Diesel engine mixer and exhaust gas aftertreatment system

Abstract

The present invention provides a diesel engine mixer and exhaust gas after-treatment system, wherein the first mixing section comprises: a first shell; a swirl tube, which is arranged inside the first shell and coaxially with the first shell; a plurality of axial steel cables, which are symmetrically arranged on both sides of the swirl tube, one end of any axial steel cable is fixed on the swirl tube, and the other end is fixed on the first shell, and a viscous damper is installed on the axial steel cable, wherein the number of axial steel cables on any side is not less than four and is an even number; a mounting tube, which is arranged between the swirl tube and the first shell and coaxially with the swirl tube; a steel wire layer, which is an annular structure, is fixed between the mounting tube and the swirl tube, and is fixedly connected to any axial steel cable. In the diesel engine mixer and exhaust gas after-treatment system of the present application, the axial steel cable plays the role of fixing the steel wire layer. For medium and heavy exhaust gas after-treatment devices, due to the pulling effect of the axial steel cable, it is possible to avoid the problem of the center of the steel wire layer collapsing or the steel wire layer falling off due to the soft material of the steel wire layer.

Description

Technical Field

[0001] The invention relates to the technical field of mixers, and in particular to a diesel engine mixer and an exhaust gas after-treatment system. Background Art

[0002] Selective catalytic reduction (SCR) technology is a technology used to eliminate nitrogen oxides (NOx) in engine exhaust. This technology uses ammonia (NH3) produced by the hydrolysis of urea to convert nitrogen oxides (NOx) in exhaust gas into nitrogen (N2) under the action of a catalyst.

[0003] The SCR mixer is a device installed between the engine exhaust pipe and the SCR carrier. It is mainly used to improve the uniformity of the mixing of urea and exhaust gas and improve the NOx conversion efficiency.

[0004] Prior art patent number CN216811844U discloses an SCR mixer and an engine aftertreatment system, including an outer tube, an air inlet and an air outlet; an air inlet guide plate, arranged at the air inlet; steel wool, arranged at the air outlet; a drainage structure, arranged in the outer tube and located downstream of the air inlet guide plate; a conical tube, arranged between the steel wool and the drainage structure, the conical tube having a large mouth end and a small mouth end, the drainage structure is connected to the large mouth end, and the steel wool is connected to the small mouth end.

[0005] Among them, steel wool has a good crushing effect on urea droplets. When the exhaust gas carries urea droplets through the steel wool, the urea droplets are broken down into multiple smaller droplets, increasing the evaporation area of ​​the urea droplets, thereby reducing the risk of urea crystallization; at the same time, the structure of steel wool is intricate, and urea and exhaust gas are mixed more evenly. However, the steel wool mixer is usually a whole piece of steel wool filled in the mixing tube as a whole, and the periphery is brazed with the mixing tube. Because steel wool is soft and lacks strength, it can only be used in diesel engine exhaust after-treatment devices with relatively small mixing tube diameters. For medium and heavy after-treatment devices, the diameter of the mixing tube is large. Since the material of steel wool is soft, it is easy to cause reliability problems, such as the collapse of the center of the steel wool or the shedding of the steel wool. Summary of the invention

[0006] In view of the above problems, the present invention provides a diesel engine mixer.

[0007] A diesel engine mixer comprises a first mixing part, which comprises: a first shell; a swirl tube arranged inside the first shell and coaxially arranged with the first shell; a plurality of axial steel cables symmetrically arranged on both sides of the swirl tube, one end of any axial steel cable is fixed on the swirl tube, and the other end is fixed on the first shell, and a viscous damper is installed on the axial steel cable, wherein the number of axial steel cables on any side is not less than four and is an even number; a mounting tube arranged between the swirl tube and the first shell and coaxially arranged with the swirl tube; a steel wire layer in an annular structure, fixed between the mounting tube and the swirl tube, and fixedly connected to any axial steel cable.

[0008] In a preferred embodiment, either side of the steel wire layer further includes an oblique steel cable, which is fixed on the steel wire layer in an annular structure and fixedly connected to the axial steel cable.

