Exhaust gas aftertreatment mixing device and exhaust gas aftertreatment device

Abstract

An exhaust gas aftertreatment mixing device includes a housing, a mixing tube located within the housing, and a partition plate fixed to the periphery of the mixing tube. The housing has a mounting portion for mounting a urea nozzle, which sprays atomized urea droplets into the mixing tube. The exhaust gas aftertreatment mixing device further includes a urea crushing plate located within the mixing tube. The urea crushing plate includes a bottom wall, side walls extending upward from both sides of the bottom wall, and first and second wings extending outward from the side walls respectively. This invention also relates to an exhaust gas aftertreatment device including an exhaust gas aftertreatment mixing device. Compared to the prior art, this invention, by setting a urea crushing plate within the mixing tube, can break urea droplets into smaller particles, promoting urea droplet evaporation and reducing the risk of urea crystallization.

Description

Technical Field

[0001] This invention relates to an exhaust gas aftertreatment mixing device and an exhaust gas aftertreatment device, belonging to the field of engine exhaust gas aftertreatment technology. Background Technology

[0002] Studies have shown that the uniformity of ammonia distribution in exhaust aftertreatment systems (such as selective catalytic reduction systems, SCR systems) significantly impacts the overall performance and durability of the system. Uneven ammonia distribution can lead to excessive ammonia in some areas, causing ammonia leakage, while in other areas with low ammonia levels, the conversion efficiency of nitrogen oxides (NOx) is too low. Prolonged uneven ammonia distribution can also lead to uneven catalyst aging, thus affecting the overall performance of the catalyst. If the urea droplets are large, they are difficult to evaporate and easily form urea crystals, which can clog the exhaust pipe and reduce engine power performance in severe cases. Summary of the Invention

[0003] The purpose of this invention is to provide a tail gas aftertreatment mixing device and a tail gas aftertreatment device that can promote the evaporation of urea droplets.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a tail gas aftertreatment mixing device, comprising a housing, a mixing pipe located within the housing, and a partition plate fixed to the periphery of the mixing pipe; the housing is provided with a mounting portion for mounting a urea nozzle, the urea nozzle being used to spray atomized urea droplets into the mixing pipe; the partition plate divides the housing into a first space and a second space, the partition plate including a first plate located on one side of the mixing pipe, a second plate located on the other side of the mixing pipe, and a third plate connecting the first plate and the second plate, the third plate having a through hole for the mixing pipe to pass through; the mixing pipe including a first space located within the first space; The device includes a first pipe section within the space and a second pipe section within the second space. The first pipe section has at least two first openings located on its two sides, and the first openings are connected to the first space. The second pipe section has at least two second openings located on its two sides, and the second openings are connected to the second space. The exhaust gas aftertreatment mixing device also includes a urea crushing plate located in the mixing pipe. The urea crushing plate includes a bottom wall, side walls extending upward from both sides of the bottom wall, and a first wing and a second wing extending outward from both sides of the side walls. The first wing and the second wing are respectively fixed at positions near the lower edge of the first opening.

[0005] As a further improvement of the present invention, the first wing is provided with a first arc-shaped surface fixed on the inner wall of the mixing tube, and the second wing is provided with a second arc-shaped surface fixed on the inner wall of the mixing tube.

[0006] As a further improvement of the present invention, the first wing and the second wing are at the same height and are parallel to the bottom wall.

[0007] As a further improvement of the present invention, the first tube is provided with a first circumferential wall located between the two first openings and exposed in the first space, and the first circumferential wall is provided with a plurality of perforations communicating with the first space.

[0008] As a further improved technical solution of the present invention, the urea crushing plate includes an extension portion that extends horizontally from the bottom wall to the first circumferential wall, and the extension portion protrudes horizontally from the first wing portion and the second wing portion.

[0009] As a further improvement of the present invention, the extension is suspended in the mixing tube.

[0010] As a further improvement of the present invention, the housing is provided with a first axis, the mixing tube is provided with a second axis, the first axis is perpendicular to the second axis; the mixing tube is arranged vertically; the first plate and the second plate both extend vertically and in opposite directions, and the third plate extends horizontally.

