CN215595697U

CN215595697U - SCR mixer and have its engine

Info

Publication number: CN215595697U
Application number: CN202121482701.5U
Authority: CN
Inventors: 卞增涛; 刘伟达; 李俊普; 刘兴龙
Original assignee: Weichai Power Co Ltd; Weichai Power Emission Solutions Technology Co Ltd
Current assignee: Weichai Power Co Ltd; Weichai Power Emission Solutions Technology Co Ltd
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2022-01-21
Anticipated expiration: 2031-06-30

Abstract

The utility model belongs to the technical field of engines, and particularly relates to an SCR mixer and an engine. Waste gas flows into the cyclone tube from the air inlet of connecting the chamber, under the effect of first water conservancy diversion piece and little pipe diameter, forms rotatory disturbance, mixes effectually with urea, and the rear end design of cyclone tube is the flaring state, has increased the air current flow cross-sectional area, is favorable to reducing the backpressure.

Description

SCR mixer and have its engine

Technical Field

The utility model belongs to the technical field of engines, and particularly relates to an SCR mixer and an engine.

Background

This section provides background information related to the present disclosure only and is not necessarily prior art.

As road and non-road emission regulations upgrade, NOx emission requirements are getting tighter. The whole vehicle working condition is more abominable, and the low-temperature low-discharge capacity working condition accounts for than bigger, and under this working condition, the urea spraying receives the air current effect of moving down, and the concentration in the blender bottom is higher, has reduced ammonia distribution uniformity, and it is difficult to reach the standard to discharge, and the baffle back air current dead zone that the blender was hit to a large amount of urea of spouting simultaneously forms the crystallization easily and blocks up, makes SCR inefficacy.

SUMMERY OF THE UTILITY MODEL

The utility model aims to at least solve the problems of poor mixing effect of an SCR mixer and easy generation of urea crystal blockage in the prior art, and the aim is realized by the following technical scheme:

a first aspect of the utility model proposes an SCR mixer comprising:

the urea spraying device comprises a shell, wherein a connecting cavity is formed in the shell, the shell is provided with an air inlet and an air outlet, the air inlet and the air outlet are communicated through the connecting cavity, and the top end of the connecting cavity is provided with a urea nozzle opening;

the first end of the rotational flow pipe is arranged corresponding to the urea nozzle opening, the rotational flow pipe comprises a first pipe section and a second pipe section connected with the bottom of the first pipe section, the first pipe section and the second pipe section are both in a circular truncated cone shape, an included angle between a bus and an axis of the second pipe section is larger than an included angle between the bus and the axis of the first pipe section, a plurality of first rotational flow holes are formed in the first pipe section, the rotational flow pipe further comprises a first flow deflector arranged on the first rotational flow holes, the appearance of the first flow deflector is matched with the first rotational flow holes, and part of the first flow deflector is connected with the first pipe section;

the first perforated pipe is arranged in the cyclone pipe in a penetrating mode and arranged at intervals with the cyclone pipe, and a plurality of first overflowing holes are formed in the first perforated pipe.

The SCR mixer provided by the utility model is provided with the cyclone pipe with the reducing pipe structure, waste gas flows into the cyclone pipe from the air inlet of the connecting cavity, and under the action of the first flow deflector and the small pipe diameter, strong rotary disturbance is formed and is intensively mixed with urea spray sprayed into the cyclone pipe, so that urea liquid drops are dispersed and crushed for the second time, small liquid drops with smaller diameter are formed, and the evaporation is easier. The rear end of the cyclone tube is designed to be in a flaring state, so that the flow cross section of the airflow is increased, and the reduction of back pressure is facilitated. In addition, the first perforated pipe is arranged inside the cyclone pipe, and the first perforated pipe and the cyclone pipe are coaxial. The first overflowing hole increases the air flow in the pipe, and is beneficial to the early-stage mixing of the air flow and the urea spray.

In addition, the SCR mixer according to the present invention may have the following additional technical features:

in some embodiments of the present invention, the first swirl hole is a rectangular hole extending along an axial direction of the first pipe section, the first pipe section is further provided with a plurality of second swirl holes, the second swirl hole extends along the axial direction of the first pipe section, the swirl pipe further includes a second baffle plate disposed on the second swirl hole, an outer shape of the second baffle plate is matched with the second swirl hole, a length of the first swirl hole is greater than a length of the second swirl hole, the first swirl hole is disposed near a top of the first pipe section, and the second swirl hole is disposed near a bottom of the first pipe section.

In some embodiments of the present invention, the cyclone tube further comprises a third tube section connected to the bottom of the second tube section, and the third tube section is a straight tube structure.

