WO2019128164A1 - Mixing device for exhaust post-processing, and package therefor - Google Patents

Abstract

A mixing device (100) for exhaust post-processing, comprising a shell (1) and a mixing assembly (2) positioned in the shell, wherein the mixing assembly comprises a first plate (3), a second plate (4), a third plate (5) and a mixer (6), wherein the first plate is provided with a first inlet and a second inlet which are respectively positioned at two sides; the mixer comprises a bulge part as well as a fourth space and a fifth space which are positioned below the bulge part; the bulge part is provided with a first side edge and a second side edge, wherein the first side edge is provided with a plurality of first perforations which communicate between a third space and the fourth space, and the second side edge is provided with a plurality of second perforations which communicate between the third space and the fifth space. By means of the described arrangement, heat exchange is enhanced and crystallization resistance is improved.

Description

Exhaust aftertreatment mixing device and its package

The present application claims the priority of the Chinese patent application filed on Dec. 29, 2017, filed on Jan. 29,,,,,,,,,,,,,,,,,,,,,,, .

Technical field

The invention relates to an exhaust gas post-treatment mixing device and a package thereof, and belongs to the technical field of engine exhaust gas post-treatment.

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 post-treatment mixing device and its package to solve the above technical problems.

Summary of the invention

It is an object of the present invention to provide an exhaust gas post-treatment mixing device having strong anti-crystallization ability and an exhaust gas post-treatment package having the exhaust gas post-treatment mixing device.

In order to achieve the above object, the present invention adopts the following technical solution: an exhaust gas after-treatment mixing device comprising a casing and a mixing assembly located in the casing, wherein the casing is provided to install a urea nozzle to the mixing a mount for injecting urea in the assembly, the mixing assembly including a first plate, a second plate, a third plate between the first plate and the second plate, and the first plate a mixer between the plate and the third plate, wherein the first plate is provided with a first inlet and a second inlet respectively located at two sides, the mixer comprising a communication with the first inlet a first space, a second space communicating with the second inlet, and a third space between the first space and the second space, the top of the first space being connected to the third space The top of the second space is also in communication with the third space; the mixer is provided with a ridge protruding from the bottom into the third space, and a fourth space below the ridge And the fifth space and the fourth space a sixth space between the fifth space and the fifth space; the ridge portion is provided with a first side and a second side, and the first side is provided to communicate the third space and the fourth space a plurality of first perforations, the second side is provided with a plurality of second perforations connecting the third space and the fifth space; the second plate is provided with a first communication with the fourth space An outlet and a second outlet communicating with the fifth space; the third plate is provided with a first through hole communicating with the sixth space and for respectively guiding the airflow from the first through hole The first space and the second through hole of the second space.

As a further improved technical solution of the present invention, the first inlet is in axial communication with the first space, and the second inlet is axially connected to the second space, the first space and the The second space is substantially in radial communication with the third space, the first outlet is in axial communication with the fourth space, and the second outlet is axially connected to the fifth space The sixth space is in axial communication with the first through hole.

As a further improved technical solution of the present invention, the third plate is provided with a first baffle portion for axially located in the fourth space and for axially located in the fifth space. a second baffle portion.

As a further improvement of the present invention, the second through holes are respectively located outside the first baffle portion and the second baffle portion; between the second plate and the third plate A seventh space is provided, and the second through holes respectively communicate the seventh space and the first space and the seventh space and the second space.

As a further improved technical solution of the present invention, the mixer is provided with a first curved wall and a first partition wall cooperating with the first curved wall, the first space is located at the first curved wall Between the first partition wall and the first partition wall.

As a further improvement of the present invention, the first partition wall is provided with a first fixing portion fixed to the bottom of the first curved wall and a first extending arm located inside the first curved wall; A first swirling direction is defined between the first curved wall and the first dividing wall.

As a further improved technical solution of the present invention, the mixer is provided with a second curved wall and a second dividing wall cooperating with the second curved wall, and the second space is located at the second curved wall Between the second partition wall.

