| 摘要 |
PURPOSE:To improve the reliability of an actuator operation in a change-over means for changing over the natural frequency of intake by constituting the actuator for driving the change-over means from a pressure operated system having as a drive source the supercharging pressure generated by the operation of a supercharger. CONSTITUTION:An intake path 11 communicating to an intake port 4 has a surge tank 12 and the intake path 11 at the upstream side of said tank 12 becomes a common intake path A. Also, the intake path 11 downstream of said tank 12 constitutes an independent intake path B of each cylinder from a branch pipe path 12b and an independent intake pipe 17. Said path B is connected to a subsurge tank 20 through a communicating path 19 having a switch valve 21 interposed as a change-over means. Then, the switch valve 21 is operated by a pressure operated system actuator 31, and an operating chamber 34 of the actuator 31 communicates so the intake path A between a throttle valve 16 and a compressor wheel 22a of a supercharger 22 through a piping 41, a three-way change-over valve 42 and a piping 43.
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