| 摘要 |
PURPOSE:To enhance knocking detecting preciseness, by detecting knocking by extracting a plurality of knocking characteristic frequency components while comparing the same with a predetermined reference level corresponding to the number of revolution of an engine. CONSTITUTION:A vibration pick-up 1 for detecting engine vibration is provided to an engine block and used as a sensor for extracting knocking. Band pass filters 6, 7, 8 each of which is synchronous to knocking characteristics frequency. That is, the band pass filter 6 is synchronous to base frequency of knocking while the band pass filter 7 to harmonics and the band pass filter 8 to harmonics. Detection parts 9, 10, 11 each of which carries out level detection while rectifying the output of each filter and a detection part 12 performs rectification while calculating the sum of each filter output. A numeral 13 shows the input terminal of an ignition timing signal from a destributor and, by this ignition timing signal engne revolution number information is obtained from a revolution number calculating circuit 14. |
