| 摘要 |
PURPOSE:To prevent the occurrence of over rich, by a method wherein, in a suction secondary air feeder, a large quantity of secondary air is forcibly fed during deceleration. CONSTITUTION:An orifice 13 for regulating idling is located in a secondary air passage 12, an air control passage 14 is installed in a manner to run around the orifice 13, and an air control valve 15, which is adapted to operate in response to a negative pressure, is mounted in the air control passage 14. The sectional area of the flow passage of the air control passage 14 is varied according to the magnitude of a negative pressure exerted on a negative pressure chamber 15a, and as the negative pressure decreases, the area increases. A pressure exerted on the negative pressure chamber 15a is fed through a pressure feed passage 17 from an electromagnetic valve 16, and the interior of the electromagnetic valve 16 is communicated with the part, on the downstream side of a throttle valve 5 through a negative pressure passage 18 and is also communicated with the part, on the upstream side of the orifice 13, of the secondary air passage 12. During deceleration, the electromagnetic valve 16 the air control valve 15 are forcibly opened and held in said condition to prevent the occurrence of over rich. |