In some embodiments of the present invention, the first overflowing hole is a circular hole, the first perforated pipe is further provided with a plurality of elongated holes, the elongated holes extend along a circumferential direction of the first perforated pipe, the circular hole is disposed near a top of the first perforated pipe, and the elongated holes are disposed near a bottom of the first perforated pipe.

In some embodiments of the utility model, the plurality of first overflow apertures form a first array on the first perforated tube, the plurality of elongated apertures form a second array on the first perforated tube, and the first array has an area greater than the area of the second array.

In some embodiments of the utility model, the SCR mixer further includes a second perforated pipe disposed coaxially with the outlet of the connection chamber, a sidewall of the second perforated pipe being disposed toward the second end of the cyclone pipe, the second perforated pipe being provided with a plurality of second overflowing holes.

In some embodiments of the utility model, the portion of the second perforated tube facing the cyclone tube is not provided with the second overflowing holes, and the remaining portion of the second perforated tube is provided with a third array formed by a plurality of the second overflowing holes.

In some embodiments of the utility model, the SCR mixer further includes a tapered pipe through which the second perforated pipe is connected to the gas outlet, and an end of the tapered pipe having a smaller diameter is connected to the second perforated pipe.

In some embodiments of the present invention, the SCR mixer further includes a baffle plate, the baffle plate is provided with a through hole, the cyclone tube is connected to the housing through the baffle plate, and a connection position of the cyclone tube and the housing is located between the air inlet and the air outlet.

In some embodiments of the utility model, the first perforated tube has a length less than the cyclone tube, and the first perforated tube further comprises a plurality of brackets disposed at a bottom of the first perforated tube, the brackets abutting the baffle.

A second aspect of the utility model provides an engine comprising an SCR mixer as set forth in the first aspect of the utility model.

The engine according to the second aspect of the present invention has the same advantages as the SCR mixer according to the first aspect of the present invention, and will not be described in detail herein.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the utility model. Also, like parts are designated by like reference numerals throughout the drawings. In the drawings:

fig. 1 schematically shows a structural schematic of an SCR mixer according to an embodiment of the utility model.

Fig. 2 schematically shows a structural view of a swirl tube of an SCR mixer according to an embodiment of the utility model.

Fig. 3 schematically shows a structural view of a first perforated pipe of an SCR mixer according to an embodiment of the present invention.

Fig. 4 schematically shows a structural view of a second perforated pipe of an SCR mixer according to an embodiment of the present invention.

Fig. 5 schematically shows a structural view of a baffle plate of an SCR mixer according to an embodiment of the present invention.

The reference symbols in the drawings denote the following:

10: a housing, 11: connecting cavity, 12: air inlet, 13: air outlet, 14: a urea nozzle opening;

20: swirl tube, 21: first tube section, 22, second tube section, 23: first swirl hole, 24: first guide vane, 25: second swirl holes, 26: second guide vane, 27: a third tube section;

30: first porous pipe, 31: first overflowing hole, 32: elongated hole, 33: a support;

40: second porous pipe, 41: a second overflowing hole;

50: tapered tube, 51: baffle, 52: and a through hole.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only, and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless specifically identified as an order of performance. It should also be understood that additional or alternative steps may be used.

Although the terms, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, an element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

For convenience of description, spatially relative terms, such as "inner", "outer", "inner", "side", "lower", "below", "upper", "above", and the like, may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. Thus, the example term "below … …" can include both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

As shown in fig. 1 to 5, a first aspect of the present invention provides an SCR mixer, including:

the urea spraying device comprises a shell 10, wherein a connecting cavity 11 is formed in the shell 10, the shell 10 is provided with an air inlet 12 and an air outlet 13, the air inlet 12 is communicated with the air outlet 13 through the connecting cavity 11, and the top end of the connecting cavity 11 is provided with a urea nozzle opening 14;

the urea nozzle comprises a cyclone tube 20, wherein a first end of the cyclone tube 20 is arranged corresponding to a urea nozzle opening 14, the cyclone tube 20 comprises a first tube section 21 and a second tube section 22 connected with the bottom of the first tube section 21, the first tube section 21 and the second tube section 22 are both in a circular truncated cone shape, an included angle between a generatrix of the second tube section 22 and an axis is larger than an included angle between the generatrix of the first tube section 21 and the axis, a plurality of first cyclone holes 23 are formed in the first tube section 21, the cyclone tube 20 further comprises a first flow deflector 24 arranged on the first cyclone holes 23, the shape of the first flow deflector 24 is matched with the first cyclone holes 23, and part of the first flow deflector 24 is connected with the first tube section 21;

the first perforated pipe 30, the first perforated pipe 30 is arranged in the cyclone pipe 20 and is arranged with the cyclone pipe 20 at intervals, and the first perforated pipe 30 is provided with a plurality of first overflowing holes 31.

