WO2019140892A1

WO2019140892A1 - Exhaust aftertreatment apparatus

Info

Publication number: WO2019140892A1
Application number: PCT/CN2018/100377
Authority: WO
Inventors: 李军良; 王聪; 吴健; 王伟
Original assignee: 天纳克（苏州）排放系统有限公司
Priority date: 2018-01-19
Filing date: 2018-08-14
Publication date: 2019-07-25
Also published as: CN110056411A

Abstract

Provided is an exhaust aftertreatment apparatus (200), comprising a first aftertreatment assembly (300), an exhaust inlet (301), a second aftertreatment assembly (400), an exhaust outlet (401), and a mixing chamber assembly (100). The mixing chamber assembly (100) comprises a housing (1) and a mixer (2) located in said housing (1). The mixer (2) comprises a mixing tube (21) and a partition (22) which fixes the mixing tube (21) inside the chamber body; the partition (22) divides the chamber body into a first chamber body (131) and a second chamber body (132); the mixing tube (21) comprises a conical part (211); said conical part (211) comprises a first inner chamber body (212), a plurality of fins (213) around the outer periphery of the first inner chamber body (212) and distributed along its circumference, and a plurality of open slots corresponding to the plurality of fins (213) and in communication with the first inner chamber body (212). In such an arrangement, the gas flow forms a rotating flow to enter the mixing tube, the distance and time for carbamide evaporation are increased, and the uniformity of gas flow mixing is improved.

Description

Exhaust aftertreatment device

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

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 aftertreatment system (eg, selective catalytic reduction system, SCR system) has an important impact on the overall performance and durability of the system. If the distribution of ammonia (NH ₃ ) is uneven, the nitrogen oxide (NOx) conversion efficiency is too low, and if the urea injection amount is increased in order to satisfy the discharge performance, ammonia leakage contamination is likely to occur. At the same time, the urea droplets are easily deposited when they are exposed to a wall surface having a relatively low temperature, and when the crystal is severely formed, the exhaust pipe is blocked, resulting in a decrease in engine power performance. Increasing the mixing uniformity of ammonia molecules can effectively improve the urea utilization rate and reduce the urea injection amount, thereby reducing the risk of urea crystallization.

Therefore, it is necessary to provide an exhaust aftertreatment device capable of improving the mixing uniformity of ammonia molecules to solve the above technical problems.

Summary of the invention

An object of the present invention is to provide an exhaust aftertreatment device capable of uniformly mixing an exhaust gas of an engine with urea droplets.

To achieve the above object, the present invention adopts the following technical solution: an exhaust aftertreatment device including a first aftertreatment assembly, an exhaust inlet in communication with the first aftertreatment assembly, and the first aftertreatment a second aftertreatment component arranged side by side of the assembly, an exhaust outlet in communication with the second aftertreatment component, and a mixing chamber assembly connecting the first and second aftertreatment components, the mixing chamber assembly including a housing and a mixer located within the housing, wherein the housing is provided with a first opening, a second opening located beside the first opening, for mounting a urea nozzle to inject urea droplets onto the mixer a mount and a cavity connecting the first opening and the second opening, the mixer comprising a mixing tube located in the cavity, an end bowl cooperating with the mixing tube, and the mixing tube a baffle secured in the cavity, the baffle separating the cavity into a first cavity and a second cavity, the mixing tube including a tapered portion in the first cavity, wherein The tapered portion includes the first inner portion a plurality of fins surrounding the periphery of the first inner cavity and circumferentially distributed, and a plurality of slots corresponding to the plurality of fins and communicating with the first inner cavity; the end bowl And a second inner cavity communicating with the first inner cavity and at least one cleaning hole communicating the second inner cavity and the first cavity.

As a further improved technical solution of the present invention, the first post-processing component is arranged in parallel with the second post-processing component, the first post-processing component is provided with a first axis, and the mixing pipe is provided with a second axis. The first axis is perpendicular to the second axis.

As a further improved technical solution of the present invention, the end bowl is adjacent to the mounting seat, and the urea nozzle is used to inject urea droplets into the mixing tube.

