WO2017054179A1

WO2017054179A1 - Swirl mixing type exhaust aftertreatment box and system

Info

Publication number: WO2017054179A1
Application number: PCT/CN2015/091250
Authority: WO
Inventors: Murat ERMANOTAN; Christian Alt
Original assignee: Robert Bosch Gmbh
Priority date: 2015-09-30
Filing date: 2015-09-30
Publication date: 2017-04-06
Also published as: KR20180057638A; KR102520281B1; CN109069997B; CN109069997A

Abstract

An aftertreatment box for treating engine exhaust comprises first to third chambers (2,3,4), an exhaust inlet member (14) and a treating fluid inlet member (15) for inputting a stream of exhaust and a jet of exhaust treating fluid into the first chamber (2) respectively, and a tubular treatment assisting element (9) extending through the second chamber (3) and opened into the third chamber (4). The exhaust inlet member (14) is arranged in an orientation that allows a swirl motion of the stream of exhaust to be generated in the first chamber (2), and the treating fluid inlet member (15) is arranged in an orientation that allows the treating fluid to flow into the swirl stream of exhaust and be mixed therein. An exhaust aftertreatment system comprises such an aftertreatment box and a treating fluid injection device.

Description

Swirl Mixing Type Exhaust Aftertreatment Box and System

Technical Field

The present invention relates to an aftertreatment system for treating exhaust discharged from an engine, especially a diesel engine.

Background Art

Exhaust of an engine contains harmful components. For reducing the emitted amount of harmful components in exhaust, on one hand, engine technique is continuously upgraded and improved for suppress the generation of harmful components, and on the other hand, adequate aftertreatment technique is selected to reduce the amount of harmful components in exhaust.

For example, selective catalytic reduction (SCR) can be used for reducing the amount of nitrogen oxides (NOx) in the exhaust of a diesel engine by 50％or more. A typical SCR module injects an aqueous urea solution into hot exhaust. The urea solution is atomized and evaporated in the exhaust stream to generate NH₃ which can be used as a reaction agent. NH₃ reacts with nitrogen oxides and oxygen under the assistance of a catalyst to form carbon dioxide, nitrogen and water which are harmless.

According to prior art, the SCR module is generally assembled to an exhaust pipe of the engine. For increasing the evaporating speed of the urea solution, a static mixer may be disposed in the exhaust pipe. The jet of urea solution hits the static mixer so the droplets of urea solution are broke up into smaller sizes which can be evaporated more quickly. The static mixer may also generate a turbulence of the mixture of the smaller urea solution droplets and the exhaust in the exhaust pipe, which further results in quick evaporating of the urea solution. In order that the urea solution is completely evaporated and reacted with nitrogen oxides, the SCR module has to be mounted at a location which is long enough to the tip of the exhaust pipe. This needs a large mounting space.

Box type SCR modules, which have reduced lengths, have been developed in recent years. Urea solution and exhaust are mixed in a box type SCR module along a path which changes direction several times. However, there is still room for synchronously optimizing the size and mixing degree of box type SCR modules.

Summary of the Invention

An object of the present invention is to provide an exhaust aftertreatment system for engine exhaust which has reduced size and increased mixing degree.

For this end, the invention in one aspect provides an aftertreatment box for treating engine exhaust, which comprises:

a casing defining a first chamber, a second chamber below the first chamber and a third chamber beside the second chamber, the second chamber being separated from the first chamber by a separation plate having an opening therein, the third chamber being separated from but still in fluid communication with the second chamber；

an exhaust inlet member and a treating fluid inlet member mounted to the casing for inputting a stream of exhaust and a jet of exhaust treating fluid into the first chamber respectively； and

a tubular treatment assisting element extending through the second chamber and opened into the third chamber；

wherein the exhaust inlet member is arranged in an orientation that allows a swirl motion of the stream of exhaust to be generated in the first chamber； and

wherein the treating fluid inlet member is arranged in an orientation that allows the exhaust treating fluid to flow into the swirl stream of exhaust and be mixed therein.

