Mixer and exhaust aftertreatment system comprising same

Abstract

The utility model relates to a mixer and an exhaust aftertreatment system comprising the same. The mixer comprises a shell, the shell is provided with an air inlet, an air outlet and a spraying opening, the flowing direction of exhaust airflow from upstream to downstream is the direction from the air inlet to the air outlet, and in the flowing direction, a mixing space is provided for the area between the air inlet and the air outlet; the jet orifice is used for providing reducing agent spray to enter an inlet of the mixer, and the jet orifice corresponds to a jet direction; the partition plate piece is located in the mixing space and divides the mixing space into a first space and a second space, and the partition plate piece comprises a first molded surface, a second molded surface and a third molded surface; the first molded surface, the second molded surface and the third molded surface form a step structure, and one of the first molded surface, the second molded surface and the third molded surface is at least directly connected with the other one of the first molded surface, the second molded surface and the third molded surface.

Description

TECHNICAL FIELD

[0001] The present application relates to an engine exhaust aftertreatment system, and more particularly to a mixer and an exhaust aftertreatment system. BACKGROUND

[0002] Engine exhaust aftertreatment systems treat hot exhaust gases produced by an engine with various upstream exhaust components to reduce emissions of pollutants. The various upstream exhaust components can include one or more of the following: pipes, filters, valves, catalytic converters, mufflers, etc. For example, the upstream exhaust components direct the exhaust gases into a Diesel Oxidation Catalyst (DOC) having an inlet and an outlet. Downstream of the Diesel Oxidation Catalyst can be a Diesel Particulate Filter (DPF). Downstream of the Diesel Oxidation Catalyst and optional Diesel Particulate Filter is a Selective Catalytic Reduction (SCR) reactor having an inlet and an outlet. The outlet passes the exhaust gases to downstream exhaust components. A mixer is positioned downstream of the outlet of the DOC or the DPF and upstream of the inlet of the SCR. The exhaust gases enter the mixer, and an injector is used to inject a spray of urea water solution into the exhaust stream upstream of the SCR so that the mixer can mix the urea and exhaust gases together sufficiently uniformly for discharge into the SCR for a reduction reaction to produce nitrogen and water to reduce the engine's emissions of nitrogen oxides.

[0003] However, the existing mixer still has room for improvement. The inventor has found in long-term practice that for the case where the urea crystallization rate is required to be relatively strict, it is necessary to further simplify the structure of the mixer and reduce the structural complexity inside the mixer to reduce the welding points inside the mixer to reduce urea crystallization.

[0004] Therefore, there is a need in the art for a mixer with a low urea crystallization rate and an engine exhaust aftertreatment system with low nitrogen oxide emissions. SUMMARY

[0005] It is an object of the present application to provide a mixer.

[0006] It is another object of the present application to provide an exhaust aftertreatment system.

[0007] A mixer according to a first aspect of the present application for an exhaust aftertreatment system, comprising: a housing providing an inlet, an outlet, and a spray opening, an exhaust gas flow direction from upstream to downstream being from the inlet to the outlet, a region between the inlet and the outlet providing a mixing space in the flow direction, the spray opening providing an entrance of a reductant spray into the mixer, the spray opening corresponding to a spray direction; a partition member in the mixing space and separating the mixing space into a first space and a second space, the partition member comprising a first profile, a second profile, and a third profile; the first profile, the second profile, and the third profile forming a stepped structure, and one of the first profile, the second profile, and the third profile being directly connected to another of the first profile, the second profile, and the third profile; the first profile providing a flow guide surface corresponding to a flow guide space, the second profile and the third profile defining a first mixing space, and the second profile having a flow-through opening communicating the first space and the second space, a projection of the spray opening in the spray direction on the second profile being located at the opening; wherein the partition member defines a flow and mixing path of the exhaust gas and the reductant spray comprising: a first portion of the exhaust gas flowing through the flow guide surface of the first profile into the first mixing space, a second portion of the exhaust gas directly entering the first mixing space, the first portion of the exhaust gas, the second portion of the exhaust gas, and the reductant spray entering the first mixing space from the spray opening forming a mixed flow, and the mixed flow flowing through the flow-through opening to a second mixing space of the second space.

[0008] In one or more embodiments of the mixer, the first profile has a bypass inlet, the bypass inlet providing a flow path comprising: a third portion of the exhaust gas flowing directly from the flow guide space to the second mixing space through the bypass inlet.

