CN219344808U - Mixer and exhaust aftertreatment system - Google Patents

Abstract

The present utility model relates to a mixer and an exhaust aftertreatment system. The mixer comprises a cover body and a base, wherein the cover body and the base surround and define a containing space, the base comprises an air inlet opening and an air outlet opening, and the containing space comprises an air inlet area corresponding to the air inlet opening, an air outlet area corresponding to the air outlet opening and a middle area positioned between the air inlet area and the air outlet area; the mixing pipe is used for providing a mixing space for mixing the reducing agent and the exhaust gas, one end of the mixing pipe extends from the air inlet area to the air outlet area from the other end of the mixing pipe, one end of the mixing pipe is positioned in the air inlet area, and the other end of the mixing pipe is positioned in the air outlet area; the separator separates the air inlet area and the air outlet area, and the mixing pipe penetrates through the separator and is supported by the separator, so that the mixing pipe is a channel communicated with the air inlet area and the air outlet area.

Description

Mixer and exhaust aftertreatment system

Technical Field

The utility model relates to the field of exhaust gas treatment, in particular to a mixer and an exhaust gas aftertreatment system.

Background

Exhaust aftertreatment systems treat hot exhaust gases produced by an engine through various upstream exhaust components to reduce emissions pollutants. Various upstream exhaust components may include one or more of the following: pipes, filters, valves, catalysts, mufflers, etc. For example, an upstream exhaust component directs exhaust gas into a diesel oxidation catalyst (Diesel Oxidation Catalyst, DOC) having an inlet and an outlet. A diesel particulate trap (Diesel Particulate Filter, DPF) may be provided downstream of the diesel oxidation catalyst. Downstream of the diesel oxidation catalyst and optional diesel particulate filter is a selective catalytic reduction reactor (Selective Catalytic Reduction, SCR) having an inlet and an outlet. The outlet communicates exhaust gas to a downstream exhaust component. A mixer (mixer) is positioned downstream of the outlet of the DOC or DPF, upstream of the inlet of the SCR. Within the mixer, the exhaust gas produces a swirling or rotating motion. An injector (injector) is used to inject a reductant, such as an aqueous urea solution, into the exhaust stream upstream of the SCR so that the mixer can mix the urea and exhaust sufficiently together for discharge into the SCR for a reduction reaction to produce nitrogen and water to reduce nitrogen oxide emissions from the engine. However, there are improvements in existing mixers, such as further improvements in the uniformity of mixing of exhaust gas with urea, reduced urea crystallization, etc.

Accordingly, there is a need in the art for a mixer with good mixing uniformity, low urea crystallization rate, and exhaust aftertreatment system with low emissions of nitrogen oxides.

Disclosure of Invention

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

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

A mixer according to a first aspect of the present application for an exhaust aftertreatment system, comprising a cover; the base is surrounded by the cover body and the base to define an accommodating space, the base comprises an air inlet opening and an air outlet opening, and the accommodating space comprises an air inlet area corresponding to the air inlet opening, an air outlet area corresponding to the air outlet opening and a middle area between the air inlet area and the air outlet area; the mixing pipe is used for providing a mixing space for mixing the reducing agent and the exhaust gas, one end of the mixing pipe extends from the air inlet area to the air outlet area from the other end of the mixing pipe, one end of the mixing pipe is positioned in the air inlet area, and the other end of the mixing pipe is positioned in the air outlet area; the separator separates the air inlet area from the air outlet area, and the mixing pipe penetrates through the separator and is supported by the separator, so that the mixing pipe is a channel for communicating the air inlet area and the air outlet area; the mixing pipe comprises a first pipe and a second pipe sleeved by the first pipe, wherein a first air inlet opening is formed in the upstream section of the pipe wall of the first pipe, a first rotational flow structure is arranged at the first air inlet opening, an air flow bypass channel is formed by a radial gap between the second pipe and the first pipe, a second air inlet opening is formed in the pipe wall of the second pipe, corresponding to the axial area of the first air inlet opening, a second rotational flow structure is arranged at the second air inlet opening, and an inlet for the injected reducing agent to enter the mixing space is provided at the upstream port of the second pipe.

In one or more embodiments of the mixer, the axial length of the second air inlet opening is smaller than the axial length corresponding to the injection length of the injector.

In one or more embodiments of the mixer, the first tube has an upstream porous region upstream of the partition corresponding to the intake zone; the first tube also has a downstream porous region downstream of the separator corresponding to the gas outlet region.

