Abstract: In an engine (1), supercharged by a turbocompressor unit and provided with a bypass pipe (14), the exhaust gas manifold (13) of the engine has a small and constant section, the junction between the bypass pipe (14) and the gas inlet (11) of the turbine (5) is located upstream of the first junction (18) between the manifold (13) and pipes (12) connecting the work chambers (2) of the engine (1) to the manifold (13) and the bypass pipe (14) includes throttling means (15) which are such that the difference between the total pressures prevailing directly in the outlet (7) of the compressor (6) and upstream of the turbine (5) substantially only depend on the first of said pressures.

Abstract: The engine is supercharged by two turbocharger units which are capable of being put into operation in succession and their compressors are capable of supplying air to the engine in parallel. When the turbocharger unit is not in operation, the outlet of its compressor is put in communication through a bypass passage with the inlet of its turbine by means of flaps or the like.