Reduction fluid mixer

Abstract

A mixer includes a reducing fluid ejector, a disc ejector, a resilient pad, and a hollow mixing chamber. The reducing fluid ejector is configured to inject reducing fluid into an exhaust stream. The reducing fluid ejector is arranged along an axis. A disc ejector support extends about the axis. The resilient pad is disposed on the disc ejector support. The hollow mixing chamber extends about the axis and is disposed on the resilient pad, and is spaced apart from the disc ejector support by the resilient pad. The hollow mixing chamber is conical.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to French Patent Application No. 2302689, filed on March 22, 2023, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to a reducing fluid mixer for exhaust lines. background

[0004] The exhaust pipe delivers exhaust gases from the internal combustion engine outlet to nozzles leading outdoors. Exhaust gas purification equipment is arranged along the exhaust pipe to ensure that the gases exiting the nozzles are as clean as possible. This purification equipment can be a selective catalytic reduction (SCR) or a catalyst. This catalyst purifies the mixture of exhaust gases and a reducing fluid through catalytic reduction, as catalytic reduction converts nitrogen oxides (NOx) contained in the exhaust gases into harmless compounds such as nitrogen, N2, and water (H2O). For this purpose, it is recommended to use a mixer upstream of the catalyst that can thoroughly mix the exhaust gases with the reducing fluid. The reducing fluid is typically ammonia or its precursors, such as an aqueous solution of urea.

[0005] The exhaust stream passes through a mixer. The mixer includes a reducing agent injector capable of injecting reducing fluid into the exhaust stream.

[0006] According to one possible embodiment, the injector is arranged along an axis. The injector is supported by a generally disc-shaped support member surrounding the same axis. The mixer also includes a generally conical or cylindrical hollow mixing chamber surrounding the same axis. This mixing chamber is arranged coaxially with and opposite to the support member. Exhaust gas enters the mixing chamber through perforations formed in the wall of the support member or the mixing chamber, or through a gap disposed between the support member and the mixing chamber, to mix with the reducing fluid therein.

[0007] Manufacturing tolerances in both the support and the mixing chamber can lead to excessive deviations in the clearance dimension.

[0008] Therefore, a device is sought to generate a repeatable gap between the support and the mixing chamber.

[0009] Because the mixer is integrated into the exhaust line and the exhaust gas passes through it, it is subject to very significant temperature changes. Therefore, the mixer and the technical solutions implemented must be able to withstand the significant dimensional changes caused by thermal expansion and high temperatures. Overview

[0010] Therefore, this disclosure relates to a reducing fluid mixer for an exhaust pipeline through which an exhaust flow can pass. The reducing fluid mixer includes: a reducing fluid injector capable of injecting reducing fluid into the exhaust flow, the reducing fluid injector being arranged along an axis; a generally disc-shaped injector support surrounding the same axis; and a generally conical or cylindrical hollow mixing chamber surrounding the same axis, the hollow mixing chamber being arranged coaxially opposite to the support, wherein the mixer further includes an elastic pad disposed between the support and the mixing chamber.

[0011] Specific features or embodiments that can be used alone or in combination are:

[0012] - The pad is a metal mesh.

[0013] - The pad has a generally flat cross-section that is approximately perpendicular to the axis.

[0014] - The support includes a cylindrical ring along the axis, coaxial with the axial end of the mixing chamber, and a pad with an L-shaped cross-section, one branch of the "L" being approximately perpendicular to the axis, and the other branch of the "L" being located between the axial end of the mixing chamber and the ring.

[0015] The ring includes at least one first opening, and the axial end of the mixing chamber includes at least one second opening, the second opening being arranged substantially opposite to the at least one first opening.

[0016] - The axial end of the mixing chamber includes at least one leg capable of being axially supported on the pad.

[0017] - The at least one support leg includes at least two support legs.

[0018] - The mixing chamber includes at least one perforation, which is preferably circular or elliptical.

[0019] This disclosure relates to a mixer comprising:

[0020] A reducing fluid ejector, the reducing fluid ejector being configured to inject reducing fluid into an exhaust stream, the reducing fluid ejector being arranged along an axis;

[0021] A disc-shaped injector support extending about the axis;

[0022] An elastic pad, the elastic pad being disposed on the disc-shaped injector support; and

[0023] A hollow mixing chamber extends about the axis and is disposed on the elastic pad and spaced apart from the disc-shaped injector support by the elastic pad, the hollow mixing chamber being conical.