[0009] In a preferred embodiment, the steel wire layer is a regular hexagonal structure formed by interlacing multiple steel wires.

[0010] In a preferred embodiment, the diesel engine mixer further comprises: a plurality of deflection pipes, which are evenly installed in the steel wire layer and have diameters on both sides larger than the diameter in the middle.

[0011] In a preferred embodiment, the viscous damper includes: a tube body, with a shell mounting portion and a steel cable mounting portion respectively provided on the top and bottom sides; two shaft rods, respectively fixedly connected to the shell mounting portion and the steel cable mounting portion, and extending into the inner side of the tube body; two buffer springs, arranged on the inner side of the tube body, symmetrically arranged on the top and bottom sides of the tube body, and a shaft rod is arranged on the inner side of any buffer spring; two pistons, respectively fixedly connected to the two shaft rods, and arranged on the inner sides of the two buffer springs; and a damping fluid is arranged between the two pistons.

[0012] In a preferred embodiment, the diesel engine mixer also includes a second mixing section, which includes: a second shell, fixed on one side of the first shell and coaxially arranged with the first shell; a cylinder, installed on the inner side of the second shell; and fixedly connected to the second shell through a partition on the side away from the first shell, and fixedly connected to the second shell through a tripod on the side close to the first shell; a spiral blade, fixed on the outside of the cylinder, wherein the airflow rotation direction generated by the spiral blade is opposite to the airflow rotation direction generated by the swirl tube; through holes, evenly opened on the cylinder and the spiral blade.

[0013] In a preferred embodiment, the cylinder is not coaxially arranged with the second housing.

[0014] An exhaust gas aftertreatment system includes a diesel engine mixer.

[0015] 1. In the diesel engine mixer of the present application, at the first mixing section, a part of the exhaust gas enters the steel wire layer and is cut and broken by the steel wire layer, and the other part of the exhaust gas enters the interior of the swirl tube, and then enters the steel wire layer through the swirl holes on the peripheral side, and generates a rotating airflow in the steel wire layer. The rotating airflow collides with the other part of the exhaust gas, intensifying the effect of exhaust gas turbulence, which is beneficial to the breakage and decomposition of urea aqueous solution droplets, accelerates the mixing of urea and exhaust gas, and avoids the formation of urea crystals.

[0016] 2. In the diesel engine mixer of the present application, the axial steel cable plays the role of fixing the steel wire layer. For medium and heavy-duty exhaust after-treatment devices, when the diameter of the mixing tube is large, the pulling effect of the axial steel cable can avoid the problem of the center of the steel wire layer collapsing or the steel wire layer falling off due to the soft material of the steel wire layer.

[0017] 3. The diesel engine mixer of the present application fixes the swirl tube through an axial steel cable, so that when the swirl tube is impacted by the exhaust gas, it will cause the swirl tube to swing slightly, thereby causing the entire steel wire layer to swing and deform in different directions, thereby intensifying the effect of exhaust gas turbulence, which is beneficial to the breakup and decomposition of urea aqueous solution droplets, accelerates the mixing of urea and exhaust gas, and avoids the formation of urea crystals. After the deformation of the steel wire layer is stable, each component returns to its original position. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other characteristics, features and advantages of the present invention will become clear by reading the following description of exemplary embodiments with reference to the accompanying drawings. The accompanying drawings, which are incorporated into the specification and constitute a part of the specification, illustrate embodiments of the present invention and are used together with the description to explain the principles of the present invention. In these drawings, similar reference numerals are used to represent similar elements. The drawings described below are some embodiments of the present invention, not all embodiments. For those of ordinary skill in the art, other drawings can be obtained from these drawings without paying creative work.

[0019] Figure 1 The structure diagram of the diesel engine mixer of the present invention;

[0020] Figure 2 The structural diagram of the first mixing section of the diesel engine mixer of the present invention;

[0021] Figure 3 The structural diagram of the second mixing section of the diesel engine mixer of the present invention;

[0022] Figure 4 A cross-sectional view of the diesel engine mixer at position AA of the present invention;

[0023] Figure 5 Structural diagram of diesel engine mixer embodiment 2 of the present invention;

[0024] Figure 6A side view of the steel wire layer and steel cable of the diesel engine mixer of the present invention;

[0025] Figure 7 A magnified view of the position of the diesel engine mixer B of the present invention;

[0026] Figure 8 Airflow state diagram of position B of diesel engine mixer of the present invention;

[0027] Fig. 9 The structural diagram of the viscous damper of the present invention;

[0028] Fig.10 Structural diagram of diesel engine mixer embodiment 7 of the present invention;

[0029] Fig.11 Structural diagram of the exhaust gas aftertreatment system of the present invention.

