Intake system of a multi-cylinder internal combustion engine

摘要

A multi-cylinder internal combustion engine comprising a plurality of cylinders each having a helically-shaped intake port. The helically-shaped intake port comprises a helical portion having the outlet open end, and an inlet passage portion having an inlet open end and tangentially connected to the helical portion. The intake valve is arranged in the outlet open end. The engine further comprises a common connecting passage and a plurality of branch connecting passages each being in communication with the common connecting passage. Each of the branch connecting passages opens into the inlet open end of the corresponding helically-shaped intake port at a position near the upper wall of the helically-shaped intake port.