CN215109110U

CN215109110U - Mixer and engine exhaust aftertreatment system

Info

Publication number: CN215109110U
Application number: CN202121771745.XU
Authority: CN
Inventors: 彭玉玺; 王聪; 张超
Original assignee: Faurecia Emissions Control Technologies Development Shanghai Co Ltd
Current assignee: Faurecia Emissions Control Technologies Development Shanghai Co Ltd
Priority date: 2021-07-30
Filing date: 2021-07-30
Publication date: 2021-12-10
Anticipated expiration: 2031-07-30

Abstract

The utility model relates to a blender and engine exhaust after-treatment system. The mixer comprises a swirl tube, wherein the tube wall of the swirl tube comprises an air inlet opening section and a tube body section located at the downstream of the air inlet opening section, the air inlet opening section is provided with a plurality of air inlet openings, the air inlet openings are distributed along the circumferential direction of the tube wall, a swirl structure is arranged on the air inlet openings, an injection inlet is provided at the upstream side of the swirl tube, and a mixing channel of the mixer is provided in the swirl tube; the sleeve is sleeved on the periphery of the cyclone tube; the annular baffle set up in the sleeve pipe with the radial clearance of whirl pipe, the annular baffle radial inner with the whirl pipe the body section is connected, radial outer end with sheathed tube inner wall connection, the annular baffle has a plurality of intercommunication openings for the upstream and downstream intercommunication of annular baffle constitutes the exhaust gas flow bypass passageway of blender.

Description

Mixer and engine exhaust aftertreatment system

Technical Field

The utility model relates to an exhaust-gas treatment field especially relates to a blender and engine exhaust after-treatment system.

Background

Engine exhaust aftertreatment systems treat hot exhaust gases produced by the engine through various upstream exhaust components to reduce exhaust pollutants. The 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 (DOC) having an inlet and an outlet. Downstream of the Diesel oxidation catalyst, a Diesel Particulate Filter (DPF) may be arranged. Downstream of the diesel oxidation catalyst and the optional diesel particulate filter is a Selective Catalytic Reduction (SCR) reactor having an inlet and an outlet. The outlet passes the 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 rotational motion. An injector (injector) is used to inject a reductant, such as an aqueous urea solution, into the exhaust stream from upstream of the SCR so that the mixer can sufficiently mix the urea and exhaust together for discharge into the SCR for reduction to produce nitrogen and water to reduce the nitrogen oxide emissions of the engine.

However, there are still improvements to existing mixers, such as the need to reduce urea crystallization and reduce manufacturing costs, among others.

Accordingly, there is a need in the art for a mixer with low urea crystallization rate and an engine exhaust aftertreatment system with low nitrogen oxide emissions, as well as a mixer and an engine exhaust aftertreatment system that are inexpensive to manufacture.

SUMMERY OF THE UTILITY MODEL

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

Another object of the utility model is to provide an engine exhaust aftertreatment system.

The utility model discloses a mixer according to an aspect for engine exhaust aftertreatment system, including the whirl pipe, the pipe wall of whirl pipe includes air inlet opening section and is located the pipe body section of air inlet opening section low reaches, air inlet opening section has a plurality of air inlet openings, a plurality of air inlet openings along the circumference distribution of pipe wall, air inlet opening is provided with the whirl structure, the upstream side of whirl pipe provides the injection inlet, the interior mixing channel that provides the mixer of whirl pipe; the sleeve is sleeved on the periphery of the cyclone tube; the annular baffle set up in the sleeve pipe with the radial clearance of whirl pipe, the annular baffle radial inner with the whirl pipe the body section is connected, radial outer end with sheathed tube inner wall connection, the annular baffle has a plurality of intercommunication openings for the upstream and downstream intercommunication of annular baffle constitutes the exhaust gas flow bypass passageway of blender.

In one or more embodiments of the mixer, the annular baffle is axially positioned in an upstream region of the duct section and adjacent to the intake opening section.

In one or more embodiments of the mixer, the shroud includes a first shroud segment that is nested within the swirl tube and a second shroud segment that extends downstream from the first shroud segment.

In one or more embodiments of the mixer, the annular baffle has a plurality of communication openings uniformly distributed in the circumferential direction, and each communication opening is provided with a first swirl vane.

In one or more embodiments of the mixer, the upstream end of the tube wall of the swirl tube comprises a mounting portion for mounting and fixing the swirl tube.

In one or more embodiments of the mixer, the swirl structure includes a second swirl blade corresponding to each air inlet opening, the second swirl blade extending obliquely toward the inside and/or outside of the swirl tube.