[0030] In the figure: 100, first mixing section; 10, first shell; 11, swirl tube; 20, axial steel cable; 30, viscous damper; 40, mounting tube; 41, steel wire layer; 21, inclined steel cable; 42, deflection tube; 31, tube body; 32, shell mounting part; 33, steel cable mounting part; 34, shaft; 35, buffer spring; 36, piston; 37, damping fluid; 200, second mixing section; 50, second shell; 51, cylinder; 511, partition; 512, tripod; 52, spiral blade; 53, through hole. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily without conflict.

[0032] The diesel engine mixer is described in detail below in conjunction with the accompanying drawings and embodiments.

[0033] Example 1

[0034] A diesel engine mixer comprises a first mixing section 100, which comprises: a first shell 10; a swirl tube 11, which is arranged inside the first shell 10 and is coaxial with the first shell 10; a plurality of axial steel cables 20, which are symmetrically arranged on both sides of the swirl tube 11, one end of any axial steel cable 20 is connected to the swirl tube 11, and the other end is connected to the first shell 10, and a viscous damper 30 is installed on the axial steel cables 20, wherein the number of axial steel cables 20 on any side is not less than four and is an even number; a mounting tube 40, which is arranged between the swirl tube 11 and the first shell 10 and is coaxial with the swirl tube 11; a steel wire layer 41, which is annular, is connected between the mounting tube 40 and the swirl tube 11, and is fixedly connected to any axial steel cable 20.

[0035] During operation, at the position of the first mixing section 100, a part of the exhaust gas enters the position of the steel wire layer 41 and is cut and broken by the steel wire layer 41, and the other part of the exhaust gas enters the interior of the cyclone tube 11, and then enters the steel wire layer 41 through the cyclone holes on the peripheral side, and generates a rotating airflow in the steel wire layer 41. The rotating airflow collides with the other part of the exhaust gas, intensifying the turbulence effect of the exhaust gas, which is beneficial to the breakage and decomposition of urea aqueous solution droplets, accelerates the mixing of urea and exhaust gas, and avoids the formation of urea crystals.

[0036] In addition, the axial steel cable 20 serves to fix the steel wire layer 41. For medium and heavy-duty exhaust after-treatment devices, when the diameter of the mixing tube is large, the pulling effect of the axial steel cable 20 can prevent the center of the steel wire layer 41 from collapsing or falling off due to the soft material of the steel wire layer 41.

[0037] At the same time, the swirl tube 11 is fixed by the axial steel cable 20, so that when the swirl tube 11 is impacted by the exhaust gas, it will cause the swirl tube 11 to swing slightly, and then drive the steel wire layer 41 as a whole to swing and deform in different directions, thereby intensifying the effect of exhaust gas turbulence, which is beneficial to the breakup and decomposition of urea aqueous solution droplets, accelerates the mixing of urea and exhaust gas, and avoids the formation of urea crystals. After the deformation of the steel wire layer 41 is stabilized, each component returns to its original position.

[0038] The swing amplitude of the swirl tube 11 is mainly adjusted by the viscous damper 30, which is specifically regulated according to the maximum damping force and the maximum stroke of the viscous damper 30. When a viscous damper 30 with a large damping force is used, it can even ensure that the swirl tube 11 hardly swings.

[0039] The steel wire layer 41 may be fixed to the mounting tube 40 by brazing or bolting.

[0040] Example 2

[0041] Embodiment 2 is an improvement on Embodiment 1. Specifically, either side of the steel wire layer 41 further includes an oblique steel cable 21 . The oblique steel cable 21 is fixed on the steel wire layer 41 in an annular structure and is fixedly connected to the axial steel cable 20 .

