WO2020143391A1

WO2020143391A1 - Engine exhaust aftertreatment mixing device

Info

Publication number: WO2020143391A1
Application number: PCT/CN2019/124981
Authority: WO
Inventors: 李军良; 吴涛涛; 崔杰
Original assignee: 天纳克（苏州）排放系统有限公司
Priority date: 2019-01-10
Filing date: 2019-12-13
Publication date: 2020-07-16
Also published as: CN109538337A

Abstract

Disclosed is an engine exhaust aftertreatment mixing device (100), comprising a housing (1) for mounting a urea nozzle, a first baffle plate (2) mounted inside the housing, and a second baffle plate (3) mounted inside the housing and spaced apart from the first baffle plate, wherein the housing forms a mixing cavity (10) located between the first baffle plate and the second baffle plate. The engine exhaust aftertreatment mixing device further comprises a support plate (4) located in the mixing cavity and a fine fiber element (5) mounted on the support plate. The mixing cavity comprises a first cavity (101) and a second cavity (102); the first baffle plate is provided with an exhaust inlet (21) in communication with the first cavity; and the second baffle plate is provided with an exhaust outlet (33) in communication with the second cavity. The urea nozzle is used for spraying atomized urea droplets into the mixing cavity. The fine fiber element is used for allowing exhaust gas and the urea droplets to pass through same so as to further increase the breaking down and evaporation of the urea droplets.

Description

Engine exhaust aftertreatment mixing device

This application claims the priority of the Chinese patent application with the application date of January 10, 2019, application number 201910023028.X, and the invention titled "engine exhaust aftertreatment mixing device", the entire content of which is incorporated by reference in this application in.

Technical field

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

Background technique

At present, the metal structure of the mixer is used to achieve the mixing of urea droplets and exhaust gas. Usually, porous plates, fins and other structures are set in the mixer to make the urea droplets collide with the metal structure mixer to break the urea droplets into smaller droplets, which is conducive to evaporation and pyrolysis on the metal surface .

In the prior art, the direction of the air flow and the mixing of the urea droplets and the exhaust gas have been arranged by designing the Z-shaped separator and the mixing tube to match; however, the Z-shaped separator has a complicated structure and plays a role in high-temperature exhaust It is easy to deform underneath.

Therefore, it is necessary to provide a new type of solution to solve the above technical problems.

Summary of the invention

The object of the present invention is to provide an engine exhaust aftertreatment mixing device with strong mixing performance and simple structure.

In order to achieve the above object, the present invention adopts the following technical solution: an engine exhaust aftertreatment mixing device, which includes a housing for installing a urea nozzle, a first baffle installed in the housing, and a housing installed in the housing A second baffle in the body and spaced apart from the first baffle, the housing forms a mixing chamber between the first baffle and the second baffle, and the engine exhaust aftertreatment The mixing device further includes a support plate located in the mixing cavity and a fine fiber element mounted on the support plate, the mixing cavity includes a first cavity at one end of the fine fiber element and the fine fiber A second cavity at the other end of the element; the first baffle is provided with an exhaust inlet communicating with the first cavity, and the second baffle is provided with a communication with the second cavity Exhaust outlet; the urea nozzle is used to spray atomized urea droplets into the mixing chamber, and the fine fiber element is used for exhaust gas and the urea droplets to pass through to further increase the urea liquid Dropping and evaporation.

As a further improved technical solution of the present invention, the fine fiber element is a steel wool or a foamed metal or ceramic porous material.

As a further improved technical solution of the present invention, the first cavity is located at the upper end of the fine fiber element, and the second cavity is located at the lower end of the fine fiber element.

As a further improved technical solution of the present invention, the first baffle is provided with two exhaust inlets and a perforation between the two exhaust inlets.

As a further improved technical solution of the present invention, the second baffle is provided with a blocking wall portion that seals the first cavity from the rear end.

As a further improved technical solution of the present invention, the second baffle includes extensions extending downward from the baffle wall portion, and there are two exhaust gas outlets located on both sides of the extension respectively.

As a further improved technical solution of the present invention, the extending portion deviates away from the first baffle, and the end of the extending portion is fixed on the inner wall of the housing.

As a further improved technical solution of the present invention, the support plate is fixed together with the first baffle and the second baffle, and the support plate is provided with a first side wall that shrinks toward the fine fiber element and Second sidewall.

