Helically-shaped intake port of an internal combustion engine

摘要

Helically-shaped intake port comprising a helical portion and an inlet passage portion which is tangentially connected to the helical portion and is slightly curved. The intake valve is arranged at the open outlet end of the helical portion. The upper wall of the helical portion extends to a helix terminating portion from the connecting position, and the inlet passage portion is connected to the helical portion. The height between the outlet open end and the upper wall of the helical portion, which is located at the helix terminating portion, is equal to or larger than the diameter of the outlet open end.