| 摘要 |
PURPOSE: To heighten the resolution of idling engine speed control and guarantee idling engine speed control temporarily when the severance of wire is generated to an idling valve driving solenoid (fail safe). CONSTITUTION: An idling air flow valve driving solenoid is divided into two coils 12A, 12B, and these coils are connected in parallel. At the first idling time, a controller 3 selects both coils 12A, 12B through switching elements 4A, 4B and controls the current quantity to these coils according to a demanded first idling air flow rate. At the normal idling time, the controller 3 selects only one of the coils 12A, 12B and controls the current quantity to one coil according to the demanded idling air flow rate. When the severance of wire is generated to one of the coils 12A, 12B, the coil without the severance of wire is selected through the switching element to perform duty control. |
