Exhaust gas mixing device for tail gas after-treatment

Abstract

The utility model provides a tail gas after-treatment gas outlet mixing device which comprises a barrel extending in the axial direction, the barrel comprises a gas inlet end and a gas outlet end, the gas outlet end is provided with a groove, a catalyst assembly and an inner spiral pipe are arranged in the barrel, the inner spiral pipe extends in the radial direction and is arranged in the groove of the gas outlet end, and the outer spiral pipe is arranged in the groove of the gas outlet end. The inner spiral pipe comprises a rotational flow section and an outflow section, the rotational flow section and the outflow section are fixedly connected and communicated, the rotational flow section is arranged in the barrel and provided with a plurality of rotational flow holes, the rotational flow holes are formed in the circumferential direction of the rotational flow section at intervals, and the outflow section protrudes out of the barrel; the end cover assembly is arranged at the gas outlet end of the cylinder body and enables tail gas to flow out from the inner spiral pipe; and the sensor assembly is arranged on the outflow section of the inner spiral pipe. According to the embodiment of the utility model, the inner spiral pipe is additionally arranged at the gas outlet end of the cylinder body, so that the rotational flow effect of tail gas is improved, the NOx component mixing degree is improved, and the detection precision of the sensor assembly can be further improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of tail gas treatment, and particularly relates to an exhaust gas post-treatment outlet mixing device. Background Technique

[0002] With the full implementation of the national VI standard for diesel vehicles in China, the market's performance requirements for post-treatment devices are becoming increasingly stringent. The national VI regulations require that NOx sensors be arranged before and after the post-treatment device to monitor the conversion efficiency of NO x (nitrogen oxides), and the results of real-time monitoring will be dynamically input into the ECU (electronic control unit) to accurately match and control the urea injection amount, so as to meet the operating requirements of the whole vehicle. Therefore, the accurate reading of NO x will seriously affect the emission results.

[0003] Currently, it is generally achieved by adjusting the calibration to meet the control requirements, and this method is limited by the calibration method itself. On the one hand, due to the influence of the performance of the upstream mixer, when reaching the SCR (selective catalytic reduction), there will be differences in the flow rate, temperature, and concentration of each component of the gas flow; on the other hand, the consistency of the SCR process itself will also affect the conversion efficiency of SCR for NOx, further resulting in differences in the NOx distribution after the SCR outflow. In addition, due to the difference in size between the SCR and the tail pipe diameter in terms of structure, the flow-through cross-section changes, and the NOx sensor arranged at one place in the circumferential direction of the outlet will not be able to obtain a sufficient tail gas sample, which will lead to unstable and distorted NOx readings. At the same time, in the prior art, after flowing out from the SCR, the NO x components need to flow through a pipeline with a length of at least 5 times the pipe diameter before the various components in the exhaust gas can be fully mixed, and then the values read by the NOx sensor can comprehensively represent the component state. Based on this, the exhaust gas of the tail gas post-treatment device needs a mixing device to improve the reading accuracy of the NOx sensor. Summary of the Invention

[0004] To solve at least one technical problem in the prior art, an embodiment of the utility model provides an exhaust gas post-treatment outlet mixing device to improve the accuracy of exhaust gas detection. To achieve the above technical purposes, the technical solution adopted in the embodiment of the utility model is as follows:

[0005] An embodiment of the utility model provides an exhaust gas post-treatment outlet mixing device, including:

[0006] A cylinder body extending axially, the cylinder body includes an air inlet end and an air outlet end, a groove is provided at the air outlet end, and a catalyst assembly is provided in the cylinder body.

[0007] The inner rotating tube extends radially and is arranged in the groove at the air outlet end. The inner rotating tube includes a swirling section and an outflow section. The swirling section is fixedly connected and communicated with the outflow section. The swirling section is arranged in the cylinder body and is provided with a plurality of swirling holes. The plurality of swirling holes are arranged at intervals along the circumferential direction of the swirling section. The outflow section protrudes from the cylinder body;

[0008] The end cover assembly is arranged at the air outlet end of the cylinder body, and enables the tail gas to flow out from the inner rotating tube;

[0009] The sensor assembly is arranged on the outflow section of the inner rotating tube.