According to the utility model discloses an engine exhaust aftertreatment system of an aspect, including above arbitrary one the blender to and the sprayer, the sprayer with reductant liquid spraying to spray in the whirl pipe, the sprayer is located air inlet opening's upper reaches, reductant liquid spraying follows the injection inlet gets into mix with waste gas in the whirl pipe.

In one or more embodiments of the exhaust aftertreatment system, the exhaust aftertreatment system further comprises a first portion connecting an axially upstream side of the mixer to provide the exhaust gas to enter the mixer from the intake opening, a second portion connecting an axially downstream side of the mixer such that the flow of gas mixed within the mixer flows out of the sleeve to the second portion.

In one or more embodiments of the exhaust aftertreatment system, the first portion includes a first housing providing a first flow space for exhaust gas to flow in the first flow space into the mixer, the first housing further providing an injector mount for mounting the injector; the second portion includes a second housing providing a second flow space such that the gas stream flowing out of the mixer flows in the second flow space.

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

The utility model discloses an advance effect include but not limited to, set up in through the ring baffle the sleeve pipe with the radial clearance of whirl pipe to and the intercommunication open-ended structure through the ring baffle, constitute waste gas air current bypass passageway to the pipe wall fully heating of whirl pipe, make urea fully decompose, reduce the urea crystallization, promoted the life and the reliability of blender. And moreover, the size and the number of the communication openings of the annular baffle plate can be adjusted to adapt to different engine exhaust gas aftertreatment systems, and the structure of the mixer is not required to be changed on a large scale, so that the universality of the mixer is good, and the research, development and processing cost is reduced. Meanwhile, the exhaust gas post-treatment system adopting the mixer also has the advantages of long service life, good reliability and low research, development and manufacturing costs.

Drawings

The above and other features, properties and advantages of the present invention will become more apparent from the following description of the embodiments with reference to the accompanying drawings, it being noted that the drawings are given by way of example only and are not drawn to scale, and should not be taken as limiting the scope of the invention, which is actually claimed, wherein:

FIG. 1 is a schematic illustration of an engine exhaust aftertreatment system according to an embodiment.

FIG. 2 is a schematic diagram of the internal structure of an engine exhaust aftertreatment system according to an embodiment.

FIG. 3 is a schematic diagram of a mixer and eductor according to an embodiment.

Fig. 4 is a schematic structural diagram of another perspective of the mixer of an embodiment.

FIG. 5 is a schematic view of the cyclone tube of the mixer according to an embodiment.

FIG. 6 is a side view of the swirl tube of FIG. 5.

FIG. 7 is a schematic structural view of an annular baffle of the mixer of an embodiment.

Reference numerals:

100-exhaust gas aftertreatment system

101-diesel oxidation catalyst

102-diesel particulate trap

103-selective catalytic reduction reactor

10-first part

20-second part

1-Mixer

11-swirl tube

110-air inlet opening

111-intake opening section

112-pipe body section

113-swirl structure

114-injection inlet

115-second swirl vane

116-mounting part

12-sleeve

121-first casing section

122-second casing section

13-Ring baffle

131-communication opening

132-first swirl vane

170-mixing channel

180-waste gas flow bypass channel

104-first housing

1040 injector mount

1041-first air intake part

1042-first air outlet part

204-second housing

2041-second air intake part

2042 second air outlet part

2-ejector

Detailed Description

The following discloses many different embodiments or examples for implementing the subject technology described. Specific examples of components and arrangements are described below to simplify the present disclosure, but these are merely examples and are not intended to limit the scope of the present invention.

