| 摘要 |
The output signal of a mechanical engine knock sensor is supplied to two similar treatment branches through different input filters, one, for the main signal, which passes frequencies at which engine knock signals are known to occur and for a reference signal by a filter which passes only frequencies likely to contain few or no components of knock signals. If both signals show a sharp of rise occurring at the same time or with less than a predetermined time offset, the peak value of each signal is stored and utilized to weight inversely the amplification of the signal value during the declining phase following the peak. It has been discovered that engine knock signals fall off more slowly from a peak than other motor noises. Consequently, when the weighted signals are compared and show a consistent difference exceeding a predetermined threshold, an engine knock detection signal is produced. |
