Mixer for engine tail gas after-treatment system

Abstract

The utility model relates to a mixer for an engine tail gas after-treatment system, the mixer for the engine tail gas after-treatment system comprises a first mixing pipe and a nozzle structure, the nozzle structure communicates with an inner cavity of the first mixing pipe and is used for spraying a urea solution towards the inner cavity of the first mixing pipe, and the inner cavity of the first mixing pipe is provided with a spiral channel; an inlet of the spiral channel is located in the side face of the first mixing pipe, the spiral channel spirally extends around the axis of the first mixing pipe, the first mixing pipe is provided with a first end and a second end which are opposite along the axis of the first mixing pipe, and the spiral channel penetrates through the first end and the second end; the tail gas can enter the spiral channel from the inlet, is mixed with the urea solution in the process of flowing along the spiral channel, and then is discharged out of the first mixing pipe from the second end. According to the mixer for the engine tail gas aftertreatment system, the mixing uniformity of tail gas and a urea solution can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of exhaust gas treatment equipment, and in particular to a mixer for an engine exhaust gas after-treatment system. Background Art

[0002] Faced with severe environmental challenges and the implementation of China VI regulations, vehicle exhaust emissions are becoming increasingly stringent. SCR technology injects a urea solution, which evaporates and pyrolyzes to produce ammonia (NH3), which then reduces NOx to N2 in the catalyst.

[0003] Typically, a mixer is used to mix exhaust gas and urea solution. However, due to its size, the channel for mixing exhaust gas and urea solution in the mixer is short, resulting in poor mixing of the urea solution and exhaust gas. This can lead to severe urea crystallization in the exhaust line, blocking the exhaust channel and thus affecting engine performance. Utility Model Content

[0004] Based on this, it is necessary to provide a mixer for an engine exhaust after-treatment system that can improve the mixing uniformity of exhaust gas and urea solution.

[0005] A mixer for an engine exhaust after-treatment system includes a first mixing tube and a nozzle structure. The nozzle structure is connected to the inner cavity of the first mixing tube and is used to spray a urea solution toward the inner cavity of the first mixing tube. The inner cavity of the first mixing tube has a spiral channel. The inlet of the spiral channel is located on the side of the first mixing tube, and the spiral channel extends spirally around the axis of the first mixing tube. In addition, the first mixing tube has a first end and a second end opposite to each other along its own axis, and the spiral channel passes through the first end and the second end. The exhaust gas can enter the spiral channel from the inlet and mix with the urea solution while flowing along the spiral channel, and then be discharged from the first mixing tube from the second end.

[0006] In one embodiment, the nozzle structure is disposed at a first end of the first mixing tube and is configured to spray the urea solution toward the second end. The first mixing tube includes an arc plate that spirally extends around the axis of the first mixing tube, such that a spiral channel is formed between the walls of the arc plate.

[0007] In one embodiment, at least a portion of the wall surface of the arc plate is provided with an air inlet hole, and the exhaust gas can enter the spiral channel through the air inlet hole from the side of the first mixing tube.

[0008] In one embodiment, the arc plate includes a first section and a second section spliced ​​along its own extension direction, the first section is located at the outermost layer along the radial direction of the first mixing tube, and the first section has a free end and a connecting end, the connecting end is connected to the second section, an inlet is formed between the free end and the second section, and the air inlet is opened in the second section.

[0009] In one embodiment, a plane perpendicular to the exhaust gas intake direction and passing through the axis of the first mixing tube is defined as a preset plane, and the preset plane includes a first plane portion and a second plane portion respectively located on both sides of the axis of the first mixing tube, and is freely located on the leeward side of the first plane portion or on the first plane portion, and the connection end is located on the windward side of the second plane portion or on the second plane portion.

[0010] In one embodiment, the radius R2 of the free end 142a of the first mixing tube 10 forms an angle γ with the first planar portion 151, 0°≤γ<90°; the diameter of the connecting end of the first mixing tube forms an angle α with the second planar portion, 0°≤α≤60°.

[0011] In one embodiment, the air inlet holes are distributed at intervals on the second section along the axial direction of the first mixing tube; and / or, the air inlet holes are distributed at intervals on the second section along the circumferential direction of the first mixing tube.