As a further improvement of the technical solution of the present invention, the cleaning hole is used for a small amount of exhaust gas to enter the mixing tube from the cleaning hole.

As a further improved technical solution of the present invention, the mixing tube is in communication with the second cavity.

As a further improved technical solution of the present invention, the partition plate is provided with an opening corresponding to the mixing tube.

As a further improved technical solution of the present invention, the mixer is further provided with steel wool fixed in the mixing tube, the steel wool is used for the exhaust gas and the urea droplets to pass through to further increase The urea droplets are broken and evaporated.

As a further improved technical solution of the present invention, the exhaust aftertreatment device has a U shape, and the first aftertreatment component includes a diesel oxidation catalyst and a diesel particulate trap located downstream of the diesel oxidation catalyst, the first The secondary aftertreatment component includes a selective catalytic reducing agent.

Compared to the prior art, the present invention divides the cavity into a first cavity and a second cavity by providing a partition, wherein the mixing tube includes a tapered portion located in the first cavity, The tapered portion includes a plurality of fins distributed in the circumferential direction. The arrangement is such that the airflow enters the mixing tube in a swirling manner, increasing the distance and time of evaporation of the urea, improving the uniformity of the airflow mixing, and improving the anti-crystallization ability.

DRAWINGS

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

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

Fig. 3 is a front view of Fig. 2;

Figure 4 is a rear elevational view of Figure 2.

Figure 5 is a plan view of Figure 2 .

Figure 6 is a bottom plan view of Figure 2 .

Figure 7 is a left side view of Figure 2.

Figure 8 is a right side view of Figure 2.

Figure 9 is a schematic cross-sectional view taken along line A-A of Figure 7.

Figure 10 is a cross-sectional view taken along line B-B of Figure 5.

Figure 11 is a partially exploded view of Figure 1.

Figure 12 is a partially exploded view of another angle of Figure 11;

Figure 13 is a further exploded perspective view of Figure 12 .

Detailed ways

Referring to Figures 1 to 13, the present invention discloses an exhaust aftertreatment device 200 including a first aftertreatment assembly 300, an exhaust inlet 301 in communication with the first aftertreatment assembly 300, and a second aftertreatment component 400 in which the first aftertreatment assembly 300 is arranged side by side, an exhaust outlet 401 in communication with the second aftertreatment component 400, and an interface connecting the first and

second aftertreatment components

300, 400 The mixing chamber assembly 100. In the illustrated embodiment of the invention, the exhaust aftertreatment device 200 is U-shaped, and the first aftertreatment assembly 300 includes a diesel oxidation catalyst (DOC) and diesel particulates located downstream of the diesel oxidation catalyst. A collector (DPF), the second aftertreatment component 400 comprising a selective catalytic reducing agent (SCR).

The mixing chamber assembly 100 includes a housing 1 and a mixer 2 mounted within the housing 1.

In the illustrated embodiment of the invention, the housing 1 is provided with an end plate 11, a housing 12 that mates with the end plate 11, and a cavity 13 located within the housing 12. The end plate 11 is provided with a first opening 111 and a second opening 112 located below the first opening 111. The first opening 111 is for supplying airflow, and the second opening 112 is for supplying airflow. A mount 121 is welded to the top of the outer casing 12. The mount 121 is for mounting a urea nozzle (not shown) to inject urea droplets into the mixer 2. The cavity 13 communicates with the first opening 111 and the second opening 112.

The mixer 2 includes a mixing tube 21 located in the cavity 13, an end bowl 24 cooperating with the mixing tube 21, and a partition 22 fixing the mixing tube 21 in the cavity 13. The partition 22 divides the cavity 13 into a first cavity 131 that communicates with the first opening 111 and a second cavity 132 that communicates with the second opening 112. The mixing tube 21 includes a tapered portion 211 located within the first cavity 131, wherein the tapered portion 211 includes a first inner cavity 212 surrounding the periphery of the first inner cavity 212 and along A plurality of fins 213 are circumferentially distributed and a plurality of slots 214 corresponding to the plurality of fins 213 and in communication with the first inner cavity 212. The arrangement is such that the airflow is rotated into the mixing tube 21, which increases the distance and time for the evaporation of the urea, improves the uniformity of the airflow mixing, and improves the resistance to crystallization. The end bowl 24 is provided with a second inner cavity 241 communicating with the first inner cavity 212 and at least one cleaning hole 242 communicating with the second inner cavity 241 and the first cavity 212. A small amount of exhaust gas is supplied from the cleaning hole 242 into the mixing tube 21, thereby reducing the risk of urea crystallization.

