WO2018095140A1

WO2018095140A1 - Exhaust post-treatment device

Info

Publication number: WO2018095140A1
Application number: PCT/CN2017/104326
Authority: WO
Inventors: 白冰; 李万雄; 李硕
Original assignee: 天纳克（苏州）排放系统有限公司
Priority date: 2016-11-25
Filing date: 2017-09-29
Publication date: 2018-05-31
Also published as: CN108104912A

Abstract

An exhaust post-treatment device comprises a housing (1), a cyclone pipe (31) and a post-treatment carrier. The housing comprises a cylindrical portion (10), an end cover (13) and an air inlet pipe (11). The end cover is provided with a nozzle mounting seat (132) for installing a urea nozzle. The cylindrical portion is provided with a cavity communicating with the air inlet pipe. The exhaust post-treatment device also comprises an air guide trumpet cone (14) connected to the cyclone pipe at downstream of the cyclone pipe, and a cyclonic mixing device at downstream of the air guide trumpet cone. The cyclone pipe includes a swirl plate (311) in the cavity. The air guide trumpet cone is provided with a through hole to engage the cyclone pipe. In this way, by providing the air guide trumpet cone, the flow velocity of the air flow is increased and the air flow is guided, thereby reducing the risk of urea crystallizing in the cavity.

Description

Exhaust aftertreatment device

The present application claims priority to Chinese Patent Application Serial No. No. No. No. No. No. No. No. No. No. No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No

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. In addition, the uneven distribution of urea droplets may cause the local tube wall or mixed structure temperature to be too low to form crystallization, which may block the tail gas pipe when severe, resulting in a decrease in engine power performance.

Therefore, it is necessary to provide a novel exhaust gas aftertreatment device to solve the above technical problems.

Summary of the invention

It is an object of the present invention to provide an exhaust aftertreatment device that is uniformly mixed and has a low risk of urea crystallization.

In order to achieve the above object, the present invention adopts the following technical solution: an exhaust gas after-treatment device including a casing, a swirl tube located in the casing, and a post-processing carrier located downstream of the swirl tube, the shell The body includes a cylindrical portion, an end cover fixed at one end of the cylindrical portion, and an intake pipe mounted on the cylindrical portion, the end cover being provided with a urea nozzle for mounting into the swirl tube a nozzle mount for injecting urea droplets, the cylindrical portion being provided with a cavity in communication with the intake pipe, the exhaust aftertreatment device further comprising a pipe connected to the swirl tube and located downstream of the swirl tube An air guiding horn cone and a swirling mixing device located downstream of the air guiding horn cone, the swirling tube, the air guiding horn cone and the swirling mixing device are all located in the cavity, the rotation The flow tube includes a swirling vane in the cavity, and the air guiding horn is provided with a through hole that engages the swirling tube.

As a further improvement of the technical solution of the present invention, the air guiding horn is provided with a first flange portion extending toward the swirl tube, and the first flange portion is provided with a first one for holding the swirl tube Opening.

As a further improved technical solution of the present invention, the air guiding horn is provided with a second flange welded to the inner side of the cylindrical portion. unit.

As a further improvement of the technical solution of the present invention, the air guiding horn is provided with a tapered surface between the first flange portion and the second flange portion, and the tapered surface is provided with a plurality of through holes, A plurality of perforations are formed in a circle and adjacent to the second flange portion.

As a further improved technical solution of the present invention, the swirling mixing device is provided with a central portion facing the swirling tube to force the reverse flow of the airflow and a spoiler located at the periphery of the central portion.

As a further improved technical solution of the present invention, the central portion is provided with an arcuate ridge protruding toward the swirl tube.

As a further improved technical solution of the present invention, the spoiler is formed by punching the swirling mixing device outward, and the swirling mixing device is provided with a punching hole corresponding to the spoiler.

As a further improved technical solution of the present invention, the end cap is provided with a recessed portion that is recessed into the cavity, and the nozzle mount is located in the recessed portion.

As a further improved technical solution of the present invention, the swirl tube includes a plurality of openings in front of the swirling sheet, and the opening is adjacent to the mounting seat and communicates with the cavity.

