INTAKE AND EXHAUST SYSTEM FOR MULTI-CYLINDER ENGINE

摘要

A multi-cylinder engine intake and exhaust having a plurality of independent exhaust passages each connected to an exhaust port in a respective one of a plurality of cylinders, a collecting pipe connected to downstream ends of the plurality of independent exhaust passages, and a volume-enlarged portion provided downstream with respect to the collecting pipe. Each of at least a downstream portion of each of the plurality of independent exhaust passages and at least an upstream portion of the collecting pipe is formed such that a cross-sectional area thereof gradually decreases toward a downstream direction. The volume-enlarged portion is formed such that a cross-sectional area thereof is relatively increased so as to cause a positive pressure wave of exhaust gas reaching the volume-enlarged portion to be reflected and converted to a negative pressure wave.