| 摘要 |
PURPOSE:To more adequately operate the selective control for exhaust gas recirculation (EGR) and air-fuel ratio in accordance with the operating state of an engine, by further controlling VC negative pressure with venturi negative pressure in response to a load of the engine. CONSTITUTION:VC negative pressure produced in an intake throttle valve part 23 goes through the fourth negative pressure passage 43 from the second VC hole 42 and is guided to a negative pressure chamber in a negative pressure regulator switch 38. While venturi negative pressure is guided to a negative pressure chamber 52 in a variable orifice device 44 from a negative pressure take-off port 31 through the second negative pressure passage 32 and the fifth negative pressure passage 57. When the negative pressure regulator switch 38 is turned off, a coil 40 in a negative pressure regulating valve 37 is not excited to both close the second atmospheric air introducing passage 35 and open the third atmospheric air introducing passage 36. Accordingly, the venturi negative pressure is guided to a VVT valve 28 in a state as it is, then the VC negative pressure guided to an exhaust gas recirculation (EGR) valve 22 is controlled in such a manner that a rate of the EGR in response to the load of an engine is obtained. |
