Abstract: A method and device for detection of knocking in an internal combustion engine which can not only detect knocking but also an abnormal condition of a cooling liquid in a liquid cooled engine. The device detects the vibration or pressure fluctuations of the cooling liquid generated by both knocking and the operating of the coolant pump.

Abstract: A knocking detecting device for an internal combustion engine including: a casing in the form of an annular member fastened substantially perpendicularly to an outer sidewall of the engine block; a support member made of a vibration-isolating material such as rubber or synthetic resin, and having one end fastened to the casing and the other end projecting a predetermined distance from the outer sidewall of the engine block to a position within a water chamber or a coolant water passage; a pressure-sensitive member including pressure-sensitive surfaces mounted on the projecting end of the support member, facing away from each other and extending perpendicularly to the outer sidewall of the engine block, for detecting as a change in an electrical signal pressure vibrations transmitted as a knocking sound to the pressure-sensitive surfaces through coolant water from the partition when knocking is produced in the combustion chamber; and lead wires for delivering the electrical signal change responsive to the knoc