In one or more embodiments of the mixer, the second tube has a porous region downstream of the second air inlet opening.

In one or more embodiments of the mixer, the first air inlet opening is a slot-shaped hole, the second air inlet opening is a circular hole structure, the upstream porous region, the downstream porous region, and the porous region are all circular hole structures, and the aperture of the second air inlet opening is larger than the apertures of the upstream porous region, the downstream porous region, and the porous region.

In one or more embodiments of the mixer, the swirling directions of the first and second swirling structures are the same or opposite.

In one or more embodiments of the mixer, the length of the first tube is greater than or less than the second tube, the downstream port of the first tube is downstream or upstream of the downstream port of the second tube, and the downstream port of the first tube is in a bevel or flat cut configuration.

In one or more embodiments of the mixer, the inlet opening and/or the outlet opening is provided with a porous structure.

In one or more embodiments of the mixer, the cover includes a first portion disposed opposite one end of the mixing tube, a second portion disposed opposite the other end of the mixing tube; the first portion provides a corresponding mounting area for mounting the injector and the second portion has a contour shape that is substantially arc-shaped symmetrical about the axis of the mixing tube.

An exhaust aftertreatment system according to a second aspect of the present application comprises the mixer of the first aspect, and an injector capable of spraying reductant liquid into the mixing tube of the mixer such that exhaust gas is mixed with reductant in the mixing space.

In one or more embodiments of the exhaust aftertreatment system, the exhaust aftertreatment system further includes a first exhaust treatment portion coupled to the inlet opening of the mixer to provide exhaust gas from the inlet opening into the mixer, and a second exhaust treatment portion coupled to the outlet opening of the mixer such that the mixed gas flow within the mixer flows out to the second exhaust treatment portion.

In one or more embodiments of the exhaust aftertreatment system, a diesel particulate trap or a diesel oxidation catalyst of the first exhaust treatment portion is connected with the mixer, and a selective catalytic reduction reactor of the second exhaust treatment portion is connected with the mixer.

In one or more embodiments of the exhaust aftertreatment system, the reductant is a urea solution.

The advancing effects of the present application include, but are not limited to, the synergistic effect of the first tube, the second tube, and the baffle through the mixing tube, so that better mixing of the exhaust gas with the reductant spray can be achieved, less urea crystallization with better ammonia uniformity. The principle is that the mixing pipe is called as a main channel for communicating an air inlet area and an air outlet area of the mixer through the partition plate, so that exhaust gas enters the mixing pipe as much as possible to be mixed with reducing agent spray, and the swirling action of the exhaust gas in the mixing pipe is favorable for fully mixing urea spray and exhaust gas through the nested structure of the first pipe and the second pipe and the first swirling structure and the second swirling structure of the side wall, and meanwhile, the urea is fully heated and the urea is less in crystallization through the arrangement of the airflow bypass channel; the exhaust aftertreatment system adopting the mixer has high nitrogen oxide treatment efficiency and less emission.

Drawings

The above and other features, properties and advantages of the present application will become more apparent from the following description of the embodiments and the accompanying drawings, which are to be taken as examples only, are not drawn to scale and should not be construed as limiting the scope of protection actually required by the present application, wherein:

FIG. 1 is a schematic diagram of an exhaust aftertreatment system of an embodiment;

FIGS. 2A-2C are schematic illustrations of a mixer and eductor assembly according to one embodiment;

FIGS. 3A and 3B are schematic views showing an internal structure of a mixer, a mixer and an ejector combination according to an embodiment;

FIGS. 4A and 4B are schematic views of the internal structure of a mixer, mixer and eductor assembly of an embodiment, respectively, from another perspective;

FIGS. 5A and 5B are schematic views showing structures of a first pipe and a second pipe of a mixing pipe of a mixer according to an embodiment;

FIGS. 6A and 6B are schematic views of the exterior and interior structures, respectively, of a mixing tube and eductor combination of a mixer according to one embodiment;

FIGS. 7A and 7B are schematic diagrams illustrating side views of mixing tubes according to one embodiment and another embodiment, respectively;

FIGS. 8A and 8B are schematic diagrams illustrating top views of a mixer, mixer and eductor combination, respectively, according to one embodiment;

fig. 9A and 9B are schematic views of porous structures of an air inlet opening and an air outlet opening of a base of a mixer according to an embodiment.

