| 摘要 |
PURPOSE:To prevent an engine from run-away and stopping, by detecting to which side an engine speed deviates at this time by shifting a control current of a control valve for control of an idling speed against a normal value. CONSTITUTION:An upstream side of a throttle valve 3 and a surge tank 4 are connected by a bypass duct 21 with each other and an engine speed at the time of idling is kept at a fixed speed by controlling a cross-sectional flowing area of a bypass duct 21 by a control valve for control of an idling speed. An electronic controller 40 controls a fuel injection valve 41, the control valve 22 and an igniiter 46. Abnormality of the control valve 22 is decided by detecting that to which side an engine speed at this time deviates against that when it is in a normal value by shifting a control current of the control valve 22 against the normal value to be decided as a function of an operation state of an engine. Run-away or stoppage of the engine can be prevented from occurring in this manner. |
