SCR mixer and tail gas treatment system
By designing specific cyclone holes and strip hole structures in the cyclone tube and the mixing inner tube of the SCR mixer, the problem of increasing back pressure of the existing SCR mixer is solved, and the back pressure is reduced and urea and exhaust gas is improved. The effect of mixing uniformity further improves the power and economy of the engine.
Patent Information
- Application Number
- CN202420584948.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-25
- Publication Date
- 2025-02-07
- Estimated Expiration
- 2034-03-25
AI Technical Summary
When the existing SCR mixers take into account the uniformity of urea and exhaust gas, they lead to an increase in back pressure, affecting the power and economics of the engine.
A SCR mixer is designed, adopting a combined structure of a cyclone tube and a mixing inner tube. A plurality of cyclone holes distributed in the circumferential direction are provided on the cyclone tube, and strips are processed on the circumferential outer wall of the mixing inner tube. The angle between the cyclone hole and the plane where the cyclone sheet is located is not less than 25 degrees.
By increasing the intake area of the cyclone hole and the airflow contact area of the mixing inner pipe, the back pressure inside the SCR mixer is effectively reduced, the pressure loss is reduced, and the mixing uniformity of urea and exhaust gas is taken into account, which improves the engine motivation and economicality.
Smart Images
Figure CN222436451U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of vehicle tail gas treatment, in particular to an SCR mixer and a tail gas treatment system. Background Art
[0002] In the field of vehicle exhaust treatment, Selective Catalytic Reduction (SCR) refers to the use of a reducing agent (such as ammonia, liquid ammonia or urea) to selectively react with nitrogen oxides in exhaust gas under the action of a catalyst to generate non-toxic and non-polluting nitrogen and water.
[0003] The SCR mixer is a key component in the selective catalytic reduction technology. Its main function is to fully mix the urea aqueous solution with the exhaust gas to provide the best conditions for the subsequent catalytic reduction reaction. The SCR mixer needs to consider the pressure loss caused by the injection mixing section to ensure that it will not have a significant impact on the power and economy of the engine. At the same time, the SCR mixer must also have high mixing uniformity, good anti-crystallization ability and excellent durability to ensure long-term stable operation.
[0004] In the existing SCR mixer, in order to take into account the uniformity of mixing urea and exhaust gas, the back pressure is relatively large, which affects the power and economy of the engine. Utility Model Content
[0005] The utility model aims to provide an SCR mixer and an exhaust gas treatment system, which are used to solve the problem of increased back pressure caused by the current consideration of mixing urea and exhaust gas uniformity, effectively reduce the back pressure, and thus improve the power and economy of the engine.
[0006] To achieve this purpose, the utility model adopts the following technical solutions:
[0007] SCR mixer, including:
[0008] A swirl tube, wherein the swirl tube is provided with a plurality of swirl holes spaced apart along the circumferential direction, and the swirl tube is provided with a swirl sheet extending along a side wall of the swirl hole toward the outside of the swirl tube, and the angle between the swirl hole and the plane where the swirl sheet is located is not less than 25 degrees;
[0009] The inner mixing tube is coaxial with the swirl tube and is disposed inside the swirl tube. The inner mixing tube has a plurality of strip holes distributed at intervals along the circumferential direction.
[0010] As an optional solution for an SCR mixer, the swirl tube includes a conical tube and a cylindrical tube connected to the conical tube, the swirl hole is located on the conical tube, and the SCR mixer also includes an exhaust port and a urea nozzle, the urea nozzle is arranged at the top of the mixing inner tube, and the exhaust port is connected to the cylindrical tube.
[0011] As an optional solution for an SCR mixer, the swirl holes are arranged in an array at intervals along the axial direction of the tapered tube.
[0012] As an optional solution for an SCR mixer, the cylindrical tube and the conical tube are an integrated structure.
[0013] As an optional solution of an SCR mixer, the long side of the strip-shaped hole is parallel to the axial direction of the inner mixing tube.
[0014] As an optional solution for an SCR mixer, a plurality of through holes are opened on the cylindrical tube along the circumferential side wall, and the interior of the cylindrical tube is connected to the exhaust port through the through holes.
[0015] As an optional solution of an SCR mixer, the SCR mixer further includes an exhaust chamber, the exhaust chamber is connected to the cylindrical tube through the exhaust port, and a baffle with vent holes on the surface is provided in the exhaust port.
[0016] As an optional solution for an SCR mixer, the baffle shields a portion of the exhaust port.
