| 摘要 |
PURPOSE:To promote the prevention of rough idle operation and the reduction of fuel consumption while prevent the generation of abnormally high supercharge pressure, by cheaply constituting a device combining a relief valve and a negative pressure switching valve. CONSTITUTION:When an engine is in idle operation, a control device, moving rightward a diaphragm 21 against a spring 24 by a negative pressure in a port part 15 acting on the third port 16 of a negative pressure switching valve 7, introduces the negative pressure also to a relief valve 6 by opening a valve 22. In this way, the device, moving rightward a diaphragm 12 of the relief valve 6 against a spring 13 and opening a valve 9, relieves charging air pressure in a surge tank 8 to a relief port 29. On the contrary, when the engine is in operation by high car speed running, a solenoid valve 26 is opened by a car speed sensor, and the pressure in the surge tank 8 acts so as to lift the diaphragm 12 of the relief valve 6 through a port 10. In this way, the device, opening the valve 9, similarly relieves the charging pressure in the surge tank 8.
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