| 摘要 |
PURPOSE:To identify a background noise and a knocking signal more clearly by making a detective level of the knocking signal higher to prevent a malfunction at high speed running of an engine when the engine runs over a certain r.p.m. CONSTITUTION:Vibration of an engine is converted into electric signals by a knock sensor A1. A band pass filter A2 identifies knocking frequency in the electric signals and sends an output to an amplifier A3 for amplification. A voltage in proportion to a background noise involved in the output is taken out from it and compared with an output voltage of the amplifier A3 by a comparator A5. It outputs a knock signal when the result exceeds a certain value. Based on the signal, an ignition control B controls an ignition timing so as to be delayed from an ignition timing executed at a knocking and a comparison knock signal detective level of said comparator A5 is made higher when an output of an engine speed detector A10 rises over a specific value. |