[0017] As an optional solution of an SCR mixer, the exhaust port is circular, the baffle is semicircular, and the baffle is used to shield the exhaust port.
[0018] An exhaust gas treatment system comprises the SCR mixer described in any of the above schemes.
[0019] Beneficial effects:
[0020] In the first aspect, by setting the angle between the swirl hole and the plane where the swirl plate is located to be not less than 25 degrees, the angle between the swirl hole and the plane where the swirl plate is located is increased, and the intake area of the swirl hole is increased, which can reduce the internal back pressure of the SCR mixer, thereby reducing the pressure loss. Furthermore, by processing strip holes on the circumferential outer wall of the mixing inner tube, compared with the circular hole feature in the prior art, the intake volume of the exhaust gas flow is increased, and the contact probability of the exhaust gas flow and urea is also increased, and the flow resistance is reduced, so that the SCR mixer can effectively reduce the back pressure while taking into account the uniformity of the mixing of urea and exhaust gas, thereby improving the power and economy of the engine;
[0021] In the second aspect, the exhaust gas treatment system using the SCR mixer can further reduce pressure loss while ensuring the uniformity of mixing urea and exhaust gas, thereby improving the power of the vehicle and user experience. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 This is a structural schematic diagram of a first-view of an SCR mixer with a partially hidden shell provided by an embodiment of the utility model;
[0023] Figure 2 This is a first-view schematic diagram of the cooperation between the swirl tube and the mixing inner tube provided in an embodiment of the utility model;
[0024] Figure 3 This is a second perspective schematic diagram of the cooperation between the swirl tube and the mixing inner tube provided in an embodiment of the utility model;
[0025] Figure 4 It is a schematic diagram of the structure of the mixing inner tube provided in an embodiment of the utility model;
[0026] Figure 5 It is a structural schematic diagram of a second viewing angle of an SCR mixer with a partially hidden shell provided by an embodiment of the utility model.
[0027] In the figure:
[0028] 1. swirl tube; 11. conical tube; 111. swirl hole; 112. swirl sheet; 12. cylindrical tube; 121. through hole;
[0029] 2. Mixing inner tube; 21. Strip hole;
[0030] 3. Exhaust port; 31. Baffle; 311. Vent hole;
[0031] 4. Urea nozzle;
[0032] 5. Shell. DETAILED DESCRIPTION
[0033] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.
[0034] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0035] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.
[0036] In the description of this embodiment, the terms "upper", "lower", "right", etc., are based on the directions or positions shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.
[0037] Please see attached Figure 1 -Attached Figure 3 The first aspect of the present embodiment relates to an SCR mixer, which specifically includes a swirl tube 1 and a mixing inner tube 2. The swirl tube 1 is provided with a plurality of swirl holes 111 distributed along the circumferential direction. The swirl tube 1 has a swirl sheet 112 extending toward the outside of the swirl tube 1 along a side wall of the swirl hole 111. The angle between the swirl hole 111 and the plane where the swirl sheet 112 is located is not less than 25 degrees. The mixing inner tube 2 is coaxial with the swirl tube 1 and is disposed inside the swirl tube 1. The mixing inner tube 2 has a plurality of strip holes 21 distributed along the circumferential direction.
[0038] As a critical component of the vehicle's exhaust treatment system, the SCR mixer can provide a mixing contact space for the mixing of urea and vehicle exhaust gas, while ensuring the sufficiency and uniformity of the mixing of urea and vehicle exhaust gas, which is conducive to the efficient reaction of nitrogen oxides in the exhaust gas and the generation of non-toxic and non-polluting nitrogen and water. In the existing SCR mixer, in order to fully mix urea and vehicle exhaust gas to improve the reaction efficiency of urea, the internal structure of the SCR mixer needs to adapt to the increase of the vortex flow rate after the urea and vehicle exhaust gas are mixed. The angle between the swirl hole 111 and the plane where the swirl plate 112 is located is usually not more than 15 degrees. Although this scheme can increase the vortex speed of urea and vehicle exhaust gas in the SCR mixer to ensure accelerated mixing, thereby ensuring the uniformity of the mixing of the two, due to the limitation of the angle, the internal back pressure of the SCR mixer is increased, and the pressure loss of the internal mixed fluid is large. In this embodiment, the angle between the swirl hole 111 and the plane where the swirl plate 112 is located is designed to be not less than 25 degrees. By increasing the angle between the swirl hole 111 and the plane where the swirl plate 112 is located, the intake area and intake volume through the swirl hole 111 are effectively increased, which is beneficial to reduce the back pressure inside the SCR mixer, thereby reducing the pressure loss. Furthermore, by processing the strip holes 21 on the circumferential outer wall of the mixing inner tube 2, compared with the circular hole characteristics in the prior art, the contact area and contact probability between the exhaust gas flow and urea are increased, and the flow resistance is reduced, thereby taking into account the uniformity of the mixing of vehicle exhaust gas and urea. Therefore, the SCR mixer involved in this embodiment can effectively reduce the back pressure while taking into account the uniformity of the mixing of urea and exhaust gas, thereby improving the power and economy of the engine.