According to a possible embodiment of the invention, the treating fluid inlet member defines a jetting direction at its opening to the first chamber, the jetting direction having a first direction component perpendicular to the flowing direction of the exhaust in front of the treating fluid inlet member and a second direction component along the flowing direction of the exhaust in front of the treating fluid inlet member.

According to a possible embodiment of the invention, the exhaust swirls in the first chamber in multi-layers, and the treating fluid inlet member is located at a height so that it faces towards upper layers, especially the top layer, of the swirl flow.

According to a possible embodiment of the invention, the exhaust inlet member and the treating fluid inlet member are disposed to be adjacent to each other, each having a central axis that is substantially horizontal, and the separation plate is also substantially horizontal.

According to a possible embodiment of the invention, the opening is a circular hole, and the central axis of the exhaust inlet member is offset from the center of the opening in a radial direction of the opening.

According to a possible embodiment of the invention, the exhaust inlet member and the treating fluid inlet member are both disposed adjacent to a top wall of the casing.

According to a possible embodiment of the invention, the target component comprises NOx, the exhaust treating fluid is an aqueous urea solution, and the treatment assisting element is a selective catalytic reduction converter in which a catalyst is disposed.

According to a possible embodiment of the invention, the third chamber is separated from the second chamber by an additional separation plate, the additional separation plate being formed with perforations for establishing fluid communication between the third chamber and the second chamber.

According to a possible embodiment of the invention, the third chamber is disposed beside both the first and second chambers and is separated from the first and second chambers by an additional separation plate, the additional separation plate having a first portion that separates the third chamber from the first chamber in a sealing manner and a second portion that separates the third chamber from the second chamber, the second portion being formed with perforations for establishing fluid communication between the third chamber and the second chamber.

According to a possible embodiment of the invention, the separation plate is perpendicular to the additional separation plate and connected to it, the first and second portions of the additional separation plate being divided by the connection between the separation plate and the additional separation plate.

According to a possible embodiment of the invention, the additional separation plate is further formed with a first mounting hole in which a portion of the treatment assisting element is supported, and a wall portion of the casing is formed with a second mounting hole in which another portion of the treatment assisting element is supported.

According to a possible embodiment of the invention, the aftertreatment box further comprises an outlet fitting member connected to the another portion of the treatment assisting element, and an outlet pipe coupled to the outlet fitting member and disposed to be oblique from the central axis of the treatment assisting element.

According to a possible embodiment of the invention, the aftertreatment box further comprises a target component sensor mounted to the outlet fitting member for sensing the concentration of the target component in the outlet fitting member.

According to a possible embodiment of the invention, the aftertreatment box further comprises a temperature sensor for sensing the temperature of the input exhaust in the first chamber.

According to a possible embodiment of the invention, the aftertreatment box further comprises one or more flow deflectors arranged in the first chamber for directing the exhaust to form the swirl flow.

The invention in another aspect provides an exhaust aftertreatment system, which comprises an aftertreatment box described above and a treating fluid injection device assembled to the aftertreatment box via the treating fluid inlet member.

According to a possible embodiment of the invention, the treating fluid injection device comprises a treating fluid dosing module.

According to the invention, the box design for the exhaust aftertreatment system is compact. Meanwhile, the mixing degree of the exhaust treating fluid with the exhaust is increased by swirl motion.

Brief Description of the Drawings

The foregoing and other aspects of the invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings, in which:

Figure 1 is a front sectional view of an aftertreatment box according to a possible embodiment of the invention；

Figure 2 is a partially cut-away top view of the aftertreatment box；

Figure 3 is a right side view of the aftertreatment box；

Figure 4 a front view of a vertical separation plate of the aftertreatment box；

Figure 5 is a top view showing schematically the flow of exhaust in a swirl mixing chamber the aftertreatment box；

Figure 6 is a top view showing schematically the flow of an exhaust treating fluid in the swirl mixing chamber； and

Figure 7 is a vertical view showing schematically the flow of the mixture of the exhaust and the exhaust treating fluid in the aftertreatment box.

