| 摘要 |
PROBLEM TO BE SOLVED: To detect occurrence of knocking with high accuracy using vibration analysis by a frequency conversion means such as an FFT. SOLUTION: Window FFT is performed with respect to a combustion pressure waveform to calculate oscillation strength FFTi of combustion pressure (=Pcyl) in each window. The maximum window (=w2) out of the calculated FFTi is identified, and an analysis period is set so that the timing corresponding to the window is set as start timing. The length of the analysis period is set depending on engine speed. The higher the engine speed is, longer the overlap of the window becomes. COPYRIGHT: (C)2005,JPO&NCIPI |