Reference numerals:

100-an exhaust aftertreatment system, 101-a first exhaust treatment section, 102-a second exhaust treatment section, 10-a mixer, 20-an injector;

1-a cover body, 11-a first part, 12-a second part;

2-a base, 21-an air inlet opening, 211-a first partition, 22-an air outlet opening, 221-a second partition;

3-accommodating space, 31-air inlet area, 32-air outlet area and 33-middle area;

4-mixing tube, 40-mixing space, 401-one end of mixing tube, 402-the other end of mixing tube, 41-first tube, 411-first inlet opening, 4111-first swirl structure, 4112-first swirl vane, 412-upstream porous region, 413-downstream porous region, 414-downstream port of first tube, 42-second tube, 420-upstream port of second tube, 421-second inlet opening, 4211-second swirl structure, 4212-second swirl vane, 422-porous region, 423-downstream port of second tube, 424-weld leg, 43-bypass channel, axis of A1-mixing tube;

5-separator.

Detailed Description

The following discloses a number of different embodiments or examples of implementing the subject technology. Specific examples of components and arrangements are described below for purposes of simplifying the disclosure, and are, of course, merely examples and are not intended to limit the scope of the present application.

It is appreciated that references in the following description to "one embodiment," "an embodiment," and/or "some embodiments" mean a particular feature, structure, or characteristic described in connection with at least one embodiment of the present application. Thus, it should be emphasized and should be appreciated that two or more references to "an embodiment" or "one or more embodiments" in various positions in this specification are not necessarily referring to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of the present application may be combined as suitable.

The mixer and exhaust aftertreatment system described herein are examples of an automotive exhaust aftertreatment system, but are not intended to exclude other applications. For example, the present utility model can be applied to other vehicles or machines, such as agricultural machines, marine engines, and train engines, and the mixer and exhaust gas aftertreatment system described in the application may be applied to any equipment that requires treatment of nitrogen oxides.

Referring to FIG. 1, in one embodiment, exhaust aftertreatment system 100 may be a U-shaped structure, as shown in FIG. 1, with first exhaust treatment portion 101, second exhaust treatment portion 102 arranged substantially in parallel, and mixer 10 connecting the two between first exhaust treatment portion 101 and second exhaust treatment portion 102. The first exhaust treatment portion 101 is connected to an inlet opening of the mixer 10 to provide exhaust gas from the inlet opening 21 into the mixer 10, and the second exhaust treatment portion 102 is connected to an outlet opening 22 of the mixer 10 such that the mixed gas flow in the mixer 10 flows out to the second exhaust treatment portion 102. The component of the first exhaust treatment portion 101 connected to the mixer 10 may be a diesel oxidation catalyst (Diesel Oxidation Catalyst, DOC), a diesel particulate trap (Diesel Particulate Filter, DPF), and the component of the first exhaust treatment portion 101 connected to the mixer may be a selective catalytic reduction reactor (Selective Catalytic Reduction, SCR). The diesel oxidation catalyst and the diesel particulate filter described above are common terms in the art, but are not limited to DOC and DPF, and can only be used in exhaust aftertreatment systems for diesel engines. The exhaust gas discharged from the internal combustion engine sequentially passes through the diesel oxidation catalyst for treating unburned hydrocarbon and carbon monoxide in the exhaust gas, the diesel particle trap for treating particle pollutants in the exhaust gas, then enters the mixer 10, is mixed with the spray of the reducing agent liquid, typically urea solution, sprayed by the sprayer 20, and the mixed gas flows out of the mixer 10 to the second exhaust gas treatment part 102, and then enters the mixed gas flow of the selective catalytic reduction reactor for carrying out reduction reaction to generate nitrogen and water, so as to treat nitrogen oxides in the exhaust gas. It will be appreciated that the exhaust component is not limited to that described above, e.g., in some exhaust aftertreatment systems, the particulate trap may be omitted.

Referring to fig. 2A to 9B, in some embodiments, the mixer 10 includes a cover 1, a base 2, a mixing tube 4, and a baffle 5. The cover 1 and the base 2 enclose a containing space 3, the base 2 includes an air inlet opening 21 and an air outlet opening 22, and the containing space 3 includes an air inlet region 31 corresponding to the air inlet opening 21, an air outlet region 32 corresponding to the air outlet opening 22, and an intermediate region 33 therebetween.