[0009] In one or more embodiments of the mixer, further comprising a strike plate in the second mixing space, the strike plate providing a flow path comprising: the mixed flow entering the second mixing space and striking the strike plate and dividing into at least a first branch flow and a second branch flow along the strike plate.

[0010] In one or more embodiments of the mixer, further comprising an outlet partition having at least a first outlet opening and a second outlet opening, the outlet partition being disposed in a third mixing space downstream of the third profile, the third mixing space being in the second space.

[0011] In one or more embodiments of the mixer, the strike plate is disposed downstream of the bypass inlet, the mixed flow being on one side of the strike plate, and the third portion of the exhaust gas being on another side of the strike plate opposite the one side.

[0012] In one or more embodiments of the mixer, the first mixing space is further provided with a swirler having a swirler opening, and the swirler corresponds to the injection port, and the mixing path provided by the swirler includes: the first portion of the exhaust gas, and the second portion of the exhaust gas entering the swirler through the swirler opening to form a rotational flow, and the rotational flow and the reducing agent spray entering the first mixing space form a mixed fluid; wherein the injection range of the reducing agent spray injected into the first mixing space is limited to the range of the internal space surrounded by the swirler.

[0013] In one or more embodiments of the mixer, the first mixing space is defined by the partition member and the inner wall surface of the shell; or the first mixing space is defined by the partition member only.

[0014] In one or more embodiments of the mixer, the normal direction of the first profile is perpendicular to the normal direction of the second profile, and the normal direction of the second profile is perpendicular to the normal direction of the third profile.

[0015] According to the second aspect of the application, an exhaust gas aftertreatment system comprises the mixer according to the first aspect, and an injector, wherein the reducing agent spray injected by the injector enters the mixer from the injection port.

[0016] In one or more embodiments of the exhaust gas aftertreatment system, the reducing agent is urea solution.

[0017] The further effects of the application include but are not limited to,

[0018] By arranging the structures of the first profile, the second profile and the third profile of the single partition member, a single partition member is realized as a multifunctional member inside the shell of the mixer, which at least integrates the functions of air inlet flow guide and provides the boundary of the mixer space of the mixer, etc., reduces the structural complexity inside the mixer, thereby reducing the welding point positions inside the mixer, especially reducing the welding point positions in the direction of the reducing agent injection of the injector, such as urea injection, thereby reducing the risk of urea crystallization at the welding point positions, reducing the urea crystallization of the whole mixer, improving the performance stability and service life of the mixer. In addition, the engine exhaust gas aftertreatment system using the above-mentioned mixer is efficient in nitrogen oxide treatment and has low emissions. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above and other features, properties, and advantages of the application will become more apparent by reference to the following description of the application, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the application. It is to be noted that the drawings are not drawn to scale and are merely intended to conceptually illustrate the principles of the application, and should not be considered as limiting the scope of the application as actually claimed. In the drawings:

[0020] Figure 1 is a structural diagram of an exhaust gas aftertreatment system of an embodiment.

[0021] Figure 2A 、 Figure 2B 、 Figure 2C is a structural diagram of a mixer of the first embodiment.

[0022] Figure 3A 、 Figure 3B 、 Figure 3C 、 Figure 3D is a parts diagram of the mixer of the first embodiment.

[0023] Figure 4A 、 Figure 4B and Figure 4C 、 4D is a diagram of a mixing path of the mixer corresponding to the first embodiment.

[0024] Figure 5A 、 Figure 5B 、 Figure 5C is a structural diagram of a mixer of the second embodiment.

[0025] Figure 6A 、 Figure 6B 、 Figure 6C 、 Figure 6D is a parts diagram of the mixer of the second embodiment.

[0026] Figure 7A 、 Figure 7B 、 Figure 7C 、 Figure 7D is a parts diagram of the mixer of the first embodiment.