As a further improvement of the present invention, the second partition wall is provided with a second fixing portion fixed to the bottom of the second curved wall and a second extending arm located inside the second curved wall. A second swirling direction is defined between the second curved wall and the second dividing wall, wherein the first swirling direction is one of a clockwise and a counterclockwise direction, and the second swirling direction is Clockwise and counterclockwise.

As a further improved technical solution of the present invention, the ridge is connected between the first curved wall and the second curved wall; the mixer further includes a first bend fixed under the ridge a rotating portion and a second turning portion, wherein the fourth space is located at least between the first bending portion and the first side, and the fifth space is located at least at the second bending portion Between the second side.

As a further improvement of the present invention, the first swirling direction and the second swirling direction are both in a cross section of the casing; the fourth space and the fifth space are also respectively defined a third swirling direction and a fourth swirling direction in the cross section, wherein the third swirling direction is substantially the same as the first swirling direction, the fourth swirling direction and the second The direction of the swirl is approximately the same.

As a further improved technical solution of the present invention, the ridge, the first curved wall and the second curved wall are formed by bending a single piece, and are substantially ω-shaped as a whole.

As a further improved technical solution of the present invention, the urea nozzle is used to spray atomized urea droplets into the third space.

The invention further relates to an exhaust aftertreatment package comprising a first aftertreatment carrier assembly, a second aftertreatment carrier assembly downstream of the first aftertreatment carrier assembly, and downstream of the second aftertreatment carrier assembly And a third aftertreatment carrier assembly, the exhaust aftertreatment package further comprising the foregoing exhaust aftertreatment mixing device between the second aftertreatment carrier assembly and the third aftertreatment carrier assembly.

Compared with the prior art, the mixer of the present invention makes full use of the cross section of the casing, increases the distance and time of urea evaporation in a limited space, and improves the uniformity of airflow mixing; And a second through hole for guiding the airflow from the first through hole to the first space and the second space respectively, so as to be arranged, the airflow with a higher temperature can be directed to the positive portion of the ridge On the opposite side, the heat transfer is enhanced and the efficiency of urea evaporation is improved.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic perspective view of a tail gas aftertreatment mixing device of the present invention.

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

Figure 3 is a left side view of Figure 1.

Figure 4 is a right side view of Figure 1.

Figure 5 is a perspective view showing the housing of Figure 1 removed.

Figure 6 is a perspective view of another angle of Figure 5.

Fig. 7 is a partially exploded perspective view of Fig. 5;

Figure 8 is a front elevational view showing the first sheet of Figure 3 removed.

Figure 9 is a schematic cross-sectional view taken along line A-A of Figure 8.

Fig. 10 is an exploded perspective view of Fig. 7;

Detailed ways

Referring to Figures 1 through 10, the present invention discloses an exhaust aftertreatment mixing device 100 for use in an aftertreatment system such as an SCR to treat engine exhaust. The exhaust aftertreatment mixing device 100 includes a housing 1 and a mixing assembly 2 mounted within the housing 1.

In the illustrated embodiment of the present invention, the casing 1 has a cylindrical shape, and is provided with a mounting plate 11 recessed into the casing 1 and a mounting seat 12 welded to the mounting plate 11. The mount 12 is used to mount a urea nozzle (not shown) to inject urea droplets into the mixing assembly 2.

The mixing assembly 2 includes a first plate 3, a second plate 4, a third plate 5 between the first plate 3 and the second plate 4, and the first plate 3 and a mixer 6 between the third plate 5. The first plate 3, the second plate 4, and the third plate 5 are each fixed in the casing 1. The first plate 3 is provided with a first inlet 31 and a second inlet 32 respectively located on both sides. In addition, the first plate 3 is further provided with a recess 33 located below it.

Referring to FIG. 4, FIG. 6 and FIG. 10, the second plate 4 is provided with a first outlet 41 and a second outlet 42 on both sides thereof. The first outlet 41 and the second outlet 42 are both located at the edge of the second panel 4.

The third plate 5 is provided with a first baffle portion 51, a second baffle portion 52, a first through hole 53 between the first baffle portion 51 and the second baffle portion 52, and a location The first baffle portion 51 and the two second through holes 54 outside the second baffle portion 52 are described.

