PURPOSE:To eliminate noise and prevent a detection circuit from making erroneous operation in a captioned device to detect knocking and control the ignition timing, by providing a circuit for cutting ignition noise in a short detection circuit of a knock sensor. CONSTITUTION:In a short amplifier of an abnormality detection circuit ABD, the collector of a transistor T25 is connected to a part of connection between a resistance R28 which determines the time constant for charging a condenser C8 and a rectifying diode D18, and this transistor T25 is put on synchronously with a master timing NM for deleting the output from an operation amplifier OP6 and cutting ignition noise. At this stage, a condenser C26 is inserted between the base and the emission of the transistor T25, and the operaion of the transistor T25 is delayed from the master timing by 1msec for eliminating noise effectively.
展开▼
