Engine knocking meter

摘要

An engine knocking meter detects a pressure in a cylinder by a pressure sensor, clips a detected signal by a clipping circuit to cut low level noises, supplies an output signal of the clipping circuit to a filter circuit to eliminate noises having frequencies which lie beyond a frequency band of a knocking signal, and supplies an output signal of the filter circuit to a gate which is driven within a given crank angle under the control of a signal from a crank angle sensor mounted on a crank shaft of an engine, for separating the knocking signal.