Exhaust recirculation system

An automotive piston engine has an exhaust gas return system which all important functions within a single housing (1). The components within the unit are an exhaust gas return valve (19), an exhaust gas cooling unit (10) with heat exchanger (15), a by-pass passage (8) with a regulator flap (33). In addition, the exhaust gas return valve has a valve seat (31) that is cooled by a coolant from the exhaust gas cooling unit (10).