Referring to FIG. 5 to FIG. 10, the mixer 6 includes a first space 61 communicating with the first inlet 31, a second space 62 communicating with the second inlet 32, and the first space 61 and a third space 63 between the second spaces 62, a top of the first space 61 is in communication with the third space 63, and a top of the second space 62 is also connected to the third space 63. . The first space 61, the second space 62, and the third space 63 are blocked by the second plate 4 and the third plate 5 in the axial direction (the exhaust gas entering direction), so that a part of the airflow It is necessary to enter the third space 63 from the first and second spaces 61, 62. The urea nozzle is for injecting atomized urea droplets into the third space 63.

Specifically, the mixer 6 includes a first curved wall 64, a first dividing wall 65 that cooperates with the first curved wall 64, a second curved wall 66, and the second curved wall 66. a mating second partition wall 67 and a ridge 68 projecting from the bottom into the third space 63, wherein the first space 61 is located at the first curved wall 64 and the first partition wall Between the 65, the second space 62 is located between the second curved wall 66 and the second partition wall 67, and the third space 63 is located at the first partition wall 65 and the second partition wall 67. between. The first partition wall 65 is provided with a first fixing portion 651 fixed to the bottom of the first curved wall 64 and a first extending arm 652 located inside the first curved wall 64. Referring to FIG. 8 , a first swirl direction S1 is defined between the first curved wall 64 and the first partition wall 65 . The second partition wall 67 is provided with a second fixing portion 671 fixed to the bottom of the second curved wall 66 and a second extending arm 672 located inside the second curved wall 66. A second swirl direction S2 is defined between the second curved wall 66 and the second dividing wall 67. The first swirl direction S1 is one of clockwise and counterclockwise, and the second swirl direction S2 is the other of clockwise and counterclockwise. Referring to the hollow arrows in FIG. 8, in the illustrated embodiment of the present invention, the first swirl direction S1 is a clockwise direction, and the second swirl direction S2 is a counterclockwise direction. With such an arrangement, the cross section of the exhaust gas post-treatment mixing device 100 can be fully utilized to form a double swirling manner to increase the mixing distance between the urea and the exhaust gas, improve the uniformity of evaporation and mixing of the urea, and have strong anti-crystallization ability. In the illustrated embodiment of the invention, the ridge 68 is coupled between the first curved wall 64 and the second curved wall 66. The raised portion 68, the first curved wall 64, and the second curved wall 66 are formed by bending a single sheet and are generally ω-shaped as a whole.

Referring to FIG. 7 to FIG. 10 , the ridge portion 68 is provided with a first side 681 , a second side 682 , and a first top edge connecting the first side 681 and the second side 682 . 683. A first bottom edge 684 extending outward from a bottom of the first side edge 681 and a second bottom edge 685 extending outward from a bottom of the second side edge 682. In the illustrated embodiment of the present invention, the angle between the first side 681 and the second side 682 is an acute angle, and the first top edge 683, the first bottom edge 684, and the second bottom edge 685. They are all in the shape of an arc.

The mixer 5 is provided with a first turning portion 71 and a second turning portion 72 located below the ridges 68, wherein the mixer 5 further includes a fourth space 74 located below the ridges 68. And a fifth space 75 and a sixth space 76 between the fourth space 74 and the fifth space 75; the fourth space 74 is located at least at the first bending portion 71 and the first side The fifth space 75 is located between the sides 681 at least between the second curved portion 72 and the second side 682. As shown in FIG. 10, the first side 681 is provided with a plurality of first through holes 6811 communicating with the third space 63 and the fourth space 74, and the second side 682 is provided with the first side Three spaces 63 and a plurality of second perforations 6821 of the fifth space 75.

The first perforation 6811 and the second perforation 6821 are advantageous for achieving urea crushing to become finer particles and enhancing heat exchange, thereby facilitating better evaporation. In the illustrated embodiment of the invention, the sixth space 76 allows the exhaust to heat the ridges 68, further reducing the risk of crystallization.