Detailed Description of Preferred Embodiments

The invention generally relates to an exhaust aftertreatment system for engine exhaust, the exhaust aftertreatment system being configured to inject an exhaust treating fluid into an exhaust stream so that the exhaust treating fluid is mixed with the exhaust and acts on the exhaust to reduce the amount of at least one target (probably harmful) component in the exhaust.

In the context of the disclosure, the engine may be an internal combustion engine that uses any type of fuels, like diesel, gasoline and natural gas. The target component in the exhaust to be reduced may be any component that can be acted on by an exhaust treating fluid. The exhaust treating fluid may be any fluid that can act on the target component to be reduced, for example, by physical action and/or chemical reaction. The exhaust treating fluid may be in the form of liquid, gas or a mixture of them, for example, a solution of a solute in a solvent. A treatment assisting element may be provided for achieving or enhancing the action of the exhaust treating fluid on the target component. The treatment assisting element may provide physical and/or chemical assistant function to the mixture of the exhaust treating fluid and the exhaust. For example, the treatment assisting element may be a catalyst, a heating element, a radiation emitter, etc.

An embodiment of the exhaust aftertreatment system of the invention mainly comprises a treating fluid injection device and an aftertreatment box. The treating fluid injection device injects an exhaust treating fluid into the aftertreatment box, so that the exhaust treating fluid is mixed with the exhaust.

In a particular embodiment of the invention, the exhaust treating fluid comprises a reaction agent which can be chemically reacted with the exhaust. In this case, the treating fluid injection device may be a reaction agent dosing module which injects the reaction agent into the aftertreatment box in a metered manner, so that the reaction agent is mixed with the exhaust and then chemical reactions are produced between them under the help of a catalyst.

A more particular embodiment of the exhaust aftertreatment system of the invention will be described with reference to the drawings. In this embodiment, the exhaust aftertreatment system is configured for reducing nitrogen oxides in exhaust discharged from an engine, especially a diesel engine. It is, however, appreciated that the scope of the invention also covers the applications in reducing other target components in exhaust discharged from other types of engines.

Figures 1 to 3 show an aftertreatment box of an exhaust aftertreatment system of the invention. The aftertreatment box comprises a substantially rectangular parallelepiped casing 1 formed by panels, such as metal panels welded together, defining an internal space encircled by walls, i.e., a top wall 1a, a bottom wall 1b, a right side wall 1c, a left side wall 1d, a front wall 1e and a back wall 1f. The casing 1 defines a length in X direction between the right and left

side walls

1c and 1d, a width in Y direction between the front and the

back walls

1e and 1f, and a height in Z direction between the top and

bottom walls

1a and 1b. X and Y axes as shown are horizontal and Z axis is vertical. The top wall 1a, the bottom wall 1b and the right side wall 1c are substantially flat, while the left side wall 1d, the front wall 1e and the back wall 1f are slightly bulge outwardly. Preferably, the front and the

back walls

1e and 1f each have substantially the same curvature through its length in X direction.

The internal space is divided into a swirl mixing chamber (first chamber) 2, an SCR converter chamber (second chamber) 3 and a selective catalytic reduction (SCR) inlet chamber (third chamber) 4 by a horizontal separation plate 5 and a vertical separation plate 6.

The separation plate 6 extends in a Y-Z plane and is connected in a sealing manner to the top and

bottom walls

1a and 1b and the front and the

back walls

1e and 1f. The separation plate 5 extends in an X-Y plane and is connected to the front and the

back walls

1e and 1f, the right side wall 1c and the separation plate 6.

The separation plate 5 is substantially rectangular, having a circular through hole 7 in the central portion of it. At least one rib 8 may be formed around the through hole 7 to increase the strength of the separation plate 5. The rib 8, preferably being convex upwardly, may form a continuous circle around the through hole 7, or be in the form of a set of discrete arc segments. For avoiding any deposition on the area between the rib 8 and the periphery of the separation plate 5, small holes may be formed in this area through the separation plate 5. Alternatively, there are small clearances between the corners of the separation plate 5 and the front and the

back walls

1e and 1f, the right side wall 1c and the separation plate 6.

