イオン電流を用いた時間-周波数解析によるノッキング検出

概要

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It is well Known that the conventional method to detect presence and strength of the knocking by the ion current using the band pass filter is effective up to now. However, as compression ratio increases, there is a stationary wave in the ion current waveform and its frequency components and amplitude of the waveform are almost same as that of the knocking. Therefore the distinction of knocking and the standing wave becomes difficult by the conventional detection method. In this study, a new knocking detection technique which based on the difference of time-frequency properties of knocking and the standing wave was proposed. It first constitutes two band-pass complex real-signal mother wavelets (BC-RMW), and then thereby takes out the knocking ingredient and detects a change share of the wavelet coefficient of the knocking by using them. Furthermore, the proposed method was applied to the distinction of knocking and the standing wave and its effectiveness was inspected.