CN216922270U

CN216922270U - SCR mixing arrangement and engine

Info

Publication number: CN216922270U
Application number: CN202220054857.1U
Authority: CN
Inventors: 张军
Original assignee: Weichai Power Co Ltd; Weichai Power Emission Solutions Technology Co Ltd
Current assignee: Weichai Power Co Ltd; Weichai Power Emission Solutions Technology Co Ltd
Priority date: 2022-01-10
Filing date: 2022-01-10
Publication date: 2022-07-08
Anticipated expiration: 2032-01-10

Abstract

The utility model discloses an SCR mixing device and an engine, wherein the mixing device comprises a mixing pipe, a first mixing cavity and a second mixing cavity are axially arranged in the mixing pipe, a cyclone pipe is arranged in the first mixing cavity, the cyclone pipe is provided with an air inlet end and an air outlet end, the air inlet end is connected with a tail pipe of the engine, the air outlet end is communicated with the second mixing cavity, a vortex mixer is arranged in the second mixing cavity and comprises a plurality of blades, at least part of regions of the blades are bent around the axis of the mixing pipe so that fluid can form rotating vortex through the blades, and the blades are provided with overflowing openings. After urea liquid drops are on the wall of the blade, the wall area of the urea liquid drops is reduced due to the existence of the overflowing port, the heat exchange efficiency of the blade is improved, and the risk of crystallization of the urea liquid drops is greatly reduced. And the air flow can pass through the blade through the flow passing opening, so that urea crystals on the blade can be blown off by the impact force of the air flow, and the urea crystals are prevented from being accumulated on the blade.

Description

SCR mixing arrangement and engine

Technical Field

The utility model belongs to the technical field of engine aftertreatment, and particularly relates to an SCR mixing device and an engine.

Background

SCR (Selective Catalytic Reduction) is a technology for removing nitrogen oxides (NOx) from diesel exhaust. By mixing urea into engine exhaust gas, ammonia (NH) generated by hydrolysis of urea is utilized₃) Converting nitrogen oxides (NOx) in exhaust gas into nitrogen (N) under the action of catalyst₂)。

The SCR mixer is a device arranged between an engine exhaust pipe and an SCR carrier, and is mainly used for improving the mixing effect of urea and exhaust gas and improving the NOx conversion efficiency.

The SCR mixer generally includes a mixing tube and a swirl tube disposed within the mixing tube for causing the flow of air entering the mixing tube to rotate, facilitating mixing of the exhaust gas and urea. Some SCR mixers are also provided with worm blades inside the mixing tube to further swirl the gas flow inside the mixing tube, further accelerating the mixing effect of the exhaust gas and urea.

However, when the gas flow mixed with urea droplets passes through the swirl vanes, the urea droplets adhere to the surfaces of the worm wheel blades, and the urea absorbs heat during the decomposition reaction, and further, the urea in the droplets precipitates and adheres to the surfaces of the worm wheel blades, and gradually accumulates to form urea crystals, which affects the reaction efficiency of the urea, and thus the atomization effect of the SCR mixer is reduced.

SUMMERY OF THE UTILITY MODEL

The utility model provides an SCR mixing device and an engine, which aim to solve at least one of the technical problems.

The technical scheme adopted by the utility model is as follows:

the utility model provides a SCR mixing arrangement, includes the hybrid tube, the inside of hybrid tube is provided with first hybrid chamber and second hybrid chamber along the axial, be provided with the cyclone tube in the first hybrid chamber, the cyclone tube has the inlet end and gives vent to anger the end, the inlet end is used for being connected with the engine tail pipe, the end intercommunication of giving vent to anger the second hybrid chamber, be provided with the vortex mixer in the second hybrid chamber, the vortex mixer includes a plurality of blades, at least partial region of blade winds the axis of hybrid tube is crooked, so that the fluid process the blade forms rotatory vortex, the mouth of overflowing has been seted up to the blade.

The blade include plane portion and with the curved surface portion that plane portion linked firmly, plane portion be on a parallel with the axis setting of hybrid tube, curved surface portion winds the axis of hybrid tube is crooked, it locates to flow through the mouth curved surface portion.

The overflowing openings are arranged on the curved surface part at intervals.

The curved surface part is provided with a plurality of groups of the overflowing openings, the overflowing openings of each group are uniformly arranged at intervals along the radial direction of the mixing pipe, and the overflowing openings of two adjacent groups are arranged along the axial direction of the mixing pipe in a staggered manner.

