| 摘要 |
PURPOSE:To enable control of intake negative pressure by detecting the deceleration and opening an EGR control valve in a communication path between the intake path in the downstream of throttle valve and the exhaust path. CONSTITUTION:Deceleration is detected on the basis of the engine rotation and the throttle valve opening, then the actual negative pressure Pm in the intake path 7a is compared with the decision negative pressure P. If the actual negative pressure P, it is decided to be deceleration to feed a signal from a control unit 51 to drive means 27 thus to full open EGR control valve 15. Under full-open operation of valve 15, closing operation of solenoid valves 53, 55 against the first and second atmospheric air take-in ports 37, 39 is lengthened through duty control of the control unit 51 to increase the negative pressure in the negative pressure chamber 33. Upon reaching to the open-valve level, the path 29b is choked with a diaphragm 31 to block supply of negative pressure from the intake path 7a into the negative pressure chamber 33 thus to open the EGR path 13 through said valve 15. |
