Knock Detection by Means of the Spark Plug
Nick Collings, Steve Dinsdale, Derek Eade · SAE technical papers on CD-ROM/SAE technical paper series · 1986
This paper describes a system for knock detection in automobile engines using the spark plug. Operation is based on detection of the effect of the characteristic pressure fluctuations in the cylinder on the conductivity of the slightly ionized combustion gases in the vicinity of the plug gap. A signal processing method is described which gives adequate signal to noise ratio up to high engine speed.