KNOCKING DETECTION METHOD FOR INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To produce a correct background signal by comparing the signals from the vibration detecting element in the first and second crank angle ranges and deciding the knocking while varying the first range in accordance to the calculated firing timing. CONSTITUTION:MPU62 will calculate the optimal firing timing t then calculate the starting time t1 of the background detection interval while at the time t1 the integrating operation of the rectified signal from a knock sensor 12 will start to calculate such that the end of said detection interval will be immediately before the time t thus to complete the integration of the first integrating circuit 51. Then the knock detection interval t3-t4 is calculated. MPU62 will contain the A/D conversion level (b) from the first integrating circuit 51 in RAM64 during the background detection interval while contain the A/D conversion level (a) from the second integrating circuit 53 in RAM64 during the knock detection interval. Then (a) and K.b are compared to decide the existence of the knocking. Since the background detection interval range is calculated in accordance to the calculated firing timing, the inconvenient noise such as the firing noise can be eliminated.