The mixing pipe 4 provides a mixing space 40 in which the reducing agent and the exhaust gas are mixed, and as shown with reference to fig. 3A to 4B, one end 401 to the other end 402 of the mixing pipe extends from the inlet region 31 to the outlet region 32, one end 401 of the mixing pipe is located in the inlet region 31, and the other end 402 of the mixing pipe is located in the outlet region 32.

The partition 5 partitions the inlet region 31 and the outlet region 32, and the mixing pipe 4 passes through the partition 5 and is supported by the partition 5 such that the mixing pipe 4 is a passage communicating the inlet region 31 and the outlet region 32. In some embodiments, the partition 5 may be connected to the cover 1, the base 2, and the outer wall of the mixing tube 4 through a welded seam structure, so that the mixing tube 4 is supported firmly, and the mixing tube can be kept stable even under the working condition of strong vibration, so that the relative positions of the injector 20 and the axis of the mixing tube 4 are kept stable, which is beneficial to the mixing effect. In addition, the partition 5 makes the mixing pipe 4 be a channel communicating with the air inlet area 31 and the air outlet area 32, the meaning of the mixing pipe is mainly or even the only channel, and the meaning of the main channel is that most of the exhaust gas flows from the air inlet area 31 to the air outlet area 32 through the mixing pipe 4, but a small proportion of the exhaust gas is not discharged from a connecting gap of the partition 5, or small holes are formed in the partition 5 in some cases to reduce the exhaust back pressure, but the area of the small holes is far smaller than the area of the partition 5, so that most of the exhaust gas still passes through the mixing pipe. In the embodiment shown in fig. 4A and 4B, the number of the partition plates 5 is one, but not limited thereto, and may be two, for example, as long as the space in the intermediate region 33 allows, and the number of the partition plates 5 may be increased to support the mixing pipe 4 more firmly.

Referring to fig. 5A to 7B, the mixing tube 4 includes a first tube 41 and a second tube 42 sleeved by the first tube 41, an upstream section of a tube wall of the first tube 41 has a first air inlet opening 411, the first air inlet opening 411 is provided with a first swirl structure 4111, a radial gap between the second tube 42 and the first tube 41 forms an air flow bypass channel 43, an axial region of the tube wall of the second tube 42 corresponding to the first air inlet opening 411 has a second air inlet opening 421, and the second air inlet opening 421 is provided with a second swirl structure 4211, wherein, referring to fig. 6A and 6B, an upstream port 420 of the second tube provides an inlet of injected reducing agent into the mixing space 40. It will be appreciated that the longer the axial length of the first air inlet 411 and the first swirl structure 4111 provided therein, the stronger the swirling effect is facilitated, but the structural strength is affected. The second air inlet 421 is used to assist the swirling effect of the first air inlet 411, and preferably, the axial length of the second air inlet 421 is smaller than the axial length corresponding to the injection length of the injector 20, so as to avoid urea spray from the second air inlet 421. The injection length of the injector 20 is referred to herein as the longest injection length in accordance with the corresponding design operating conditions.

With continued reference to fig. 5A and 5B, in some embodiments, the first tube 41 has an upstream porous region 412, where the upstream porous region 41 is located upstream of the partition 5, corresponding to the air intake region 31, and as to the specific location of the upstream porous region 412, it may be downstream of the first air intake openings 411 or may be disposed between the first air intake openings 411, for example, may be in an axial region between two first air intake openings 411 as shown in the figures. The first tube 41 also has a downstream porous region 413, the downstream porous region 413 being located downstream of the partition 5, corresponding to the gas outlet region 32. The provision of the upstream porous zone 412 has the advantage that the exhaust back pressure can be reduced and the amount of exhaust gas can be increased slightly here, so that the temperature corresponding to this zone increases, avoiding the urea spray accumulating near the wall of the corresponding second pipe 42 here to form a liquid film, to further reduce urea crystallization. The downstream porous region 413 has the beneficial effects of reducing exhaust back pressure, enabling the urea in the exhaust region to be mixed with the exhaust gas more uniformly, and further improving ammonia uniformity. As shown in fig. 5B, in some embodiments, the second tube 42 has a porous region 422, the porous region 422 extending axially from downstream of the second air inlet opening 421 to the downstream end of the second tube 42, which may enhance heat exchange of the exhaust gas with the second tube 42 to ensure decomposition of the urea spray and reduce urea crystallization. It will be appreciated that the use of the porous region 422 affects the strength of the second tube 42, and thus, if the requirement for urea crystallization is met without the porous region 422, no further provision of the porous region 422 is required.

