| 摘要 |
PURPOSE:To surely judge a knock by measuring the bias voltage to be added to the knock sensor output with a bias voltage measuring means, and outputting the reference signal containing the bias set voltage value. CONSTITUTION:A microcomputer 5 is operated by an engine key action. The judgment value of a measurement signal generating means 15 is set to the minimum and compared with the bias voltage B by a comparator 7 via a reference signal generating means 12 and a D/A converter 6 while being increased. The judgment value when the output of the comparator 7 is converted into a high level is stored. The judgment value is set to the maximum, the judgment value when the output of the comparator 7 is converted into a low level while being decreased is obtained, and the average value between this value and the stored judgment value is set to the bias set value. During the knock gate period, knock judgment signals Kn... containing the bias set value are outputted to judge the presence of a knock, during the noise gate period, noise reference signals Nn... containing the bias set value are outputted to calculate the knock judgment level with the background noise level. |