As a further improved technical solution of the present invention, the intake pipe is perpendicular to the swirl tube; the exhaust aftertreatment device further includes a support base for supporting the intake pipe, and the support seat is welded in the casing The intake pipe passes through the support seat, and the post-treatment carrier is a selective catalytic reducing agent.

Compared with the prior art, the present invention improves the mixing uniformity of the exhaust gas and the urea droplets by providing the swirling sheet. In addition, by providing a gas-conducting horn cone, the flow velocity of the airflow is increased and the airflow is guided, thereby reducing the risk of crystallization of urea in the cavity.

DRAWINGS

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

Fig. 2 is a partially exploded perspective view of Fig. 1;

Figure 3 is an exploded perspective view of another angle of Figure 2.

Fig. 4 is an exploded perspective view of Fig. 1;

Figure 5 is a plan view of Figure 1.

Fig. 6 is a schematic cross-sectional view taken along line A-A of Fig. 5.

Figure 7 is a perspective view of the housing of Figure 1 and the post-process carrier removed.

Figure 8 is a left side elevational view of the air horn cone of Figure 4;

Figure 9 is a rear elevational view of the air guiding horn cone of Figure 4;

Figure 10 is a right side view of the air guiding horn cone of Figure 4;

detailed description

Referring to Figures 1 through 7, the present invention discloses an exhaust aftertreatment device 100 for treating exhaust gas from an engine. The exhaust aftertreatment device 100 includes a housing 1, a mixing assembly 3 located within the housing 1, and a post-processing carrier 2 located downstream of the mixing assembly 3.

In the illustrated embodiment of the present invention, the casing 1 has a cylindrical shape including a cylindrical portion 10 and one end fixed to the cylindrical portion 10 (in the illustrated embodiment of the present invention, the front end) The end cap 13, the intake pipe 11 attached to the tubular portion 10, and the air outlet pipe 12. The cylindrical portion 10 is provided with a cavity 101 that communicates with the intake pipe 11. The exhaust aftertreatment device 100 further includes a support base 15 for supporting the intake pipe 11, the support base 15 being welded in the housing 1, and the intake pipe 11 passing through the support base 15. In the illustrated embodiment of the invention, the post-treatment carrier 2 is a selective catalytic reducing agent.

The end cap 13 is provided with a recess 131 for receiving a urea nozzle (not shown) to protect the urea nozzle and save space. A mounting seat 132 for mounting the urea nozzle is disposed in the recess 131, and the urea nozzle is configured to inject urea droplets into the mixing assembly 3.

The mixing assembly 3 includes a swirl tube 31, an air horn cone 14 connected to the swirl tube 31 and downstream of the swirl tube 31, and a swirl mixing downstream of the air horn cone 14 Device 32. The swirl tube 31, the air horn cone 14 and the swirl mixing device 32 are all located within the cavity 101. In the illustrated embodiment of the invention, the intake pipe 11 is perpendicular to the swirl tube 31. The swirl tube 31 includes a swirling sheet 311 located in the cavity 101 and a plurality of openings 312 in front of the swirling sheet 311. The opening 312 is adjacent to the mounting seat 132 and is in communication with the cavity 101.

Referring to FIGS. 7 to 10 , the air guide horn cone 14 is provided with a first flange portion 143 extending toward the swirl tube 31 and a second flange portion welded to the inner side of the housing 1 . 144, wherein the first flange portion 143 is provided with a first opening 145 for holding the swirl tube 31. The air guiding horn cone 14 is provided with a tapered surface 146 between the first flange portion 143 and the second flange portion 144. The tapered surface 146 is provided with a plurality of through holes 147, and the plurality of through holes 147 It is enclosed in a circle and is close to the second flange portion 144. The second flange portion 144 is the same as the extending direction of the first flange portion 143. By providing the tapered surface 146, the flow velocity of the airflow is increased and the airflow is guided, which reduces the risk of urea crystallizing in the cavity. In addition, the perforations 147 on the one hand reduce the system back pressure and on the other hand increase the flow of the gas stream, thereby further reducing the risk of urea crystallization.