[0012] In one embodiment, the mixer for the engine exhaust after-treatment system also includes a shell and a mounting seat. The mounting seat is installed inside the shell and divides the inside of the shell into an intake side and an outlet side. The mounting seat is provided with a through hole. The first mixing tube is located on the intake side and is fixedly mounted on the mounting seat, and the second end is connected to the outlet side through the through hole. The exhaust gas can enter the spiral channel from the intake side through the inlet and flow into the outlet side.

[0013] In one embodiment, the mounting seat includes a middle plate and two side plates, the two side plates are respectively located on both sides of the middle plate and connected to the middle plate to form a "Z"-shaped mounting seat; a through hole is opened in the middle plate, and the two side plates are respectively fixedly connected to the inner wall of the shell.

[0014] In one embodiment, the mixer for the engine exhaust after-treatment system also includes a second mixing tube, which is located on the air outlet side and fixedly mounted on the mounting base. The second mixing tube is connected to the through hole, and a plurality of swirl blades are provided in the second mixing tube, and the swirl blades are distributed at intervals along the circumference of the second mixing tube; wherein the exhaust gas can rotate and circumvent the disturbance of the plurality of swirl blades.

[0015] Compared to existing technologies, the mixer for an engine exhaust aftertreatment system provided in this application extends the flow path between exhaust gas and urea solution by providing a spiral channel within the first mixing tube, thereby ensuring thorough mixing of the exhaust gas and urea solution. Furthermore, the nozzle structure sprays the urea solution from the first end toward the second end, and the spiral channel runs through the first and second ends. This allows the urea solution to more easily enter various locations along the cross-section of the spiral channel, thereby improving the uniformity of the mixing of the urea solution and exhaust gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 An axonometric view of a mixer for an engine exhaust after-treatment system according to one embodiment of the present application;

[0018] Figure 2 A side view of a mixer for an engine exhaust after-treatment system according to one embodiment of the present application;

[0019] Figure 3 for Figure 2 Cross-sectional view at AA;

[0020] Figure 4 This is a schematic diagram of the assembly of the mounting base, the first mixing tube, and the second mixing tube in one of the embodiments provided in this application;

[0021] Figure 5 for Figure 4 Schematic diagram from another perspective.

[0022] Figure numerals: 100, mixer for engine exhaust after-treatment system; 10, first mixing tube; 11, first end; 12, second end; 13, spiral channel; 131, inlet; 14, arc plate; 141, air inlet hole; 142, first section; 143, second section; 15, preset plane; 151, first plane portion; 152, second plane portion; 20, nozzle structure; 30, shell; 31, air inlet side; 32, air outlet side; 40, mounting seat; 41, through hole; 42, middle plate; 43, side plate; 50, second mixing tube; 51, swirl blade. DETAILED DESCRIPTION

[0023] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0024] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the specification of this application are for illustrative purposes only and do not represent the only implementation method.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0026] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it can mean that the first feature is directly in contact with the second feature, or the first feature and the second feature are indirectly in contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it can mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is higher in level than the second feature. When a first feature is "below," "below," or "below" a second feature, it can mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is lower in level than the second feature.

[0027] Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in the specification of this application includes any and all combinations of one or more of the relevant listed items.

[0028] See also Figures 1 to 5The present application provides a mixer 100 for an engine exhaust aftertreatment system. The mixer 100 includes a first mixing tube 10 and a nozzle structure 20. The nozzle structure 20 communicates with the inner cavity of the first mixing tube 10 and is used to spray a urea solution into the inner cavity of the first mixing tube 10. The inner cavity of the first mixing tube 10 includes a spiral channel 13. An inlet 131 of the spiral channel 13 is located on the side of the first mixing tube 10. The spiral channel 13 spirally extends around the axis of the first mixing tube 10. The first mixing tube 10 has a first end 11 and a second end 12 that are opposite to each other along its axis. The spiral channel 13 extends through the first end 11 and the second end 12. Exhaust gas can enter the spiral channel 13 from the inlet 131 and mix with the urea solution as it flows along the spiral channel 13 before exiting the first mixing tube 10 from the second end 12. The provision of the spiral channel 13 within the first mixing tube 10 extends the flow path of the exhaust gas and the urea solution, thereby ensuring thorough mixing of the exhaust gas and the urea solution.

