Method and apparatus for measuring knock

Claim 1

AN APPARATUS FOR MEASURING KNOCK IN A SPARK-IGNITION INTERNAL COMBUSTION ENGINE WHICH INCLUDES DETECTING MEANS LOCATED EXTERNALLY OF SAID ENGINE, SAID DETECTING MEANS BEING RESPONSIVE TO THE SOUND ORIGINATING WITHIN SAID ENGINE AND HAVING AN OUTPUT CIRCUIT GENERATING A SIGNAL CORRESPONDING IN FREQUENCY AND AMPLITUDE TO SAID SOUNDS, FILTERING MEANS TO WHICH THE OUTPUT CIRCUIT OF SAID DETECTING MEANS IS CONNECTED AS AN INPUT, SAID FILTERING MEANS HAVING AN OUTPUT CIRCUIT RESPONSIVE TO THAT PORTION OF SAID SIGNAL WITHIN THE RANGE OF FROM ABOUT 6 KC. TO 7 KC.; AND INTEGRATING MEANS TO WHICH THE OUTPUT OF SAID FILTERING MEANS IS CONNECTED AS AN INPUT, SAID INTEGRATING MEANS HAVING AN OUTPUT CIRCUIT RESPONSIVE TO THE AMPLITUDE AND DURATION OF THE SIGNAL RECEIVED BY THE INTEGRATING MEANS AS AN INPUT THERETO WHICH YIELDS THE SUMMATION OF THE AREAS UNDER THE PULSE CURVES FOR THE LAST-MENTIONED SIGNAL; WHEREBY THE KNOCK INTENSITY IS INDICATED BY THE OUTPUT OF SAID INTEGRATING MEANS.