[0010] Furthermore, a plurality of small holes are also arranged on the inner rotating tube. The small holes are arranged on one side of the swirling holes close to the outflow section.

[0011] Furthermore, swirling fins are arranged on one side of any one of the swirling holes. The swirling fins extend towards the inner side of the inner rotating tube.

[0012] Furthermore, the included angle between the swirling fins and the inner wall of the inner rotating tube is 15 - 45°.

[0013] Furthermore, a heat insulation cover is also included. The heat insulation cover extends axially and is sleeved on the cylinder body. The heat insulation cover is fixedly connected with the cylinder body.

[0014] Furthermore, heat insulation cotton is included and is arranged between the heat insulation cover and the cylinder body.

[0015] Furthermore, a plurality of reinforcing ribs are arranged on the outer wall of the cylinder body. Any one of the reinforcing ribs extends along the circumferential direction of the cylinder body.

[0016] Furthermore, the catalyst assembly includes:

[0017] The first-stage catalyst is arranged in the cylinder body,

[0018] The first gasket is arranged between the first-stage catalyst and the inner wall of the cylinder body. The first gasket can fix the first-stage catalyst;

[0019] The second-stage catalyst is arranged in the cylinder body and between the first-stage catalyst and the inner rotating tube;

[0020] The second gasket is arranged between the second-stage catalyst and the inner wall of the cylinder body. The second gasket can fix the second-stage catalyst.

[0021] Furthermore, the sensor assembly includes at least three sensor mounting seats. The three sensor mounting seats are arranged at intervals along the circumferential direction of the outflow section;

[0022] A temperature sensor is provided on the sensor mounting seat, a NOx sensor is provided on the sensor mounting seat, and a PM sensor is provided on the sensor mounting seat.

[0023] Further, the end cap assembly includes:

[0024] An end cap, provided at the gas outlet end and covering the swirl section;

[0025] A connecting section, connecting the groove at the gas outlet end to the outer wall of the inner swirl tube.

[0026] The beneficial effects brought by the technical solution provided by the embodiment of the present invention are:

[0027] In the embodiment of the present invention, an inner swirl tube is added at the gas outlet end of the cylinder body. This structure increases the swirl effect of the tail gas, improves the mixing degree of the NOx component, and at the same time reduces the pressure loss, thereby improving the detection accuracy of the sensor assembly. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of the tail gas post-treatment gas outlet mixing device in the embodiment of the present invention.

[0029] Figure 2 It is an exploded view of the tail gas post-treatment gas outlet mixing device in the embodiment of the present invention.

[0030] Figure 3 It is a cross-sectional view of the tail gas post-treatment gas outlet mixing device in the embodiment of the present invention.

[0031] Figure 4 It is a left view of the tail gas post-treatment gas outlet mixing device in the embodiment of the present invention.

[0032] Figure 5 It is a schematic structural diagram of the inner swirl tube in the embodiment of the present invention. Detailed Embodiments

[0033] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] In the description of the embodiments of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0035] In the description of the embodiments of the present utility model, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", "connection" 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 directly connected, or indirectly connected through an intermediate medium, and can also be the communication inside two elements. It can be a wireless connection or a wired connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0036] In addition, the technical features involved in different embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0037] The embodiments of the present utility model provide an exhaust gas post-treatment gas mixing device, including:

[0038] A cylinder body 1 extending along the axial direction. The cylinder body 1 includes an air inlet end 1a and an air outlet end 1b. A groove is provided at the air outlet end 1b. A catalyst assembly 2 is provided in the cylinder body 1.

[0039] An inner rotating pipe 3 extending along the radial direction and disposed in the groove at the air outlet end 1b. The inner rotating pipe 3 includes a swirling section 3a and an outflow section 3b. The swirling section 3a and the outflow section 3b are fixedly connected and communicated. The swirling section 3a is disposed in the cylinder body 1 and is provided with a plurality of swirling holes 31. The plurality of swirling holes 31 are arranged at intervals along the circumferential direction of the swirling section 3a. The outflow section 3b protrudes from the cylinder body 1.

[0040] An end cover assembly 4 is disposed at the air outlet end 1b of the cylinder body 1 to allow the exhaust gas to flow out from the inner rotating pipe 3.

[0041] A sensor assembly 5 is disposed on the outflow section 3b of the inner rotating pipe 3.