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

Referring to fig. 1 and 2, in an embodiment, the exhaust gas after-treatment system 100 may be a box-type structure, as shown in fig. 2, including a first portion 10 and a second portion 20 respectively located at two sides in a box structure 200, and a mixer 1 and an exhaust component located in an installation space between the two sides, wherein the mixer 1 and the exhaust component may be installed and fixed by a partition of the first portion 10 and the second portion 20. The exhaust component may be, for example, a Diesel Oxidation Catalyst 101 (DOC), a Diesel Particulate Filter 102 (DPF), a Selective Catalytic Reduction reactor 103 (SCR). The diesel oxidation catalyst and the diesel particulate trap described above are terms commonly used in the art, but are not limited to DOC and DPF, which can only be used in exhaust gas after-treatment systems of diesel engines. As shown in fig. 1 and 2, a mixer 1, a diesel oxidation catalyst 101, a diesel particulate trap 102, and a selective catalytic reduction reactor 103 are disposed between both sides of the box-type structure, and one axial end of the mixer 1 is connected to the first portion 10 and the other axial end thereof is connected to the second portion 20. The exhaust gas passes through a diesel oxidation catalyst 101 in sequence for treating unburned hydrocarbon and carbon monoxide in the exhaust gas, a diesel particle trap 102 for treating particulate pollutants in the exhaust gas enters a mixer 1 again in a first part 10 to be mixed with a reducing agent liquid, generally urea solution spray, sprayed by an injector 2, the mixed gas flow flows out of the mixer 1 to a second part 20, and then enters a selective catalytic reduction reactor 103 to be subjected to reduction reaction to generate nitrogen and water, and nitrogen oxides in the exhaust gas are treated. It is to be understood that the exhaust components are not limited to those described above, and that the particulate trap 102 may be omitted, for example, in some exhaust aftertreatment systems.

As shown in fig. 2 to 7, in some embodiments, the mixer 1 includes a swirl tube 11, a sleeve 12 coaxially disposed, the sleeve 12 is disposed around the swirl tube 11, and an annular baffle 13 disposed in a radial gap between the sleeve 12 and the swirl tube 11. The tube wall of the swirl tube 11 comprises an air inlet section 111 and a tube section 112 located downstream of the air inlet section 111, the air inlet section 111 has a plurality of air inlets 110, the plurality of air inlets 110 are distributed along the circumferential direction of the tube wall, the air inlets 110 are provided with swirl structures 113, an injection inlet 114 is provided at the upstream side of the swirl tube 11, an inlet for injecting a reducing agent, typically urea solution, into the mixer is provided, and a mixing channel 170 of the mixer is provided in the swirl tube 11. A spray of urea solution enters the swirl tube from the injector 2 from the injection inlet 114 and a majority of the exhaust gas enters from the plurality of inlet openings 110. The annular baffle 13 is arranged in the radial gap between the sleeve 12 and the cyclone tube 11, the radial inner end of the annular baffle 13 is connected with the tube body section 112 of the cyclone tube 11, the radial outer end is connected with the inner wall of the sleeve 12, the annular baffle 13 is provided with a plurality of communicating openings 131, so that the upstream and downstream of the annular baffle 13 positioned in the radial gap between the sleeve 12 and the cyclone tube 11 are communicated to form an exhaust gas flow bypass passage 180 of the mixer 1, and part of exhaust gas flows along the exhaust gas flow bypass passage 180 formed between the sleeve 12 and the cyclone tube 11.

The flow of exhaust gas in an exhaust aftertreatment system may be as described in connection with fig. 2-4, with the direction of the arrows in fig. 2 being illustrative of the direction of flow of the gas stream. In the exhaust gas aftertreatment system, the first part 10 on one side comprises a first housing 104. The first housing provides a first flow space S1, the air inlet section 111 has at least a partial air inlet area located in the first flow space S1, most of the exhaust gas flows in the first flow space S1 and enters the mixer 1 from the plurality of air inlet openings 110, and forms a swirling flow through the swirling structure 113, the swirling exhaust gas is mixed with the spray of urea solution sprayed from the injector 2 entering from the injection inlet 114 of the swirling pipe, and the urea solution is decomposed during the mixing process. The exhaust gas flowing along the exhaust gas flow bypass passage 180 heats the wall surface of the pipe body section 112 of the cyclone pipe 11, so as to ensure the temperature in the mixing passage, and the urea solution droplets sprayed to the inner wall of the pipe body section 112 or the liquid film formed by the droplets can be timely decomposed, thereby reducing urea crystals. The mixed airflow of the rotational flow output after mixing in the rotational flow pipe 11 and the waste gas of the waste gas airflow bypass passage 180 are continuously mixed in the sleeve 12, so that the waste gas of the mixed airflow output from the mixer and the reducing components are uniformly mixed, and the rotational flow effect is good.

