Patent ID: 7225779

Claim:
An intake system for an internal combustion engine, comprising: an intake manifold defining an inlet passage, an intake passage communicating the inlet passage with an intake port of the engine and a resonance chamber communicating with the intake passage via a communication passage; an outer tube supported by the intake manifold and having an axial end communicating with the inlet passage and an opening defined in a circumferential wall thereof for communication with the resonance chamber; an inner tube rotatably and coaxially received in the outer tube, the inner tube defining a communication passage inlet port at an axial end on a same side as the axial end of the outer tube, an internal bore defining the communication passage, an opening defined in a circumferential wall thereof for defining a communication outlet port jointly with the opening in the circumferential wall of the outer tube; and a power actuator for turning at least one of the outer tube and inner tube according to an operating condition of the engine; wherein the openings of the inner tube and outer tube are configured such that at least one of a distance between the communication inlet port and communication outlet port, and an opening area of the communication outlet port changes in relation with a relative rotational angle between the inner tube and outer tube.