[0011] As a further improvement of the present invention, the first plate is provided with a first arc-shaped surface that abuts against the first tube, and the second plate is provided with a second arc-shaped surface that abuts against the second tube.

[0012] As a further improvement of the present invention, the exhaust gas aftertreatment mixing device includes a plate located at the bottom of the mixing pipe, and the plate has an arc-shaped protrusion extending into the second pipe section in the middle.

[0013] The present invention also relates to an exhaust gas aftertreatment device, comprising an upstream exhaust gas aftertreatment package, a downstream exhaust gas aftertreatment package, and a connecting pipe connecting the upstream exhaust gas aftertreatment package and the downstream exhaust gas aftertreatment package; the upstream exhaust gas aftertreatment package is U-shaped and includes a first aftertreatment unit, a second aftertreatment unit, and a connecting housing connecting the first aftertreatment unit and the second aftertreatment unit; the downstream exhaust gas aftertreatment package includes the aforementioned exhaust gas aftertreatment mixing device and a third aftertreatment unit located downstream of the exhaust gas aftertreatment mixing device; the connecting pipe is provided with a flexible junction.

[0014] Compared to existing technologies, the present invention, by setting a urea crushing plate in the mixing tube, can break urea droplets into smaller particles, promote the evaporation of urea droplets, and reduce the risk of urea crystallization. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the exhaust gas aftertreatment device of the present invention.

[0016] Figure 2 yes Figure 1 A partial exploded view of the midstream and downstream exhaust gas aftertreatment packaging.

[0017] Figure 3 yes Figure 2 A three-dimensional schematic diagram of the aftertreatment and mixing device for intermediate exhaust gases.

[0018] Figure 4 yes Figure 3 A three-dimensional diagram from another angle.

[0019] Figure 5 yes Figure 4 The left view.

[0020] Figure 6 yes Figure 4 The right view.

[0021] Figure 7 It is along Figure 4 A cross-sectional view of line AA in the middle.

[0022] Figure 8 It is along Figure 5 A cross-sectional view of the BB line.

[0023] Figure 9 It is to remove Figure 4 A three-dimensional schematic diagram of the area behind the middle shell.

[0024] Figure 10 yes Figure 9 3D exploded view. Detailed Implementation

[0025] Please refer to Figures 1 to 10As shown, this invention discloses an exhaust aftertreatment device 100 for treating exhaust gases from a diesel engine. The exhaust aftertreatment device 100 includes an upstream exhaust aftertreatment package 200, a downstream exhaust aftertreatment package 300, and a connecting pipe 400 connecting the upstream and downstream exhaust aftertreatment packages 200 and 300. In the illustrated embodiment, the upstream exhaust aftertreatment package 200 is generally U-shaped and includes a first aftertreatment unit 201 (e.g., diesel oxidation catalyst, DOC), a second aftertreatment unit 202 (e.g., diesel particulate filter, DPF), and a connecting housing 203 connecting the first and second aftertreatment units 201 and 202. The downstream exhaust aftertreatment package 300 includes an exhaust aftertreatment mixing device 301 and a third aftertreatment unit 302 (e.g., selective catalytic reduction agent, SCR) located downstream of the exhaust aftertreatment mixing device 301. The connecting pipe 400 is provided with a flexible junction 401 to absorb vibration.

[0026] The exhaust gas aftertreatment mixing device 301 includes a housing 1, a mixing pipe 2 located inside the housing 1, a partition 3 fixed around the periphery of the mixing pipe 2, a urea crushing plate 4 located in the middle of the mixing pipe 2, and a plate 5 located at the bottom of the mixing pipe 2.

[0027] Please refer to Figure 3 As shown in the illustrated embodiment of the present invention, the housing 1 is cylindrical and has a first axis 10; the mixing tube 2 is cylindrical and has a second axis 20, the first axis 10 and the second axis 20 intersecting each other. Preferably, the first axis 10 is perpendicular to the second axis 20. Of course, in other embodiments, the housing 1 and the mixing tube 2 can also be other shapes, such as elliptical. The housing 1 is provided with a mounting portion 11 for mounting a urea nozzle (not shown), the urea nozzle being used to spray atomized urea droplets into the mixing tube 2.

