Patent ID: 11927193
Assignee: GARRETT TRANSPORTATION I INC.
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F  H  Y | IPC F  H

Claim 7:
8. A multi-stage charging device for a fuel cell system with a fuel cell stack, the charging device comprising:
a shaft that is supported for rotation about an axis;
a first compressor stage cooperatively defined by a first compressor wheel and a first compressor housing;
a motor section with a stator and a rotor;
a second compressor housing that partly defines a second compressor stage;
a turbine housing that partly defines a turbine section;
a plural wheel member that is fixed on the shaft, the plural wheel member having a second compressor wheel and a turbine wheel arranged back-to-back and sharing a common outer radial edge, the second compressor wheel supported in the second compressor housing and the turbine wheel supported in the turbine housing;
the first compressor wheel, the rotor, the second compressor wheel, and the turbine wheel fixed to the shaft to rotate as a unit relative to the first compressor housing, the stator, the second compressor housing, and the turbine housing;
the first compressor stage configured to compress an inlet fluid stream and direct a low pressure fluid stream toward the second compressor stage;
the second compressor stage configured to compress the low pressure fluid stream and direct a high pressure fluid stream toward the fuel cell stack;
the turbine wheel configured to be driven in rotation by an exhaust stream from the fuel cell stack;
the plural wheel member being one-piece, unitary, and formed of a thermally conductive material that thermally couples the second compressor stage and the turbine section and defines a thermal path through which the turbine section absorbs heat from the second compressor stage; and
an air bearing system that supports the shaft, the first compressor wheel, and the plural wheel member for rotation as a unit relative to the first compressor housing, the second compressor housing, and the turbine housing, the air bearing system disposed axially between the first compressor wheel and the plural wheel member.