[0027] Reference Signs:

[0028] 100 - exhaust gas aftertreatment system

[0029] 101 - diesel oxidation catalyst

[0030] 102 - diesel particulate filter

[0031] 103 - selective catalytic reduction reactor

[0032] 10 - mixer

[0033] 1 - housing

[0034] 11 - inlet

[0035] 12 - outlet

[0036] 13 - injection port

[0037] 14 - mixing space

[0038] 141 - first space

[0039] 141 1 - flow guiding space

[0040] 141 2 - first mixing space

[0041] 142 - second space

[0042] 142 1 - second mixing space

[0043] 142 2 - third mixing space

[0044] 15 - gas outlet partition

[0045] 151 - first gas outlet opening

[0046] 152 - second gas outlet opening

[0047] 16 - swirler

[0048] 161 - swirler opening

[0049] 162 - inner space

[0050] 17 - impact plate

[0051] 2 - partition element

[0052] 21 - first profile

[0053] 21 1 - flow guiding face

[0054] 21 2 - bypass inlet

[0055] 22 - second profile

[0056] 22 1 - flow-through opening

[0057] 23 - third profile

[0058] 20 - injector

[0059] 201 - first partial flow

[0060] 202 - second partial flow

[0061] 301 - first portion of exhaust gas

[0062] 302 - second portion of exhaust gas

[0063] 303 - third portion of exhaust gas

[0064] 304 - reducing agent spray

[0065] 305 - swirl DETAILED DESCRIPTION

[0066] The subject matter technology is described in the detailed description, the claims, and the appended drawings. Various embodiments of the subject matter technology are described in the detailed description, the claims, and the appended drawings. In order to facilitate the description, specific examples of elements and arrangements are described herein. These are examples only and are not intended to limit the scope of the application.

[0067] It is to be noted that the terms "one embodiment", "an embodiment", and / or "some embodiments" as may be used herein are intended to mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Thus, use of the terms "one embodiment", "an embodiment", and / or "some embodiments" in various places in the specification are not necessarily intended to refer to the same embodiment, unless otherwise specifically indicated. Furthermore, it is to be noted that certain features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0068] The mixer and exhaust aftertreatment system described in the present application is exemplified by the exhaust aftertreatment system of an automobile, but is not limited to the application of the exhaust aftertreatment system of an automobile. For example, the mixer and exhaust aftertreatment system described in the present application can be applied to other vehicles or machines, such as agricultural machines, marine engines, and train engines, as long as the machines are equipped with an exhaust aftertreatment system for treating nitrogen oxides.

[0069] Reference Figure 1 As shown in the figure, in one embodiment, the exhaust aftertreatment system 100 can be a straight-through structure, i.e., a straight-through exhaust aftertreatment system. The exhaust aftertreatment system 100 comprises, in order from upstream to downstream along the axial direction, a diesel oxidation catalyst 101 (DOC), a diesel particulate filter 102 (DPF), a mixer 10, and a selective catalytic reduction reactor 103 (SCR). The diesel oxidation catalyst and the diesel particulate filter described above are conventional terms in the field, but are not limited to the exhaust aftertreatment system of a diesel engine. For example, the diesel oxidation catalyst and the diesel particulate filter can be used in the exhaust aftertreatment system of a gasoline engine.

[0070] Examination Figure 1As shown, the exhaust gas is sequentially treated by the diesel oxidation catalyst 101 to remove unburned hydrocarbons and carbon monoxide, and the diesel particulate filter 102 to remove particulate matter, and then enters the mixer 10 to mix with the reductant spray, typically urea solution, sprayed by the injector 20. The mixture of the reductant spray and the exhaust gas flows out of the mixer 10 and enters the selective catalytic reduction reactor 103, where the mixture is subjected to a reduction reaction to generate nitrogen and water under the action of the catalyst, thereby removing nitrogen oxides from the exhaust gas. It is understood that the exhaust gas aftertreatment system 100 is not limited to the above description. For example, in some exhaust gas aftertreatment systems, the diesel particulate filter 102 can be omitted. The exhaust gas aftertreatment system is not limited to the in-line structure shown in the figure. For example, the exhaust gas aftertreatment system can also have a U-shaped structure, i.e., the mixer 10 is connected to the diesel particulate filter 102, the diesel oxidation catalyst 101 on one side, and the selective catalytic reduction reactor 103 on the other side, forming a U-shaped exhaust gas aftertreatment system.

[0071] Reference Figures 2A to 7D As shown, in some embodiments, such as the first embodiment and the second embodiment, the mixer 10 for the exhaust gas aftertreatment system 100 includes a housing 1 and a partition member 2.

[0072] The housing 1 provides an inlet 11, an outlet 12, and an injection port 13. The flow direction of the exhaust gas from upstream to downstream is from the inlet 11 to the outlet 12. In the flow direction, the region between the inlet 11 and the outlet 12 provides a mixing space 14. The injection port 13 is used to provide an entrance for the reductant spray into the mixer 10, and the injection port 13 corresponds to an injection direction. For example, in the first embodiment, the injection port 13 is provided on the side wall of the housing 1. Figures 2A to 7D As shown, the inlet 11 and the outlet 12 are respectively provided at the two axial ends of the housing 1, and the injection port 13 is provided on the side wall of the housing 1.