In the illustrated embodiment, each of the swirl mixing chamber 2, the SCR converter chamber 3 and the SCR inlet chamber 4 has a substantially rectangular shape in plan view. However, they may each have other shapes, like circular or elliptic, and they may be defined by suitable walls other than those illustrated.

An SCR converter 9, in the form of a substantially tube, is disposed in the SCR converter chamber 3 and extends into the SCR inlet chamber 4.

The separation plate 6, as shown in Figure 4, has an upper portion and a lower portion, divided by the connection line along which the separation plate 5 is connected to the separation plate 6. The lower portion is formed with a mounting hole 10 and a lot of perforations 11 around the mounting hole 10. The perforations 11 may be in the form of holes, slits, slots or in any other suitable forms. The upper portion does not have any hole or perforation in it and separates the swirl mixing chamber 2 with respect to the SCR inlet chamber 4 in a substantially sealing manner.

The right side wall 1c is formed with a similar mounting hole, aligned with the mounting hole 10. The SCR converter 9 is inserted through the two mounting holes and fixed here so that the SCR converter 9 is supported by the right side wall 1c and the separation plate 6, with the central axis of the SCR converter 9 being aligned in X direction. The two mounting holes have inner diameters substantially equal to the outer diameters of corresponding portions the SCR converter 9. The SCR converter 9 is sealed with respect to the right side wall 1c at its mounting hole. For increasing their supporting strength, the right side wall 1c and the separation plate 6 may each be formed with a flange at the edge around the mounting hole.

In X direction, the SCR converter 9 extends through the entire SCR converter chamber 3, and extends at its inner axial end (inlet end) into the SCR inlet chamber 4 to a certain length. The outer axial end (outlet end) of the SCR converter 9 is disposed in the right side wall 1c or exposed outside the right side wall 1c by a small length, and an outlet fitting member 12, which is in the form of a hollow semisphere, is attached to the outer axial end of the SCR converter 9. An outlet pipe 13 is connected to a lower portion of the outlet fitting member 12. The outlet pipe 13 has a central axis intersecting with the central axis of the SCR converter 9, but is obliquely deflected from it in both Y and Z directions, as shown in Figures 1 and 3. Fluid communication is established between the SCR converter 9, the outlet fitting member 12 and the outlet pipe 13.

A catalyst 9a for SCR reaction is disposed in the SCR converter 9. The catalyst 9a starts at the inner axial end of the SCR converter 9 and extends in X direction in it. Preferably, the catalyst 9a does not reach the outer axial end of the SCR converter 9. The catalyst 9a may be in the form of several tubular segments.

As shown in Figures 2 and 3, an exhaust inlet member 14 is mounted to the front wall 1e, being in fluid communication with the swirl mixing chamber 2, for introducing a stream of exhaust into the swirl mixing chamber 2. The mounting location of the exhaust inlet member 14 is in a corner area of the front wall 1e between the top wall 1a and the right side wall 1c.

The exhaust inlet member 14 is preferably horizontally disposed, having a central axis extending substantially in Y direction so that the stream of exhaust flows into the swirl mixing chamber 2 mainly in Y direction. Alternatively, the central axis of the exhaust inlet member 14 may be slightly oblique upwardly or downwardly from Y direction.

The central axis of the exhaust inlet member 14 is offset from the central axis of the through hole 7 by a distance in X direction.

By arranging the exhaust inlet member 14 in this way, when exhaust flows into the outlet fitting member 12 via it, the exhaust flows first mainly in Y direction, and is then deflected by the back wall 1f, the separation plate 6 and the front wall 1e to change its direction in sequence. Thus a swirl flow of exhaust is generated in the swirl mixing chamber 2, as schematically indicated by arrows in Figures 5 and 7. The swirl flow is substantially around a vertical swirl axis O that passes through the central point of the through hole 7. The exhaust swirls in the swirl mixing chamber 2 in multi-layers (multi-turns) as shown in Figure 7.