[0029] Optionally, the nozzle structure 20 is provided at the first end 11 and is used to spray the urea solution from the first end 11 toward the second end 12. As can be seen from the spiral channel 13 running through the first end 11 and the second end 12, during the process of spraying the urea solution from the first end 11 toward the second end 12, it can be dispersed to various positions of the spiral channel 13 along the cross section of the first mixing tube 10, thereby facilitating sufficient mixing with the exhaust gas in the spiral channel 13, that is, facilitating improved uniformity of mixing of the urea solution and the exhaust gas. Optionally, in one embodiment, as Figure 4 As shown, the first mixing tube 10 includes a circular plate 14 that spirally extends around the axis of the first mixing tube 10, forming a spiral channel 13 between the walls of the circular plate 14. This makes the first mixing tube 10 simple in structure and easy to manufacture. Specifically, the first mixing tube 10 can be formed from a single circular plate 14 that is bent around the axis of the first mixing tube 10; alternatively, the first mixing tube 10 can be formed by sequentially joining multiple smaller circular plates 14 around the axis of the first mixing tube 10.

[0030] In other embodiments, the first mixing tube 10 may also be configured as a common circular tube, and a baffle is provided in the circular tube, thereby defining the spiral channel 13 through the baffle.

[0031] Furthermore, air inlet holes 141 are formed on at least a portion of the wall surface of the arc plate 14, allowing exhaust gas to enter the spiral channel 13 from the side of the first mixing tube 10 through the air inlet holes 141. The air inlet holes 141 facilitate the entry of exhaust gas into the spiral channel 13. Optionally, the air inlet holes 141 can be configured as circular holes, elliptical holes, or polygonal holes.

[0032] For example, in one embodiment, Figure 4 and Figure 5 As shown, the arc plate 14 includes a first section 142 and a second section 143 spliced ​​along its own extension direction. The first section is located at the outermost layer along the radial direction of the first mixing tube 10, and the first section 142 has a free end 142a and a connecting end 142b. The connecting end 142b is connected to the second section 143. The free end 142a and the second section 143 are surrounded by an inlet 131, and the air inlet hole 141 is opened in the second section 143. In other words, the first section 142 is located at the outermost layer to form the inlet 131 and the portion of the spiral channel 13 near the inlet 131, thereby guiding the exhaust gas into the spiral channel 13 and circulating along the spiral channel 13. In actual use, the second section 143 is closer to the exhaust gas intake direction relative to the first section 142, thereby facilitating the exhaust gas to pass through the air inlet hole 141 on the second section 143 and enter the spiral channel 13.

[0033] The air inlet holes 141 are spaced apart along the axial direction of the first mixing tube 10 on the second section 143; alternatively, the air inlet holes 141 are spaced apart along the circumference of the first mixing tube 10 on the second section 143; alternatively, the air inlet holes 141 are spaced apart along the axial direction of the first mixing tube 10 on the second section 143, and further, the air inlet holes 141 are spaced apart along the circumference of the first mixing tube 10 on the second section 143. This allows the exhaust gas to enter the spiral channel 13 more evenly.

[0034] For example, in one embodiment, the air inlet holes 141 are evenly spaced apart on the second section 143 along the axial direction of the first mixing tube 10, and the air inlet holes 141 are evenly spaced apart on the second section 143 along the circumference of the first mixing tube 10. Furthermore, a plane perpendicular to the exhaust gas intake direction and passing through the axis of the first mixing tube 10 is defined as a predetermined plane 15. The predetermined plane 15 includes a first planar portion 151 and a second planar portion 152, respectively located on opposite sides of the axis of the first mixing tube 10. Furthermore, the free end 142a is located on the leeward side of the first planar portion 151 or on the first planar portion 151, and the connecting end 142b is located on the windward side of the second planar portion 152 or on the second planar portion 152.

