Exhaust aftertreatment device

Abstract

An exhaust gas aftertreatment device includes a first aftertreatment component, an exhaust gas inlet, a second aftertreatment component, an exhaust gas outlet and a mixing chamber component. The mixing chamber component includes a shell and a mixer located in the shell. The mixer includes a mixing tube and a partition that fixes the mixing tube in a cavity, the partition divides the cavity into a first cavity and a second cavity, and the mixing tube includes a tapered portion, wherein the tapered portion includes a first inner cavity, a plurality of fins surrounding the periphery of the first inner cavity and distributed circumferentially, and a plurality of slots corresponding to the plurality of fins and connected to the first inner cavity. With such an arrangement, the airflow enters the mixing tube in a swirl manner, which increases the distance and time of urea evaporation and improves the uniformity of airflow mixing.

Description

Technical Field

[0001] The invention relates to an exhaust gas after-treatment device, belonging to the technical field of engine exhaust gas after-treatment. Background Art

[0002] Studies have shown that the uniformity of ammonia distribution in the exhaust aftertreatment system (such as the selective catalytic reduction system, SCR system) pipeline has an important impact on the overall performance and durability of the system. If ammonia (NH3) is unevenly distributed, the nitrogen oxide (NOx) conversion efficiency will be too low. If the urea injection amount is increased to meet the emission performance, it is easy to cause ammonia leakage pollution. At the same time, urea droplets are easy to deposit when they come into contact with the wall surface with lower temperature. When the crystallization is serious, it will block the exhaust pipe and cause the engine power performance to decrease. Improving the mixing uniformity of ammonia molecules can effectively improve the utilization rate of urea, reduce the urea injection amount, and thus reduce the risk of urea crystallization.

[0003] Therefore, it is necessary to provide an exhaust gas after-treatment device that can improve the mixing uniformity of ammonia molecules to solve the above technical problems. Summary of the invention

[0004] The object of the present invention is to provide an exhaust gas aftertreatment device capable of evenly mixing the exhaust gas of an engine with urea droplets.

[0005] To achieve the above-mentioned object, the present invention adopts the following technical scheme: an exhaust gas after-treatment device, comprising a first after-treatment component, an exhaust gas inlet connected to the first after-treatment component, a second after-treatment component arranged side by side with the first after-treatment component, an exhaust gas outlet connected to the second after-treatment component, and a mixing chamber component connecting the first and second after-treatment components, the mixing chamber component comprising a shell and a mixer located in the shell, wherein the shell is provided with a first opening, a second opening located beside the first opening, a mounting seat for mounting a urea nozzle to spray urea droplets onto the mixer, and a mounting seat connecting the first opening and the second opening. A cavity with two openings, the mixer includes a mixing tube located in the cavity, an end bowl matched with the mixing tube and a partition fixing the mixing tube in the cavity, the partition divides the cavity into a first cavity and a second cavity, the mixing tube includes a conical portion located in the first cavity, wherein the conical portion includes a first inner cavity, a plurality of fins surrounding the periphery of the first inner cavity and distributed circumferentially, and a plurality of slots corresponding to the plurality of fins and connected to the first inner cavity; the end bowl is provided with a second inner cavity connected to the first inner cavity and at least one cleaning hole connecting the second inner cavity with the first cavity.

[0006] As a further improved technical solution of the present invention, the first after-treatment component is arranged in parallel with the second after-treatment component, the first after-treatment component is provided with a first axis, the mixing tube is provided with a second axis, and the first axis is perpendicular to the second axis.

[0007] As a further improved technical solution of the present invention, the end bowl is close to the mounting seat, and the urea nozzle is used to spray urea droplets into the mixing tube.

[0008] As a further improved technical solution of the present invention, the cleaning hole is used to allow a small amount of exhaust gas to enter the mixing tube from the cleaning hole.

[0009] As a further improved technical solution of the present invention, the mixing tube is communicated with the second cavity.

[0010] As a further improved technical solution of the present invention, the partition is provided with an opening corresponding to the mixing tube.

[0011] As a further improved technical solution of the present invention, the mixer is further provided with steel wool fixed in the mixing tube, and the steel wool is used for the exhaust gas and the urea droplets to pass through, so as to further increase the breakage and evaporation of the urea droplets.

