| 摘要 |
PURPOSE:To detect knocking of an engine accurately and calculate background level by converting a signal of a knock sensor to a digital value using a microcomputer with an A/D converter and then performing a computation. CONSTITUTION:A vibration signal of a knock sensor 1 which detects a vibration of an engine main unit is amplified by an amplifier 2 and a needed frequency component is extracted by a filter 3 and is input into a microcomputer 4 with a high-speed A/D converter. Also, a crank angle signal of a crank angle sensor 5 is also input to the microcomputer 4 and is used for setting a knock detection interval and judging an engine operation status, etc. The microcomputer 4 continuously samples a digital value and integrates the differences between the digital values and background levels in a detection section. The integration value is compared with a judgment level for performing knocking judgment and then a knock strength is obtained. The detected knock judgment signal and the knock strength are input to an engine control microcomputer 6 and is used for controlling an ignition timing. A signal of the knock sensor 1 is converted to the digital value by the microcomputer 4, thus enabling knocking to be detected and the background level to be calculated highly accurately. |
