Nozzled Turbine

• US 20140338328A1
• Filed: 05/17/2013
• Published: 11/20/2014
• Est. Priority Date: 05/17/2013
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Kruiswyk, Richard W., Delvecchio, Kerry A., Wolk, Matthew T., Hergart, Carl-Anders, Lusardi, Christopher, Swar, Rohan
• Granted Patent: US 9,157,396 B2
• Time in Patent Office: Days
• US Class Current: 60/605.2
• CPC Class Codes: F01D 9/026 Scrolls for radial machines or engines
• CPC Class Codes: F01D 9/04 forming ring or sector
• CPC Class Codes: F01D 9/045 for radial flow machines or engines
• CPC Class Codes: F01D 9/047 Nozzle boxes
• CPC Class Codes: F02M 26/05 High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor

Abstract

A turbine includes a turbine housing having two gas passages of substantially the same flow area. A nozzle ring is disposed in the housing and around the turbine wheel. The nozzle ring includes first and second outer rings, and an inner ring disposed between the first and second outer rings. First and second pluralities of vanes are disposed between the rings. The second outer ring has a thicker cross section than the first outer ring such that a larger flow area is created between the first outer ring and the inner ring than a flow area created between the second outer ring and the inner ring.

Claims

1. A turbine, comprising:

a turbine housing including at least two gas passages having substantially the same flow area and disposed on opposing sides of a divider wall;

a turbine wheel having a plurality of blades;

a nozzle ring connected to the turbine housing and disposed around the turbine wheel, the nozzle ring having;

a first outer ring,

an inner ring disposed adjacent the first outer ring, said inner ring having an annular shape and disposed in axial alignment with the divider wall,

a second outer ring disposed adjacent the inner ring, said second outer ring having a thicker cross section than the first outer ring;

a first plurality of vanes fixedly disposed between the first outer and the inner rings, the first plurality of vanes defining a first plurality of inlet openings therebetween that are in fluid communication with a slot formed in the nozzle ring and surrounding the turbine wheel;

a second plurality of vanes fixedly disposed between the second outer and the inner rings, the second plurality of vanes defining a second plurality of inlet openings therebetween that are in fluid communication with the slot;

wherein the first plurality of inlet openings collectively defines a first flow outlet area that is larger than a second flow outlet area collectively defined by the second plurality of inlet openings.

2. The turbine of claim 1,

wherein each of the first plurality of inlet openings defines a respective first throat area, which represents a minimum cross-sectional flow area of the respective first inlet opening, and a respective first outlet area, which is defined at a boundary between the respective first inlet opening and the slot;

wherein each respective first throat area is substantially equal to each respective first outlet area;

wherein each of the second plurality of inlet openings defines a respective second throat area, which represents a minimum cross-sectional flow area of the respective second inlet opening, and a respective second outlet area, which is defined at a boundary between the respective second inlet opening and the slot; and

wherein each respective second throat area is substantially equal to each respective second outlet area.

3. The turbine of claim 1, wherein, during operation, a first portion of exhaust gas entering the turbine housing passes through the first plurality of inlet openings and a second portion of exhaust entering the turbine housing passes through the second plurality of inlet openings, and wherein a variation of a ratio between the first and second portions is less than 5% when a speed of the exhaust gas passing through the first and second pluralities of inlet openings changes from subsonic to supersonic and vice versa.

4. The turbine of claim 3, wherein the first flow area is equivalent to a first nozzle of a converging/diverging type, the first nozzle having a first equivalent throat area and a first equivalent outlet area, and wherein the second flow area is equivalent to a second nozzle of a converging/diverging type, the second nozzle having a second equivalent throat area and a second equivalent outlet area.

5. The turbine of claim 4, wherein the first portion depends on a size of the first equivalent outlet area when the speed of the exhaust gas is subsonic and on a size of the of the first equivalent throat area when the speed of the exhaust gas is supersonic.

6. The turbine of claim 5, wherein the first equivalent throat area is about 940 square millimeters, and wherein the second equivalent throat area is about 406 square millimeters.

7. The turbine of claim 1, wherein each of the first and second pluralities of vanes includes 15 vanes.

8. The turbine of claim 1, wherein the second outer ring forms a smooth protrusion peripherally around the second outer ring along a sidewall thereof facing the inner ring such that the smooth protrusion encroaches into a cross sectional flow area between the inner ring and the second outer ring.

9. The turbine of claim 1, wherein the nozzle ring is disposed within a bore formed in the turbine housing, and wherein the turbine further includes a retainer disposed to retain the nozzle ring within the bore of the housing, the retainer extending peripherally around the nozzle ring and connected to the housing by fasteners.

10. An internal combustion engine, comprising:

a divided turbine having first and second inlets;

a first plurality of cylinders connected to a first exhaust conduit, the first exhaust conduit being connected to the first inlet of the divided turbine;

a second plurality of cylinders connected to a second exhaust conduit, the second exhaust conduit being connected to the second inlet of the divided turbine;

a balance valve disposed to selectively route exhaust gas from the first exhaust conduit to the second exhaust conduit;

an exhaust gas recirculation (EGR) system including a valve that selectively fluidly connects the first exhaust conduit with an intake system of the engine;

wherein the divided turbine includes;

a turbine housing including two gas passages having substantially the same flow area and disposed on opposing sides of a divider wall, the two gas passages being fluidly connected to the first and second inlets of the divided turbine;

a turbine wheel having a plurality of blades;

a nozzle ring connected to the turbine housing and disposed around the turbine wheel, the nozzle ring having;

a first outer ring,

an inner ring disposed adjacent the first outer ring, said inner ring having an annular shape and disposed in axial alignment with the divider wall,

a second outer ring disposed adjacent the inner ring, said second outer ring having a thicker cross section than the first outer ring;

a first plurality of vanes fixedly disposed between the first outer and the inner rings, the first plurality of vanes defining a first plurality of inlet openings therebetween that are in fluid communication with a slot formed in the nozzle ring and surrounding the turbine wheel;

a second plurality of vanes fixedly disposed between the second outer and the inner rings, the second plurality of vanes defining a second plurality of inlet openings therebetween that are in fluid communication with the slot;

wherein the first plurality of inlet openings collectively defines a first flow outlet area that is larger than a second flow outlet area collectively defined by the second plurality of inlet openings.