[0039] Optionally, the swirl tube 1 includes a conical tube 11 and a cylindrical tube 12 connected to the conical tube 11, the swirl hole 111 is located on the conical tube 11, and the SCR mixer also includes an exhaust port 3 and a urea nozzle 4, the urea nozzle 4 is arranged at the top of the mixing inner tube 2, and the exhaust port 3 is connected to the cylindrical tube 12.
[0040] In this embodiment, the structure of the swirl hole 111 and the swirl sheet 112 can help the vehicle exhaust gas to take in air in a tangential direction, thereby increasing the flow rate of the vortex inside the swirl tube 1 and achieving accelerated mixing with urea. A urea nozzle 4 is arranged at the top opening of the mixing inner tube 2, and the urea nozzle 4 is arranged on the inner wall of the shell 5. The urea nozzle 4 can directly spray macroscopic mist-like urea particles in a conical shape toward the inside of the mixing inner tube 2, and then the urea particles are fully mixed with the airflow of the exhaust gas in the mixing inner tube 2, and further enter the exhaust port 3 through the cylindrical tube 12 to the subsequent reduction reaction device. The design of the conical tube 11 can generate a strong centrifugal force field, so that the mixed airflow rotates in the body of the conical tube 11. Due to the conical structure, the pressure and shear force on the liquid during the flow process gradually increase, which helps the urea particles to further disperse and dissolve. The cylindrical tube 12 helps to expand the exhaust channel of the urea particles and the vehicle exhaust gas.
[0041] Optionally, the swirl holes 111 are arranged in an array at intervals along the axial direction of the tapered tube 11 .
[0042] In this embodiment, the swirl tube 1 is provided with multiple sections along the axial direction, and each section structure is provided with multiple swirl holes 111 along the circumferential direction. The opening lengths of the swirl holes 111 in different sections can be the same or different. In this embodiment, the opening length of the swirl holes 111 close to the urea nozzle 4 is greater than the opening length of the swirl holes 111 far from the urea nozzle 4, so as to adapt to the conical structure of the swirl tube 1 and improve the flow rate of the internal airflow. In addition, the swirl tube 1 will reduce the structural strength of the entire swirl tube 1 due to the existence of the swirl holes 111. If the swirl tube 1 adopts a single array of swirl holes 111, the hollow area of the entire tube body is large, and the strength is seriously reduced. Therefore, the swirl tube 1 of this embodiment adopts a multi-section spaced array of swirl holes 111 along the axial direction to ensure the connection of each section structure and improve the overall strength of the swirl tube 1.
[0043] Optionally, the cylindrical tube 12 and the conical tube 11 are an integrated structure.
[0044] In this embodiment, the integrated structure of the cylindrical tube 12 and the conical tube 11 can ensure the overall strength of the cyclone tube 1 and can effectively reduce the cost of the SCR mixer compared to the split structure.
[0045] Please further combine the attached Figure 4 and attached Figure 5 Optionally, the long side of the strip hole 21 is parallel to the axial direction of the mixing inner tube 2 .
[0046] In this embodiment, the strip hole 21 is a rectangular hole, and the long side of the strip hole 21 is consistent with the axial extension direction of the mixing inner tube 2, so as to avoid the existence of tangential components in multiple directions after the airflow passes through the strip hole 21, promote the stable flow of the airflow when entering the mixing inner tube 2, and improve the quality and stability of the mixing.
[0047] Optionally, a plurality of through holes 121 are provided on the cylindrical tube 12 along the circumferential side wall, and the interior of the cylindrical tube 12 is connected to the exhaust port 3 through the through holes 121 .