[0012] As a further improved technical solution of the present invention, the exhaust after-treatment device is U-shaped, the first after-treatment component includes a diesel oxidation catalyst and a diesel particulate filter located downstream of the diesel oxidation catalyst, and the second after-treatment component includes a selective catalytic reducer.

[0013] Compared with the prior art, the present invention divides the cavity into a first cavity and a second cavity by setting a partition, wherein the mixing tube comprises a conical portion located in the first cavity, and the conical portion comprises a plurality of fins distributed along the circumferential direction. Such a configuration enables the airflow to enter the mixing tube in a swirling manner, thereby increasing the distance and time for urea evaporation, improving the uniformity of airflow mixing, and improving the anti-crystallization ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a three-dimensional schematic diagram of the exhaust gas after-treatment device of the present invention.

[0015] Figure 2 yes Figure 1 A three-dimensional diagram from another angle.

[0016] Figure 3 yes Figure 2 main view.

[0017] Figure 4 yes Figure 2 Rear view of.

[0018] Figure 5 yes Figure 2 Top view of the .

[0019] Figure 6 yes Figure 2 Bottom view of .

[0020] Figure 7 yes Figure 2 Left view of .

[0021] Figure 8 yes Figure 2 Right view of .

[0022] Fig. 9 yes Figure 7 Schematic diagram of the cross section along line AA.

[0023] Fig.10 yes Figure 5 Schematic diagram of the cross section along line BB.

[0024] Fig.11 yes Figure 1 Partial exploded view of the .

[0025] Fig.12 yes Fig.11 Partially exploded view from another angle.

[0026] Fig.13 yes Fig.12 Further exploded view. DETAILED DESCRIPTION

[0027] Please refer to Figures 1 to 13 As shown, the present invention discloses an exhaust aftertreatment device 200, which includes a first aftertreatment component 300, an exhaust inlet 301 connected to the first aftertreatment component 300, a second aftertreatment component 400 arranged side by side with the first aftertreatment component 300, an exhaust outlet 401 connected to the second aftertreatment component 400, and a mixing chamber component 100 connecting the first and second aftertreatment components 300 and 400. In the illustrated embodiment of the present invention, the exhaust aftertreatment device 200 is U-shaped, the first aftertreatment component 300 includes a diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF) located downstream of the diesel oxidation catalyst, and the second aftertreatment component 400 includes a selective catalytic reducer (SCR).

[0028] The mixing chamber assembly 100 includes a housing 1 and a mixer 2 installed in the housing 1 .

[0029] In the illustrated embodiment of the present invention, the housing 1 is provided with an end plate 11, a shell 12 matched with the end plate 11, and a cavity 13 located in the shell 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 used for airflow inflow, and the second opening 112 is used for airflow outflow. A mounting seat 121 is welded to the top of the shell 12. The mounting seat 121 is used to mount a urea nozzle (not shown) to spray urea droplets into the mixer 2. The cavity 13 communicates the first opening 111 with the second opening 112.

[0030] The mixer 2 includes a mixing tube 21 located in the cavity 13, an end bowl 24 matched with the mixing tube 21, and a partition 22 for fixing the mixing tube 21 in the cavity 13. The partition 22 divides the cavity 13 into a first cavity 131 connected to the first opening 111 and a second cavity 132 connected to the second opening 112. The mixing tube 21 includes a conical portion 211 located in the first cavity 131, wherein the conical portion 211 includes a first inner cavity 212, a plurality of fins 213 surrounding the periphery of the first inner cavity 212 and distributed in the circumferential direction, and a plurality of slots 214 corresponding to the plurality of fins 213 and connected to the first inner cavity 212. Such a configuration is conducive to the airflow rotating into the mixing tube 21, increasing the distance and time of urea evaporation, improving the uniformity of airflow mixing, and improving the anti-crystallization ability. The end bowl 24 is provided with a second inner cavity 241 connected to the first inner cavity 212 and at least one cleaning hole 242 connecting the second inner cavity 241 and the first cavity 212, so that a small amount of exhaust gas can enter the mixing tube 21 from the cleaning hole 242, thereby reducing the risk of urea crystallization.

