Knocking detector for IC engine - has digital frequency analyser supplied by vibration signals picked up from sensor for engine and=or cylinder internal pressure vibration

摘要

An a-d converter (28) picks-up the vibration signals produced by the sensor (1) at sequential intervals during the firing stroke of the I.C engine. A c.p.u. (25) processes the picked-up vibration signals for digital frequency analysis and to calculate the knock indices on the basis of the set main frequency components. The c.p.u. compares the largest calculated knock index with a preset threshold value provided by a background vibration level and a top level in order to detect the occurence of knocking. The engine vbibration pick-up block comprises an amplifier (26), a band-pass filter (27) and the a-d converter. The sensor (1), a crankshaft reference position sensor (2), air flow rate sensor (4). ADVANTAGE - High signal-to-noise ratio and sensitivity. Copes with heavy loads and high r.p.m. of engine.