Misfire Detection of Spark Ignition Engines Using a New Technique Based on Mean Output Power

Abstract

Control and detection of misfire are an essential part of onboard diagnosis (OBD) of modern spark ignition (SI) engines. This study proposes a novel modelbased technique for misfire detection for a multicylinder SI engine. The new technique uses a dynamic engine model to determine mean output power, which is then used to calculate a new parameter for misfire detection. The new parameter directly relates to combustion period and is sensitive to engine speed fluctuations caused by misfire. The new technique requires only measured engine speed data and is computationally viable for use in a typical engine control unit (ECU). The new technique is evaluated experimentally on a fourcylinder 1.6l SI engine. Three types of misfire are studied including single, continuous, and multipleevent. The steadystate and transient experiments were done for a wide range of engine speeds and engine loads, using a vehicle chassis dynamometer and onroad vehicle testing. The validation results show that the new technique is able to detect all three types of misfire with up to 94% accuracy during steadystate conditions. The new technique is augmented with a compensation factor to improve the accuracy of the technique for transient operations. The resulting technique is shown to be capable of detecting misfire during both transient and steadystate engine conditions.