[0042] In a specific embodiment, such as Figure 3As shown, the cylinder 1 extends from right to left, the right side of the cylinder 1 is the air inlet end 1a, the left side is the air outlet end 1b, the left side is provided with the inner rotating tube 3, the inner rotating tube 3 extends from top to bottom, the upper section of the inner rotating tube 3 is the swirl section 3a, and the lower end is the outflow section 3b. Since the end cover assembly 4 is arranged at the left end of the cylinder 1 and plays a sealing role, the airflow can enter the cylinder 1 from the right side, and flow out of the exhaust gas post-treatment outlet mixing device from the swirl section 3a of the inner rotating tube 3 through the outflow section 3b. The cylinder 1 is provided with a catalyst assembly 2, and the outflow section 3b is provided with the sensor assembly 5. After the airflow passes through the catalyst of the cylinder 1, it swirls in the swirl section 3a. When it flows out, the outflow section 3 The sensor on b can detect the specific value of the airflow. This structure increases the swirl effect of the exhaust gas, further improves the mixing degree of the NOx components, ensures that there is exhaust gas at the sensor component 5, and thus can improve the detection accuracy of the sensor component 5. This structure not only eliminates the influence of the exhaust gas due to the difference in upstream states, but also utilizes the change in the flow cross-section to transition and mix itself, so that the exhaust gas is fully mixed. The position of the sensor component to detect NOx is no longer restricted, thereby improving the stability and accuracy of NOx detection. At the same time, this structure can also reduce pressure loss by deepening the inner rotating tube into the cylinder body and increasing the fixing area of ​​the inner rotating tube, the cylinder body and the end cover assembly, thereby improving the structural strength of the exhaust post-treatment outlet mixing device.

[0043] The specific configuration of the inner spiral tube 3 in the present application is not limited. The end of the swirl section 3a away from the outflow section 3b can be directly welded to the inner wall of the cylinder 1, or the end of the swirl section 3a away from the outflow section 3b can be closed and then welded to the inner wall of the cylinder 1. The swirl holes 31 on the inner spiral tube 3 can be rectangular, oblong, square, etc. The number of swirl holes 31 is also not limited, and multiple groups of swirl holes can be provided. In a specific embodiment, Figure 3 As shown, the inner rotating tube 3 is provided with two groups of swirl holes 31 , and the two groups of swirl holes 31 are arranged at intervals along the axial direction of the inner rotating tube 3 .

[0044] In another specific embodiment, Figure 5 As shown, the swirl holes 31 include three groups of swirl holes 31, and the three groups of swirl holes 31 are arranged at intervals along the axial direction of the inner swirl tube 3. In this embodiment, the inner swirl tube 3 is also provided with a plurality of small holes 33, and the small holes 33 are arranged on one side of the swirl holes 31 close to the outflow section 3b. The number of the small holes 33 can be adaptively adjusted according to actual needs. When the exhaust gas flows out, the small holes 33 can increase the effect of exhaust gas mixing, thereby adjusting the concentration distribution of each component in the exhaust gas, and ensuring the test accuracy of the sensor assembly 5.

[0045] Further, a swirl fin 32 is provided on one side of any one of the swirl holes 31, and the swirl fin 32 extends towards the inside of the inner swirl tube 3.

[0046] As Figure 4 shown, the swirl fin 32 can cause the air flow to swirl and generate a spiral flow, thereby ensuring that the sensor on the outflow section 3b can detect the air flow and improving the detection accuracy.

[0047] Further, the included angle between the swirl fin 32 and the inner wall of the inner swirl tube 3 is 15 - 45°, and at this angle, the swirl effect of the swirl tube on the air flow is better.

[0048] Further, a heat insulation cover 6 is further included. The heat insulation cover 6 extends axially and is sleeved on the cylinder body 1. The heat insulation cover 6 is fixedly connected to the cylinder body 1. The heat insulation cover 6 can prevent the tail gas from causing thermal damage to the components around the tail gas post - treatment outlet mixing device. The heat insulation cover 6 and the cylinder body 1 can be fixedly connected by welding, or mounting holes can be provided on the heat insulation cover 6 and the cylinder body 1, and then the heat insulation cover 6 and the cylinder body 1 are threadedly connected with mounting screws.

