| 摘要 |
PURPOSE:To make it possible to exhibit the output power of an engine at its maximum, by updating learning values in accordance with the maximum values of compensating spark retardation amounts which are set in accordance with the presence of knocking, for a plurality of engine operating ranges so that the ignition timing is spark-advanced when the frequency of occurrence of knocking is low. CONSTITUTION:During operation of an engine 10, a control circuit 20 computes a basic spark advance in accordance with the load of an engine and the like given by output signals from a rotating angle sensor 18 and an air flowmeter 24. Further, the basic spark advance is compensated in accordance with such a compensating spark retardation amount that during occurrence of knocking, the ignition timing is spark-retarded while during no occurrence of knocking, the ignition timing is spark-advanced, and therefore, an ignitor is controlled. In this case, the operating range is divided into a plurality of sections in accordance with the rotational speed of the engine, and a learning value which is updated in accordance with the maximum value of the compensated spark retardation amount for each section is obtained. Further, when it is judged that the frequency of occurrence of knocking is low during the operation of the engine through low and middle rotational speed ranges and the present frequency of occurrence of knocking is low, the ignition timing is spark-advanced. |