The bending angle of the curved surface part towards one end of the mixing pipe is larger than the bending angle of the curved surface part far away from one end of the mixing pipe.

The lateral wall of whirl pipe is provided with whirl blade and whirl mouth, the slope of whirl blade is fixed in the lateral wall of whirl pipe, so that the whirl blade with the contained angle has between the lateral wall of whirl pipe, the incline direction of whirl blade with the crooked opposite direction of blade.

First hybrid chamber is including being located the intraductal first cavity of whirl, and be located the second cavity in the whirl outside, SCR mixing arrangement still includes the separation piece, the separation piece set up in the whirl pipe with between the vortex mixer, so that first cavity with the second hybrid chamber intercommunication, just the second cavity with the second hybrid chamber is isolated.

The periphery of vortex mixer is provided with connecting portion, connecting portion orientation one side of hybrid tube has the connection cambered surface.

A partial region of the blade facing one end of the mixing tube is bent around an axis of the mixing tube to constitute the connecting portion.

The utility model also discloses an engine which comprises the exhaust nozzle and the SCR mixing unit communicated with the exhaust nozzle, wherein the SCR mixing unit comprises the SCR mixing device.

Due to the adoption of the technical scheme, the utility model has the beneficial effects that:

1. the swirl tube and the vortex mixer are respectively arranged in the first mixing cavity and the second mixing cavity of the mixing tube, so that airflow and urea spray input into the mixing tube form rotary fluid under the swirl action of the swirl tube, the mixing effect of urea liquid drops and gas is improved, the reaction speed is accelerated, then the mixed fluid enters the second mixing cavity, and a vortex is formed under the action of the vortex mixer, so that the mixing uniformity is further improved.

The blade is provided with the overflowing port, so that after urea liquid drops are on the upper wall of the blade, due to the existence of the overflowing port, the wall area of the urea liquid drops is reduced, the heat exchange efficiency of the blade is improved, the risk of crystallization of the urea liquid drops on the surface of the blade is greatly reduced, and the failure rate of the SCR mixing device is reduced. In addition, the flow-through opening can enable the air flow to pass through the blade through the flow-through opening, so that urea liquid drops or urea crystals on the blade can be blown off by the impact force of the air flow, and the urea crystals are prevented from being accumulated on the blade.

2. As a preferred embodiment of the present invention, the blade includes a planar portion and a curved portion fixedly connected to the planar portion, the planar portion is disposed parallel to an axis of the mixing tube, the curved portion is curved around the axis of the mixing tube, and the flow-passing opening is opened in the curved portion. In use, the plane part mainly plays a role in dredging fluid and guiding the fluid to flow to the curved surface part, so that the fluid is in softer contact with the plane part, the curved surface part plays a role in swirling the fluid, the fluid flows along the curved surface of the curved surface part to form a vortex, so that the fluid is in more violent contact with the curved surface part, the overflowing port is arranged on the curved surface part, the number of holes formed in the blade is reduced on the basis of effectively reducing urea crystallization on the surface of the blade, the cost is saved, the processing difficulty is reduced, and the strength of the blade is improved.

3. In a preferred embodiment of the present invention, a bending angle of the curved surface portion toward one end of the mixing pipe is larger than a bending angle of the curved surface portion away from one end of the mixing pipe. The curved surface portion is followed the crooked angle of the radial direction of mixing tube is bigger and bigger, promptly the curved surface portion is along the radial outside guide effect to the fluid of mixing tube is bigger and bigger for the fluid is followed the radial outside vortex effect of mixing tube is better more, helps the formation of fluid vortex more, makes the flow of fluid more smooth, accelerates the mixture of urea and air current, improves mixing efficiency.

4. As a preferred embodiment of the present invention, a swirl vane and a swirl port are disposed on a side wall of the swirl tube, the swirl vane is obliquely fixed to the side wall of the swirl tube so as to form an included angle between the swirl vane and the side wall of the swirl tube, and an oblique direction of the swirl vane is opposite to a bending direction of the vane. The process rotatory fluid that the whirl pipe formed gets into behind the second mixing chamber, form reverse vortex, make the fluid in the second mixing chamber takes place the turbulent flow, and the fluid moves more unordered before forming the vortex, can further promote the mixed effect of urea and air current, promotes the homogeneity of the ammonia distribution that produces after the urea decomposes simultaneously, reduces the risk of urea crystallization.

