Method for localising knocking in internal combustion engines

Pressure sensors are placed in a plane of the cylinder head joint. At least one of the sensors is offset from the plane of the other sensors. Three sensors are used where the appearance of a noise source is in a known plane, otherwise four sensors are used. The method is applicable to a controlled ignition combustion engine and to Diesel engines to determine the location of an auto-ignition point. Method of locating a auto-ignition source rattle in an engines combustion chamber: (a) several pressure sensors are fitted in the combustion chamber; pressure waves received from the sensors are recorded; the pressure wave propagation speed is determined; the pressure wave arrival time shift between the noise source and the sensors is measured; the difference between the noise source and the different sensors is determined; the spatial location of the noise source in the chamber is deduced.