# US 2013/0152582 A1 · Compressor recirculation into annular volume

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- Number: US 2013/0152582 A1
- Document ID: US20130152582A1
- Status: Published application
- Kind: A1
- Application number: 13/817,906
- Filed: 2011-08-30
- Published: 2013-06-20
- Earliest claimed: 2010-09-02
- Assignees: BorgWarner Inc.
- Inventors: Paul K. Anschel; David G. Grabowska; Brock Fraser
- Web page: https://patentgrep.com/patent/US20130152582A1

## CPC

- F04D 27/0238: {Details or means for fluid reinjection}
- F01D 9/026: {Scrolls for radial machines or engines}
- F01D 17/105: {by passing part of the fluid}
- F01D 17/165: {for radial flow, i.e. the vanes turning around axes which are essentially parallel to the rotor centre line (F01D17/167 takes precedence)}
- F02B 37/16: by bypassing charging air
- F02C 6/12: Turbochargers, i.e. plants for augmenting mechanical power output of internal-combustion piston engines by increase of charge pressure
- F02M 26/06: Low pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust downstream of the turbocharger turbine and reintroduced into the intake system upstream of the compressor
- F02M 26/09: Constructional details, e.g. structural combinations of EGR systems and supercharger systems; Arrangement of the EGR and supercharger systems with respect to the engine
- F02M 26/19: Means for improving the mixing of air and recirculated exhaust gases, e.g. venturis or multiple openings to the intake system
- F05D 2220/40: in turbochargers
- Y02T 10/12: Improving ICE efficiencies
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

To solve the problems of compressor wheel blade flow separation causing surge type noises when a compressor return or recirculation valve is opened or closed, bypass airflow from a compressor recirculation valve is fed into an annular volume, defined between inner and outer walls or shaped as a radially expanded, axially flattened cylindrical space in the compressor inlet, so that the generally unidirectional radial flow from the compressor recirculation valve is re-directed and organized as it is turned from generally radial to generally axial, merging with the general inlet flow and presenting the compressor wheel with airflow of “circumferentially uniform” flow velocity.

## Claims

### Claim 1

A compressor for compressing gas, said compressor comprising:
a compressor wheel (20) including a plurality of blades each of which includes a leading edge (24), a trailing edge and an outer free edge, said wheel being mounted for rotation within a housing,
the housing including a compressor inlet (14) upstream of the compressor wheel and a compressor discharge (15) downstream of said compressor wheel,
wherein the inlet comprises:
an outer channel wall (22) extending away from the compressor wheel in an upstream direction and forming a gas intake portion in the upper inlet section,
an inner channel wall (21) within the outer channel wall, comprising an inlet section (14) extending away from the compressor wheel upstream of the leading edges (24) of the compressor wheel and an inducer section (14a) downstream of the leading edges (24) of the compressor wheel, and
an annular cavity (23) defined between the inner and outer channel walls, with an annular opening of the annular cavity (23) at the upstream end of the inner channel wall between the inner and outer channel walls,
said compressor further comprising a compressor return valve system comprising a compressor recirculation valve (CRV)(80) associated with a bypass duct providing fluid communication between the compressor discharge (15) and the annular cavity (23).

### Claim 2 (depends on 1)

The compressor as in claim 1, further comprising at least one inducer recirculation slot in the inner channel wall (21) upstream of the inducer.

### Claim 3 (depends on 2)

The compressor as in claim 2, wherein said inducer recirculation slot (25) is substantially annular.

### Claim 4 (depends on 1)

The compressor as in claim 1, wherein the inner channel wall (21) and the outer channel wall (22) are generally co-axial.

### Claim 5 (depends on 1)

The compressor as in claim 1, further comprising at least one flow directional control device located in said annular cavity.

### Claim 6 (depends on 5)

The compressor as in claim 5, wherein said flow directional control device includes at least one strut.

### Claim 7 (depends on 1)

The compressor as in claim 1, wherein the air flowing from the CRV exhaust tangentially enters the annular cavity.

### Claim 8

A compressor for compressing gas, said compressor comprising:
a compressor wheel (20) including a plurality of blades each of which includes a leading edge (24), a trailing edge and an outer free edge, said wheel being mounted for rotation within a housing,
the housing including a compressor inlet (14) upstream of the compressor wheel and a compressor discharge (15) downstream of said compressor wheel,
wherein the inlet comprises a channel wall (22) extending away from the compressor wheel in an upstream direction, and including an axially flattened, radially expanded cylindrical volume annularly open to the compressor inlet (14), axially upstream of the leading edge of the compressor wheel,
said compressor further comprising a compressor return valve system comprising a compressor recirculation valve (CRV)(80) associated with a bypass duct providing fluid communication between the compressor discharge (15) and the to axially flattened, radially expanded cylindrical volume.

### Claim 9 (depends on 8)

The compressor as in claim 8, wherein said axially flattened, radially expanded cylindrical volume is generally co-axial with said compressor inlet (14).

### Claim 10 (depends on 8)

The compressor as in claim 8, wherein said axially flattened, radially expanded volume is has a center that is not co-axial with said compressor inlet (14).

### Claim 11 (depends on 8)

The compressor as in claim 8, wherein the depth of the radial expansion of said axially flattened, radially expanded volume is greater than the axial height of said expanded volume.

### Claim 12

A low pressure EGR system for an internal combustion engine comprising:
a compressor for compressing air to be supplied to the engine;
a turbine stage including a turbine housing having an exhaust gas inlet for receiving exhaust gas from said engine, and an exhaust gas outlet, and a turbine wheel driven by the exhaust gas from the engine;
an exhaust gas return duct by which exhaust gases to be returned to the engine are introduced to the compressor; and
a boost air duct by which the air compressed in the compressor is supplied to the engine,
wherein said compressor comprises:
a compressor wheel (20) driven by the turbine wheel and including a plurality of blades each of which includes a leading edge (24), a trailing edge and an outer free edge, said wheel being mounted for rotation within a compressor housing and operable between choked flow and a surge line, the compressor housing including a compressor inlet (14) upstream of the compressor wheel and a compressor discharge (15) downstream of said compressor wheel,
wherein the inlet comprises:
an outer channel wall (22) extending away from the compressor wheel in an upstream direction and forming a gas intake portion in the upper inlet section,
an inner channel wall (21) within the outer channel wall, comprising an inlet section (14) extending away from the compressor wheel upstream of the leading edges (24) of the compressor wheel and an inducer section (14a) downstream of the leading edges (24) of the compressor wheel, and
an annular cavity (23) defined between the inner and outer channel walls, with an annular opening of the annular cavity (23) at the upstream end of the inner channel wall between the inner and outer channel walls, and
wherein said exhaust gases to be returned to the engine are introduced via the exhaust gas return duct into the compressor annular cavity (23).

### Claim 13

(canceled)