[0024] In some embodiments, the elastic pad is made of metal mesh.

[0025] In some embodiments, the elastic pad has a planar cross-section perpendicular to the axis.

[0026] In some embodiments, the disc-shaped injector support includes a cylindrical ring extending around the axial end of the axis, the elastic pad, and the hollow mixing chamber, the cylindrical ring being coaxial with the axial end.

[0027] In some embodiments, the elastic pad has an "L"-shaped cross-section such that a first branch of the "L"-shaped cross-section is perpendicular to the axis, and a second branch of the "L"-shaped cross-section is located between the axial end and the cylindrical ring.

[0028] In some embodiments, the cylindrical ring includes at least one first opening; and the axial end includes at least one second opening, the at least one second opening being arranged opposite to the at least one first opening.

[0029] In some embodiments, the hollow mixing chamber includes at least one perforation.

[0030] In some embodiments, each of the at least one perforation is disposed between one of the at least one second opening and the hollow mixing chamber.

[0031] In some embodiments, the axial end includes at least one leg axially supported on the elastic pad.

[0032] In some embodiments, the axial end includes a plurality of legs, each of which is axially supported on the elastic pad.

[0033] In some embodiments, the hollow mixing chamber includes at least one perforation.

[0034] In some embodiments, each of the at least one perforation is circular or elliptical.

[0035] In some embodiments, the mixer further includes: a panel; and an exhaust duct connected to the panel; wherein the reducing fluid injector is connected to the panel.

[0036] In some embodiments, the hollow mixing chamber includes a plurality of vents.

[0037] In some embodiments, the hollow mixing chamber includes a plurality of fins, each of which is adjacent to one of the vents.

[0038] In some embodiments, the elastic pad is annular.

[0039] In some embodiments, the elastic pad is made of metal mesh; the elastic pad has a planar cross-section perpendicular to the axis; the disc-shaped injector support includes a cylindrical ring extending around the axis, the elastic pad, and the axial end of the hollow mixing chamber, the cylindrical ring being coaxial with the axial end; the elastic pad has an "L"-shaped cross-section such that a first branch of the "L"-shaped cross-section is perpendicular to the axis, and a second branch of the "L"-shaped cross-section is located between the axial end and the cylindrical ring; the cylindrical ring includes at least one first opening; the axial end includes at least one second opening, the at least one second opening being arranged opposite to the at least one first opening; the axial end includes at least one leg axially supported on the elastic pad; the axial end includes a plurality of legs, each of which axially supports the elastic pad; the hollow mixing chamber includes at least one perforation; and each of the at least one perforation is disposed between one of the at least one second opening and the hollow mixing chamber.

[0040] In some embodiments, the mixer further includes: a panel; and an exhaust duct connected to the panel; wherein the hollow mixing chamber includes at least one perforation; wherein each of the at least one perforation is circular or elliptical; wherein the reducing fluid injector is connected to the panel; wherein the hollow mixing chamber includes a plurality of vents; wherein the hollow mixing chamber includes a plurality of fins, each of the fins being adjacent to one of the vents; and wherein the elastic pad is annular.

[0041] According to a second aspect of this disclosure, an exhaust line includes such a mixer. Brief description of the attached diagram

[0042] This disclosure will be better understood by reading the following description, given by way of example only, and by referring to the accompanying drawings, in which:

[0043] Figure 1 A mixer according to the first embodiment is shown in a perspective view.

[0044] Figure 2 A mixer according to another embodiment is shown in perspective view.

[0045] Figure 3 The mixer, including several legs, is shown in a top view.

[0046] Figure 4 The details of the mixer with a flat pad are shown in a semi-axial sectional view.

[0047] Figure 5 The details of the mixer with an "L"-shaped pad are shown in a semi-axial sectional view.

[0048] Figure 6 The mixing chamber, including the legs, is shown in perspective view.

[0049] Figure 7 The mixer with legs is shown in perspective view.

[0050] Figure 8 The mixer with legs is shown in a top view.

[0051] Figure 9 A mixer according to another embodiment is shown in perspective view.

[0052] Figure 10 A mixer according to another embodiment is shown in perspective. Detailed description

[0053] refer to Figure 1 This disclosure relates to a reducing fluid mixer 1 for an exhaust pipeline. The mixer 1 includes a hollow, generally conical or cylindrical mixing chamber 4 along an axis A. The mixer 1 also includes an injector support 3, which is generally disc-shaped about the same axis A and arranged coaxially opposite to the mixing chamber 4. The mixer 1 further includes a reducing injector 2 capable of injecting reducing fluid into the mixing chamber 4 for injection into the exhaust stream. The injector 2 is arranged along the same axis A to inject reducing fluid along that axis A.

