WO2019140865A1

WO2019140865A1 - Exhaust gas aftertreatment device

Info

Publication number: WO2019140865A1
Application number: PCT/CN2018/093011
Authority: WO
Inventors: 李军良; 王聪; 毛伟; 王伟
Original assignee: 天纳克（苏州）排放系统有限公司
Priority date: 2018-01-19
Filing date: 2018-06-27
Publication date: 2019-07-25
Also published as: CN110056414A

Abstract

Disclosed is an exhaust gas aftertreatment device, comprising a first aftertreatment carrier assembly (1), a second aftertreatment carrier assembly (2), and a mixer assembly (3), wherein the mixer assembly (3) comprises a housing (31), and a mixing tube (32) and a separation plate (33) located inside the housing (31), the separation plate (33) dividing the housing (31) into a first space (331) and a second space (332); the mixing tube (32) comprises a first tube portion (321) located in the first space (331) and a second tube portion (322) located in the second space (332), wherein the first tube portion (321) is provided with at least two first openings (3211) located on two sides thereof; and the exhaust gas aftertreatment device further comprises a first shutter plate portion (351) and a second shutter plate portion (352) for blocking the front ends of the first openings (3211) respectively. By means of this arrangement, and by providing the first and second shutter plate portions for rectification, the distribution uniformity of the gas flow is improved, and the mixing effect is also improved.

Description

Exhaust aftertreatment device

The present application claims priority to Chinese Patent Application No. 201 810 054 166, the disclosure of which is incorporated herein in

Technical field

The invention relates to an exhaust gas aftertreatment device, and belongs to the technical field of engine exhaust aftertreatment.

Background technique

Studies have shown that the uniformity of ammonia distribution in the exhaust gas aftertreatment system (eg, selective catalytic reduction system, SCR system) has an important impact on the overall performance and durability of the system. If the ammonia distribution is uneven, it will lead to excessive ammonia in the local area and easy to cause ammonia leakage, while in other thin ammonia regions, the nitrogen oxide (NOx) conversion efficiency is too low. Uneven distribution of ammonia over a long period of time can result in uneven aging of the catalyst, thereby affecting the overall performance of the catalyst. The uneven distribution of urea droplets will cause the local tube wall or mixed structure temperature to be too low to form crystallization. In severe cases, the tail gas pipe will be blocked, resulting in a decrease in engine power performance.

Summary of the invention

It is an object of the present invention to provide an exhaust gas aftertreatment device which has a better mixing effect.

In order to achieve the above object, the present invention adopts the following technical solution: an exhaust aftertreatment device including a first post-processing carrier assembly, a second post-processing carrier assembly, and the first post-processing carrier assembly and the second rear Processing a mixer assembly between the carrier assemblies, wherein the mixer assembly includes a housing, a mixing tube positioned within the housing, and a baffle secured to a periphery of the mixing tube, the baffle placing the housing Dividing into a first space in communication with the first post-processing carrier assembly and a second space in communication with the second post-processing carrier assembly, the mixing tube including a first tube portion located within the first space And a second tube portion located in the second space, wherein the first tube portion is provided with at least two first openings respectively located at two sides thereof, and the exhaust gas after-treatment device further comprises an occlusion in the first The first shutter portion of the front end of the opening and the second shutter portion are such that a majority of the exhaust flow needs to bypass the first and second shutter portions to enter the first opening.

As a further improved technical solution of the present invention, the first post-treatment carrier assembly, the second post-treatment carrier assembly, and the mixer assembly are arranged in a straight line.

As a further improved technical solution of the present invention, the housing is provided with a first axis, and the mixing tube is provided with a second axis, the first axis intersecting the second axis.

As a further improvement of the invention, the first axis is perpendicular to the second axis.

As a further improved technical solution of the present invention, the first pipe portion includes a connecting portion between the first openings, and the exhaust gas after-treatment device includes a shutter welded on the connecting portion, the first The shutter portion and the second shutter portion are located on both sides of the shutter.

As a further improved technical solution of the present invention, the exhaust gas aftertreatment device is provided with a nozzle mounting seat on the casing and used to install a urea nozzle to spray the atomized urea solution into the mixing tube.

As a further improved technical solution of the present invention, the exhaust gas after-treatment device further includes steel wool located in the mixing tube, wherein the steel wool is used for the exhaust gas and the urea liquid droplet to pass through to further increase The urea droplets are broken and evaporated.

As a further improved technical solution of the present invention, the first post-treatment carrier assembly includes a diesel particulate filter, and the second post-treatment carrier assembly includes a selective catalytic reducing agent.

As a further improvement of the present invention, the exhaust aftertreatment device further includes an oxidation catalyst upstream of the first aftertreatment carrier assembly.

