| 摘要 |
PURPOSE:To prevent a knocking control from deteriorating due to resolving power of a comparison level, by changing a knocking decision value respectively by an upper value and a lower value when the comparison level with a knocking sensor output repeats the two values. CONSTITUTION:A knocking detecting circuit 25, in case of comparing an output from a knocking sensor 4 with a comparison level, performs a feedback control of the comparison level so that a comparison output obtains a predetermined value. Here a control device, when the comparison level repeats two of the upper value and the lower value in accordance with a level relation between the comparison output and the predetermined value, sets a knocking decision value smaller than the reference value for the comparison level of the upper value while the knocking decision value larger than the reference value for the comparison level of the lower value. In this way, an engine, which permits a knocking decision to be performed similarly to setting the decision value substantially to an intermediate value even when the comparison level obtains the intermediate value by resolving power repeating the two values, enables a knocking control to be prevented from deteriorating due to the resolving power. |