[0073] The partition member 2 is located in the mixing space 14 and divides the mixing space 14 into a first space 141 and a second space 142, and the partition member 2 comprises a first profile 21, a second profile 22 and a third profile 23; the first profile 21, the second profile 22 and the third profile 23 constitute a stepped structure, and one of the first profile 21, the second profile 22 and the third profile 23 is directly connected to another one of the first profile 21, the second profile 22 and the third profile 23; the first profile 21 provides a flow guide surface 211, corresponding to a flow guide space 1411, the second profile 22 and the third profile 23 define a first mixing space 1412, and the second profile 22 has a flow-through opening 221 which communicates the first space 141 and the second space 142, and a projection of the second profile 22 in the jet direction of the jetting port 13 is located in the flow-through opening 221. In addition, the flow-through opening 221 can also be a mounting site of a cyclone member 16 to be described later, so the second profile 22 can also serve to provide a mounting position of the cyclone member 16.

[0074] As shown in Figure 3A , Figure 6A , in some embodiments, the specific structure of the partition member 2 can be that the normal direction of the first profile 21 and the second profile 22 is perpendicular, and the normal direction of the second profile 22 and the third profile 23 is perpendicular, i.e. a vertical stepped structure, but not limited thereto, for example, the first profile 21 and the second profile 22 can also be non-perpendicular, for example, the normal direction of the first profile 21 and the second profile 22 is obliquely intersected, and the normal direction of the second profile 22 and the third profile 23 is obliquely intersected, all of which are not limited thereto. The advantage of the vertical structure is that it can improve the compactness of the mixer, and specifically, it can minimize the distance occupied by the partition member 2 in the flow direction, thereby providing more flow space for the flow downstream of the partition member 2.

[0075] As shown in Figures 2A to 4D , the structure forming the first mixing space 1412 can be as shown in the first embodiment, i.e. the first mixing space 1412 is defined only by the partition member 2, for example, only by Figures 2A to 4D the second profile 22 and the third profile 23.

[0076] As shown in Figures 5A to 7D , the structure forming the first mixing space 1412 can be as shown in the second embodiment, i.e. the first mixing space 1412 is defined by the partition member 2 and the inner wall surface of the shell 1, i.e. for example, by Figures 5A to 7DThe second surface 22 and the third surface 23 shown are jointly defined by the inner wall surface of the shell 1. The structure of the mixing space 1412 formed by the first embodiment has better swirling and mixing effects. However, it can be seen that the third surface 23 of the first embodiment surrounds the second surface 22 as a whole, and the third surface 23 has a curved structure, making its structure relatively complex. In contrast, the structure of the third surface 23 of the second embodiment can essentially be considered a planar structure, which is easier to process, manufacture, and design, resulting in lower costs.

[0077] refer to Figures 4A to 4D ,as well as Figures 7A to 7D As shown, the partition 2 defines the flow and mixing path of the exhaust gas and the reducing agent spray, including: the first part of the exhaust gas 301 enters the first mixing space 1412 through the guide surface 211 of the first profile 21, the second part of the exhaust gas 302 directly enters the first mixing space 1412, the first part of the exhaust gas, the second part of the exhaust gas and the reducing agent spray 304 entering the first mixing space 1412 from the injection port 13 form a mixed fluid, and flow through the flow opening 221 to the second mixing space 1421 of the second space 142.

[0078] The beneficial effect of this is that by setting the first, second, and third surfaces of a single baffle, a multifunctional component with multiple functions is realized within the mixer housing. This component integrates at least functions such as air intake guidance and providing the boundary of the mixer space, reducing the structural complexity inside the mixer. This reduces the number of welding points inside the mixer, especially in the direction of reducing agent injection, such as urea injection, thereby reducing the risk of urea crystallization at the welding points, lowering the overall urea crystallization of the mixer, and improving the performance stability and service life of the mixer.