[0028] The partition 3 divides the housing 1 into a first space 311 for communication with the upstream exhaust aftertreatment package 200 and a second space 312 for communication with the third aftertreatment unit 302. Please refer to... Figure 9 and Figure 10 As shown, the partition 3 is generally Z-shaped, comprising a first plate 31 located on one side of the mixing tube 2, a second plate 32 located on the other side of the mixing tube 2, and a third plate 33 connecting the first plate 31 and the second plate 32. The third plate 33 has a through hole 34 for the mixing tube 2 to pass through. In the embodiment illustrated in the present invention, the mixing tube 2 is arranged vertically; the first plate 31 and the second plate 32 both extend vertically and in opposite directions, while the third plate 33 extends horizontally. Specifically, as shown... Figure 9 As shown, the first plate 31 is located at the upper right of the mixing tube 2, and the second plate 32 is located at the lower left of the mixing tube 2. The first plate 31 has a first arc-shaped surface 35 in the middle that abuts against the mixing tube 2, and the second plate 32 has a second arc-shaped surface 36 in the middle that abuts against the mixing tube 2.

[0029] The mixing pipe 2 includes a first pipe section 21 located within the first space 311 and a second pipe section 22 located within the second space 312. The first pipe section 21 has at least two first openings 211 on each side, and the second pipe section 22 has at least two second openings 221 on each side. The first openings 211 communicate with the first space 311, and the second openings 221 communicate with the second space 312. The first openings 211 allow airflow to enter, and the second openings 221 allow airflow to exit, creating a double swirling effect. In the illustrated embodiment, the first pipe section 21 also has a first circumferential wall 23 located between the two first openings 211 and exposed within the first space 311. The first circumferential wall 23 has a plurality of perforations 231 communicating with the first space 311. Exhaust gas in the first space 311 can enter the mixing pipe 2 through the first openings 211 and the perforations 231. The perforations 231 can improve airflow distribution and regulate back pressure. The first tube portion 21 is further provided with a second circumferential wall 24 opposite to the first circumferential wall 23, and the second circumferential wall 24 is used to abut against the first arcuate surface 35 on the first tube portion 21. The second tube portion 22 is provided with a third circumferential wall 25 located below the first circumferential wall 23, and the third circumferential wall 25 is used to abut against the second arcuate surface 36 on the second tube portion 22.

[0030] The urea crushing plate 4, as its name suggests, is used to break up urea droplets ejected from the urea nozzle into smaller particles, thereby facilitating urea evaporation and reducing the risk of urea crystallization. The urea crushing plate 4 includes a bottom wall 41, side walls 42 extending upwards from both sides of the bottom wall 41, and a first wing 43 and a second wing 44 extending outwards from the side walls 42, respectively. The first wing 43 and the second wing 44 are fixed near the lower edge of the first opening 211. The first wing 43 has a first arcuate surface 431 fixed to the inner wall of the mixing tube 2, and the second wing 44 has a second arcuate surface 441 fixed to the inner wall of the mixing tube 2. The first wing 43 and the second wing 44 are at the same height and are parallel to the bottom wall 41. Furthermore, the urea crushing plate 4 also includes an extension 45 extending horizontally from the bottom wall 41 towards the first circumferential wall 23. The extension 45 protrudes horizontally from the first wing 43 and the second wing 44. The extension 45 is suspended in the mixing tube 2, meaning that the extension 45 does not contact the inner wall of the mixing tube 2. This arrangement allows the urea crushing plate 4 to effectively crush urea without excessively increasing the system back pressure.

[0031] The plate 5 is located at the lower end of the second tube 22. The plate 5 has an arc-shaped protrusion 51 extending towards the second tube 22 in the middle to guide the airflow in the opposite direction, forming a double vortex. In the embodiment illustrated in the figure, the plate 5 is sealed and installed at the lower end of the second tube 22. The plate 5 can prevent urea droplets from being directly sprayed onto the housing 1, and also reduces the risk of urea crystallization.