A treating fluid inlet member 15 is mounted to the right side wall 1c, being in fluid communication with the swirl mixing chamber 2, for injecting a jet of aqueous urea solution (exhaust treating fluid) , such as AdBlue, into the swirl mixing chamber 2. The mounting location of the treating fluid inlet member 15 is in a corner area of the right side wall 1c between the top wall 1a and the front wall 1e, near the exhaust inlet member 14. The central axis of the treating fluid inlet member 15, preferably horizontal, is higher than the central axis of the outlet pipe 13 so that the opening of the treating fluid inlet member 15 in the swirl mixing chamber 2 faces upper layers (turns) , especially the top layer (turn) , of the swirl flow.

Further, the central axis of the treating fluid inlet member 15 is deflected from X direction to be obliquely facing away from the front wall 1e so that the urea solution is injected into the swirl mixing chamber 2 with an injection direction having a direction component perpendicular to the flow direction of the exhaust in front of the treating fluid inlet member 15 and a direction component along the flow direction of the exhaust.

It is appreciated the exhaust inlet member 14 and the treating fluid inlet member 15 can be arranged on other locations or other walls of the aftertreatment box.

By arranging the treating fluid inlet member 15 in this manner, the urea solution is injected into the outlet fitting member 12 in a direction oblique with respect to the flow direction of the exhaust it faces. Under the effect of the flowing exhaust, droplets of the urea solution flow in an area substantially defined between the treating fluid inlet member 15 and the separation wall 6 and the back wall 1f, as schematically indicated by short lines in Figure 6. Upon impacting on the separation wall 6 and the back wall 1f, some droplets of urea solution are split into smaller droplets which will be enrolled into the swirl flow of the exhaust to be mixed and evaporated therein. The swirl movement in the swirl mixing chamber 2 contributes to an increased extent of mixing of the treating agent in the exhaust. The other part of droplets may form a liquid film on the separation wall 6 and the back wall 1f, which will be evaporated quickly under the high temperature resulted from the exhaust. NH₃ is generated by evaporating the urea solution.

In order to facilitate the forming of the swirl movement, flow deflectors can be arranged in the swirl mixing chamber 2.

A temperature sensor can be disposed in a wall of the aftertreatment box for sensing the temperature of the inlet exhaust. The temperature can be used in determining and adjusting the metered amount of the urea solution.

As shown in Figure 7, the mixture of NH₃ and exhaust swirls in the swirl mixing chamber 2 in multi-layers and then, at the bottom layer of the swirl flow, flows into the SCR converter chamber 3 downwardly through the through hole 7 in the separation plate 5. There is nearly no droplets of the urea solution in liquid phase in the downward flow. In the SCR converter chamber 3, the mixture flows about the SCR converter 9, substantially in X direction towards the lower portion of the separation plate 6. Then, the mixture passes through the perforations 11 in the separation plate 6 and enters into the SCR inlet chamber 4. In the SCR inlet chamber 4, the mixture reverses its direction and flows into the SCR converter 9.

In the flow path of the mixture from the swirl mixing chamber 2 to the SCR converter 9, the mixture changes its direction several times. Thanks for the swirl movement and then the changing of directions, NH₃ is fully mixed with the exhaust to a vary high degree. In the SCR converter 9, the homogenous mixture flows in X direction, and selective catalytic reduction reaction is produced between NH₃ and nitrogen oxides in the exhaust and oxygen, under the assistance of the catalyst 9a, to form carbon dioxide, nitrogen and water which will be discharged from the SCR converter 9 from the outlet pipe 13.

It is noted that, in the illustrated embodiment, the SCR inlet chamber 4 is disposed beside both the swirl mixing chamber 2 and the SCR converter chamber 3. However, in a variant not shown, the SCR inlet chamber 4 may be disposed beside only the SCR converter chamber 3, In this case, the separation plate 6 only separates the SCR inlet chamber 4 and the SCR converter chamber 3 and is thus formed only by the lower portion of the separation plate 6 described above. The space above the SCR inlet chamber 4 can be used for disposing other elements, even the exhaust inlet member 14. In another variant, the SCR inlet chamber 4 is disposed beside the whole swirl mixing chamber 2 and a part of the SCR converter chamber 3.