5. In a preferred embodiment of the present invention, the vortex mixer is provided at an outer periphery thereof with a connection portion having a connection arc surface on a side facing the mixing pipe. The vortex mixer passes through connecting portion link firmly in the inner wall of hybrid tube, the connection cambered surface of connecting portion with the inner wall shape adaptation of hybrid tube has increased connecting portion with the area of contact of hybrid tube, the convenient connection, and improve connecting portion with the joint strength of hybrid tube inner wall prevents the vortex mixer is followed drop on the hybrid tube.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model and not to limit the utility model. In the drawings:

FIG. 1 is a schematic view of the internal structure of the mixing tube according to an embodiment of the present invention;

FIG. 2 is a top view of the mixing tube of FIG. 1;

FIG. 3 is a bottom view of the mixing tube of FIG. 1;

FIG. 4 is a schematic view of the mixing tube of FIG. 1 from another perspective;

FIG. 5 is a schematic view of the blade according to an embodiment of the present invention;

FIG. 6 is a front view of the blade of FIG. 5;

fig. 7 is a schematic structural view of the blocking member according to an embodiment of the present invention.

Wherein:

1, mixing a tube; 11 a first mixing chamber; 111 a first cavity; 112 a second cavity; 12 a second mixing chamber;

2, a cyclone tube; 21 swirl vanes; 22 a swirl port;

3, a vortex mixer; 31 blades; 311 a planar portion; 312 curved surface portion; 313 flow through port; 32 a connecting part; 321 is connected with the cambered surface;

4 a barrier; 41 a conduction region; 42 barrier region.

Detailed Description

In order to more clearly explain the overall concept of the utility model, the following detailed description is given by way of example in conjunction with the accompanying drawings.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

In addition, in the description of the present invention, it is to be understood that the terms "inner", "outer", "axial", "radial", and the like, indicate orientations or positional relationships based on those shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. In the description herein, references to the terms "implementation," "embodiment," "one embodiment," "example" or "specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

As shown in fig. 1 to 7, an SCR mixing device includes a mixing tube 1, a first mixing chamber 11 and a second mixing chamber 12 are axially disposed inside the mixing tube 1, a swirl tube 2 is disposed in the first mixing chamber 11, the swirl tube 2 has an inlet end 23 and an outlet end 24, the inlet end 23 is used for being connected to a tail pipe of an engine, the outlet end 24 is communicated with the second mixing chamber 12, a vortex mixer 3 is disposed in the second mixing chamber 12, the vortex mixer 3 includes a plurality of blades 31, at least a part of the blades 31 are bent around an axis of the mixing tube 1, so that a fluid passes through the blades 31 to form a rotating vortex, and the blades 31 are provided with flow passing ports 313.

According to the utility model, the urea is mixed with the exhaust gas discharged by the engine in the mixing cavity, the temperature of the exhaust gas is higher, the urea is subjected to hydrolysis and pyrolysis reaction by utilizing the heat of the exhaust gas to produce ammonia gas, and the ammonia gas selectively reduces the nitrogen oxides in the exhaust gas into nitrogen under the action of the catalyst so as to meet the emission requirement.

It should be noted that the mode of injecting urea into the mixing pipe 1 is not limited in the present invention, and in a preferred embodiment, a urea injection unit provided on the engine mixes a fixed amount of urea aqueous solution with gas and injects the urea aqueous solution into the swirl pipe 2 at a high pressure, so that the urea aqueous solution is injected into the swirl pipe 2 in a mist form. When specifically using, engine exhaust's waste gas and urea solution all follow swirl tube 2 axial certainly near the gas end 23 spouts into in the swirl tube 2 to improve air current flow efficiency and whirl effect.

According to the utility model, the swirl tube 2 and the vortex mixer 3 are respectively arranged in the first mixing cavity 11 and the second mixing cavity 12 of the mixing tube 1, so that the airflow and urea spray input into the mixing tube 1 form a rotary fluid under the swirling action of the swirl tube 2, the mixing effect of urea liquid drops and gas is improved, the reaction speed is accelerated, then the mixed fluid enters the second mixing cavity 12 again, and a vortex is formed under the action of the vortex mixer 3, so that the mixing uniformity is further improved.

It will be appreciated that the vanes 31 are spaced about the axis of the mixing tube 1 as shown in figure 3.

