Abstract
Keywords:
Misfire detection, Post-oscillation, Weighting factor
Abstract
This paper presents a misfire monitoring method by using the weighting factor. According to OBD II (On-Board Diagnostics) regulations of the CARB (California Air Resources Board), an ECU (Electrical Control Unit) should detect misfires which occur in the internal combustion engine. A misfire is followed by post-oscillations for short duration. Sometimes, the amplitude of oscillations may be as high as misfire and can be falsely detected as another misfire. To prevent this, the software designers do not attempt to detect another misfire for this short duration, during which the post oscillations exist. Because of this, ECU does not detect all the misfires and hence, the unstable state of automobile cannot be detected. If this happens for a long time, automobile may get damaged. To solve these problems, this paper suggests a new algorithm to detect misfire by using weighting factor. Weighting factor is a concept to distinguish the misfire with the post oscillation and to improve the detection rate. This value of weighting factor is used for counting the misfire. This paper also shows the result of experiment done on an automobile using this software. The software is implemented using ASCET-SD which is preferred in the design of engine control. The result shows the feasibility of improving the misfire detection by implementing this algorithm.