Referring to fig. 7A and 7B, in some embodiments, the specific form of the swirl structure may be that the first swirl structure 4111 includes a first swirl blade 4112 corresponding to each first air inlet opening 411, and the second swirl structure 4211 includes a second swirl blade 4212 corresponding to each second air inlet opening 421, as shown in fig. 7A, and in one embodiment, the swirl directions of the first swirl structure 4111 and the second swirl structure 4211 are the same, that is, the arrow of the direction of the extension of the airflow guided by the first swirl blade 1112 and the arrow of the direction of the extension of the airflow guided by the second swirl blade 1212 point to the same side, as shown in fig. 7B, and in another embodiment, the swirl directions of the first swirl structure 4111 and the second swirl structure 4211 are opposite, that is, the arrow of the direction of the extension of the airflow guided by the first swirl blade 4112 and the arrow of the direction of the extension of the airflow guided by the second swirl blade 4212 point to different sides. The rotational flow directions are the same or opposite, and are selected according to the actual mixing uniformity requirement and the back pressure requirement. For example, when the swirling effect of the first swirling structure 4111 is too strong to break the spray of urea spray, the opposite direction adjustment may be used, and when the swirling direction is the same, the swirling is further enhanced. It will be appreciated that the form of the swirl structure is not limited to that shown in this figure, for example, it is not possible that each air inlet opening is provided with a swirl vane, nor is the shape of the swirl vane limited to that shown in the figure, for example, the structure similar to the elongated vane of the first swirl vane 4112 shown in the figure, and the structure of the second swirl vane 4212 is a concave structure from a semicircle formed by punching.

Exhaust aftertreatment systems treat hot exhaust gases produced by an engine through various upstream exhaust components to reduce emissions pollutants. Within the mixer, the exhaust gas produces a swirling or rotating motion. An injector (injector) is used to inject a reductant, such as an aqueous urea solution, into the exhaust stream upstream of the SCR so that the mixer can mix the urea and exhaust sufficiently together for discharge into the SCR for a reduction reaction to produce nitrogen and water to reduce nitrogen oxide emissions from the engine. Critical technical requirements for the mixer include urea crystallization requirements and ammonia uniformity requirements, i.e. requirements for the urea to decompose sufficiently in the mixer without crystallization, and high mixing uniformity, i.e. ammonia distribution uniformity index (NH ₃ Hereinafter referred to as ammonia Uniformity) is high.

The beneficial effects of adopting above embodiment scheme include, through the synergism of first pipe, second pipe and the baffle of hybrid tube, so can realize better exhaust and reducing agent spraying's mixed effect, less urea crystallization is with better ammonia degree of consistency. The principle is that the mixing pipe is called as a main channel for communicating an air inlet area and an air outlet area of the mixer through the partition plate, so that exhaust gas enters the mixing pipe as much as possible to be mixed with reducing agent spray, and the swirling action of the exhaust gas in the mixing pipe is favorable for fully mixing urea spray and exhaust gas through the nested structure of the first pipe and the second pipe and the first swirling structure and the second swirling structure of the side wall, and meanwhile, the urea is fully heated and the urea is less in crystallization through the arrangement of the airflow bypass channel; the exhaust aftertreatment system adopting the mixer has high nitrogen oxide treatment efficiency and less emission.

With continued reference to fig. 3A-6B, in some embodiments, the first air inlet opening 411 may be a slotted aperture, the second air inlet opening 421 may be a circular aperture structure, the upstream porous region 412, the downstream porous region 413, and the porous region 422 may each be a circular aperture structure, and the aperture size of the second air inlet opening 421 may be greater than the aperture sizes of the upstream porous region 41, the downstream porous region 413, and the porous region 422. However, the present utility model is not limited thereto, and for example, the upstream porous region 412, the downstream porous region 413, and the porous region 422 may be formed by grooved holes, or may be formed by mixed holes such as grooved holes and circular holes.

