Device for detecting the knocking phenomenon in controlled-ignition internal combustion engines, based on the use of ionization probes

A device for detecting the knocking phenomenon in a controlled-ignition internal combustion engine equipped with an ignition system for effecting electrical discharge to spark plugs of said engine with a preselected basic adjustment of ignition advance relative to the upper dead center of the various engine pistons, said device being capable of detecting the possible occurrence of the knocking phenomenon in the explosion chamber of at least one of the engine cylinders, said device comprising at least two ionization probes both arranged in said chamber in a zone generally the farthest from the spark plug where the incipient knocking phenomenon normally occurs, said two probes being furthermore positioned comparatively apart from one another essentially along the direction of propagation of a flame front from the associated spark plug, and further comprising an electronic circuit which receives signals coming from said two probes, said circuit including means for detecting the time interval existing between the two signals and for comparing said time interval with a threshold interval to assess if the detected time interval is longer than the threshold interval, to discriminate if the combustion is regular or is not due to the occurrence of knocking phenomena.