[0032] In the embodiment illustrated in this invention, when engine exhaust gas enters the first space 311, it enters the mixing pipe 2 through the first opening 211 and the perforation 231. When the injection conditions are met, the urea nozzle injects urea into the mixing pipe 2, and the atomized urea droplets mix with the engine exhaust gas and move downstream. The urea droplets hitting the urea crushing plate 4 are further broken into smaller particles, thus facilitating urea evaporation. Subsequently, the airflow enters the second space 312 through the second opening 221 and reaches the third after-treatment unit 302 located downstream. Under the action of the plate 5, it can better reverse the airflow (e.g., upward) to form a double swirl. This arrangement increases the distance and time for urea evaporation through the swirl, improves the uniformity of airflow mixing, and further reduces the risk of urea crystallization.

[0033] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. The understanding of this specification should be based on those skilled in the art. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still make modifications or equivalent substitutions to the present invention. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A tail gas aftertreatment mixing device, comprising a housing, a mixing pipe located within the housing, and a partition plate fixed to the periphery of the mixing pipe; the housing is provided with a mounting portion for mounting a urea nozzle, the urea nozzle being used to spray atomized urea droplets into the mixing pipe; the partition plate divides the housing into a first space and a second space, the partition plate including a first plate located on one side of the mixing pipe, a second plate located on the other side of the mixing pipe, and a third plate connecting the first plate and the second plate, the third plate having a through hole for the mixing pipe to pass through; the mixing pipe including a first pipe section located in the first space and a second pipe section located in the second space, wherein the first pipe section has at least two first openings respectively located on both sides thereof, the first openings communicating with the first space; the second pipe section has at least two second openings respectively located on both sides thereof, the second openings communicating with the second space; characterized in that: The exhaust gas aftertreatment mixing device also includes a urea crushing plate located in the mixing pipe. The urea crushing plate includes a bottom wall, side walls extending upward from both sides of the bottom wall, and a first wing and a second wing extending from both sides of the side walls respectively. The first wing and the second wing are respectively fixed at a position close to the lower edge of the first opening.

2. The exhaust gas aftertreatment mixing device as described in claim 1, characterized in that: The first wing is provided with a first arc-shaped surface fixed on the inner wall of the mixing tube, and the second wing is provided with a second arc-shaped surface fixed on the inner wall of the mixing tube.

3. The exhaust gas aftertreatment mixing device as described in claim 2, characterized in that: The first wing and the second wing are at the same height and are parallel to the bottom wall.

4. The exhaust gas aftertreatment mixing device as described in claim 1, characterized in that: The first tube has a first circumferential wall located between the two first openings and exposed in the first space, and the first circumferential wall has a plurality of perforations communicating with the first space.

5. The exhaust gas aftertreatment mixing device as described in claim 4, characterized in that: The urea crushing plate includes an extension that extends horizontally from the bottom wall to the first circumferential wall, the extension protruding horizontally from the first wing and the second wing.

6. The exhaust gas aftertreatment mixing device as described in claim 5, characterized in that: The extension is suspended in the mixing tube.

7. The exhaust gas aftertreatment mixing device as described in claim 1, characterized in that: The housing is provided with a first axis, and the mixing tube is provided with a second axis, the first axis being perpendicular to the second axis; the mixing tube is arranged vertically; the first plate and the second plate both extend vertically and in opposite directions, and the third plate extends horizontally.

8. The exhaust gas aftertreatment mixing device as described in claim 7, characterized in that: The first plate has a first arc-shaped surface that abuts against the first tube, and the second plate has a second arc-shaped surface that abuts against the second tube.

9. The exhaust gas aftertreatment mixing device as described in claim 1, characterized in that: The exhaust gas aftertreatment mixing device includes a plate located at the bottom of the mixing pipe, and the plate has an arc-shaped protrusion extending into the second pipe section in the middle.

10. An exhaust gas aftertreatment device, comprising an upstream exhaust gas aftertreatment package, a downstream exhaust gas aftertreatment package, and a connecting pipe connecting the upstream exhaust gas aftertreatment package and the downstream exhaust gas aftertreatment package; the upstream exhaust gas aftertreatment package is U-shaped and includes a first aftertreatment unit, a second aftertreatment unit, and a connecting housing connecting the first aftertreatment unit and the second aftertreatment unit; characterized in that: The downstream exhaust aftertreatment package includes an exhaust aftertreatment mixing device as described in any one of claims 1 to 9 and a third aftertreatment unit located downstream of the exhaust aftertreatment mixing device; the connecting pipe is provided with a flexible junction.

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