| 摘要 |
PURPOSE:To enlarge width of knocking detection signal and minimize attenuation time, by providing an air gap between a magnetic oscillator and a center magnetic path member, and also by allowing magnetic powder to be held in this air gap. CONSTITUTION:An oscillation occurring on a cylinder block is conducted to an oscillator 22 through a housing 21. In accordance with frequency and magnitude of this oscillation, and oscillating section of the oscillator 22 oscillates keeping pace with the knocking oscillation, and distance of a gap G between the oscillating section and the center magnetic path member 26 is varied in accordance with the knocking. As magnetic powder 30 is given to this gap G, it is possible to obtain a given value Q and attenuation time with simplicity and facility by changing volume of this powder 30. |