As a further improved technical solution of the present invention, the first side wall and/or the second side wall have an inclined portion for guiding the air flow to the thin fiber element.

As a further improved technical solution of the present invention, the support plate includes a connecting wall connecting the first side wall and the second side wall, and the connecting wall is provided with a mounting hole for mounting the fine fiber element.

Compared with the prior art, the present invention provides a fine fiber element so that urea droplets are sufficiently broken and mixed on the surface and inside of the fine fiber element. In addition, by arranging the support plate and the fine fiber elements mounted on the support plate between the first baffle and the second baffle, the structure is skillfully simplified.

BRIEF DESCRIPTION

FIG. 1 is a schematic perspective view of an engine exhaust aftertreatment mixing device of the present invention.

FIG. 2 is an exploded perspective view of FIG. 1.

Fig. 3 is a left side view of Fig. 1.

Fig. 4 is a right side view of Fig. 1.

5 is a schematic cross-sectional view taken along line A-A in FIG. 3.

detailed description

Referring to FIGS. 1 to 5, the present invention discloses an engine exhaust aftertreatment mixing device 100, which is used in an engine exhaust aftertreatment package to treat engine exhaust. The engine exhaust aftertreatment package includes a first aftertreatment carrier assembly (not shown), a second aftertreatment carrier assembly (not shown) located downstream of the first aftertreatment carrier assembly, and a second A third post-processing carrier assembly (not shown) downstream of the post-processing carrier assembly. The engine exhaust aftertreatment mixing device 100 is located between the second aftertreatment carrier assembly and the third aftertreatment carrier assembly. Preferably, the first aftertreatment carrier assembly is an oxidation catalyst (DOC), the second aftertreatment carrier assembly is a diesel particulate trap (DPF), and the third aftertreatment carrier assembly is a selective catalytic reduction (SCR) .

The engine exhaust aftertreatment mixing device 100 includes a housing 1, a first baffle 2 installed in the housing 1, and a spaced apart from the first baffle 2 installed in the housing 1 Second baffle 3. The housing 1 is substantially cylindrical in the illustrated embodiment of the present invention, and includes a mounting seat 11 for mounting a urea nozzle.

As shown in FIG. 5, the housing 1 forms a mixing chamber 10 between the first baffle 2 and the second baffle 3. The engine exhaust aftertreatment mixing device 100 further includes a support plate 4 located in the mixing chamber 10 and a fine fiber element 5 mounted on the support plate 4. The mixing chamber 10 includes a first cavity 101 at one end of the fine fiber element 5 and a second cavity 102 at the other end of the fine fiber element 5. In the illustrated embodiment of the present invention, the first cavity 101 is located at the upper end of the fine fiber element 5, and the second cavity 102 is located at the lower end of the fine fiber element 5.

Please refer to FIG. 1 and FIG. 3, the first baffle 2 has a disc shape. Preferably, the outer edge of the first baffle 2 is fixed on the inner wall of the housing 1 by welding. The first baffle 2 is provided with an exhaust inlet 21 that communicates with the first cavity 101. Preferably, there are two exhaust gas inlets 21, which are arranged symmetrically. The first baffle 2 further includes a perforation 22 between the two exhaust inlets 21, and the perforation 22 can adjust the back pressure. As for the number and size of the perforations 22, it can be flexibly set according to actual needs. The perforation 22 further includes a plurality of through holes 23 located at the lower edge of the arc and arranged in an arc shape. The through holes 23 communicate with the second cavity 102 to adjust the back pressure.

As shown in FIGS. 1, 4 and 5, the second baffle 3 is provided with a wall portion 31 that seals the first cavity 101 from the rear end, and extends downward from the wall portion 31 Extension 32 and exhaust outlets 33 located on both sides of the extension 32 respectively. The outer edge of the second baffle 3 is welded and fixed on the inner wall of the housing 1, including the end of the extension 32. In the illustrated embodiment of the present invention, the extending portion 32 deviates away from the first baffle 2, and the extending portion 32 is provided with an inclined portion 321.

