Post-treatment system

Abstract

Post-treatment system, comprehensive: a heat holding box in which a heat holding chamber is formed, and wherein the heat holding box is provided with an air inlet and an air outlet which communicate with the heat holding chamber; a mixer arranged in the heat retention chamber, wherein a mixing chamber is formed in the mixer, and wherein the mixer is provided with a first inlet and a first outlet which communicate with the mixing chamber, the first inlet communicating with the air inlet; and a catalyst arranged in the heat retention space, wherein a catalytic space is formed in the catalyst, and wherein the catalyst is provided with a second inlet and a second outlet which communicate with the catalytic space, wherein the second inlet communicates with the first outlet, and wherein the second outlet communicates with the heat retention space.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of engine exhaust treatment and, more particularly, to an aftertreatment system. STATE OF THE ART

[0002] As society pays increasing attention to environmental protection, emissions regulations for diesel vehicles have become increasingly strict. Therefore, diesel-powered vehicles are generally equipped with an aftertreatment system that can purify the vehicle's exhaust gases, ensuring that the vehicle's exhaust meets emissions regulations.

[0003] An aftertreatment system generally includes a mixer and a selective catalytic reduction device. The interior of the mixer and the interior of the selective catalytic reduction device are connected. Exhaust gases emitted by the vehicle can enter the mixer, allowing the reducing agent, such as urea solution, to evaporate in the mixer and decompose into reducing gas. After the reducing gas is mixed with the exhaust gas, it can enter the interior of the catalytic reduction device to undergo a catalytic reduction reaction and produce clean nitrogen and water, thus purifying the exhaust gas. CONTENT OF THE PRESENT INVENTION

[0004] The present disclosure provides an aftertreatment system. The aftertreatment system includes a heat retention box, a mixer, and a catalyst. A heat retention space is formed in the heat retention box, and the heat retention box is provided with an air inlet and an air outlet communicating with the heat retention space. The mixer is arranged in the heat retention space, and a mixing chamber is formed in the mixer, and the mixer is provided with a first inlet and a first outlet communicating with the mixing chamber. The first inlet communicates with the air inlet. The catalyst is arranged in the heat retention space, and a catalytic space is formed in the catalyst, and the catalyst is provided with a second inlet and a second outlet communicating with the catalytic space.The second inlet is in communication with the first outlet, the second outlet being in communication with the heat retention space.

[0005] Based on the aftertreatment system provided by the embodiments of the present disclosure, the exhaust gas may enter the mixing chamber of the mixer through the air inlet and the first inlet. The urea solution may be sprayed into the mixing chamber. Since the temperature of the exhaust gas is relatively high, the exhaust gas entering the mixing chamber may create a higher-temperature environment in the mixing chamber. In this way, the urea solution in the mixing chamber may evaporate and decompose into reducing gas. The reducing gas and the exhaust gas are mixed in the mixing chamber to form a mixed gas. At this time, the mixed gas contains ammonia gas, nitrogen oxide compounds (e.g., nitrogen oxide, nitrogen dioxide, etc.), and the like. The mixed gas in the mixing chamber may enter the catalytic space through the first outlet and the second inlet.A catalyst can also be placed in the catalytic chamber, which can play a catalytic role, accelerating the selective catalytic reduction reaction between ammonia gas and nitrogen oxide compounds in the exhaust gas, thus producing clean nitrogen and water. Since the second outlet is connected to the heat-retaining chamber, the high-temperature gas in the catalytic chamber can be discharged into the heat-retaining chamber through the second outlet. Since the mixer is located in the heat-retaining chamber, the high-temperature gas in the heat-retaining chamber can surround the mixer.

[0006] In some embodiments, the heat-retaining box comprises a top wall, a bottom wall, and a side wall, with the bottom wall being opposite the top wall and spaced apart from it. The side wall is annular and arranged between the top wall and the bottom wall, and, together with the top wall and the bottom wall, encloses the heat-retaining chamber.

[0007] Both the mixer and the catalyst extend in a direction perpendicular to the bottom wall. The second outlet is positioned toward the bottom wall. The air outlet is provided on the top wall or the side wall. Along the direction perpendicular to the bottom wall, the second outlet and the air outlet are at different heights.