[0042] By providing the oblique steel cables 21 , the two side surfaces of the steel wire layer 41 form a relatively stable whole, thereby preventing the steel wire layer 41 at the center position of two adjacent axial steel cables 20 from collapsing to a greater extent.

[0043] Example 3

[0044] Embodiment 3 is an improvement on Embodiment 1. Specifically, the steel wire layer 41 is a regular hexagonal structure formed by interlacing multiple steel wires.

[0045] By replacing conventional steel wool with staggered regular hexagonal steel wire layers 41, although the intricate structure of the steel wool disappears, the center collapse of the steel wool can be avoided, and the regular hexagonal steel wire layers 41 can still effectively break up the urea solution.

[0046] Example 4

[0047] Embodiment 4 is an improvement on Embodiment 1. Specifically, the diesel engine mixer further comprises: a plurality of bias flow tubes 42. The plurality of bias flow tubes 42 are evenly installed in the steel wire layer 41, and the diameters on both sides are larger than the diameter in the middle.

[0048] The diameter of the two sides of the bias pipe 42 is large, and the diameter of the middle part is small. A part of the exhaust gas passes through the bias pipe 42, and the other part of the exhaust gas generates irregular turbulence around the bias pipe 42, which is beneficial to the breakup and decomposition of urea aqueous solution droplets, accelerates the mixing of urea and exhaust gas, and avoids the formation of urea crystals.

[0049] Example 5

[0050] Example 5 defines the specific structure of the viscous damper 30. Specifically, the viscous damper 30 includes: a tube body 31, with a shell mounting portion 32 and a steel cable mounting portion 33 on the top and bottom sides respectively; two shaft rods 34, which are fixedly connected to the shell mounting portion 32 and the steel cable mounting portion 33 respectively, and extend into the inner side of the tube body 31; two buffer springs 35, which are arranged on the inner side of the tube body 31, symmetrically arranged on the top and bottom sides of the tube body 31, and a shaft rod 34 is arranged on the inner side of any buffer spring 35; two pistons 36, which are fixedly connected to the two shaft rods 34 respectively, and are arranged on the inner sides of the two buffer springs 35; and a damping fluid 37 is arranged between the two pistons 36.

[0051] When working, the shaft 34 drives the piston 36 to move in the tube body 31 , and squeezes the damping fluid 37 back and forth, so that the vibration of the vortex tube 11 is reduced, thereby controlling the back and forth swing amplitude of the vortex tube 11 .

[0052] Example 6

[0053] Embodiment 6 is an improvement on Embodiment 1. Specifically, the diesel engine mixer further comprises a second mixing section 200, which comprises: a second shell 50, which is fixed on one side of the first shell 10 and is coaxially arranged with the first shell 10; a cylinder 51, which is installed on the inner side of the second shell 50 and is fixedly connected to the second shell 50 via a partition 511 on the side away from the first shell 10, and is fixedly connected to the second shell 50 via a tripod 512 on the side close to the first shell 10; a spiral blade 52, which is fixed on the outer side of the cylinder 51, wherein the airflow rotation direction generated by the spiral blade 52 is opposite to that generated by the swirl tube 11; and through holes 53, which are evenly arranged on the cylinder 51 and the spiral blade 52.

[0054] During operation, the exhaust gas first enters the cylinder 51 at the position of the second mixing section 200, and then a part of the exhaust gas enters the spiral blade 52 through the through hole 53 to generate a rotating airflow, and the other part directly enters the swirl tube 11. The airflow entering the spiral blade 52 collides with the airflow flowing out of the swirl tube 11 at the steel wire layer 41. The two airflows with different rotation directions can intensify the effect of exhaust gas turbulence, which is beneficial to the breakage and decomposition of urea aqueous solution droplets, accelerates the mixing of urea and exhaust gas, and avoids the formation of urea crystals.

[0055] Example 7

[0056] Embodiment 7 is an improvement on Embodiment 1. Specifically, the cylinder 51 and the second shell 50 are not coaxially arranged.

