AIR INTAKE DEVICE FOR MULTI-CYLINDER ENGINE

摘要

An air intake device for a multi-cylinder engine, comprising a bypass control valve (10) allowing the downstream side end of a bypass upstream side passage (12a) to communicate with the upstream side ends of a plurality of bypass downstream side passages (12b<SUB>1</SUB>, 12b<SUB>2</SUB>) and controlling the degree of the communication. The bypass control valve (10) comprises a cylindrical valve chamber (18) and a piston-like valve element (26) slidably fitted into the valve chamber (18). The downstream side end of the bypass upstream side flow passage (12a) is opened to one end face of the valve chamber (18), and the upstream side ends of the plurality of bypass downstream side passages (12b<SUB>1</SUB>, 12b<SUB>2</SUB>) are opened to the side face of the valve chamber (18) by moving them to one side of a plane (P1) including the axis (Y) of the valve chamber (18) so that the upstream side ends of the bypass downstream side passages (12b<SUB>1</SUB>, 12b<SUB>2</SUB>) can be opened and closed by the slidable movement of the valve element (26). Thus, a first idle air amount supplied to each cylinder can be uniformized by suppressing the lateral vibration of the valve element by the negative pressure of intake air to stabilize the control of the opening of the bypass downstream side passages by the valve element.