The blade 31 is provided with the overflowing port 313, so that after urea droplets are coated on the wall of the blade 31, the coated area of the urea droplets is reduced due to the existence of the overflowing port 313, the heat exchange efficiency of the blade 31 is improved, and the risk of crystallization of the urea droplets on the surface of the blade 31 is greatly reduced. Meanwhile, the existence of the flow passing opening 313 enables the air flow to pass through the blade 31 through the flow passing opening 313, thereby helping to blow off the urea liquid drops or urea crystals on the blade 31 by the impact force of the air flow and preventing the urea crystals from accumulating on the blade 31.

The structure of the blade 31 is not particularly limited, and may be one of the following embodiments:

the first implementation mode comprises the following steps: in the present embodiment, the entire blade 31 is bent around the axis of the mixing pipe 1 to enhance the guiding action of the blade 31 to the fluid and promote the formation of the vortex.

The second embodiment: in the present embodiment, as shown in fig. 5 to 6, the blade 31 includes a flat surface portion 311 and a curved surface portion 312 fixedly connected to the flat surface portion 311, the flat surface portion 311 is disposed parallel to the axis of the mixing pipe 1, the curved surface portion 312 is bent around the axis of the mixing pipe 1, and the flow passage opening 313 is opened in the curved surface portion 312.

In use, the plane portion 311 mainly serves as a canalization for fluid, and guides the fluid to flow to the curved surface portion 312, so that the fluid is in softer contact with the plane portion 311, the curved surface portion 312 serves as a rotational flow for the fluid, and the fluid flows along the curved surface of the curved surface portion 312, so as to form a vortex, so that the fluid is in more severe contact with the curved surface portion 312, and therefore, the flow passing port 313 is arranged on the curved surface portion 312, so that the number of holes formed in the blade 31 is reduced on the basis of effectively reducing the crystallization of urea on the surface of the blade 31, the cost is saved, the processing difficulty is reduced, and the strength of the blade 31 is improved.

In addition, because the surface of plane portion 311 is more level and smooth, consequently it is a plurality of the blade 31 passes through plane portion 311 links firmly together, has reduced the degree of difficulty of connecting, has improved each the connection stability between the blade 31.

Further, as shown in fig. 1 and 5 to 6, the flow openings 313 are multiple and are disposed at intervals on the curved surface portion 312.

The plurality of flow ports 313 are distributed at intervals, so that the area of the opening area of the curved surface part 312 is increased, the wall contact area of urea droplets is further reduced, and the crystallization prevention effect is improved.

In this embodiment, the arrangement of the flow ports 313 is not particularly limited, and in a preferred embodiment, as shown in fig. 6, the curved surface portion 312 is provided with a plurality of sets of the flow ports 313, the flow ports 313 of each set are uniformly spaced along the radial direction of the mixing tube 1, and the flow ports 313 of two adjacent sets are arranged along the axial direction of the mixing tube 1 in a staggered manner.

Two sets of adjacent flow port 313 is followed the axial of hybrid tube 1 is crisscross, has reduced blade 31 is followed the trompil quantity of hybrid tube 1 axial direction has improved blade 31's structural strength disperses blade 31's atress makes blade 31 atress is more even, avoids certain region of blade 31 takes place stress concentration and deformation or damage.

Of course, the flow ports 313 may be arranged in other manners, for example, the flow ports 313 are arranged in an array on the blades 31 along the axial direction and the radial direction of the mixing pipe 1, and are not limited in this respect.

As a preferred example of the present embodiment, as shown in fig. 5, the curved surface 312 is bent at a larger angle toward the end of the mixing pipe 1 than the curved surface 312 is bent at the end away from the mixing pipe 1.

The curved surface portion 312 is bent at an increasingly larger angle along the radial direction of the mixing tube 1, that is, the curved surface portion 312 has an increasingly larger guiding effect on the fluid along the radial direction of the mixing tube 1, so that the effect of the fluid on the vortex is better along the radial direction of the mixing tube 1, the formation of the fluid vortex is facilitated, the fluid flow is smoother, the mixing of urea and the air flow is accelerated, and the mixing efficiency is improved.

The shape of the swirl tube 2 is not specifically limited, and may be one of the following embodiments:

the first implementation mode comprises the following steps: in the present embodiment, as shown in fig. 1 and 4, the diameters of the air inlet end 23 and the air outlet end 24 are equal, so that the cyclone tube 2 has a cylindrical tubular structure.

Adopt the columniform structure, made things convenient for the manufacturing of whirl pipe 2 has reduced the manufacturing degree of difficulty to make things convenient for the installation of whirl blade, improved whirl blade with whirl pipe 2's joint strength, in order to improve whirl pipe 2's life.