The second section 20 at the other side includes a second housing 204, and the second housing 204 provides a second flow space S2 where the mixed gas stream output from the mixer 1 flows to the selective catalytic reduction reactor 103 after flowing through the second flow space S2. The specific structure may be that the first flow space S1 includes a first air inlet portion 1041 and a first air outlet portion 1042, the first air inlet portion 1041 is connected to a first exhaust component, such as the diesel particulate trap 102; at least part of the air inlet area of the air inlet opening section 111 is positioned at the first air outlet part 1042; the second flow space S2 includes a second inlet portion 2041, a second outlet portion 2042, the second inlet portion 2041 being connected to an axially downstream side of the sleeve 12 of the mixer 1 such that the mixed gas flow formed by the mixer 1 flows into the second flow space S2, and the second outlet portion 2042 being connected to a second exhaust component, such as the selective catalytic reduction reactor 103. Additionally, in some embodiments, as shown in FIG. 2, the injector 2 may be an injector mount 1040 provided mounted to the first housing 104, which may allow for a compact system for exhaust aftertreatment.

Bearing and knowing, the beneficial effect who adopts above embodiment lies in, sets up in sleeve pipe 12 and cyclone tube 11's radial clearance through ring baffle 13 to and the structure of the intercommunication opening 131 through ring baffle 13, constitute exhaust gas flow bypass passage 180, fully heat the pipe wall of cyclone tube 11, make urea fully decompose, reduce the urea crystallization, promoted the life and the reliability of blender. In addition, the size of the communication opening 131 of the annular baffle plate can be adjusted to adapt to different engine exhaust gas aftertreatment systems, the structure of the mixer does not need to be changed on a large scale, the universality of the mixer is good, and the research, development and processing cost is reduced. Meanwhile, the exhaust gas post-treatment system adopting the mixer also has the advantages of long service life, good reliability and low research, development and manufacturing costs.

Referring to fig. 3 and 4, in some embodiments, the annular baffle 13 may be installed at a position where the annular baffle 13 is located at an axial position in an upstream region of the body section 112 of the cyclone tube 11 and adjacent to the inlet opening section 111, that is, the annular baffle 13 is located in the body section 112 and is located as close to the inlet opening section 111 as possible in the axial direction, so that the exhaust gas flow of the exhaust gas flow bypass passage 180 can be adjusted more accurately, and the exhaust gas flow bypass passage 180 can ensure that the required exhaust gas heating effect on the body section 112 of the exhaust gas flow bypass passage 180 can prevent urea from crystallizing, and the sufficient swirling exhaust gas can be sufficiently mixed with urea spray, thereby ensuring the mixing effect of the mixer.

With continued reference to fig. 4 and 7, in some embodiments, the specific structure of the annular baffle 13 may be that the plurality of communication openings 131 are uniformly distributed along the circumferential direction, for example, as shown in fig. 6, six communication openings 131 are uniformly distributed along the circumferential direction, and each communication opening 131 is correspondingly provided with a first swirl vane 132, so that a swirling motion of the exhaust gas can also be created in the exhaust gas flow bypass passage 180, so that after the exhaust gas enters the sleeve 12 from the flow bypass passage 180, the effect of mixing the two flows of mixed gas of the exhaust gas and the urea spray formed in the swirl pipe 11 is more uniform, so that the swirling effect after the two flows are mixed is better, and further, the urea is fully decomposed and fully mixed with the exhaust gas. And, can also effectively reduce or even eliminate the backward flow of mixed gas stream from mixing passageway 170 to exhaust gas stream bypass passageway 180, reduce the liquid film wall built-up of urea at body section 112 exit end, further reduce the risk of urea crystallization.

Referring to fig. 3 and 4, the sleeve 12 and the swirl tube 11 are configured such that the sleeve 12 extends axially downstream from the swirl tube 11, that is, the sleeve 12 includes a first sleeve section 121 sleeved on the swirl tube 11 and a second sleeve section 122 extending downstream from the first sleeve section 121, and the second sleeve section 122 is a portion of the sleeve 12 extending axially downstream from the swirl tube 11. Such beneficial effect lies in, can make the waste gas of mixing in the mixing channel of whirl pipe 11 further intensive mixing with urea spraying, prolongs the mixing distance between the two, also makes urea fully decompose.

As shown in fig. 5 and 6, in one or more embodiments, the swirl structure 113 of the swirl tube 11 may specifically include a second swirl vane 115 corresponding to each air inlet opening 110, and the second swirl vane 115 extends obliquely toward the inner and/or outer portion of the swirl tube 11. In the embodiment shown in fig. 6, the swirl vanes 115 have both the portion 1151 extending obliquely toward the inner direction of the swirl tube 11 and the portion 1152 extending obliquely toward the outer direction of the swirl tube 11, but not limited thereto, for example, only the portion 1151 extending obliquely toward the inner direction of the swirl tube 11 or only the portion 1152 extending obliquely toward the outer direction of the swirl tube 11, and the swirl vane arrangement thus configured can make the exhaust gas flow entering the mixing channel swirl well.

