| 摘要 |
PURPOSE:To simplify a fail safe mechanism, by a method wherein a negative chamber for driving a diaphragm formed integrally with a weighing valve to open and close a bypass passage running around a throttle valve, and the opening area of an orifice to release the negative chamber to the open air is varied according to the temperature state of an engine. CONSTITUTION:A throttle valve chamber 6 having a throttle valve 4 and a bypass passage 5 for idling is situated in a suction pipe 2, and an idle control device 15 is placed in the bypass passage 5. The idle control device 15 has a weighing valve 22 capable of being seated on a seat 21 located in the middle part of the bypass passage 5. The weighing valve 22 is driven by means of a diaphragm 26 displaced by means of a negative pressure in a negative pressure chamber 28, decided according to an amount of a gap between the one end of a plunger 31 driven by an electromagnetic coil 33 and the one end of a central shaft 23 of the weighing valve 22. The negative pressure chamber 28 is opened to the open air through a leak orifice 40. In this case, the opening area of the leak orifice 40 is varied by a temperature-sensitive type valve mechanism 42 displaced depending upon temperature. |