In the illustrated embodiment of the invention, the swirl mixing device 32 is substantially disk-shaped and is provided facing the swirl tube 31 is a central portion 321 for forcing a reverse flow of the airflow and a spoiler 322 located at the periphery of the central portion 321 . The center portion 321 is provided with an arcuate ridge 323 that protrudes toward the swirl tube 31. The spoiler 322 is formed by punching the swirling mixing device 32 outward, and the swirling mixing device 32 is provided with a punching hole 324 corresponding to the spoiler 322. The punching holes 324 can reduce back pressure. Of course, depending on different design requirements, a plurality of through holes 325 may also be provided in the swirl mixing device 32 to further reduce back pressure.

When the exhaust gas of the engine enters the cavity 101 from the intake pipe 11, most of the exhaust gas is rotated into the swirl pipe 31 under the guidance of the swirling vane 311, and a small amount of exhaust gas enters the swirling pipe 31 from the opening 312. When the injection conditions are satisfied, the urea nozzle injects urea into the swirl tube 31, and the atomized urea droplets are mixed with the exhaust gas of the engine and rotated downstream. The air horn cone 14 allows the mixture of exhaust gas and urea droplets to flow better, reducing the risk of urea crystallization. Subsequently, the air flow is forced to reverse (for example, forward) by the action of the ridges 323. The airflow after the diffusion passes through the punching holes 324 and the through holes 325, and is secondarily mixed by the spoiler 322. This arrangement increases the distance and time of urea evaporation, improves the uniformity of airflow mixing, and reduces the risk of urea crystallization.

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 gas aftertreatment device comprising a casing, a swirl tube located in the casing, and a post-treatment carrier located downstream of the swirl tube, the casing including a cylindrical portion fixed to the tubular shape An end cap at one end of the portion and an intake pipe mounted on the cylindrical portion, the end cap being provided with a nozzle mount for mounting a urea nozzle to inject urea droplets into the swirl tube, the cartridge The cavity is provided with a cavity communicating with the intake pipe, wherein the exhaust gas after-treatment device further comprises an air-conducting horn cone connected to the swirling pipe and located downstream of the swirling pipe and located at the a swirl mixing device downstream of the air horn cone, the swirl tube, the air horn cone and the swirl mixing device are all located in the cavity, and the swirl tube comprises a cavity The swirling vane is provided with a through hole for engaging the swirl tube.
The exhaust gas aftertreatment device according to claim 1, wherein the air guiding horn is provided with a first flange portion extending toward the swirl tube, and the first flange portion is provided with a retaining portion. The first opening of the swirl tube.
The exhaust gas aftertreatment device according to claim 2, wherein the air guide horn is provided with a second flange portion welded to the inner side of the tubular portion.
The exhaust gas aftertreatment device according to claim 3, wherein said air guiding horn is provided with a tapered surface between said first flange portion and said second flange portion, said tapered surface A plurality of perforations are provided, the plurality of perforations enclosing a loop and adjacent to the second flange portion.
The exhaust gas aftertreatment device according to claim 1, wherein said swirling mixing device is provided with a central portion facing said swirling tube to force a reverse flow of the airflow, and a spoiler located at a periphery of said central portion .
The exhaust gas aftertreatment device according to claim 5, wherein the center portion is provided with an arcuate ridge portion that is convex toward the swirl tube.
The exhaust gas after-treatment device according to claim 6, wherein said spoiler is formed by punching said swirling mixing device outward, said swirling mixing device being provided corresponding to said spoiler Punching.
The exhaust gas aftertreatment device according to claim 1, wherein the end cap is provided with a recessed portion recessed into the cavity, and the nozzle mount is located in the recessed portion.
The exhaust gas aftertreatment device according to claim 8, wherein said swirling tube comprises a plurality of openings in front of said swirling sheet, said opening being adjacent to said mounting seat and said cavity Connected.
The exhaust gas aftertreatment device according to claim 1, wherein said intake pipe is perpendicular to said swirl tube; said exhaust gas aftertreatment device further comprises a support seat for supporting said intake pipe, said support A seat is welded in the housing, the intake pipe passes through the support seat, and the post-treatment carrier is a selective catalytic reducing agent.