| 摘要 |
PURPOSE:To improve combustibility and emission, by providing an opening and closing valve, actuated to open in the half way of an intake stroke, in an intake passage and controlling a preset negative pressure, which determines the operation timing of said valve, to be decreased as an engine speed rises for an engine in an idle speed or more. CONSTITUTION:An engine, interposing an opening and closing valve 10 in an intake passage 6b communicating with an intake port 5 and rapidly opening said valve 10 from its existing closed condition from the half way of an intake stroke, performs adiabatic compression of intake to promote the rise of intake temperature. The opening and closing valve 10 is constituted so as to open a valve unit 13 when an intake negative pressure, inducted to a chamber 16 through a communication hole 19, reaches the preset negative pressure determined by urging force of a spring 18 and each pressure receiving area of the valve unit 13 and a diaphragm 15. While said preset negative pressure is controlled by a control means A so as to be decreased as an engine speed increases for the engine in an idle speed or more by using a preset negative pressure regulating means 30 constituted by adjusting a position of a supporting plate 31, receiving one end of the spring 18 to be supported, through a negative pressure operated actuator 32.
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