Referring to FIG. 9, the end bowl 24 is adjacent to the mounting seat 121, and the urea nozzle is used to inject urea droplets into the mixing tube 21. The mixing tube 21 is in communication with the second cavity 132. The partition 22 is provided with an opening 23 corresponding to the mixing tube 21. The mixer 2 is further provided with a steel wool 25 fixed in the mixing tube 21 for passing the exhaust gas and the urea droplets to further increase the urea droplets Broken and evaporated.

The first post-processing assembly 300 is disposed in parallel with the second post-processing assembly 400. The first post-processing assembly 300 is provided with a first axis S1, and the mixing tube 21 is provided with a second axis S2. An axis S1 is perpendicular to the second axis S2.

It should be noted that the orientations of "upper", "lower", "top", "bottom", "below" and the like described in the present invention should not be construed as limited, because these positions are different depending on the position of the components. Relationships should also be adaptively understood. In addition, the above embodiments are only intended to illustrate the present invention and do not limit the technical solutions described in the present invention, and the understanding of the present specification should be based on those skilled in the art. Although the present invention has been described in detail with reference to the embodiments of the present invention, it will be understood by those skilled in the art that the invention may be modified or equivalently substituted without departing from the invention. The spirit and scope of the invention and its modifications are intended to be included within the scope of the appended claims.

Claims

An exhaust aftertreatment device including a first aftertreatment assembly, an exhaust inlet in communication with the first aftertreatment assembly, a second aftertreatment assembly disposed side by side with the first aftertreatment assembly, and An exhaust outlet in communication with the second aftertreatment component and a mixing chamber assembly connecting the first and second aftertreatment components, the mixing chamber assembly including a housing and a mixer located within the housing, wherein The housing is provided with a first opening, a second opening on a side of the first opening, a mount for mounting a urea nozzle to inject urea droplets onto the mixer, and a communication between the first opening and the chamber a second open cavity, characterized in that the mixer comprises a mixing tube located in the cavity, an end bowl cooperating with the mixing tube, and fixing the mixing tube in the cavity a partition separating the cavity into a first cavity and a second cavity, the mixing tube including a tapered portion in the first cavity, wherein the tapered portion includes a first An inner cavity surrounding the first inner cavity a plurality of fins distributed circumferentially and a plurality of slots corresponding to the plurality of fins and communicating with the first inner cavity; the end bowl being provided in communication with the first inner cavity a second inner cavity and at least one cleaning hole connecting the second inner cavity and the first cavity.
The exhaust aftertreatment device of claim 1 wherein said first aftertreatment component is disposed in parallel with said second aftertreatment component, said first aftertreatment component being provided with a first axis, said The mixing tube is provided with a second axis that is perpendicular to the second axis.
The exhaust aftertreatment device of claim 1 wherein said end bowl is adjacent said mount and said urea nozzle is for injecting urea droplets into said mixing tube.
The exhaust aftertreatment device according to claim 3, wherein said cleaning hole is for supplying a small amount of exhaust gas from said cleaning hole into said mixing tube.
The exhaust aftertreatment device of claim 1 wherein said mixing tube is in communication with said second chamber.
The exhaust aftertreatment device according to claim 1, wherein said partition is provided with an opening corresponding to said mixing tube.
The exhaust aftertreatment device according to claim 1, wherein said mixer further comprises steel wool fixed in said mixing tube, said steel wool being used for said exhaust gas and said urea The droplets pass through to further increase the fragmentation and evaporation of the urea droplets.
The exhaust aftertreatment device according to claim 1, wherein said exhaust aftertreatment device is U-shaped, said first aftertreatment assembly comprising a diesel oxidation catalyst and diesel fuel downstream of said diesel oxidation catalyst A particle trap, the second aftertreatment component comprising a selective catalytic reducing agent.