[0054] The exhaust gas can pass through mixer 1. The exhaust gas rapidly permeates into mixing chamber 4 from the outside to the inside. The exhaust gas enters, for example, through the generatrix of a cylinder or truncated cone (e.g., through vent 14). Fins 15 adjacent to vent 14 allow the generation of vortices that promote mixing of the exhaust gas and reducing fluid. The exhaust gas and reducing fluid also permeate into mixing chamber 4 via a space provided between the axial end 9 of mixing chamber 4 and the oppositely arranged injector support 3. Openings 12, 13 and / or perforations 11 may be provided in this space to allow the exhaust gas to enter. In mixing chamber 4, the exhaust gas mixes with the reducing fluid. The resulting mixture exits mixing chamber 4 through another axial end of mixing chamber 4.

[0055] The mixing chamber 4 is arranged opposite to the support member 3. These two parts are not attached to each other. However, the distance between the mixing chamber 4 and the support member 3 should be controlled, as this distance at least partially regulates the flow rate of the exhaust gas entering the mixing chamber 4. Controlling this flow rate is important because it determines the required flow rate of the reducing fluid to be injected.

[0056] Therefore, according to one feature, the mixer 1 also includes an elastic pad 5 disposed between the support 3 and the mixing chamber 4.

[0057] Because the pad has compressive strength, it allows for repeatable positioning of the mixing chamber 4 relative to the support 3.

[0058] In addition, the elasticity of pad 5 allows it to absorb dimensional changes caused by thermal expansion.

[0059] According to another feature, pad 5 is made of metal mesh.

[0060] Based on another characteristic, more specifically in Figure 4 As shown, pad 5 has a generally flat cross-section that is generally perpendicular to axis A.

[0061] The pad 5 allows for the formation of a stop that enables the mixing chamber 4 to be axially and repeatedly positioned relative to the support 3.

[0062] Based on another characteristic, more specifically in Figure 5 As shown, the pad 5 has a generally "L"-shaped cross-section. One branch 6 of the "L" is generally perpendicular to axis A. This portion of the pad 5 forms a stop to allow the mixing chamber 4 to be repeatedly axially positioned relative to the support 3.

[0063] The support 3 advantageously includes a cylindrical ring 8 along axis A, coaxial with the axial end 9 of the mixing chamber 4. Another branch 7 of the “L” is generally parallel to axis A. Therefore, the other branch 7 lies between the axial end 9 of the mixing chamber 4 and the ring 8. This portion of the pad forms a centering guide to allow the mixing chamber 4 to be radially repositioned relative to the support 3.

[0064] Exhaust gas enters mixing chamber 4 through the busbar of mixing chamber 4. Different types of perforated bushings 11-14 are provided to allow for changes in input level and flow rate during design.

[0065] According to another feature, ring 8 includes at least one first opening 12. The axial end 9 of mixing chamber 4 opposite to support 3 includes at least one second opening 13. Advantageously, the at least one first opening 12 is arranged generally opposite to the at least one second opening 13.

[0066] This allows exhaust gas to enter the mixing chamber 4 through the openings 12 and 13 radially between the ring 8 and the mixing chamber 4.

[0067] According to another feature, the axial end 9 of the mixing chamber 4 includes at least one leg 10 capable of being axially supported on the pad 5.

[0068] This single outsole, more specifically in Figures 6 to 8 As shown, an axial stop portion is formed in the abutment pad 5 to position the mixing chamber 4 relative to the support member 3.

[0069] According to another feature, the at least one leg 10 includes at least two legs 10. This feature (in...) Figures 1 to 3 (As shown more specifically in the diagram) provides the same functionality as described above. Increasing the number of legs by adding support points to the abutment pad 5 allows for improved lateral balance of the mixing chamber 4.

[0070] According to another feature, the mixing chamber 4 includes at least one perforation 11, which is preferably circular or elliptical.

[0071] This disclosure also relates to an exhaust line including such a mixer 1.

[0072] This disclosure has been shown and described in detail in the accompanying drawings and the foregoing disclosure. This should be considered illustrative and given by way of example, and not intended to limit the disclosure to its extent. Many alternative embodiments are possible.

