Turbocharged four stroke internal combustion engine having a variable volume exhaust gas device and method of operating such an engine

The engine has two cylinders with a combustion chamber (14), and an air inlet unit (16) having a tube (20) with a valve. The cylinders have an exhaust unit (18) including a tube (22) with a valve, and a collection unit to collect exhaust gas. The collection unit includes the tubes and a collector. A tubular clearance (34) along with the collector increases collected exhaust gas volume during the operation of the engine at high speed. An independent claim is also included for a process of operating an overfed internal combustion engine.