The second embodiment: in this embodiment, the diameter of the inlet end 23 is different from the diameter of the outlet end 24, so that the cyclone tube 2 has a conical tube structure.

Specifically, the cyclone tube 2 may be in the shape of a conical tube gradually converging from the air inlet end 23 to the air outlet end 24. And then help improving the velocity of flow of air current, under the cooperation of whirl blade 21, promote the air current more and form high-speed rotatory air current in whirl pipe 2 to improve the whirlwind mixed effect of waste gas and urea, prevent that the urea liquid drop is in form the urea crystallization in whirl pipe 2.

The cyclone tube 2 may also be a tapered tube gradually expanding from the inlet end 23 to the outlet end 24. Because the gas with urea liquid drops sprayed by the nozzle is divergently enters the air inlet end 23 of the cyclone tube 2, the cyclone tube 2 is set to be in the shape of a conical tube, so that the shape of the cyclone tube 2 is closer to the shape of the urea when atomized and sprayed, the probability that the urea liquid drops directly collide with the side wall of the cyclone tube 2 can be reduced, the risk of crystallization of the urea liquid drops on the tube wall of the cyclone tube 2 is reduced, and the atomization effect of the SCR mixer is improved.

As shown in fig. 1-2, the sidewall of the cyclone tube 2 is provided with cyclone blades 21. The arrangement mode of the swirl vanes 21 is not particularly limited, and in one embodiment, the side wall of the swirl tube 2 is of a closed structure, and the swirl vanes 21 are arranged on the inner wall of the swirl tube 2. In use, the air flow and urea droplets are always inside the cyclone tube 2 and form a rotating air flow under the disturbance of the cyclone blades 21.

As a preferred embodiment, as shown in fig. 1, a cyclone blade 21 and a cyclone port 22 are disposed on a side wall of the cyclone tube 2, and the cyclone blade 21 is obliquely fixed to the side wall of the cyclone tube 2, so that an included angle is formed between the cyclone blade 21 and the side wall of the cyclone tube 2.

Because the swirl port 22 exists, make and let in the inside air current of swirl tube 2 and urea liquid drop can pass through swirl port 22 gets into swirl tube 2 with between the hybrid tube 1, and take place rotatoryly under the guide of whirl blade 21, form rotatory air current to increase the whirl route of air current, improved the whirl effect, help swirl tube 2 and swirl tube 2 with form high-speed rotatory air current between the hybrid tube 1.

Further, in the present embodiment, the inclination direction of the swirl vane 21 and the bending direction of the vane 31 are not particularly limited, and may be one of the following embodiments:

example 1: in the present embodiment, the inclination direction of the swirl vanes 21 is the same as the bending direction of the vanes 31. And then the direction of rotation of the fluid in the cyclone tube 2 is the same as the direction of rotation of the fluid in the second mixing chamber 12, so that the time for forming a vortex in the second mixing chamber 12 by the fluid is shortened, and the mixing efficiency is improved.

In a specific example, as shown in fig. 1, the swirl vanes 21 are inclined in a counterclockwise direction from the inside to the outside, and the curved direction of the vanes 31 is also in a counterclockwise direction.

Example 2: in the present embodiment, the inclination direction of the swirl vanes 21 is opposite to the bending direction of the vanes 31.

The process rotatory fluid that the whirl pipe 2 formed gets into behind the second mixing chamber 12, form reverse vortex, make the fluid in the second mixing chamber 12 takes place the turbulent flow, and the fluid moves more disorderly unordered before forming the vortex for the air current takes place to mix fiercely with urea, can further promote the mixed effect of urea and air current, promotes the homogeneity of the ammonia distribution that produces after the urea decomposes simultaneously, reduces the risk of urea crystallization.

As a preferred embodiment of the present invention, as shown in fig. 4, the first mixing chamber 11 includes a first chamber 111 located inside the cyclone tube 2, and a second chamber 112 located outside the cyclone tube 2, the SCR mixing device further includes a blocking member 4, the blocking member 4 is disposed between the cyclone tube 2 and the vortex mixer 3, so that the first chamber 111 and the second mixing chamber 12 are communicated, and the second chamber 112 and the second mixing chamber 12 are isolated.

The setting of separation piece 4 guarantees that gaseous and urea spraying are all through air intake swirl tube 2, makes the atomizing mixed effect of mixed waste gas and urea spraying reach the optimum.

Specifically, as shown in fig. 7, the blocking member 4 has an annular structure, a central region of the blocking member 4 is a conduction region 41, and an outer periphery of the conduction region 41 is a blocking region 42. The conducting region 41 corresponds to the first cavity 111, and the blocking region 42 corresponds to the second cavity 112.

