Low-Noise Ported-Shroud Compressor for a Turbocharger

A compressor, comprising:

• a compressor wheel having full blades that are N in number;
• and
• a compressor housing surrounding the compressor wheel and defining an inlet for leading fluid along a main flow path into the compressor wheel and through the compressor wheel to be compressed thereby, the compressor housing including a first housing portion that defines a volute and a second housing portion that defines an outer ring-shaped member that surrounds and is radially spaced from an inner ring-shaped member such that a generally annular space exists between a radially inward side of the outer ring-shaped member and a radially outer side of the inner ring-shaped member, the second housing portion being arranged such that an axial space exists between a downstream end of the second housing portion and an adjacent portion of the first housing portion so as to form a port slot that connects with a downstream end of the generally annular space, an axial space existing between an upstream end of the inner ring-shaped member and an adjacent part of the outer ring-shaped member, which axial space forms a passage that connects the inlet of the compressor with an upstream end of the annular space,
• the annular space forming a recirculation path or alternate flow path that fluid can pass through in either direction, depending on the particular operating condition of the compressor,
• the outer ring-shaped member being connected to the inner ring-shaped member by a plurality of circumferentially spaced struts extending between the radially outer side of the outer ring-shaped member and the radially inward side of the inner ring-shaped member, and wherein the struts are from N to 3N+1 in number.