[0031] Please refer to Fig. 9 As shown, the end bowl 24 is close to the mounting seat 121, and the urea nozzle is used to spray urea droplets into the mixing tube 21. The mixing tube 21 is connected to the second cavity 132. The partition 22 is provided with an opening 23 corresponding to the mixing tube 21. The mixer 2 is also provided with steel wool 25 fixed in the mixing tube 21, and the steel wool 25 is used for the exhaust gas and the urea droplets to pass through, so as to further increase the breakage and evaporation of the urea droplets.

[0032] The first after-treatment assembly 300 is arranged in parallel with the second after-treatment assembly 400 . The first after-treatment assembly 300 is provided with a first axis S1 , and the mixing tube 21 is provided with a second axis S2 . The first axis S1 is perpendicular to the second axis S2 .

[0033] It should be noted that the directions such as "upper", "lower", "top", "bottom", and "below" described in the present invention should not be understood in a limiting sense, because these positional relationships should also be understood adaptively according to the different placement positions of the components. In addition, 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 the technical personnel in the relevant technical field. Although the present invention has been described in detail with reference to the above-mentioned embodiments, it should be understood by those of ordinary skill in the art that the technical personnel in the relevant technical field can still modify or make equivalent substitutions to the present invention, and all technical solutions and improvements thereof 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. An exhaust aftertreatment device, comprising a first aftertreatment component, an exhaust inlet connected to the first aftertreatment component, a second aftertreatment component arranged side by side with the first aftertreatment component, an exhaust outlet connected to the second aftertreatment component, and a mixing chamber component connecting the first and second aftertreatment components, the mixing chamber component comprising a shell and a mixer located in the shell, wherein the shell is provided with a first opening, a second opening located beside the first opening, a mounting seat for mounting a urea nozzle to spray urea droplets onto the mixer, and a cavity connecting the first opening and the second opening, characterized in that: The mixer includes a mixing tube located in the cavity, an end bowl matched with the mixing tube and a partition fixing the mixing tube in the cavity, the partition divides the cavity into a first cavity and a second cavity, the mixing tube includes a conical portion located in the first cavity, wherein the conical portion includes a first inner cavity, a plurality of fins surrounding the periphery of the first inner cavity and distributed circumferentially, and a plurality of grooves corresponding to the plurality of fins and connected to the first inner cavity; the end bowl includes a cylindrical portion and a bottom wall connected to the bottom of the cylindrical portion, the cylindrical portion is provided with a second inner cavity connected to the first inner cavity and at least one cleaning hole connecting the second inner cavity with the first cavity, the conical portion includes a first end and a second end, wherein the diameter of the first end is smaller than that of the second end, and the first end of the conical portion is connected to the bottom wall.

2. The exhaust gas aftertreatment device according to claim 1, characterized in that: The first after-treatment component is arranged in parallel with the second after-treatment component. The first after-treatment component is provided with a first axis, and the mixing tube is provided with a second axis. The first axis is perpendicular to the second axis.

3. The exhaust gas aftertreatment device according to claim 1, characterized in that: The end bowl is close to the mounting seat, and the urea nozzle is used to spray urea droplets into the mixing pipe.

4. The exhaust gas aftertreatment device according to claim 3, characterized in that: The cleaning hole is used to allow a small amount of exhaust gas to enter the mixing tube from the cleaning hole.

5. The exhaust gas aftertreatment device according to claim 1, characterized in that: The mixing tube is communicated with the second cavity.

6. The exhaust gas aftertreatment device according to claim 1, characterized in that: The partition plate is provided with openings corresponding to the mixing tube.

7. The exhaust gas aftertreatment device according to claim 1, characterized in that: The mixer is further provided with steel wool fixed in the mixing tube, and the steel wool is used for the exhaust gas and the urea droplets to pass through, so as to further increase the breakage and evaporation of the urea droplets.

8. The exhaust gas aftertreatment device according to claim 1, characterized in that: The exhaust gas aftertreatment device is U-shaped, the first aftertreatment component includes a diesel oxidation catalyst and a diesel particulate filter located downstream of the diesel oxidation catalyst, and the second aftertreatment component includes a selective catalytic reducer.

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