| 摘要 |
PURPOSE:To deliver the background signal in a simple and accurate way and to detect the knocking with high accuracy and high reliability, by comparing the mean value of plural ignition cycles of the engine vibration detecting output for a prescribed period after the ignition with the output of detection within a prescribed range of the crank angle. CONSTITUTION:An interruption is applied to the processing operation of a microprocessor 62 via the crank angle sensors 16 and 18. Then the engine vibration detecting output is fetched via a knocking sensor 12 and for a prescribed period after an ignition, and the mean value is calculated among plural ignition cycles. At the same time, the output of the sensor 12 is detected in the same way for the knocking period during which the noise caused from a crank shaft, etc. is minimized. This output is turned into the best background signal when no knocking is produced, and this background signal is compared with the mean value to detect the knocking. Thus the background signal can be delivered in a simple and accurate way to ensure the detection of knocking with high accuracy and high reliability. |