It is understood that the first swirl holes 23 may be rectangular holes, elliptical holes or kidney-shaped holes, the structure of the first baffle 24 is adapted according to the shape of the first swirl holes 23, and the first baffle 24 may be formed integrally with the first pipe section 21 by bending a sheet metal or connected to the first pipe section 21 by welding. The first perforated tube 30 is preferably a circular straight tube, and the first overflowing holes 31 may be rectangular holes, elliptical holes, kidney-shaped holes, or the like.

The SCR mixer provided by the utility model is provided with the cyclone tube 20 with the reducing tube structure, waste gas flows into the cyclone tube 20 from the gas inlet 12 of the connecting cavity 11, and under the action of the first flow deflector 24 and the small tube diameter, strong rotary disturbance is formed and is intensively mixed with urea spray sprayed into the cyclone tube 20, so that urea liquid drops are dispersed and crushed for the second time, small liquid drops with smaller diameter are formed, and the evaporation is easier. The rear end of the cyclone tube 20 is designed to be in a flaring state, so that the flow cross section of the airflow is increased, and the reduction of back pressure is facilitated. In addition, a first perforated tube 30 is installed inside the cyclone tube 20, coaxially with the cyclone tube. The first overflow aperture 31 increases the amount of airflow in the tube, facilitating early mixing of the airflow with the urea spray.

In some embodiments of the present invention, the first swirl holes 23 are rectangular holes extending along the axial direction of the first pipe section 21, the first pipe section 21 is further provided with a plurality of second swirl holes 25, the second swirl holes 25 extend along the axial direction of the first pipe section 21, the swirl pipe 20 further includes a second baffle 26 disposed on the second swirl holes 25, the second baffle 26 has a shape matched with the second swirl holes 25, the length of the first swirl holes 23 is greater than that of the second swirl holes 25, the first swirl holes 23 are disposed near the top of the first pipe section 21, and the second swirl holes 25 are disposed near the bottom of the first pipe section 21. Through setting up two sections whirl hole arrays, improve the ability of overflowing and the rigidity of whirl pipe 20, and then improve the mixing performance of whirl pipe 20.

In some embodiments of the present invention, the cyclone tube 20 further includes a third tube section 27 connected to the bottom of the second tube section 22, the third tube section 27 is a straight tube structure, which facilitates the fixing by the baffle 51, and the mixed urea exhaust gas is rectified by the straight tube, which helps to improve the flow capacity of the SCR mixer.

In some embodiments of the present invention, the first overflowing hole 31 is a circular hole, the first perforated pipe 30 is further provided with a plurality of elongated holes 32, the elongated holes 32 extend along the circumferential direction of the first perforated pipe 30, the circular hole is disposed near the top of the first perforated pipe 30, and the elongated holes 32 are disposed near the bottom of the first perforated pipe 30.

Specifically, small holes are uniformly formed in the front part of the pipe body along the pipe diameter, long holes 32 are uniformly formed in the rear part of the pipe body along the pipe diameter, and the circular small holes increase the gas flow in the pipe, so that the gas flow and urea spraying can be mixed in the early stage; the elongated holes 32 facilitate the urea droplets to pass through the first-stage porous pipe, reduce the wall sticking amount at the position and reduce the crystallization risk.

In some embodiments of the present invention, the plurality of first overflow apertures 31 form a first array on the first perforated tube 30 and the plurality of elongated apertures 32 form a second array on the first perforated tube 30, the first array having an area greater than the area of the second array.

Specifically, evenly set up the aperture of diameter 8mm in the two-thirds part along the pipe diameter before the body, the rectangular hole 32 of width 5mm length 18mm is evenly set up along the pipe diameter in the one-third part behind the body, and the aperture bears the function that increases the gas flow and needs the design area bigger some, and rectangular hole 32 circulation capacity is less than little round hole, needs the design area less some, can realize that urea liquid drop flows through, and it can to reduce the wall volume at this position.

In some embodiments of the present invention, the SCR mixer further includes a second perforated pipe 40, the second perforated pipe 40 is disposed coaxially with the outlet 13 of the connection chamber 11, a sidewall of the second perforated pipe 40 is disposed toward the second end of the cyclone tube 20, and a plurality of second overflowing holes 41 are provided on the second perforated pipe 40. The second overflowing hole 41 can be a circular hole or an elliptical hole, urea and waste gas mixed by the cyclone tube 20 and the first perforated tube 30 are mixed again by the second perforated tube 40, the mixing degree of urea and waste gas is further improved, and the distribution uniformity of ammonia is improved.