[0049] Further, a heat - insulating cotton 7 is further included, which is arranged between the heat insulation cover 6 and the cylinder body 1. The heat - insulating cotton 7 increases the heat insulation effect, thereby improving the safety performance of the tail gas post - treatment outlet mixing device.

[0050] Further, a plurality of reinforcing ribs 8 are provided on the outer wall of the cylinder body 1, and any one of the reinforcing ribs 8 extends along the circumferential direction of the cylinder body 1.

[0051] The number and position of the reinforcing ribs 8 can be adjusted according to actual needs. In a specific embodiment, as Figure 2 and Figure 3 shown, two groups of reinforcing rib groups are provided on the outer wall of the cylinder body 1. The two groups of reinforcing rib groups are arranged at intervals along the axial direction of the cylinder body 1. Any one group of reinforcing rib groups includes two columns of reinforcing ribs. The two columns of reinforcing ribs are arranged at intervals along the axial direction of the cylinder body 1. At the same time, in the circumferential direction, any one column of reinforcing ribs includes four of the reinforcing ribs 8, and the four reinforcing ribs 8 are equally spaced along the circumferential direction of the cylinder body 1. This structure can improve the strength and rigidity of the cylinder body 1, save the amount of the cylinder body 1 used, reduce the weight, and lower the cost.

[0052] Further, the catalyst assembly 2 includes:

[0053] A first - stage catalyst 21, which is arranged in the cylinder body 1,

[0054] The first gasket 22 is disposed between the first-stage catalyst 21 and the inner wall of the cylinder body 1, and the first gasket 22 can fix the first-stage catalyst 21;

[0055] The second-stage catalyst 23 is disposed in the cylinder body 1 and between the first-stage catalyst 21 and the inner swirl tube 3;

[0056] The second gasket 24 is disposed between the second-stage catalyst 23 and the inner wall of the cylinder body 1, and the second gasket 24 can fix the second-stage catalyst 23.

[0057] As Figure 3 shown, in the cylinder body 1, the first-stage catalyst 21 is on the right side, and the second-stage catalyst 23 is on the left side. The first gasket 22 fixes the first-stage catalyst 21 on the inner wall of the cylinder body 1, and the second gasket 24 fixes the second-stage catalyst 23 on the inner wall of the cylinder body 1. During operation, the air flow enters the cylinder body 1 from the right side and successively passes through the first-stage catalyst 21 and the second-stage catalyst 23. NO x (nitrogen oxides) in the air flow undergoes a reduction reaction, thereby reducing NO x emissions.

[0058] Furthermore, the sensor assembly 5 includes at least three sensor mounting seats, and the three sensor mounting seats are arranged at intervals along the circumferential direction of the outflow section 3b;

[0059] A temperature sensor 51 is provided on one of the sensor mounting seats, a NOx sensor is provided on one of the sensor mounting seats, and a PM sensor is provided on one of the sensor mounting seats.

[0060] As Figure 1 and Figure 2 shown, the temperature sensor 51 is used to detect the temperature of the exhaust gas, the NOx sensor is used to detect nitrogen oxides in the air flow, and the PM (particulate matter concentration) sensor is used to detect the concentration of particulate matter in the air flow. The sensor assembly 5 is disposed in the outflow section 3b and is reasonably distributed in position. The inner swirl tube 3 ensures that the sensor assembly 5 can detect the air flow, and this structure can improve the accuracy of detection.

[0061] Furthermore, the end cap assembly 4 includes:

[0062] An end cap 41 is disposed at the air outlet end 1b and covers the swirl section 3a;

[0063] A connecting section 42 connects the groove at the air outlet end 1b to the outer wall of the inner swirl tube 3.

[0064] As Figure 1 and Figure 2As shown, the end cap 41 prevents gas from flowing out of the air outlet end 1b, causing the gas to enter the inner swirl tube 3 through the swirl holes 31 in the swirl section 3a and flow out from the outflow section 3b. The connecting section 42 can enhance the sealing performance between the inner swirl tube 3 and the air outlet end 1b.

