Air intake system for internal combustion engine

The air suction channel system includes a cooling device (5) forming the first part of a heat transfer unit (6) fitted in the exhaust return channel (4), which is thereby closed over its length. There is a cooling channel (7) in the heat transfer unit with coolant flowing through it, open on one side in the transverse direction to the direction of flow, closed by the second part (15) of the cooling device.