[0035] It should be noted that the leeward side refers to the side on the preset plane 15 that is in the same direction as the exhaust gas intake direction, and the windward side refers to the side on the preset plane 15 that is opposite to the exhaust gas intake direction. It is understandable that by arranging the free end 142a to be located on the leeward side of the first planar portion 151 or on the first planar portion 151, it is possible to avoid the arc plate 14 from blocking the entry into the spiral channel 13 from the inlet 131. By arranging the connecting end 142b to be located on the windward side of the second planar portion 152, that is, the air inlet 141 is only located on the windward side of the preset plane 15, it is possible to avoid the exhaust gas from passing through the air inlet 141 into the spiral channel 13 and then directly flowing out of the spiral channel 13 through the air inlet 141. Further, as Figure 5 As shown, the radius R2 of the free end 142a of the first mixing tube 10 forms an angle γ with the first planar portion 151, where 0°≤γ<90°. It is understood that the smaller γ is, the smaller the angle formed between the inlet 131 and the exhaust gas intake direction, thereby facilitating intake. For example, when γ = 0°, the free end 142a is located on the first planar portion 151, and the inlet 131 faces the exhaust gas intake direction. An angle of γ exceeding 90° makes it difficult for the exhaust gas to enter the inlet 131.

[0036] An angle α is formed between the radius R1 of the connecting end 142b of the first mixing tube 10 and the second flat portion 152, and 0°<α≤60°. It can be understood that the larger α is, the longer the extension length of the first section 142 is, which is conducive to guiding the exhaust gas to circulate along the spiral channel 13. However, if α is too large, the windward area of ​​the second section 143 will be small, which is not conducive to opening the air inlet 141 on the second section 143. Therefore, setting 0°≤α≤60° can not only ensure that the exhaust gas is guided to circulate along the spiral channel 13, but also ensure that the second section 143 has sufficient windward area to open the air inlet 141 on the second section 143. For example, the value of α can be 1°, 10°, 30°, 35°, 50°, 60°, etc., and can be set according to actual needs, which are not listed here one by one.

[0037] See also Figures 1 to 3 The mixer 100 for an engine exhaust aftertreatment system further includes a housing 30 and a mounting base 40. The mounting base 40 is mounted within the housing 30 and divides the interior of the housing 30 into an intake side 31 and an outlet side 32. The mounting base 40 defines a through hole 41. The first mixing pipe 10 is located on the intake side 31 and fixedly mounted on the mounting base 40. The second end 12 communicates with the outlet side 32 via the through hole 41. Exhaust gas can enter the spiral channel 13 from the intake side 31 through the inlet 131 and flow into the outlet side 32. The nozzle structure 20 is fixedly mounted on the housing 30.

[0038] like Figure 3 and Figure 4As shown, the mounting seat 40 includes a middle plate 42 and two side plates 43. The two side plates 43 are respectively located on both sides of the middle plate 42 and are connected to the middle plate 42 to form a "Z"-shaped mounting seat 40; a through hole 41 is opened in the middle plate 42, and the two side plates 43 are respectively fixedly connected to the inner wall of the shell 30.

[0039] Optionally, an air inlet hole 141 may also be provided on the side plate 43 close to the air inlet direction, so that a portion of the exhaust gas can pass through the side plate 43 from the air inlet side 31 and directly enter the air outlet side 32 .

[0040] like Figure 3 As shown, the mixer 100 for an engine exhaust aftertreatment system further includes a second mixing tube 50, located on the outlet side 32 and fixedly mounted on the mounting base 40. The second mixing tube 50 communicates with the through-hole 41 and is provided with a plurality of swirl blades 51 spaced apart along the circumference of the second mixing tube 50. The exhaust gas can swirl and circulate under the disturbance of the plurality of swirl blades 51. Thus, the exhaust gas and urea solution mixture flowing out of the first mixing tube 10 can swirl and circulate within the second mixing tube 50 after entering the second mixing tube 50, thereby further improving the uniformity of the mixing of the exhaust gas and urea solution.

[0041] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0042] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of patent protection for the present application shall be determined by the appended claims.

Claims

1. A mixer for an engine exhaust after-treatment system, characterized in that: The mixer for an engine exhaust after-treatment system comprises a first mixing tube (10) and a nozzle structure (20), wherein the nozzle structure (20) is connected to an inner cavity of the first mixing tube (10) and is used to spray a urea solution toward the inner cavity of the first mixing tube (10); The first mixing tube (10) has an inner cavity with a spiral channel (13), an inlet (131) of the spiral channel (13) is located on a side of the first mixing tube (10), and the spiral channel (13) extends spirally around the axis of the first mixing tube (10), and the first mixing tube (10) has a first end (11) and a second end (12) opposite to each other along its own axis, and the spiral channel (13) passes through the first end (11) and the second end (12); The exhaust gas can enter the spiral channel (13) from the inlet (131), mix with the urea solution while flowing along the spiral channel (13), and then be discharged from the first mixing tube (10) from the second end (12).

