| 摘要 |
PURPOSE:To prevent a shock exserted on an engine by disposing a pressure control device on a by-pass relief valve disposed on a supercharger and by increasing gradually the supercharging pressure of said supercharger, during a transitional stage, moving from the non-supercharging range to the supercharging range. CONSTITUTION:During a transitional stage in that a load on engine 1 is raised and a main throttle valve 10 is widely opened, a supplementary throttle valve 26 begins to open as well as a supercharger is driven. At this time, a supercharging pressure is low, since a relief valve 28 is widely opened. Then, after a detector 34 detects the opening operation of said throttle valve 26, said detector 34 operates a three-way valve 33 and introduces gradually a suction negative pressure to a negative pressure chamber 31c of an actuator 31 in a control device 29 to close said relief valve 28. At this time, the suction negative pressure is introduced gradually to said negative pressure chamber 31c by the operation of a throtlle 35. As the result, said relief valve 28 is closed gradually, thus said supercharging pressure is raised gradually. |