With continued reference to fig. 5A and 5B, in some embodiments, the length of the first tube 41 is greater than the second tube 42, with the downstream port 414 of the first tube being downstream of the downstream port 423 of the second tube, and the downstream port 414 of the first tube being in a beveled cut configuration. By "beveled" is meant that the downstream port 414 is disposed obliquely to its axis rather than perpendicularly, such an effect may cause the flow exiting the downstream port 414 to split into two swirls, resulting in a good mixing of the exhaust gas and reducing components in the mixed flow, and easy uniform adhesion to the SCR. The person skilled in the art can adjust the effect of the swirling flow by adjusting the inclination angle of the diagonal slit and the distance position of the air outlet from the cover 1. And the structure can also achieve the effect of reducing exhaust back pressure. It will be appreciated that the downstream port 414 is not limited to a chamfer configuration, and may be, for example, a generally straight cut, with the benefit that the effective length of the straight cut first tube 41 is greater than a chamfer cut with the same length, thus providing a long path for exhaust gas flow, which is beneficial for reducing urea crystallization. It will be appreciated that the length of the first tube 41 and the location of the downstream port 414 of the first tube, the length of the second tube 42 being greater than the first tube 41, the downstream port 423 of the second tube being downstream of the downstream port 414 of the first tube, may provide a longer exhaust and urea spray mixing flow path, reducing urea crystallization, and particularly reducing urea accumulation at the weld foot 424 of the second tube 42 where the first tube 41 is connected, resulting in crystallization. Referring to fig. 8A and 8B, in some embodiments, the cover 1 includes a first portion 11, a second portion 12, the first portion 11 being disposed opposite one end 401 of the mixing tube, the second portion 12 being disposed opposite the other end 402 of the mixing tube; the first portion 11 provides a corresponding mounting area for the injectors 20, where for example the mounting seats of the injectors 20 can be provided, while the second portion 12 has a profile substantially in the shape of two arcs 121, 122 symmetrical about the axis A1 of the mixing duct 4, for example the "omega" configuration shown in the figures, so as to divide the flow exiting from the downstream port 423 into two more uniform swirls, optimizing the mixing effect.

Referring to fig. 9A and 9B, in some embodiments, the air inlet 21 shown in fig. 9A and the air outlet 22 shown in fig. 9B are porous structures, for example, the first partition 211 and the second partition 221 having porous structures as shown in fig. 9A and 9B may be disposed on the base. The arrangement of the porous structure in the air inlet opening 21 has the beneficial effects that the exhaust flow in the air inlet area 31 can be more uniform and gentle, so that the exhaust is more fully swirled by the first swirling structure 4111 arranged in the first air inlet opening 411, and the air flow is more uniform around the first pipe 41, rather than most of the air is introduced under the first pipe 41. The outlet opening 22 is provided with a porous structure, which has the advantage of further optimizing the uniformity of the mixed gas flow output from the mixer 10 and improving the ammonia uniformity so that it can be uniformly adhered to the SCR. It will be appreciated that the provision of a porous structure is a preferred embodiment and not required, for example, the provision of the first and second baffles 211, 221 allows the internal gas flow conditions to be adjusted so that the mixer 10 can meet higher performance requirements, but the provision of the first and second baffles 211, 221 correspondingly increases costs, and therefore, if the mixer 10 can meet performance requirements without a porous structure, the provision of a porous structure is not required, for example, when the length of the second exhaust treatment portion 102 downstream of the mixer is better, the distance from the outlet opening 22 to the SCR is longer, and the mixed gas flow output from the mixer 10 achieves better ammonia uniformity in a longer flow path, and therefore the provision of the second baffle 221 is not required. Conversely, if the distance from the outlet opening 22 to the SCR is short, it is likely that the second separator 221 will need to be provided.

In summary, the beneficial effects of the mixer and the exhaust aftertreatment system described in the above embodiments include that the mixer can achieve better mixing effect of exhaust and reducing agent spraying, less urea crystallization is better in ammonia uniformity, and the exhaust aftertreatment system adopting the mixer has high nitrogen oxide treatment efficiency and less emission.

Although the present utility model has been described with reference to the above embodiments, it is not intended to be limited thereto, and any person skilled in the art can make possible variations and modifications without departing from the spirit and scope of the present utility model. Therefore, any modifications, equivalent variations and modifications made to the above embodiments according to the technical substance of the present application fall within the protection scope defined by the claims of the present application, unless they depart from the content of the technical solution of the present application.