In some embodiments of the present invention, the portion of second perforated tube 40 facing swirl tube 20 is not provided with second overflow holes 41, and the remaining portion of second perforated tube 40 is provided with a third array of second overflow holes 41. The urea liquid drops which are not evaporated are prevented from directly entering the second perforated pipe 40, evaporation is enhanced through contact heat exchange with a smooth pipe wall which is not perforated, the mixing path is prolonged, and the air flow is more uniform when entering the second perforated pipe 40. The second overflow holes 41 in the tube wall promote diffusion and mixing between the ammonia and the exhaust gas stream, and also facilitate thermal evaporative decomposition of the non-evaporated urea droplets.

In some embodiments of the present invention, the SCR mixer further includes a tapered pipe 50, preferably a conical pipe 50, the second perforated pipe 40 is connected to the outlet port 13 of the housing 10 through the tapered pipe 50, and the end of the tapered pipe 50 having a smaller diameter is connected to the second perforated pipe 40. The pipe diameter of the conical pipe 50 is gradually expanded to the diameter of the carrier from the pipe diameter of the second perforated pipe 40, and the waste gas flow is diffused to the periphery when passing through the conical pipe 50, which is beneficial to improving the uniformity of the gas flow distribution before the catalyst.

In some embodiments of the present invention, the SCR mixer further includes a baffle 51, the baffle 51 is provided with a through hole 52, the cyclone tube 20 is connected to the housing 10 through the baffle 51, and the connection position of the cyclone tube 20 and the housing 10 is located between the air inlet 12 and the air outlet 13. Through set up baffle 51 between the gas outlet 13 at the air inlet 12 of shell 10 and connection chamber 11 and avoid waste gas not directly to flow out through whirl pipe 20 and first perforated pipe 30, strengthen the mixed effect of urea and waste gas, improve the homogeneity of ammonia.

In some embodiments of the present invention, the length of the first perforated pipe 30 is smaller than the length of the cyclone tube 20, the first perforated pipe 30 further includes a plurality of brackets 33 disposed at the bottom of the first perforated pipe 30, the brackets 33 abut against the baffle 51, and the brackets 33 can be clamped on the protrusions of the baffle 51, so that the assembly is convenient and the reliability is good.

A second aspect of the utility model provides an engine comprising an SCR mixer, the SCR mixer being as set out in the first aspect of the utility model.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are also included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An SCR mixer installed in a connection chamber of an aftertreatment device, comprising:

2. The SCR mixer of claim 1, wherein the first swirl hole is a rectangular hole extending in an axial direction of the first pipe section, the first pipe section is further provided with a plurality of second swirl holes, the second swirl holes extend in the axial direction of the first pipe section, the swirl pipe further comprises a second deflector arranged on the second swirl holes, the second deflector has a shape matched with the second swirl holes, the length of the first swirl holes is greater than that of the second swirl holes, the first swirl holes are arranged near the top of the first pipe section, and the second swirl holes are arranged near the bottom of the first pipe section.

3. The SCR mixer of claim 1, wherein the swirl tube further comprises a third tube section connected to the bottom of the second tube section, the third tube section being of a straight tube construction.

4. The SCR mixer of claim 1, wherein the first overflowing hole is a circular hole, and the first perforated pipe is further provided with a plurality of elongated holes extending in a circumferential direction of the first perforated pipe, the circular hole being provided near a top of the first perforated pipe, and the elongated holes being provided near a bottom of the first perforated pipe.

5. The SCR mixer of claim 4, wherein the plurality of first overflow apertures form a first array on the first perforated tube and the plurality of elongated apertures form a second array on the first perforated tube, the first array having an area greater than the area of the second array.

6. The SCR mixer of claim 1, further comprising a second perforated pipe disposed coaxially with the outlet of the connection chamber, wherein a sidewall of the second perforated pipe is disposed toward the second end of the cyclone pipe, and wherein the second perforated pipe is provided with a plurality of second overflowing holes.

7. The SCR mixer of claim 6, wherein a portion of the second perforated tube facing the swirl tube is not provided with the second overflow holes, and a remaining portion of the second perforated tube is provided with a third array of a plurality of the second overflow holes.

8. The SCR mixer of claim 7, further comprising a tapered tube through which the second perforated tube is connected to the outlet port, the tapered tube having a smaller diameter end connected to the second perforated tube.

9. The SCR mixer of any one of claims 1 to 8, further comprising a baffle plate having a through hole, wherein the cyclone tube is connected to the housing through the baffle plate, and a connection position of the cyclone tube to the housing is located between the air inlet and the air outlet.

10. An engine comprising an SCR mixer according to any one of claims 1 to 9.