[0048] A plurality of through holes 121 are provided on the outer wall of the cylindrical tube 12. The through holes 121 may be ordinary small round hole structures or other shapes. For example, they are elliptical hole structures. Those skilled in the art may adjust the type and number of the through holes 121 according to the flow rate, flow velocity and manufacturing cost. In this embodiment, a plurality of through holes 121 are provided on the outer wall of the cylindrical tube 12, so that the high-temperature airflow can pass through the through holes 121 to heat the outer wall of the cylindrical tube 12, and assist the urea to be heated into urea particles to improve the mixing efficiency. In addition, the high-speed airflow can also assist the urea to become smaller urea particles under the impact of external force by impacting the inner wall of the cylindrical tube 12, and further improve the mixing efficiency. The partially mixed urea particles and vehicle exhaust gas are discharged through the exhaust port 3 along with the airflow.
[0049] Please refer to the attached Figure 5 Optionally, the SCR mixer further includes an exhaust chamber, which is connected to the cylindrical tube 12 through an exhaust port 3 , and a baffle 31 with vent holes 311 on its surface is disposed in the exhaust port 3 .
[0050] In this embodiment, the urea particles passing through the cylindrical tube 12 are mixed with the vehicle exhaust gas and then discharged through the vent hole 311 on the baffle 31. The baffle 31 can block large urea particles or urea particles of other particle sizes that collide with the baffle 31. Through the collision, the urea particles are turned into smaller urea particles under the action of external force, thereby further improving the mixing uniformity.
[0051] Optionally, the baffle 31 blocks a portion of the structure of the exhaust port 3 .
[0052] In this embodiment, the baffle 31 partially blocks the exhaust port 3, which can effectively reduce the back pressure and pressure loss, thereby reducing the weakening effect on the air flow velocity.
[0053] Preferably, the exhaust port 3 is circular, the baffle 31 is semicircular, and the baffle 31 is used to shield the exhaust port 3 .
[0054] In this embodiment, the baffle 31 is semicircular and blocks half of the circular exhaust port 3, thereby reducing back pressure and pressure loss.
[0055] A second aspect of this embodiment also relates to an exhaust gas treatment system, which includes the above SCR mixer.
[0056] The exhaust gas treatment system using the SCR mixer can further reduce pressure loss while ensuring the uniformity of the mixing of urea and exhaust gas, thereby improving the vehicle's power and user experience.
[0057] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the scope of protection of the present invention. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the claims of the present invention.
Claims
1. SCR mixer, characterized in that, include: A swirl tube (1), wherein the swirl tube (1) is provided with a plurality of swirl holes (111) distributed at intervals along the circumferential direction, the swirl tube (1) is provided with a swirl sheet (112) extending toward the outside of the swirl tube (1) along a side wall of the swirl hole (111), and the angle between the swirl hole (111) and the plane where the swirl sheet (112) is located is not less than 25 degrees; The mixing inner tube (2) is coaxial with the swirl tube (1) and is disposed inside the swirl tube (1); the mixing inner tube (2) has a plurality of strip-shaped holes (21) distributed at intervals along the circumferential direction.
2. The SCR mixer according to claim 1, characterized in that: The swirl tube (1) comprises a conical tube (11) and a cylindrical tube (12) connected to the conical tube (11), the swirl hole (111) is located on the conical tube (11), and the SCR mixer further comprises an exhaust port (3) and a urea nozzle (4), the urea nozzle (4) is arranged at the top of the mixing inner tube (2), and the exhaust port (3) is connected to the cylindrical tube (12).
3. The SCR mixer according to claim 2, characterized in that: The swirl holes (111) are arranged in an array at intervals along the axial direction of the tapered tube (11).
4. The SCR mixer according to claim 2, characterized in that: The cylindrical tube (12) and the conical tube (11) are an integrated structure.
5. The SCR mixer according to claim 1, characterized in that: The long side of the strip-shaped hole (21) is parallel to the axial direction of the inner mixing tube (2).
6. The SCR mixer according to claim 2, characterized in that: The cylindrical tube (12) is provided with a plurality of through holes (121) along the circumferential side wall, and the interior of the cylindrical tube (12) is connected to the exhaust port (3) through the through holes (121).
7. The SCR mixer according to claim 6, characterized in that: The SCR mixer further comprises an exhaust chamber, the exhaust chamber being connected to the cylindrical tube (12) via the exhaust port (3), and a baffle (31) having a vent hole (311) on its surface is provided in the exhaust port (3).
8. The SCR mixer according to claim 7, characterized in that: The baffle (31) covers a portion of the structure of the exhaust port (3).
9. The SCR mixer according to claim 8, characterized in that: The exhaust port (3) is circular, the baffle (31) is semicircular, and the baffle (31) is used to cover the exhaust port (3).
10. The tail gas treatment system is characterized by: Comprising the SCR mixer as described in any one of claims 1-9.