Claims (13)

1. A mixer (10) for an exhaust aftertreatment system (100), comprising:

a cover (1);

-a base (2), the cover (1) and the base (2) enclosing a containment space (3), the base (2) comprising an air inlet opening (21) and an air outlet opening (22), the containment space (3) comprising an air inlet zone (31) corresponding to the air inlet opening (21), and an air outlet zone (32) corresponding to the air outlet opening (22) and an intermediate zone (33) therebetween;

a mixing tube (4) providing a mixing space (40) in which a reducing agent and an exhaust gas are mixed, one end (401) of the mixing tube extending from the air inlet region (31) to the air outlet region (32) to the other end (402), one end (401) of the mixing tube being located in the air inlet region (31), the other end (402) of the mixing tube being located in the air outlet region (32);

a partition plate (5) that separates the gas inlet region (31) and the gas outlet region (32), and the mixing pipe (4) passes through the partition plate (5) and is supported by the partition plate (5) such that the mixing pipe (4) is a passage that communicates the gas inlet region (31) and the gas outlet region (32);

wherein, mixing tube (4) include first pipe (41) and by second pipe (42) that first pipe (41) cover was established, the upstream section of the pipe wall of first pipe (41) has first inlet opening (411), first inlet opening (411) are provided with first swirl structure (4111), second pipe (42) with the radial clearance of first pipe (41) constitutes air current bypass passageway (43), the pipe wall of second pipe (42) corresponds the axial region of first inlet opening (411) has second inlet opening (421), second inlet opening (421) are provided with second swirl structure (4211), wherein, second pipe's upstream port (420) provides the entry of the reductant of injection entering mixing space (40).

2. The mixer (10) according to claim 1, wherein the axial length of the second air inlet opening (421) is smaller than the axial length corresponding to the injection length of the injector (20).

3. The mixer (10) according to claim 1, wherein said first tube (41) has an upstream porous zone (412), said upstream porous zone (412) being located upstream of said partition (5), in correspondence of said intake zone (31); the first tube (41) also has a downstream porous region (413), the downstream porous region (413) being located downstream of the separator (5) corresponding to the outlet region (32).

4. A mixer (10) as claimed in claim 3, characterized in that the second tube (42) has a porous region (422) downstream of the second air inlet opening (421).

5. The mixer (10) of claim 4, wherein the first air inlet opening (411) is a slot-shaped hole, the second air inlet opening (421) is a circular hole structure, the upstream porous region (412), the downstream porous region (413), and the porous region (422) are all circular hole structures, and the aperture of the second air inlet opening (421) is larger than the aperture of the upstream porous region (412), the downstream porous region (413), and the porous region (422).

6. The mixer (10) of claim 1, wherein the swirling directions of the first swirling structure (4111) and the second swirling structure (4211) are the same or opposite.

7. The mixer (10) of claim 1, wherein the first tube (41) has a length greater than or less than the second tube (42), the downstream port (414) of the first tube being located downstream or upstream of the downstream port (423) of the second tube, the downstream port (414) of the first tube being of a mitered or flat cut configuration.

8. The mixer (10) according to claim 1, wherein the inlet opening (21) and/or the outlet opening (22) are provided with a porous structure.

9. The mixer (10) according to claim 1, wherein the cover (1) comprises a first portion (11), a second portion (12), the first portion (11) being arranged opposite one end (401) of the mixing tube, the second portion (12) being arranged opposite the other end (402) of the mixing tube; the first portion (11) provides a corresponding mounting area for mounting the injector (20), and the profile shape of the second portion (12) is substantially arc-shaped symmetrical about the axis of the mixing tube (4).

10. An exhaust aftertreatment system (100), comprising: the mixer (10) according to any one of claims 1-9, and an injector (20), the injector (20) being capable of spraying a reductant liquid into the mixing tube (4) of the mixer (10) such that exhaust gas is mixed with reductant in the mixing space (40).

11. The exhaust aftertreatment system (100) of claim 10, wherein the exhaust aftertreatment system (100) further comprises a first exhaust treatment portion (101), a second exhaust treatment portion (102), the first exhaust treatment portion (101) being connected to the inlet opening (21) of the mixer (10) to provide exhaust gas from the inlet opening (21) into the mixer (10), the second exhaust treatment portion (102) being connected to the outlet opening (22) of the mixer (10) such that the flow of gas mixed within the mixer (10) flows out to the second exhaust treatment portion (102).

12. The exhaust aftertreatment system (100) of claim 11, wherein a diesel particulate trap or a diesel oxidation catalyst of the first exhaust treatment portion (101) is connected to the mixer (10), and a selective catalytic reduction reactor of the second exhaust treatment portion (102) is connected to the mixer (10).

13. The exhaust aftertreatment system (100) of claim 10, wherein the reductant is a urea solution.

Images