Knock detecting apparatus for combustion engines

摘要

A knock detecting apparatus for an internal combustion engine includes a vibrating sheet branched into a plurality of vibrating reeds by forming a recess from one end of the vibrating sheet. The vibrating reeds have different lengths, shapes or thicknesses, and the other end of the vibrating sheet is fixed to a supporting member which is secured to the engine thereby to allow the vibrating reeds vibrate with different resonance characteristics in response to the vibration of the engine caused by the knocking. The vibration of the vibrating sheet is detected, for examle, as a change in reluctance by forming a magnetic path through the vibrating sheet and air gaps respectively located between the free ends of the vibrating reeds and a core.