Abstract: In a supercharged pressure control valve apparatus of an internal combustion engine, a housing of supercharger has first and second by-pass air paths; a valve sheet formed on an end of the second by-pass air path; a rubber diaphragm having thick sealing part of convex and concave sectional shape at its outer periphery; a valve disc fixed to the moving part of the diaphragm and opening closing the first and the second by-pass air paths responding to movement of the diaphragm; and a casing of the valve directly fixed on the housing by sandwiching the outer periphery of the diaphragm.

Abstract: A variable capacity radial flow turbine includes a turbine housing which incorporates a turbine wheel and which forms a working gas passageway that leads to the turbine wheel and that is divided into two parts. The working gas passageway is provided with a pivotable plate-like member, so that the flow rate of the working gas flowing into the turbine wheel can be continuously changed by shifting the position of this member and thus opening or closing part of a working gas intake.