The exhaust aftertreatment system further comprises a treating fluid feeding module (for example, dosing module) that can be integrated to the aftertreatment box via the treating fluid inlet member 15 for feeding urea solution into the swirl mixing chamber 2 in metered manner.

An NOx sensor boss 16 for mounting an NOx sensor is mounted to the outlet fitting member 12. The NOx sensor boss 16 is preferably located at a position distant from the outlet pipe 13. The NOx sensor can be mounted to the NOx sensor boss 16, with a sensing end of it extending into the inner space of the outlet fitting member 12, for sensing the concentration of residual nitrogen oxides inside the treated exhaust. The concentration of residual nitrogen oxides inside the treated exhaust will be used as an index for evaluating the performance of the exhaust aftertreatment system, and some parameters of the aftertreatment box can be adjusted for optimizing the performance. These parameters include, among others:

· the inner diameter of the exhaust inlet member 14；

· the shape and size of the swirl mixing chamber 2, especially the length, width and height of the swirl mixing chamber 2 when it rectangular；

· the diameter of through hole 7 in the horizontal separation plate 5；

· the orientation and location of the treating fluid inlet member 15 with respect to the exhaust inlet member 14；

· the type of the treating fluid dosing module (for example, using various type of injectors) ； and

· the eccentricity of the exhaust inlet member 14 with respect to the center of the through hole 7.

Various configurations and applications of the aftertreatment box and the exhaust aftertreatment system can be contemplated by those skilled in the art.

In the aftertreatment box of the invention, by using a swirl mixing chamber 2 therein, the need of a long exhaust pipe (which will be superfluous up to 1000 mm) for mixing and evaporating the urea solution with the exhaust stream is eliminated.

Further, the SCR converter chamber 3 is disposed directly under the swirl mixing chamber 2, and the SCR inlet chamber 4 is disposed beside the SCR converter chamber 3 or beside both the swirl mixing chamber 2 and the SCR converter chamber 3, so a compact aftertreatment box with a smaller size is formed. The aftertreatment box can be easily applied in different kinds of vehicles or machines equipped with an internal combustion engine.

Further, the urea solution is fully evaporated and mixed in the exhaust before entering the SCR converter 9, so selective catalytic reduction reaction can be effectively happened in the SCR converter 9. Thus, the SCR converter 9 and the catalyst 9a can be reduced in size, weight and cost, while the same or better performance can be guaranteed. The size of the aftertreatment box, especially that of the swirl mixing chamber 2, is mainly depending on the exhaust mass flow rate and the desired degree of mixing. The aftertreatment box may have a significantly smaller size than the pipe that would be necessary for mixing for comparable exhaust mass flow.

Further, the reaction agent dosing module can be integrated to the aftertreatment box, so it does not need to consider the mounting location of the dosing module on a long exhaust pipe.

Further, advanced mixing concept is applied in the aftertreatment box by the swirl mixing chamber 2, so, even if there is crystallization in the swirl mixing chamber 2, there is no risk of blocking the exhaust pipe.

Further, a temperature sensor can be arranged at an optimal location on the aftertreatment box to provide more precise upstream temperature of the exhaust, which leads to more precise SCR calibration and causes lower urea consumption.

Further, the swirl mixing chamber 2 is directly formed integrally in the aftertreatment box, so the operation of mounting a separate static mixer in the exhaust pipe according to prior art is eliminated.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. The attached claims and their equivalents are intended to cover all the modifications, substitutions and changes as would fall within the scope and spirit of the invention.