11. The internal combustion engine of claim 10,

wherein each of the first plurality of inlet openings defines a respective first throat area, which represents a minimum cross-sectional flow area of the respective first inlet opening, and a respective first outlet area, which is defined at a boundary between the respective first inlet opening and the slot;

wherein each respective first throat area is substantially equal to each respective first outlet area;

wherein each of the second plurality of inlet openings defines a respective second throat area, which represents a minimum cross-sectional flow area of the respective second inlet opening, and a respective second outlet area, which is defined at a boundary between the respective second inlet opening and the slot; and

wherein each respective second throat area is substantially equal to each respective second outlet area.

12. The internal combustion engine of claim 10, wherein, during operation, a first portion of exhaust gas entering the turbine housing passes through the first plurality of inlet openings and a second portion of exhaust has entering the turbine housing passes through the second plurality of inlet openings, and wherein a variation of a ratio between the first and second portions is less than 5% when a speed of the exhaust gas passing through the first and second pluralities of inlet openings changes from subsonic to supersonic and vice versa.

13. The internal combustion engine of claim 12, wherein the first flow area is equivalent to a first nozzle of a converging/diverging type, the first nozzle having a first equivalent throat area and a first equivalent outlet area, and wherein the second flow area is equivalent to a second nozzle of a converging/diverging type, the second nozzle having a second equivalent throat area and a second equivalent outlet area.

14. The internal combustion engine of claim 13, wherein the first portion depends on a size of the first equivalent outlet area when the speed of the exhaust gas is subsonic and on a size of the of the first equivalent throat area when the speed of the exhaust gas is supersonic.

15. The internal combustion engine of claim 14, wherein the first equivalent throat area is about 940 square millimeters, and wherein the second equivalent throat area is about 406 square millimeters.

16. The internal combustion engine of claim 10, wherein each of the first and second pluralities of vanes includes 15 vanes.

17. The internal combustion engine of claim 10, wherein the second outer ring forms a smooth protrusion peripherally around the second outer ring along a sidewall thereof facing the inner ring such that the smooth protrusion encroaches into a cross sectional flow area between the inner ring and the second outer ring.

18. The internal combustion engine of claim 10, wherein the nozzle ring is disposed within a bore formed in the turbine housing, and wherein the turbine further includes a retainer disposed to retain the nozzle ring within the bore of the housing, the retainer extending peripherally around the nozzle ring and connected to the housing by fasteners.

19. A nozzle ring adapted for installation into a receiving bore in a turbine housing, the turbine housing having two flow passages having substantially the same flow area formed therewithin and separated by a divider wall, each flow passage being connected to a respective gas inlet, the receiving bore surrounding a turbine wheel when the turbine housing is assembled into a turbocharger, the nozzle ring comprising:

a first outer ring;

an inner ring disposed adjacent the first outer ring, said inner ring having an annular shape and disposed in axial alignment with the divider wall,

a second outer ring disposed adjacent the inner ring, said second outer ring having a thicker cross section than the first outer ring;

a first plurality of vanes fixedly disposed between the first outer ring and the inner ring, the first plurality of vanes defining a first plurality of inlet openings therebetween that are in fluid communication with a slot formed in the nozzle ring and adapted to surround the turbine wheel;

a second plurality of vanes fixedly disposed between the second outer and the inner rings, the second plurality of vanes defining a second plurality of inlet openings therebetween that are in fluid communication with the slot;

wherein the first plurality of inlet openings collectively defines a first flow outlet area that is larger than a second flow outlet area collectively defined by the second plurality of inlet openings.

20. The nozzle ring of claim 19,

wherein each of the first plurality of inlet openings defines a respective first throat area, which represents a minimum cross-sectional flow area of the respective first inlet opening, and a respective first outlet area, which is defined at a boundary between the respective first inlet opening and the slot;

wherein each respective first throat area is substantially equal to each respective first outlet area;

wherein each of the second plurality of inlet openings defines a respective second throat area, which represents a minimum cross-sectional flow area of the respective second inlet opening, and a respective second outlet area, which is defined at a boundary between the respective second inlet opening and the slot; and

wherein each respective second throat area is substantially equal to each respective second outlet area.

21. The nozzle ring of claim 19, wherein the first plurality of inlet openings is functionally equivalent to a first nozzle of a converging/diverging type, the first nozzle having a first equivalent throat area and a first equivalent outlet area, and wherein the second plurality of inlet openings is functionally equivalent to a second nozzle of a converging/diverging type, the second nozzle having a second equivalent throat area and a second equivalent outlet area.

22. The nozzle ring of claim 19, wherein, when the nozzle ring is installed in the turbine housing and the turbocharger is operating, the nozzle ring operates to align a gas flow passing therethrough into a flow having only radial and tangential components with respect to the turbine wheel.

23. The nozzle ring of claim 19, wherein the thicker cross section of the second outer ring contributes to increasing efficiency of the turbocharger by being disposed in a flow path of exhaust gas passing through the nozzle ring so that a flow diffusion thereof is controlled before the exhaust gas reaches the turbine wheel.