| 摘要 |
PURPOSE:To prevent deterioration of exhaust gas purification performance, by lagging the angle of ignition timing considerably if the exhaust gas flow or temperature is low under low load to increase the exhaust gas temperature while reducing the lagging angle immediately under heavy load. CONSTITUTION:Upon turning on of ignition switch 13 to start an engine 1 then the rotation increases to bring the output of comparator 22 high, a timer 23 will provide an ON-signal to a gate 20 for 120sec, for example, thus to provide a correction signal of lagging angle corresponding to the load from a correction signal generator 19 to a correction circuit 16. It is corrected such that the lagging angle of basic ignition timing from an arithmetic circuit 15 is increased under light load while decreased under heavy load. In such a manner, under low load where the catalyst temperature is low, the lagging angle is increased to increase the exhaust gas temperature thus to prevent deterioration of purification performance. While under heavy load, the lagging angle is reduced immediately to perform high output operation to assure the output performance. |
