Abstract: An exhaust gas-driven turbocharger (1) exhibits an adjustable radial turbine (2) which powers a compressor (3) by way of a common shaft (4), whereby a turbine housing (5) designed with a multiplicity of scrolls surround the turbine wheel (6) and exhibits at least two afflux ports (7a, 7b) annularly encompassing the turbine wheel (6), whose outlets (8a, 8b) at least partly surround the wheel approach (9) of the turbine wheel (6) and which are at an axial distance from one another. An annular, axially displaceable coupler (15) is provided for opening and closing the outlet (8a, 8b) of at least one afflux port (7a, 7b), so that the boost pressure of the turbine can be influenced thereby.

Abstract: As a device for stabilizing the performance characteristics, a radial compressor comprises a circulation chamber (31) which makes pressure equalization between the impeller and the intake region possible. The intake region has an intake ring (10) which makes it possible to influence the flow in the intake region so that the performance characteristics be stabilized without substantial losses. The compressor may be adapted to customer's requirements by changing the intake ring.