Referring to FIG. 8 , the fourth space 74 and the fifth space 75 respectively define a third swirling direction S3 and a fourth swirling direction S4 in the cross section, wherein the third space The swirl direction S3 is substantially the same as the first swirl direction S1, and the fourth swirl direction S4 is substantially the same as the second swirl direction S2. With such an arrangement, the cross section of the exhaust gas post-treatment mixing device 100 can be fully utilized to form a double swirling manner to increase the mixing distance between the urea and the exhaust gas, improve the uniformity of evaporation and mixing of the urea, and have strong anti-crystallization ability.

The first baffle portion 51 of the third plate 5 is located in the fourth space 74 in the axial direction, and the second baffle portion 52 of the third plate 5 is located in the fifth direction in the axial direction. The space 75 acts to block the air flow.

A seventh space 77 is disposed between the second plate 4 and the third plate 5, and the second through hole 54 communicates with the seventh space 77 and the first space 61 and communicates with the second space The seventh space 77 and the second space 62. With this arrangement, the airflow having a higher exhaust temperature can be directed to the front and back sides of the ridge portion 68 to enhance heat exchange, thereby improving the efficiency of urea evaporation.

In the illustrated embodiment of the present invention, the first inlet 31 communicates with the first space 61 in the axial direction, and the second inlet 32 communicates with the second space 62 in the axial direction, The first space 61 and the second space 62 communicate with the third space 63 substantially in the radial direction, and the first outlet 41 communicates with the fourth space 74 in the axial direction, and the second outlet 42 The fifth space 75 is communicated in the axial direction, and the sixth space 76 communicates with the first through hole 53 in the axial direction.

Referring to FIG. 8 to FIG. 10, when the exhaust gas of the engine enters the exhaust gas and processes the mixing device 100, a part of the exhaust gas enters the mixer 5 from the first and second inlets 31, 32, and the other portion The exhaust gas directly enters the sixth space 76 through the recess 33; the exhaust gas entering the first and second spaces 61, 62 is guided along the first and second swirl directions respectively under the guidance of the curved structure S1, S2 are rotated from both sides into the third space 63; when the injection condition is satisfied, the urea nozzle injects urea into the third space 63, and the atomized urea droplet is rotated and mixed with the exhaust of the engine, and passes through The first and second perforations 6811, 6821 enter the fourth and fifth spaces 74, 75. Referring to FIG. 8, the mixture of the urea droplets and the exhaust gas of the engine flows in a double swirl flow along the third swirl direction S3 and the fourth swirl direction S4 to the fourth and fifth spaces 74, 75, and finally The first and second outlets 41, 42 are separated. At the same time, the exhaust gas entering the sixth space 76 is blocked to a certain extent by the second plate 4, and the mixer 5 can be supplied with a certain degree of heating; in addition, as shown by the dotted arrow below in FIG. The first space and the second space 61, 62 can be swung through the seventh space 77 and the second through hole 54, thereby heating both the front and back sides of the ridge portion 68, thereby improving the efficiency of urea evaporation.

The present invention also relates to an exhaust aftertreatment package including a first post-process carrier assembly (not shown), a second post-process carrier assembly (not shown) downstream of the first post-process carrier assembly, and A third post-treatment carrier assembly (not shown) downstream of the second post-treatment carrier assembly. The exhaust aftertreatment mixing device is located between the second aftertreatment carrier assembly and the third aftertreatment carrier assembly. Preferably, the first post-treatment carrier assembly is an oxidation catalyst (DOC), the second post-treatment carrier assembly is a diesel particulate trap (DPF), and the third post-treatment carrier assembly is a selective catalytic reduction (SCR) .

It should be noted that the orientations of "upper", "lower", "top", "bottom" and the like described in the present invention should not be construed as limited, since these positional relationships should also be performed depending on the position of the components. Adaptive understanding. 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 (13)