As a further improvement of the present invention, the first shutter portion is provided with a first circular arc edge that abuts against the inner side of the housing, and the second shutter portion is disposed to abut the inner side of the housing. The second arc edge.

Compared with the prior art, the present invention rectifies by providing the first and second shielding portions, thereby improving the uniformity of the airflow distribution and improving the mixing effect.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of an exhaust gas aftertreatment device of the present invention.

Figure 2 is a perspective view of another angle of Figure 1.

Figure 3 is a partial exploded perspective view of Figure 1.

Figure 4 is a partially exploded perspective view of another angle of Figure 3.

Figure 5 is an exploded perspective view of the mixer assembly of Figure 3.

Figure 6 is an exploded perspective view of another angle of Figure 5.

Figure 7 is a front elevational view of Figure 1.

Figure 8 is a rear elevational view of Figure 1.

Figure 9 is a plan view of Figure 1.

Fig. 10 is a bottom view of Fig. 1;

Figure 11 is a left side view of Figure 2.

Figure 12 is a right side view of Figure 2.

Figure 13 is a cross-sectional view taken along line A-A of Figure 9.

Figure 14 is a cross-sectional view taken along line B-B of Figure 9.

Figure 15 is a schematic cross-sectional view taken along line C-C of Figure 13;

Detailed ways

Referring to Figures 1 to 15, the present invention discloses an exhaust aftertreatment device 100 for treating exhaust gas of an engine to reduce emissions of harmful substances. The exhaust aftertreatment device 100 includes a first aftertreatment carrier assembly 1, a second aftertreatment carrier assembly 2, and a mixer assembly between the first aftertreatment carrier assembly 1 and the second aftertreatment carrier assembly 2 3. In the illustrated embodiment of the invention, the first aftertreatment carrier assembly 1, the second aftertreatment carrier assembly 2, and the mixer assembly 3 are arranged in a straight line. Referring to FIG. 13, the first aftertreatment carrier assembly 1 includes a diesel particulate filter (DPF) 12, and the second aftertreatment carrier assembly 2 includes a selective catalytic reduction agent (SCR) 21. In the illustrated embodiment of the invention, the exhaust aftertreatment device 100 further includes an oxidation catalyst (DOC) 11 located upstream of the first aftertreatment carrier assembly 12. The above oxidation catalyst 11, diesel particulate filter 12 and selective catalytic reducing agent 21 are detachably connected by a clamp for maintenance and replacement.

The mixer assembly 3 includes a housing 31, a mixing tube 32 located within the housing 31, a partition 33 fixed to the periphery of the mixing tube 32, steel wool 34 located in the mixing tube 32, and a cover Board 35. The partition 33 divides the casing 31 into a first space 331 that communicates with the first aftertreatment carrier assembly 1 and a second space 332 that communicates with the second aftertreatment carrier assembly 2. The mixing tube 32 includes a first tube portion 321 located in the first space 331 and a second tube portion 322 located in the second space 332, wherein the first tube portion 321 is respectively disposed at two of the tubes At least two first openings 3211 on the side and a connection portion 3212 between the first openings 3211. The first opening 3211 is for entering airflow. The shutter 35 is welded to the connecting portion 3212, and is provided with a first shutter portion 351 and a second shutter portion 352 on both sides. The first shutter portion 351 and the second shutter portion 352 respectively block the front end of the first opening 3211, so that most of the exhaust flow needs to bypass the first and

second shutter portions

351, 352 can enter the first opening 3211. This arrangement prevents the exhaust stream from directly rushing into the mixing tube 32 and forming a reflection on the tube wall, affecting the uniformity and smoothness of the airflow mixing. In the illustrated embodiment of the present invention, the first shutter portion 351 is provided with a first circular arc edge 3511 that abuts against the inner side of the housing 31, and the second shutter portion 352 is disposed to be placed against The second circular arc edge 3521 inside the casing 31 has an effect of obstructing the airflow to rectify.

In the illustrated embodiment of the present invention, the housing 31 has a cylindrical shape and is provided with a first axis 311; the mixing tube 32 has a cylindrical shape, and is provided with a second axis 323, the first The axis 311 intersects the second axis 323. Preferably, the first axis 311 is perpendicular to the second axis 323. Of course, in other embodiments, the housing 31 and the mixing tube 32 may have other shapes, such as an elliptical shape or the like.

The partition plate 33 includes a first plate 333 on one side of the mixing tube 32, a second plate 334 on the other side of the mixing tube 32, and a connection between the first plate 333 and the second A third plate 335 of the plate 334, the third plate 335 is provided with a through hole 336 through which the mixing tube 32 passes. In the illustrated embodiment of the present invention, the mixing tube 32 is disposed obliquely; the first plate 333 is provided with a first curved surface 337 abutting against the first tube portion 321, and the second The plate 334 is provided with a second curved surface 338 that abuts against the second tube portion 322.

