Patent attributes
A centrifugal compressor includes a compressor housing, an impeller wheel which compresses intake gas from an intake-air inlet, a plurality of guide vanes disposed circumferentially along an inner circumferential wall of the intake-air channel between the intake-air inlet and the impeller wheel to swirl the intake gas around the rotational axis, a central intake-air flow path formed at an inner side of the guide vanes to allow the intake gas to flow to the impeller wheel without passing through the guide vanes, and a guide-vane moving mechanism which simultaneously changes the inclination angle of the guide vanes. Guide vanes generate swirl flow at an inner circumferential housing portion of an impeller wheel to improve a surge margin and to restrict decrease in a choke flow rate.