| 摘要 |
PURPOSE: To enhance the accuracy in failure sensing by determining the deviation between the max. and min. values of the output signals from a knock sensor, judging failure through comparison of the obtained deviation with the failure judgement level, and passing a failure judgement of the knock sensor when failure judgement occurs more than the specified frequency. CONSTITUTION: A knocking control device for a car has a knock sensor 1 which senses the knocking condition of the car in the form of engine acceleration and emits the result in the form of electric signals. An amplifier 2 amplifies the output signal of the knock sensor 1 to a voltage range which admits specific processing, and an A/D converter 3 converts the knocking intensity into digital information which admits specified processing. A processing device 4 judges failure in the sensor 1, when deviation is determined between the max. and min. values in the peak hold values at each ignition of a number of sensor output signals emitted from the sensor 1 during the specified period of time, and failure is judged by comparison of the deviation with the failure judgement level one time in each period. When failure judgement occurs more than the specified frequency, it is judged that the knock sensor 1 goes in failure. |
