Knock detecting apparatus for internal combustion engines

摘要

A knock detecting apparatus includes a vibrating means having a plate reed member adapted to vibrate in response to the vibrations of an internal combustion engine and a support member which is greater in thickness than the reed member and adapted to support the reed member, the reed and support members being made integrally from a magnetic material. When the reed member resonates upon the occurrence of knocking in the engine, the resulting change in the magnetic reluctance of the magnetic path including the reed member is sensed by a sensing coil to thereby detect the knock. The magnetic flux in the magnetic path is generated by a magnet or an excitation coil. An impedance element may be connected to the sensing coil or the excitation coil so as to correct variations in output from one coil to another.