[0073] List of reference numerals

[0074] 1: Mixer

[0075] 2: Injector,

[0076] 3: Support components

[0077] 4: Mixing chamber

[0078] 5: Pad,

[0079] 6: First branch,

[0080] 7: Second branch,

[0081] 8: Ring,

[0082] 9: Axial end

[0083] 10: Support leg,

[0084] 11: Perforation,

[0085] 12: The first opening,

[0086] 13: The second opening,

[0087] 14: Ventilation opening,

[0088] 15: Fins,

[0089] A: Axis.

Claims

1. A mixer comprising: a reducing fluid injector configured to inject a reducing fluid into an exhaust stream, the reducing fluid injector being arranged along an axis; a disc-shaped injector support extending around the axis; a resilient mat provided on the disc-shaped injector support, the resilience of the resilient mat allowing absorption of dimensional changes caused by thermal expansion; and a hollow mixing chamber extending around the axis and being provided on the resilient mat and spaced apart from the disc-shaped injector support by the resilient mat, the hollow mixing chamber being conical. The resilient mat is made of a metal mesh.

2. The mixer of claim 1, wherein, The resilient mat has a planar cross-section perpendicular to the axis.

3. The mixer of claim 2, wherein, The resilient mat has a planar cross-section perpendicular to the axis.

4. The mixer of claim 1, wherein, The disc-shaped injector support comprises a cylindrical ring extending around the axis, the resilient mat, and an axial end of the hollow mixing chamber, the cylindrical ring being coaxial with the axial end.

5. The mixer of any one of claims 1-4, wherein, The resilient mat has an "L"-shaped cross-section such that a first branch of the "L"-shaped cross-section is perpendicular to the axis and a second branch of the "L"-shaped cross-section is interposed between the axial end and the cylindrical ring.

6. The mixer of claim 5, wherein, 7. The mixer of claim 5, wherein: the cylindrical ring comprises at least one first opening; and the axial end comprises at least one second opening, the at least one second opening being oppositely arranged from the at least one first opening. The hollow mixing chamber comprises at least one perforation.

8. The mixer of claim 7, wherein, Each of the at least one perforation is provided between one of the at least one second opening and the hollow mixing chamber.

9. The mixer of claim 8, wherein, The axial end comprises at least one leg axially supported on the resilient mat.

10. The mixer of claim 5, wherein, The axial end comprises a plurality of legs, each of the plurality of legs being axially supported on the resilient mat.

11. The mixer of claim 5, wherein, The hollow mixing chamber comprises at least one perforation.

12. The mixer of any one of claims 1-4, wherein, Each of the at least one perforation is circular or elliptical.

13. The mixer of claim 12, wherein, 14. The mixer of any one of claims 1-4, further comprising: a faceplate; and an exhaust conduit coupled to the faceplate; wherein the reducing fluid injector is coupled to the faceplate. The hollow mixing chamber comprises a plurality of louvers.

15. The mixer of any one of claims 1-4, wherein, The hollow mixing chamber comprises a plurality of fins, each of the fins being adjacent to one of the louvers.

16. The mixer of claim 15, wherein, The resilient mat is annular.

17. The mixer of any one of claims 1-4, wherein, 18. The mixer of claim 1, wherein: the resilient mat is made of a metal mesh; the resilient mat has a planar cross-section perpendicular to the axis; the disc-shaped injector support comprises a cylindrical ring extending around the axis, the resilient mat, and an axial end of the hollow mixing chamber, the cylindrical ring being coaxial with the axial end; the resilient mat has an "L"-shaped cross-section such that a first branch of the "L"-shaped cross-section is perpendicular to the axis and a second branch of the "L"-shaped cross-section is interposed between the axial end and the cylindrical ring; the cylindrical ring comprises at least one first opening; and ​ the axial end includes at least one second opening disposed opposite the at least one first opening; the axial end includes at least one leg axially supported on the resilient pad; the axial end includes a plurality of legs, each of the legs axially supporting the resilient pad on; the hollow mixing chamber includes at least one perforation; and each of the at least one perforation is disposed between one of the at least one second opening and the hollow mixing chamber.

19. The mixer of any one of claims 1-4, further comprising: a faceplate; and an exhaust conduit coupled to the faceplate; wherein the hollow mixing chamber includes at least one perforation; wherein each of the at least one perforation is circular or elliptical; wherein the reducing fluid injector is coupled to the faceplate; wherein the hollow mixing chamber includes a plurality of louvers; wherein the hollow mixing chamber includes a plurality of fins, each of the fins adjacent one of the louvers; and wherein the resilient pad is annular.

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