The support plate 4 is fixed with the first baffle 2 and the second baffle 3. Preferably, the first baffle 2 and the second baffle 3 are provided with

welding grooves

211, 311, and the support plate 4 passes through the

welding grooves

211, 311 and the first baffle 2 and the The second baffle 3 is fixed by welding. The support plate 4 is provided with a first side wall 41, a second side wall 42 that contract toward the fine fiber element 5, and a connecting wall 43 that connects the first side wall 41 and the second side wall 42. The first side wall 41 and/or the second side wall 42 have an inclined portion 44 for guiding the air flow to the thin fiber element 5. The connecting wall 43 is provided with a mounting hole 431 for mounting the thin fiber element 5. In the present invention, the supporting plate 4 and the fine fiber element 5 mounted on the supporting plate 4 are arranged between the first baffle 2 and the second baffle 3, the structure is neatly simplified, and no Z-shaped baffle is required.

The thin fiber element 5 includes steel wool or foamed metal or ceramic porous material. The present invention utilizes the 3D porous structure or multi-void structure of the thin fiber element 5 (for example, steel wool), and the exhaust gas and the urea droplets pass through the thin fiber element 5, so that the urea droplets occur sufficiently on the surface and inside of the steel wool Broken and mixed. In addition, the wire diameter of steel wool is small, the gap is complicated, and the specific surface area is large. Because the specific surface area is large, a larger heat exchange area can be created in a limited space, which is conducive to the sufficient heat exchange between the urea droplets and the exhaust gas, thereby facilitating the evaporation and pyrolysis of the urea droplets and improving the anti-crystallization ability. By adjusting the density of the fine-fibre element 5, the back pressure of the system can be adjusted accordingly. As shown in FIG. 2, in the illustrated embodiment of the present invention, the thin fiber element 5 includes a pipe body 51 welded and fixed together by a brazing process. The tube body 51 is installed in the installation hole 431 and fixed with the inner wall of the installation hole 431.

In addition, the above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention. The understanding of this specification should be based on those skilled in the art, although this specification has made the invention with reference to the above embodiments. Detailed description, however, those of ordinary skill in the art should understand that those skilled in the art can still modify or equivalently replace the present invention, and all technical solutions and improvements that do not depart from the spirit and scope of the present invention should be It is covered by the scope of the claims of the present invention.

Claims

An engine exhaust aftertreatment mixing device, which includes a housing for installing a urea nozzle, a first baffle installed in the housing, and a spaced apart from the first baffle installed in the housing A second baffle, the housing forms a mixing chamber between the first baffle and the second baffle, characterized in that the engine exhaust aftertreatment mixing device further includes a A support plate in the cavity and the fine fiber element mounted on the support plate, the mixing cavity includes a first cavity at one end of the fine fiber element and a second cavity at the other end of the fine fiber element The first baffle is provided with an exhaust inlet communicating with the first cavity, the second baffle is provided with an exhaust outlet communicating with the second cavity; the urea nozzle For spraying atomized urea droplets into the mixing chamber, the fine fiber element is used for exhaust gas and the urea droplets to pass through to further increase the breakage and evaporation of the urea droplets.
The engine exhaust aftertreatment mixing device according to claim 1, wherein the thin fiber element is a steel wool or a foamed metal or ceramic porous material.
The engine exhaust aftertreatment mixing device according to claim 1, wherein the first cavity is located at the upper end of the fine fiber element, and the second cavity is located at the lower end of the fine fiber element.
The engine exhaust gas aftertreatment mixing device according to claim 1, wherein the first baffle is provided with two of the exhaust gas inlets and a perforation between the two exhaust gas inlets.
The engine exhaust aftertreatment mixing device according to claim 1, wherein the second baffle is provided with a wall portion that seals the first cavity from the rear end.
The engine exhaust aftertreatment mixing device according to claim 5, wherein the second baffle includes an extending portion extending downward from the baffle wall portion, the exhaust outlets are two and are respectively located Both sides of the extension.
The engine exhaust aftertreatment mixing device according to claim 6, wherein the extension part deviates away from the first baffle, and the end of the extension part is fixed on the inner wall of the housing .
The engine exhaust aftertreatment mixing device according to claim 1, wherein the support plate is fixed to the first baffle and the second baffle, and the support plate is provided with a The first side wall and the second side wall of the thin fiber element contract.
The engine exhaust aftertreatment mixing device according to claim 8, wherein the first side wall and/or the second side wall has an inclined portion for guiding airflow to the thin fiber element.
The engine exhaust aftertreatment mixing device according to claim 8, wherein the support plate includes a connecting wall connecting the first side wall and the second side wall, and the connecting wall is provided with an installation place Describe the mounting holes of the fine fiber element.