Claims

An aftertreatment box for treating engine exhaust comprising:

a casing (1) defining a first chamber (2) , a second chamber (3) below the first chamber (2) and a third chamber (4) beside the second chamber (3) , the second chamber (3) being separated from the first chamber (2) by a separation plate (5) having an opening (7) therein, the third chamber (4) being separated from but still in fluid communication with the second chamber (3) ；

an exhaust inlet member (14) and a treating fluid inlet member (15) mounted to the casing (1) for inputting a stream of exhaust and a jet of exhaust treating fluid into the first chamber (2) respectively； and

a tubular treatment assisting element (9) extending through the second chamber (3) and opened into the third chamber (4) ；

wherein the exhaust inlet member (14) is arranged in an orientation that allows a swirl motion of the stream of exhaust to be generated in the first chamber (2) ； and

wherein the treating fluid inlet member (15) is arranged in an orientation that allows the exhaust treating fluid to flow into the swirl stream of exhaust and be mixed therein.
The aftertreatment box of claim 1, wherein the treating fluid inlet member (15) defines a jetting direction at its opening to the first chamber (2) , the jetting direction having a first direction component perpendicular to the flowing direction of the exhaust in front of the treating fluid inlet member (15) and a second direction component along the flowing direction of the exhaust in front of the treating fluid inlet member (15) .
The aftertreatment box of claim 1, wherein the exhaust swirls in the first chamber (2) in multi-layers, and the treating fluid inlet member (15) is located at a height so that it faces towards upper layers, especially the top layer, of the swirl flow.
The aftertreatment box of any one of claims 1 to 3, wherein the exhaust inlet member (14) and the treating fluid inlet member (15) are disposed to be adjacent to each other, each having a central axis that is substantially horizontal, and the separation plate (5) is also substantially horizontal.
The aftertreatment box of claim 4, wherein the opening (7) is a circular hole, and the central axis of the exhaust inlet member (14) is offset from the center of the opening (7) in a radial direction of the opening (7) .
The aftertreatment box of any one of claims 1 to 5, wherein the exhaust inlet member (14) and the treating fluid inlet member (15) are both disposed adjacent to a top wall of the casing (1) .
The aftertreatment box of any one of claims 1 to 6, wherein the target component comprises NOx, the exhaust treating fluid is an aqueous urea solution, and the treatment assisting element (9) is a selective catalytic reduction converter in which a catalyst (9a) is disposed.
The aftertreatment box of any one of claims 1 to 7, wherein the third chamber (4) is separated from the second chamber (3) by an additional separation plate (6) , the additional separation plate (6) being formed with perforations (11) for establishing fluid communication between the third chamber (4) and the second chamber (3) .
The aftertreatment box of any one of claims 1 to 8, wherein the third chamber (4) is disposed beside both the first and second chambers (2, 3) and is separated from the first and second chambers (2, 3) by an additional separation plate (6) , the additional separation plate (6) having a first portion that separates the third chamber (4) from the first chamber (2) in a sealing manner and a second portion that separates the third chamber (4) from the second chamber (3) , the second portion being formed with perforations (11) for establishing fluid communication between the third chamber (4) and the second chamber (3) .
The aftertreatment box of claim 9, wherein the separation plate (5) is perpendicular to the additional separation plate (6) and connected to it, the first and second portions of the additional separation plate (6) being divided by the connection between the separation plate (5) and the additional separation plate (6) .
The aftertreatment box of any one of claims 8 to 10, wherein the additional separation plate (6) is further formed with a first mounting hole (10) in which a portion of the treatment assisting element (9) is supported, and a wall portion of the casing (1) is formed with a second mounting hole in which another portion of the treatment assisting element (9) is supported.
The aftertreatment box of claim 11, further comprising an outlet fitting member (12) connected to the another portion of the treatment assisting element (9) , and an outlet pipe (13) coupled to the outlet fitting member (12) and disposed to be oblique from the central axis of the treatment assisting element (9) .
The aftertreatment box of claim 12, further comprising a target component sensor mounted to the outlet fitting member (12) for sensing the concentration of the target component in the outlet fitting member (12) ； and/or

a temperature sensor for sensing the temperature of the input exhaust in the first chamber (2) .
The aftertreatment box of any one of claims 1 to 13, wherein the aftertreatment box further comprises one or more flow deflectors arranged in the first chamber (2) for directing the exhaust to form the swirl flow.
An exhaust aftertreatment system comprising:

an aftertreatment box of any one of claims 1 to 14； and

a treating fluid injection device, especially a treating fluid dosing module, assembled to the aftertreatment box via the treating fluid inlet member (15) .