Cummins Engine Company, Inc.

Cummins Inc.

Eric B Andrews

Mark R Stepper

Axel Otto Zur Loye

Steve J Willis

A system and method in which the exhaust manifold pressure is measured by a single gauge-type pressure sensor positioned in the exhaust manifold to detect misfires in all cylinders of an internal combustion engine. The pressure sensor detects the exhaust manifold pressure and feeds a signal to a microcomputer via an analog-to-digital converter. A data processing device monitors the pressure waveform created by the data from the sensor to determine if a full or partial misfire occurs. If a cylinder suffers from a partial or complete misfire, the strength of the pressure pulse for that cylinder will be reduced, thus, allowing the data processing device to identify the misfire. The data processing device may determine a misfire by computing an average peak pressure for each combustion cycle, a pressure threshold as a function of engine speed and fuel consumption rate, and a minimum pressure value based on the difference between the average peak pressure and the pressure threshold. The data processing device may alternatively determine a misfire by first computing a coefficient of variation between an observed pressure pulse and the average peak pressure and then comparing the coefficient of variation with a pressure threshold to determine if at least a partial misfire has occurred.

System and method for detecting engine cylinder misfire

An engine misfire detection system for an internal combustion engine includes a microprocessor based controller for providing an increasing fuel command signal to any cylinder in the engine. The contribution to engine speed of the particular cylinder under test is monitored and compared to the contribution to engine speed of the previous two cylinders in the firing sequence. A misfire condition is detected if the average contribution to engine speed of the cylinder under test does not exceed the greater average contribution to engine speed of the previous two cylinders by a predetermined amount after a predetermined number of engine cycles. A temporary fault is logged for the cylinder under test if such a misfire condition occurs a predetermined subsequent number of times thereafter. If such a temporary fault condition is detected during a subsequent driving cycle, a driver warning lamp is illuminated.

Active engine misfire detection system

An air intake heating and diagnostic system for an internal combustion engine includes a microprocessor based controller for activating electrical heating elements for a preheat time period prior to starting the engine and for a postheat time period after starting the engine. The controller receives inputs corresponding to intake manifold air temperature, battery temperature, vehicle speed, engine speed, and key switch position. The system continuously monitors the integrity of the various sensors, monitors the functionality of the heating elements during the postheat time period, and warns the vehicle operator by illuminating a 'check engine' lamp if certain fault conditions are detected. In both cases, the controller sets fault flags within the controller memory corresponding to the detected fault conditions.

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Columbus, IN, United States of America

Eric B Andrews