| 摘要 |
An engine knocking detection method and apparatus which can accurately separate engine knocking vibration signals from background noise signals on the basis of the waveforms of the detected engine vibration signals. Usually, engine knocking vibration signals have frequency components of from 6 to 9 KHz and envelope time constants of from 1.5 to 50 ms. Therefore, the engine knocking detection apparatus according to the present invention comprises a band-pass filter (6-9 KHz), a first smoothing circuit which outputs only engine vibration signals with envelope time constants of 1.5 ms or more and a second smoothing circuit which outputs only background noise signals with time constants of 50 ms or more, in addition to a vibration sensor, amplifiers, a rectifier, and a comparator.
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