OPERATING CHARACTERISTICS VARIABLE DEVICE FOR ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an operating characteristics variable device for an engine to improve intake air filling efficiency by improving a supercharge effect at a wide rotation speed area and enable realization of further flattening of output torque throughout a whole operation area. SOLUTION: An operating characteristics variable device for a multicylinder engine comprises a valve operating characteristics variable means (VT) capable of steppedly varying the operating characteristics of a part of suction valves (8a and 8b), and a suction characteristics variable means (SA) capable of steppedly varying the suction characteristics of a suction passage. The suction characteristics variable means is provided with a rotary valve (26) capable of effecting intercommunication in a short-circuit-form manner and disconnection between a suction collection chamber (21), situated on the side positioned upper stream of the suction passage, through rotation according to the rotation speed of an engine. The rotary valve is situated at the intermediate parts of a plurality of suction passages (22a, 22b, 22c, and 22d), arranged in juxtaposition and independently from each other. At a low rotation speed area, a part of the suction valves of each cylinder is brought into a rest, and intake air is fed through a long pipe suction passage. At a high rotation speed area, all of the suction valves are worked, and intake air is fed through a short pipe suction passage. At a middle rotation speed area, the suction passages of a cylinder group where a suction stroke is not continued are caused to effect intercommunication and interconnection.