Detection of internal combustion engine knock using time-frequency distributions

Detection methods employed in current knock control systems for spark ignition engines use a measurement of engine block vibration tuned to one or more resonance frequencies to extract knock-related information from the engine structural vibration. These techniques suffer from poor signal-to-noise ratio at high engine speed, due to background vibration. This paper presents an improved knock detection scheme capable of tracking variations in the knock resonance frequencies. Experimental results obtained on a single-cylinder research engine confirm the validity of the method