| 摘要 |
PURPOSE:To avoid influence of noises or the like, by not making the ignition timing of an engine lag when malfunctioning of a knocking sensor is detected from the difference of the outputs of the knocking sensor in at least two states of engine conditions. CONSTITUTION:Engine speed is detected by applying a crank angle signal to an F/V converter 401. In comparators 402, 403, the actual engine speed is compared with two reference engine speeds N1, N2. In case that the engine speed is N1, the output of a knocking sensor is held at a sample holding circuit 503. On the other hand, in case that the engine speed is N2, the output of the knocking sensor is held at another sample holding circuit 504. These two signals Vref1 and Vref2 are applied to a subtractor 601 and a comparator 602 to detect malfunctioning of the knocking sensor from the difference of the two signals Vref1 and Vref2. With such an arrangement, it is enabled to detect malfunctioning of a knocking sensor. |