2. The mixer for an engine exhaust after-treatment system according to claim 1, characterized in that: The nozzle structure (20) is arranged at the first end (11) of the first mixing tube (10) and is used to spray the urea solution from the first end (11) toward the second end (12); The first mixing tube (10) comprises a circular arc plate (14), and the circular arc plate (14) spirally extends around the axis of the first mixing tube (10), so that a spiral channel (13) is formed between the walls of the circular arc plate (14).

3. The mixer for an engine exhaust after-treatment system according to claim 2, characterized in that: An air inlet hole (141) is provided on at least part of the wall surface of the arc plate (14), and exhaust gas can enter the spiral channel (13) from the side of the first mixing tube (10) through the air inlet hole (141).

4. The mixer for an engine exhaust after-treatment system according to claim 3, characterized in that: The arc plate (14) comprises a first section (142) and a second section (143) spliced ​​along its own extension direction, the first section (142) being located at the outermost layer along the radial direction of the first mixing tube (10), and the first section (142) having a free end (142a) and a connecting end (142b), the connecting end (142b) being connected to the second section (143), the inlet (131) being formed between the free end (142a) and the second section (143), and the air inlet hole (141) being opened in the second section (143).

5. The mixer for an engine exhaust after-treatment system according to claim 4, characterized in that: A plane perpendicular to the exhaust gas intake direction and passing through the axis of the first mixing tube (10) is defined as a preset plane (15), wherein the preset plane (15) includes a first plane portion (151) and a second plane portion (152) respectively located on both sides of the axis of the first mixing tube (10), and the free end (142a) is located on the leeward side of the first plane portion (151) or on the first plane portion (151), and the connecting end (142b) is located on the windward side of the second plane portion (152) or on the second plane portion (152).

6. The mixer for an engine exhaust after-treatment system according to claim 5, characterized in that: An angle γ is formed between a radius R2 of the first mixing tube (10) passing through the free end (142a) and the first plane portion (151), and 0°≤γ<90°; An angle α is formed between a radius R1 of the first mixing tube (10) passing through the connecting end (142b) and the second plane portion (152), and the angle α is 0°≤α≤60°.

7. The mixer for an engine exhaust after-treatment system according to claim 4, characterized in that: Along the axial direction of the first mixing tube (10), the air inlet holes (141) are distributed at intervals on the second section (143); And / or, along the circumference of the first mixing tube (10), the air inlet holes (141) are distributed at intervals on the second section (143).

8. The mixer for an engine exhaust after-treatment system according to any one of claims 1 to 7, characterized in that: The mixer for an engine exhaust after-treatment system further comprises a housing (30) and a mounting seat (40), wherein the mounting seat (40) is mounted inside the housing (30) and divides the interior of the housing (30) into an intake side (31) and an outlet side (32), and the mounting seat (40) is provided with a through hole (41), the first mixing tube (10) is located on the intake side (31) and fixedly mounted on the mounting seat (40), and the second end (12) is connected to the outlet side (32) through the through hole (41); The exhaust gas can enter the spiral channel (13) from the air inlet side (31) through the inlet (131) and flow into the air outlet side (32).

9. The mixer for an engine exhaust after-treatment system according to claim 8, characterized in that: The mounting seat (40) includes a middle plate (42) and two side plates (43), wherein the two side plates (43) are respectively located on both sides of the middle plate (42) and connected to the middle plate (42) to form a "Z"-shaped mounting seat (40); The through hole (41) is opened in the middle plate (42), and the two side plates (43) are respectively fixedly connected to the inner wall of the shell (30).

10. The mixer for an engine exhaust after-treatment system according to claim 8, characterized in that: The mixer for the engine exhaust after-treatment system further comprises a second mixing tube (50), the second mixing tube (50) being located on the gas outlet side (32) and fixedly mounted on the mounting seat (40), the second mixing tube (50) being in communication with the through hole (41), and a plurality of swirl blades (51) being provided in the second mixing tube (50), the swirl blades (51) being distributed at intervals along the circumference of the second mixing tube (50); The exhaust gas can be circulated in a rotating manner under the disturbance action of the plurality of swirl blades (51).

Images