to advance the start of injection to improve the engine performance. When the cylinder-to-cylinder change in requested fuel quantity indicates a return to substantially steady state engine operation, the correction amount is reduced in relation to the correction amount magnitude and the cylinder firing frequency.

Transient injection timing control

A fuel control system for an internal combustion engine in which the idle fuel quantity is adjusted to maintain a predetermined desired idle speed and in which the transition between the idle fuel quantity and a scheduled off-idle fuel quantity is blended to provide for smooth engine operation.

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Livonia, MI, United States of America

Richard A Peden