The exhaust aftertreatment device 100 is provided with a nozzle mount 310 on the housing 31 for mounting a urea nozzle to inject a urea solution after atomization into the mixing tube 32.

In the illustrated embodiment of the present invention, when the exhaust of the engine passes through the first aftertreatment carrier assembly 1 into the first space 331, the exhaust gas bypasses the first and

second shutters

351, 352 from the first The opening 3211 enters the mixing tube 32. When the injection condition is satisfied, the urea nozzle injects urea into the mixing tube 32, the atomized urea droplets are mixed with the exhaust of the engine and moved downstream, then exit the mixing tube 32 and enter the second space 332, and The second post-treatment carrier assembly 2 located downstream is reached. In this way, the distance and time of urea evaporation are increased by the swirling flow, the uniformity of the airflow mixing is improved, and the risk of urea crystallization is reduced.

In addition, the present invention utilizes the 3D porous structure or multi-voided structure of the steel wool 34, the exhaust gas and the urea droplets passing through the steel wool 34 to cause sufficient breakage and mixing of the urea droplets on the surface and inside of the steel wool. In addition, due to the small wire diameter of the steel wool, the voids are complex, and the heat transfer area is large, which is beneficial to the full heat exchange between the urea droplets and the exhaust gas, thereby facilitating the evaporation and pyrolysis of the urea droplets and improving the resistance to crystallization. . The back pressure of the system can be adjusted accordingly by adjusting the density of the steel wool 34.

In addition, the above embodiments are only for illustrating the present invention and are not intended to limit the technical solutions described in the present invention. The understanding of the present specification should be based on those skilled in the art, although the present specification has been carried out with reference to the above embodiments. DETAILED DESCRIPTION OF THE INVENTION However, those skilled in the art should understand that the invention may be modified or equivalently replaced by those skilled in the art without departing from the spirit and scope of the invention. It is intended to be included within the scope of the appended claims.

Claims

An exhaust aftertreatment device comprising a first aftertreatment carrier assembly, a second aftertreatment carrier assembly, and a mixer assembly between the first aftertreatment carrier assembly and the second aftertreatment carrier assembly, wherein The mixer assembly includes a housing, a mixing tube located within the housing, and a partition secured to a periphery of the mixing tube, the partition dividing the housing into communication with the first aftertreatment carrier assembly a first space and a second space in communication with the second post-processing carrier assembly, the mixing tube including a first tube portion located in the first space and a second tube located in the second space And the first pipe portion is provided with at least two first openings respectively located at two sides thereof, wherein the exhaust gas after-treatment device further comprises a first cover that respectively blocks the front end of the first opening The plate portion and the second shutter portion are such that a majority of the exhaust flow needs to bypass the first and second shutter portions to enter the first opening.
The exhaust aftertreatment device of claim 1 wherein said first aftertreatment carrier assembly, said second aftertreatment carrier assembly and said mixer assembly are arranged in a line.
The exhaust aftertreatment device of claim 2 wherein said housing is provided with a first axis and said mixing tube is provided with a second axis, said first axis intersecting said second axis.
The exhaust aftertreatment device of claim 3 wherein said first axis is perpendicular to said second axis.
An exhaust aftertreatment device according to claim 1, wherein said first tube portion includes a connection portion between said first openings, and said exhaust gas aftertreatment device includes welding on said connection portion The shutter, the first shutter portion and the second shutter portion are located on both sides of the shutter.
The exhaust gas aftertreatment device according to claim 1, wherein the exhaust gas aftertreatment device is disposed on the casing and is configured to install a urea nozzle to spray the atomized urea solution into the mixing pipe. Nozzle mount.
The exhaust gas aftertreatment device according to claim 6, wherein said exhaust gas aftertreatment device further comprises steel wool in said mixing pipe, said steel wool being used for said exhaust gas and said urea liquid The droplets pass through to further increase the breakage and evaporation of the urea droplets.
The exhaust aftertreatment device of claim 1 wherein said first aftertreatment carrier assembly comprises a diesel particulate filter and said second aftertreatment support assembly comprises a selective catalytic reduction agent.
The exhaust aftertreatment device of claim 8 wherein said exhaust aftertreatment device further comprises an oxidation catalyst upstream of said first aftertreatment carrier assembly.
The exhaust gas after-treatment mixing device according to claim 1, wherein the first shutter portion is provided with a first circular arc edge abutting against the inner side of the casing, and the second shutter portion is provided with the first shutter portion. A second arc edge abutting the inside of the housing.