[0057] By eccentrically arranging the cylinder 51 and the second shell 50, gas channels with different cross-sections are formed between the second shell 50 and the cylinder 51, so that the flow velocity of the exhaust gas in the gas channel changes, thereby changing the turbulence degree of the exhaust gas, which is beneficial to the breakup and decomposition of urea aqueous solution droplets, accelerates the mixing of urea and exhaust gas, and avoids the formation of urea crystals.

[0058] An exhaust gas aftertreatment system includes a diesel engine mixer.

[0059] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, the elements defined by the sentence "includes..." do not exclude the existence of other identical elements in the article or device including the elements.

[0060] The above embodiments are only used to illustrate the technical solution of the present invention and are not intended to limit the present invention. The present invention is described in detail with reference to the preferred embodiments. It should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, and should be included in the scope of the claims of the present invention.

Claims

1. A diesel engine mixer, characterized in that: The diesel engine mixer comprises a first mixing section (100), the first mixing section (100) comprising: a first shell (10); a swirl tube (11) arranged inside the first shell (10) and coaxially arranged with the first shell (10); a plurality of axial steel cables (20) symmetrically arranged on both sides of the swirl tube (11), one end of any axial steel cable (20) being fixed on the swirl tube (11) and the other end being fixed on the first shell (10), and a viscous damper (30) being installed on the axial steel cable (20), wherein the number of the axial steel cables (20) on any side is not less than four and is an even number; a mounting tube (40) arranged between the swirl tube (11) and the first shell (10) and coaxially arranged with the swirl tube (11); a steel wire layer (41) having an annular structure, being fixed between the mounting tube (40) and the swirl tube (11), and being fixedly connected to any axial steel cable (20); The diesel engine mixer further comprises: a plurality of bias flow pipes (42) which are evenly installed in the steel wire layer (41) and have diameters on both sides larger than the diameter in the middle.

2. The diesel engine mixer according to claim 1, characterized in that: Any side of the steel wire layer (41) also includes an oblique steel cable (21), and the oblique steel cable (21) is fixed on the steel wire layer (41) in an annular structure and is fixedly connected to the axial steel cable (20).

3. The diesel engine mixer according to claim 1, characterized in that: The steel wire layer (41) is a regular hexagonal structure formed by a plurality of steel wires interlaced with each other.

4. The diesel engine mixer according to claim 1, characterized in that: The viscous damper (30) comprises: a tube body (31), the top and bottom sides of which are closed, and are respectively provided with a shell mounting portion (32) and a steel cable mounting portion (33); two shaft rods (34), respectively fixedly connected to the shell mounting portion (32) and the steel cable mounting portion (33), and extending into the inner side of the tube body (31), and being sealed and slidably connected to the tube body (31); two buffer springs (35), arranged on the inner side of the tube body (31), symmetrically arranged on the top and bottom sides of the tube body (31), and the shaft rod (34) is arranged on the inner side of any buffer spring (35); two pistons (36), respectively fixedly connected to the two shaft rods (34), and arranged on the inner sides of the two buffer springs (35), and the circumferential sides are sealed and slidably connected to the tube body (31); and a damping fluid (37) is arranged between the two pistons (36).

5. The diesel engine mixer according to claim 1, characterized in that: The diesel engine mixer further comprises a second mixing section (200), wherein the second mixing section (200) comprises: The second shell (50) is fixed on one side of the first shell (10) and is coaxially arranged with the first shell (10); the cylinder (51) is installed on the inner side of the second shell (50), and is fixedly connected to the second shell (50) via a partition (511) on the side away from the first shell (10), and is fixedly connected to the second shell (50) via a tripod (512) on the side close to the first shell (10); the spiral blade (52) is fixed on the outer side of the cylinder (51), wherein the airflow rotation direction generated by the spiral blade (52) is opposite to the airflow rotation direction generated by the swirl tube (11); and the through holes (53) are evenly arranged on the cylinder (51) and the spiral blade (52).

6. The diesel engine mixer according to claim 5, characterized in that: The cylinder (51) and the second shell (50) are arranged non-coaxially.

7. An exhaust gas post-treatment system, characterized in that: The diesel engine mixer comprises the diesel engine mixer as claimed in any one of claims 1 to 6.

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