An exhaust aftertreatment mixing device includes a housing and a mixing assembly located within the housing, wherein the housing is provided with a mount for mounting a urea nozzle to inject urea into the mixing assembly, wherein: The mixing assembly includes a first plate, a second plate, a third plate between the first plate and the second plate, and the first plate and the third plate a mixer between the sheets, wherein the first sheet is provided with a first inlet and a second inlet respectively on both sides, the mixer including a first space communicating with the first inlet, and the first a second space connected to the inlet and a third space between the first space and the second space, the top of the first space being in communication with the third space, the top of the second space Also in communication with the third space; the mixer is provided with a ridge protruding from the bottom into the third space, a fourth space and a fifth space located below the ridge, and at the The sixth space between the fourth space and the fifth space The ridge portion is provided with a first side edge and a second side edge, and the first side edge is provided with a plurality of first through holes connecting the third space and the fourth space, and the second side is provided There are a plurality of second perforations connecting the third space and the fifth space; the second plate is provided with a first outlet communicating with the fourth space and a second outlet communicating with the fifth space The third plate is provided with a first through hole communicating with the sixth space and a second passage for respectively connecting the airflow from the first through hole to the first space and the second space hole. The exhaust gas post-treatment mixing device according to claim 1, wherein said first inlet is in axial communication with said first space, and said second inlet is axially connected to said second space. The first space and the second space are substantially in radial communication with the third space, the first outlet is in axial communication with the fourth space, and the second outlet is axially Communicating with the fifth space, the sixth space is in axial communication with the first through hole. The exhaust gas post-treatment mixing device according to claim 2, wherein said third plate is provided with a first baffle portion for axially lying in said fourth space and for axially a second baffle portion located in the fifth space. The exhaust gas after-treatment mixing device according to claim 3, wherein the second through holes are respectively located outside the first baffle portion and the second baffle portion; the second plate and A seventh space is disposed between the third plates, and the second through holes respectively communicate the seventh space and the first space and the seventh space and the second space. The exhaust gas after-treatment mixing device according to claim 1, wherein the mixer is provided with a first curved wall and a first partition wall cooperating with the first curved wall, the first space Located between the first curved wall and the first dividing wall. The exhaust gas after-treatment mixing device according to claim 5, wherein the first partition wall is provided with a first fixing portion fixed to a bottom of the first curved wall and at the first curved wall a first extension arm of the inner side; a first swirl direction is defined between the first curved wall and the first partition wall. The exhaust gas post-treatment mixing device according to claim 6, wherein the mixer is provided with a second curved wall and a second partition wall cooperating with the second curved wall, the second space Located between the second curved wall and the second dividing wall. The exhaust gas after-treatment mixing device according to claim 7, wherein the second partition wall is provided with a second fixing portion fixed to the bottom of the second curved wall and at the second curved wall a second extending arm of the inner side, a second swirling direction defined between the second curved wall and the second dividing wall, wherein the first swirling direction is one of a clockwise and a counterclockwise direction, The second swirl direction is the other of clockwise and counterclockwise. The exhaust gas post-treatment mixing device according to claim 8, wherein said ridge portion is coupled between said first curved wall and said second curved wall; said mixer further comprising a fixed portion a first bending portion and a second bending portion below the ridge portion, wherein the fourth space is at least between the first bending portion and the first side edge, and the fifth space is at least located at the Between the second turning portion and the second side. The exhaust gas post-treatment mixing device according to claim 9, wherein said first swirling direction and said second swirling direction are both within a cross section of said casing; said fourth space and said The fifth space further defines a third swirling direction and a fourth swirling direction in the cross section, wherein the third swirling direction is substantially the same as the first swirling direction, the fourth The swirling direction is substantially the same as the second swirling direction. The exhaust gas after-treatment mixing device according to claim 7, wherein the ridge portion, the first curved wall and the second curved wall are formed by bending a single piece, and the whole is substantially Omega shape. The exhaust aftertreatment mixing apparatus of claim 1 wherein said urea nozzle is for injecting atomized urea droplets into said third space. An exhaust aftertreatment package including a first aftertreatment carrier assembly, a second aftertreatment carrier assembly downstream of the first aftertreatment carrier assembly, and a third downstream downstream of the second aftertreatment carrier assembly Processing a carrier assembly, characterized in that the exhaust aftertreatment package further comprises an exhaust aftertreatment mixing device between the second aftertreatment carrier assembly and the third aftertreatment carrier assembly, the exhaust aftertreatment mixing device The exhaust gas post-treatment mixing device according to any one of claims 1 to 12.

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