New Effective Time Domain Method for Knock Signal Denoising in Internal Combustion Engine

New Effective Time Domain Method for Knock Signal Denoising in Internal Combustion Engine

uncontrolled expansion of combustion wave in spark ignited internal combustion engine causes knock effect which seriously degrade efficiency and lifetimes of the engine. Thus, accurate knock detection and control are essential for obtaining desired performance from the engine. Usually, knock sensor is used to detect this phenomenon but it has limited accuracy especially at high engine speeds because of natural vibration and external noises. In this study an effective method based on Non-Local Mean (NLM) algorithm has been proposed to improve the knock detection accuracy. This method is evaluated based on four different indicators and four engine cylinders. The results show 32% improvement in knock detection. Also feasibility of real time execution of this method based on embedded hardware has been studied.