| 摘要 |
PURPOSE:To prevent over-rotation of an engine with excellent response as torque shock is prevented from occurring, by a method wherein, when the number of revolutions of an engine is increased to abnormal high rotation exceeding the given number of revolutions, through control of an intake air port varying means, correction is effected in a direction in which an intake air amount is limited. CONSTITUTION:A control unit 31 controls a pressure regulating valve 24 and a switching valve 25 to bring the opening of an on-off valve 17, disposed in an intake air passage 11b, to a desired value. Namely, through control of the switching valve 25, a pressure chamber 18a of an actuator 18 is released to the open air to fully close the on-off valve 17, and the pressure chamber 18a is communicated with a tank 20 to fully open the on-off valve 17. In order to regulate the opening of the on-off valve 17 to a desired value, based on a detecting output from a sensor 35, i.e., the magnitude of a negative pressure in the tank 20, duty control is effected on the pressure regulating valve 24 to escape a negative pressure in the tank 20 through a relief passage 22. Further, duty control is made on the switching valve 25 to control a ratio in which the pressure chamber 18a of the actuator 18 is communicated to the open air or the tank 20 to regulate the opening of the on-off valve 17.
|