With continued reference to fig. 3 to 5, in an embodiment, the upstream end of the tube wall of the swirl tube 11 includes a mounting portion 116 for mounting and fixing the swirl tube 11, for example, the swirl tube 11 and the first portion 10 are mounted and fixed on the mounting portion 116, so that the swirl tube 11 is not only mounted and fixed by the annular baffle 13 in the sleeve 12, but also mounted and fixed on the mounting portion 116, so that the swirl tube 11 has better connection rigidity during engine operation, i.e. can maintain higher mechanical fatigue life under the high-temperature and high-frequency vibration environment during engine operation.

It can be known from the above, adopt above-mentioned embodiment to introduce blender and exhaust gas aftertreatment system's beneficial effect including but not limited to, set up through the ring baffle in the sleeve pipe with the radial clearance of whirl pipe to and through the open-ended structure of intercommunication of ring baffle, constitute exhaust gas flow bypass channel to fully heat the pipe wall of whirl pipe, make urea fully decompose, reduce the urea crystallization, promoted the life and the reliability of blender. And moreover, the size and the number of the communication openings of the annular baffle plate can be adjusted to adapt to different engine exhaust gas aftertreatment systems, and the structure of the mixer is not required to be changed on a large scale, so that the universality of the mixer is good, and the research, development and processing cost is reduced. Meanwhile, the exhaust gas post-treatment system adopting the mixer also has the advantages of long service life, good reliability and low research, development and manufacturing costs.

Although the present invention has been described with reference to the above embodiments, it is not intended to limit the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent changes and modifications made to the above embodiments according to the technical spirit of the present invention, all without departing from the content of the technical solution of the present invention, fall within the scope of protection defined by the claims of the present invention.

Claims

1. A mixer for an engine exhaust aftertreatment system, comprising:

the mixer comprises a cyclone tube, wherein the tube wall of the cyclone tube comprises an air inlet opening section and a tube body section positioned at the downstream of the air inlet opening section, the air inlet opening section is provided with a plurality of air inlet openings, the air inlet openings are distributed along the circumferential direction of the tube wall, a cyclone structure is arranged on the air inlet openings, an injection inlet is provided at the upstream side of the cyclone tube, and a mixing channel of the mixer is provided in the cyclone tube;

the sleeve is sleeved on the periphery of the cyclone tube;

the annular baffle set up in the sleeve pipe with the radial clearance of whirl pipe, the annular baffle radial inner with the whirl pipe the body section is connected, radial outer end with sheathed tube inner wall connection, the annular baffle has a plurality of intercommunication openings for the upstream and downstream intercommunication of annular baffle constitutes the exhaust gas flow bypass passageway of blender.

2. The mixer of claim 1, wherein the axial position of the annular baffle is located in an upstream region of the duct section and adjacent to the inlet opening section.

3. The mixer of claim 1 wherein the shroud includes a first shroud segment that is nested within the swirl tube and a second shroud segment that extends downstream from the first shroud segment.

4. The mixer according to claim 1, wherein the plurality of communication openings of the annular baffle are uniformly distributed in a circumferential direction, and each communication opening is provided with the first swirl vane.

5. The mixer of claim 1 wherein the upstream end of the wall of the swirl tube includes a mounting portion for fixedly mounting the swirl tube.

6. The mixer of claim 1, wherein the swirl structure includes a second swirl vane disposed corresponding to each air inlet opening, the second swirl vane extending obliquely toward the interior and/or exterior of the swirl tube.

7. An engine exhaust aftertreatment system, comprising: the mixer of any one of claims 1-6, and an injector that sprays a spray of reductant liquid into the swirl tube, the injector being located upstream of the intake opening, the spray of reductant liquid entering the swirl tube from the injection inlet to mix with the exhaust gas.

8. The exhaust aftertreatment system of claim 7, further comprising a first portion connecting an axially upstream side of the mixer to provide exhaust gas to enter the mixer from the intake opening, a second portion connecting an axially downstream side of the mixer such that a flow of mixed gas within the mixer flows out of the sleeve to the second portion.

9. The exhaust aftertreatment system of claim 8, wherein the first portion includes a first housing providing a first flow space such that exhaust flows in the first flow space into the mixer, the first housing further providing an injector mount for mounting the injector; the second portion includes a second housing providing a second flow space such that the gas stream flowing out of the mixer flows in the second flow space.

10. The exhaust aftertreatment system of claim 7, wherein the reductant liquid is a urea solution.