| 摘要 |
PURPOSE:To effectively improve the output of an engine through-out the whole rotation area of an engine, by a method wherein the number of revolutions of an engine when an intake air port varying means is actuated is set to a valve higher than that of an engine when an exhaust passage varying means is actuated. CONSTITUTION:Based on each switching characteristics line set based on the number of revolutions of an engine, a control unit 51 controls each of 3-way electromagnetic switching valves 21 and 42. For example, switching characteristics line shows a switching time between demagnetization and excitation of the switching valve 42, and during full load, when the number of revolutions of an engine is below a give valve N1, the switching valve 42 is demagnetized, an intake air negative pressure held through utilization of a check valve 43 is fed to a pressure chamber 40a of an actuator 40 to close an on-off valve 37, and resultantly, the area of an exhaust introduction passage running to a turbine 15b is reduced. Meanwhile, when the number of revolutions of an engine is below N2(N2>N1), the switching valve 21 is demagnetized to feed an atmospheric pressure to a pressure chamber 19a of an actuator 19 to close an on-off valve 18, resulting in reduction of the area of an intake air port 3.
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