[0079] Continue to refer to Figures 2A to 7D As shown, in some embodiments, the first profile 21 has a bypass inlet 212, which provides a flow path including: the exhaust gas 303 of the third part flows directly from the guide space 1411 through the bypass inlet 212 to the second mixing space 1421. The beneficial effect of this is that the mixed fluid provides insulation / heating, promotes the thermal decomposition of urea and mixing with the exhaust gas, improves the mixing uniformity of urea and exhaust gas, increases the subsequent SCR carrier reaction rate of the system, and reduces the risk of urea crystallization in the system. It can be understood that the proportion of the exhaust gas 303 of the third part to the exhaust gas flow rate is generally small, generally below 20%, while the proportions of the exhaust gas 301 of the first part and the exhaust gas 302 of the second part are generally above 80%.

[0080] Continue to refer to Figures 2A to 7DAs shown, in some embodiments, the mixer 10 further comprises a strike plate 17, the strike plate 17 is located in the second mixing space 1421, and the strike plate 14 provides a flow path including: after the mixed fluid enters the second mixing space 1421, the mixed fluid strikes the strike plate 17 and is divided into at least a first branch flow 201 and a second branch flow 202 flowing along the strike plate 17. In this way, the spray particles of the urea solution can be further broken by the impact of the strike plate, especially the strike plate 17 can be heated by the third part of the exhaust gas 303 input by the bypass inlet 212, so that the broken small urea spray particles are more easily pyrolyzed, the uniformity of the ammonia and the exhaust gas mixed by the decomposition of the urea spray is also called the ammonia uniformity, and the strike plate can also guide the output of multiple swirls of mixed fluid, further improving the mixing effect. Continue to refer to Figures 2A to 7D As shown, in some embodiments, the specific structure of the strike plate 17 corresponding to the first branch flow 201 and the second branch flow 202 outputting multiple swirls can be that the mixer 10 further comprises an air outlet partition plate 15, the air outlet partition plate 15 has at least a first air outlet opening 151 and a second air outlet opening 152, and the air outlet partition plate 15 is arranged in the third mixing space 1422 of the downstream stroke of the third profile 23, and the third mixing space 1422 is located in the second space 142, so as to further optimize the airflow uniformity and the ammonia uniformity, and the back pressure of the mixer can be adjusted. It can be understood that the strike plate 17 can be a separate component, or can be in the form of an assembly provided with a perforated plate 171 and a strike plate 172, without being limited thereto.

[0081] In some embodiments, the strike plate 17 is arranged corresponding to the downstream of the bypass inlet 212, the mixed fluid is located on one side of the strike plate 17, and the third part of the exhaust gas 303 is located on the other side opposite to the strike plate 17. In this way, the third part of the exhaust gas 303 used for heating can be avoided to interfere with the swirl of the mixed fluid, and the third part of the exhaust gas 303 can be mixed in the third mixing space 1422 where the mixed fluid has formed a better swirl effect, further optimizing the mixing effect.

[0082] The first mixing space 1412 is further provided with a swirl member 16, the swirl member 16 has a swirl opening 161, and the swirl member 16 corresponds to the injection port 13, and the swirl member 16 can provide a mixing path including: the first part of the exhaust gas and the second part of the exhaust gas enter the swirl member 16 through the swirl opening 161 to form a swirl 305, and the swirl 305 forms a mixed fluid with the reducing agent spray 304 entering the first mixing space 1412; wherein the injection range of the reducing agent spray injected into the first mixing space 1412 is limited within the range of the internal space 162 surrounded by the swirl member.

[0083] The specific structure of the swirl member 16 can be as shown in the form of Figures 2A to 4D The swirl opening 161 of the swirl member 16 is provided with swirl vanes 163 to form a swirl, and the specific structure of the swirl member 16 can also be as shown in the form ofFigures 5A to 7D As shown, the swirl openings 161 of the swirl member 16 are helical structures themselves to form swirls, without being limited thereto.

[0084] As can be seen from the above, the beneficial effects of the mixer and the exhaust aftertreatment system according to the above embodiments include but are not limited to the following: by setting the structure of the first profile, the second profile and the third profile of the single partition member, a single partition member is realized as a multifunctional member inside the housing of the mixer, which at least integrates the functions of air inlet flow guide and provides the boundary of the mixer space of the mixer, reduces the structural complexity inside the mixer, thereby reducing the welding point positions inside the mixer, especially reducing the welding point positions in the direction of the reducing agent injection of the injector, such as urea injection, thereby reducing the risk of urea crystallization at the welding point positions, reducing the overall urea crystallization of the mixer, improving the performance stability and service life of the mixer. In addition, the engine exhaust aftertreatment system using the above mixer is efficient in nitrogen oxide treatment and has low emissions.

