Gas introducing structure of intake path

A gas introducing structure of an intake path of an internal combustion engine having a plurality of cylinders, the gas introducing system comprising:

• a common chamber;
• a gas introducing path introducing the gas from the common gas chamber into an intake port of each cylinder,
• wherein an inner peripheral surface of the gas introducing path includes:
• a bottom surface appearing as a straight line at a lower side of a perpendicular cross section of the inner peripheral surface;
• and
• a curved wall surface appearing as a convex curved line, connecting with each end of the straight line at an angle, at an upper side of the perpendicular cross section of the inner peripheral surface,
• wherein the gas introducing path is introduced into the intake path from a lower side, and a curved wall surface side of an end of the gas introducing path, opening to the intake path, projects into the intake path.