Of course, the blocking part 4 may also be provided with a through opening in the blocking area 42 to communicate the second cavity 112 with the second mixing chamber 12, and the blocking area 42 is further provided with a spoiler fin to rotate the fluid passing through the through opening to form a rotational flow or a vortex flow.

As a preferred embodiment of the present invention, as shown in fig. 1 and 5, a connecting portion 32 is provided on the outer periphery of the vortex mixer 3, and a connecting arc surface 321 is provided on a side of the connecting portion 32 facing the mixing pipe 1.

Vortex mixer 3 passes through connecting portion 32 link firmly in the inner wall of hybrid tube 1, connecting portion 32 connect cambered surface 321 with the inner wall shape adaptation of hybrid tube 1 has increased connecting portion 32 with the area of contact of hybrid tube 1, the convenient connection, and improve connecting portion 32 with the joint strength of 1 inner wall of hybrid tube prevents vortex mixer 3 is followed drop on the hybrid tube 1.

The present embodiment does not specifically limit the forming manner of the connecting portion 32, and in a specific embodiment, the connecting portion 32 is staggered with the blades 31 around the axis of the mixing tube 1, the connecting portion 31 extends outward along the radial direction of the mixing tube 1, and the connecting arc surface 321 is disposed at the outer end of the connecting portion 32.

In a preferred embodiment, as shown in fig. 5, a partial region of the blade 31 facing one end of the mixing pipe 1 is bent around the axis of the mixing pipe 1 to constitute the connecting portion 32. The connecting part 32 and the blades 31 are integrally designed by bending the end parts of the blades 31 to form the connecting part 32, so that the structure of the vortex mixer 3 is simplified, and the blades 31 are fixed on the inner wall of the mixing pipe 1 together with the connecting part 32, so that the connecting strength and the connecting stability of the blades 31 are further improved.

It should be noted that, as shown in fig. 1 and 3, the vortex mixer 3 includes a plurality of blades 31, the blades 31 are spaced around the axis of the mixing tube 1, and "the end of the blade 31 facing the mixing tube 1" herein should be understood as the end of the blade 31 away from the axis of the mixing tube 1, and correspondingly, "the end of the blade 31 facing the mixing tube 1" is the end of the blade 31 close to the axis of the mixing tube 1.

According to the engine, the tail gas discharged by the exhaust jet is mixed with the urea in the SCR mixing device, and the mixed fluid sequentially carries out rotational flow and vortex flow, so that the mixing effect is improved, and harmful gases in the waste gas are converted into harmless gases and discharged. When the fluid contacts with the vortex mixer 3, the blade 31 is provided with the overflowing port 313, so that the wall area of the urea liquid drops is reduced, the heat exchange efficiency of the blade 31 is improved, the risk of crystallization of the urea liquid drops on the surface of the blade 31 is greatly reduced, and the purification effect and the service life of the SCR mixing device are improved.

The method can be realized by adopting or referring to the prior art in places which are not described in the utility model.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments.

The above description is only an example of the present invention, and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. An SCR mixing device comprises a mixing pipe, a first mixing cavity and a second mixing cavity are arranged in the mixing pipe along the axial direction, and the SCR mixing device is characterized in that,

be provided with the cyclone tube in the first mixing chamber, the cyclone tube has the inlet end and gives vent to anger the end, the inlet end is used for being connected with the engine tail pipe, give vent to anger the end intercommunication the second mixing chamber, be provided with the vortex mixer in the second mixing chamber, the vortex mixer includes a plurality of blades, the at least part region of blade winds the axis of mixing tube is crooked, so that the fluid process the blade forms rotatory vortex, the mouth of overflowing has been seted up to the blade.

2. The SCR mixing device of claim 1,

3. The SCR mixing device of claim 2,

the overflowing openings are arranged on the curved surface part at intervals.

4. The SCR mixing device of claim 3,

5. The SCR mixing device of claim 2,

6. The SCR mixing device of claim 1,

7. The SCR mixing device of claim 1,

8. The SCR mixing device of claim 1,

9. The SCR mixing device of claim 8,

a partial region of the blade facing one end of the mixing tube is bent around an axis of the mixing tube to constitute the connection portion.

10. An engine comprising an exhaust nozzle, and an SCR mixing unit in communication with the exhaust nozzle,

the SCR mixing unit comprises the SCR mixing device of any one of claims 1 to 9.