[0065] During installation, as Figure 3 shown, first place the inner swirl tube 3 in the groove at the air outlet end 1b of the cylinder body 1, rotate the inner swirl tube 3, and position the sensor assembly 5 on the outflow section 3b at a reasonable location. At this time, weld the upper ends of the cylinder body 1 and the inner swirl tube 3. Then cover the air outlet end 1b of the cylinder body 1 with the end cap 41, and weld and connect the end cap 41 to the cylinder body 1 and the inner swirl tube 3. Finally, cover the groove with the connecting section 42, and weld the connecting section 42 to the groove and the outer wall of the inner swirl tube 3 respectively to complete the installation.

[0066] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. An exhaust gas post-treatment outlet mixing device, characterized in that: include: The cylinder (1) extends in the axial direction, the cylinder (1) comprises an air inlet end (1a) and an air outlet end (1b), the air outlet end (1b) is provided with a groove, and a catalyst assembly (2) is provided in the cylinder (1). an inner swirl tube (3) extending in a radial direction and arranged in the groove of the gas outlet end (1b); the inner swirl tube (3) comprises a swirl section (3a) and an outflow section (3b); the swirl section (3a) is fixedly connected to and communicates with the outflow section (3b); the swirl section (3a) is arranged in the cylinder (1) and is provided with a plurality of swirl holes (31); the plurality of swirl holes (31) are arranged at intervals along the circumference of the swirl section (3a); and the outflow section (3b) protrudes from the cylinder (1); An end cover assembly (4) is arranged at the gas outlet end (1b) of the cylinder (1) and allows the tail gas to flow out from the inner rotating pipe (3); The sensor assembly (5) is arranged on the outflow section (3b) of the inner rotating tube (3).

2. The exhaust gas post-treatment outlet mixing device according to claim 1, characterized in that: The inner swirl tube (3) is also provided with a plurality of small holes (33), and the small holes (33) are arranged on a side of the swirl hole (31) close to the outflow section (3b).

3. The exhaust gas post-treatment outlet mixing device according to claim 1, characterized in that: A swirl fin (32) is provided on one side of any swirl hole (31), and the swirl fin (32) extends towards the inner side of the inner swirl tube (3).

4. The exhaust gas post-treatment outlet mixing device according to claim 3, characterized in that: The angle between the swirl fin (32) and the inner wall of the inner swirl tube (3) is 15-45 degrees.

5. The exhaust gas post-treatment outlet mixing device according to claim 1, characterized in that: It also comprises a heat insulation cover (6), the heat insulation cover (6) extending in the axial direction and sleeved on the cylinder (1), the heat insulation cover (6) being fixedly connected to the cylinder (1).

6. The exhaust gas post-treatment outlet mixing device according to claim 5, characterized in that: It also includes thermal insulation cotton (7) which is arranged between the thermal insulation cover (6) and the cylinder (1).

7. The exhaust gas post-treatment outlet mixing device according to claim 1, characterized in that: A plurality of reinforcing ribs (8) are provided on the outer wall of the cylinder (1), and any one of the reinforcing ribs (8) extends along the circumference of the cylinder (1).

8. The exhaust gas post-treatment outlet mixing device according to claim 1, characterized in that: The catalyst assembly (2) comprises: The first-stage catalyst (21) is disposed in the cylinder (1). A first liner (22) is disposed between the first-stage catalyst (21) and the inner wall of the cylinder (1), and the first liner (22) is capable of fixing the first-stage catalyst (21); A second-stage catalyst (23) is disposed in the cylinder (1) and between the first-stage catalyst (21) and the inner rotating tube (3); The second gasket (24) is arranged between the second-stage catalyst (23) and the inner wall of the cylinder (1), and the second gasket (24) is capable of fixing the second-stage catalyst (23).

9. The exhaust gas post-treatment outlet mixing device according to claim 1, characterized in that: The sensor assembly (5) comprises at least three sensor mounting seats, and the three sensor mounting seats are arranged at intervals along the circumference of the outflow section (3b); A temperature sensor is arranged on one of the sensor mounting seats, a NOx sensor is arranged on one of the sensor mounting seats, and a PM sensor is arranged on one of the sensor mounting seats.

10. The exhaust gas post-treatment outlet mixing device according to claim 1, characterized in that: The end cover assembly (4) comprises: An end cover (41) is provided at the gas outlet end (1b) and covers the swirl section (3a); A connecting section (42) connects the groove of the gas outlet end (1b) and the outer wall of the inner rotating tube (3).

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