| 摘要 |
PURPOSE:To return to the normal rotation region stably and prevent the occurrence of vibration and noise caused by hunting by decreasing the degree of the spark advance angle as the rotating speed is increased in the engine stop preventing rotation region. CONSTITUTION:A microcomputer 41 controls the ignition timing via an ignition drive circuit 42 without allowing an ignition plug to misfire when the engine rotating speed is lower than the preset rotating speed based on the information of the shift load, rotating speed, and throttle opening. If the engine rotating speed is decreased too low out of the normal rotation region, the maximum spark advance value in the engine stop preventing rotation region is set in steps so that the combustion is completed reliably before an exhaust valve 47 is opened, thus the engine stop is prevented. When the engine rotating speed is increased gradually, the degree of the spark advance angle is not returned at a stretch but returned to the lag angle side in steps or smoothly. The engine rotating speed is thereby prevented from being decreased due to the deterioration of the combustion state again. |