[0085] Although the above embodiments are disclosed as above, the present application is not intended to be limited thereto, and any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solutions of the present application, fall within the protection scope defined by the claims of the present application.

Claims

1. A mixer (10) for an exhaust gas aftertreatment system (100), characterized by The application relates to a shell (1) which provides an air inlet (11), an air outlet (12) and a spray port (13), the flow direction of an exhaust gas flow from upstream to downstream is from the air inlet (11) to the air outlet (12), the area between the air inlet (11) and the air outlet (12) provides a mixing space (14) in the flow direction, the spray port (13) is used for providing a reducing agent spray into the inlet of the mixer (10), and the spray port (13) corresponds to a spray direction. A partition member (2) is located in the mixing space (14) and separates the mixing space (14) into a first space (141) and a second space (142), the partition member (2) comprises a first profile (21), a second profile (22) and a third profile (23), the first profile (21), the second profile (22) and the third profile (23) form a stepped structure, and one of the first profile (21), the second profile (22) and the third profile (23) is directly connected with another one, the first profile (21) provides a flow guide surface (211) and corresponds to form a flow guide space (1411), the second profile (22) and the third profile (23) define a first mixing space (1412), and the second profile (22) has a flow-through opening (221) which communicates the first space (141) and the second space (142), and the projection of the spray port (13) in the spray direction on the second profile (22) is located in the opening (221). The flow and mixing paths of the exhaust gas and the reducing agent spray defined by the partition member (2) include that a first part of the exhaust gas (301) enters the first mixing space (1412) through the flow guide surface (211) of the first profile (21), a second part of the exhaust gas (302) directly enters the first mixing space (1412), the first part of the exhaust gas, the second part of the exhaust gas and the reducing agent spray (304) entering the first mixing space (1412) from the spray port (13) form a mixed fluid, and the mixed fluid flows to a second mixing space (1421) of the second space (142) through the flow-through opening (221). The first profile (21) has a bypass inlet (212), and the flow path provided by the bypass inlet (212) includes that a third part of the exhaust gas (303) directly flows to the second mixing space (1421) from the flow guide space (1411) through the bypass inlet (212).

2. The mixer (10) of claim 1, wherein The application further comprises an impact plate (17) located in the second mixing space (1421), and the flow path provided by the impact plate (17) includes that the mixed fluid impacts the impact plate (17) after entering the second mixing space (1421) and is divided into at least a first branch flow (201) and a second branch flow (202) which flow along the impact plate (17).

3. The mixer (10) of claim 2, wherein, ​ 4. The mixer (10) of claim 3, wherein Further comprising an air outlet partition (15) having at least a first air outlet opening (151) and a second air outlet opening (152), the air outlet partition (15) is arranged in a third mixing space (1422) downstream of the third profile (23), the third mixing space (1422) is located in the second space (142).

5. The mixer (10) of claim 3, wherein, The impingement plate (17) is arranged downstream of the bypass inlet (212), the mixed fluid is located on one side of the impingement plate (17), and the third portion of exhaust gas (303) is located on the other side of the impingement plate (17) in the opposite direction.

6. The mixer (10) of claim 1, wherein, The first mixing space (1412) is further provided with a swirler (16) having a swirler opening (161), and the swirler (16) corresponds to the injection port (13), the mixing path provided by the swirler (16) includes: the first portion of exhaust gas and the second portion of exhaust gas entering the swirler (16) through the swirler opening (161) to form a swirl flow (305), and the swirl flow (305) forms a mixed fluid with the reductant spray (304) entering the first mixing space (1412); wherein the injection range of the reductant spray injected into the first mixing space (1412) is limited within the range of the internal space (162) surrounded by the swirler.

7. The mixer (10) of claim 1, wherein, The first mixing space (1412) is defined by the partition member (2) and the inner wall surface of the shell (1); or the first mixing space (1412) is only defined by the partition member (2).

8. The mixer (10) of claim 1, wherein, The normal direction of the first profile (21) and the second profile (22) is perpendicular, and the normal direction of the second profile (22) and the third profile (23) is perpendicular.

9. An exhaust gas aftertreatment system (100), characterized by The mixer (10) comprises the mixer (10) according to any one of claims 1-8, and an injector (20) injecting a reductant spray into the mixer (10) from the injection port (13).

10. The exhaust aftertreatment system (100) of claim 9, characterized in that, The reductant is urea solution.

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