[0008] In some embodiments, the catalytic converter comprises a main body and a plurality of connecting sections. The main body has a main body side wall. The main body side wall is annular and encloses the catalytic space with the second inlet and the second outlet. The main body side wall is connected to the top wall. The plurality of connecting sections are located on a side of the main body side wall facing the bottom wall, and the plurality of connecting sections are spaced apart from one another along the circumferential direction of the second outlet. One end of the connecting section is connected to the main body side wall, and the other end of the connecting section is connected to the bottom wall. An air distribution opening is formed between two adjacent connecting sections.

[0009] In some embodiments, the connecting portion includes a vent hole. The vent hole is an alternative through-hole used to circulate the gas exiting the second outlet.

[0010] In some embodiments, it is provided that the vent hole is arranged on at least one connecting section towards the mixer.

[0011] In some embodiments, the catalyst is provided in a plurality. The second inlets of the plurality of catalysts are all in communication with the first outlet.

[0012] In some embodiments, the aftertreatment system further includes a first communication element, wherein the first communication element is arranged on the top wall and, together with the top wall, encloses a first communication chamber. The first outlet and the plurality of second inlets are all in communication with the first communication chamber.

[0013] In some embodiments, the first communication element is mounted on a side of the top wall that is remote from the bottom wall. A first communication port and a plurality of second communication ports are provided on the top wall, which are in communication with the first communication chamber. The first connection port is connected to the first outlet. A second communication port is in communication with the second inlet.

[0014] In some embodiments, the aftertreatment system further includes a particulate filter disposed between the lower wall and the upper wall, and wherein the particulate filter is disposed outside the heat retention space and connected to the heat retention box. The particulate filter forms a filter chamber with a third inlet and a third outlet, wherein the third outlet is in communication with the air inlet. SHORT DESCRIPTION OF THE DRAWING Fig. 1 is a first schematic diagram of an aftertreatment system according to some embodiments of the present disclosure. Fig. 2 is a sectional view of point AA in Fig. 1; Fig. 3 is a second schematic diagram of a post-processing system according to some embodiments of the present disclosure. Fig. 4 is a partial schematic diagram of an aftertreatment system according to some embodiments of the present disclosure. Fig. 5 is a third schematic diagram of a post-processing system according to some embodiments of the present disclosure. Fig. 6 is a fourth schematic diagram of a post-processing system according to some embodiments of the present disclosure. Fig. 7 is a fifth schematic diagram of a post-processing system according to some embodiments of the present disclosure. Fig. 8 is a sectional view of point BB in Fig. 7. DETAILED DESCRIPTION

[0015] In order to enable those skilled in the art to better understand the technical solutions of the embodiments of the present disclosure, the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0016] In describing the present disclosure, it should be understood that the orientations or positional relationships indicated by the terms "center," "top," "bottom," "front," "rear," "inside," "outside," and the like are the orientations or positional relationships shown based on the drawings and are provided only for the convenience of describing the present disclosure and simplifying the description, rather than stating or implying that the stated device or element must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present disclosure.

[0017] The terms "first," "second," and the like are used for descriptive purposes only and should not be understood to indicate or imply a relative importance or to implicitly specify the set of technical features recited. Therefore, features defined by expressions such as "first," "second," and the like may explicitly or implicitly include one or more of these features. In the description of the present disclosure, "multiple" means two or more than two unless otherwise specified.

[0018] When describing the present disclosure, it should be noted that the terms "installation" and its variations, "connecting" and its variations, and "connecting" and its variations, unless expressly stated and limited otherwise, are to be understood in the broadest sense. For example, "connecting" may refer to a fixed connection, a detachable connection, or an integral connection; it may refer to a mechanical or electrical connection; "connecting" may refer to a direct connection, an indirect connection via an intermediate medium, or it may refer to an internal communication between two elements. Those of ordinary skill in the art can understand the meanings of the above terms in the present disclosure according to actual situations.

[0019] In the description of the specification, the features, structures, materials, or special features in any one or more embodiments or examples may be combined in any suitable manner.

[0020] As society pays more and more attention to environmental protection, the exhaust gases of diesel engines contain a variety of environmentally harmful substances such as carbon monoxide (CO), hydrocarbons (HC), nitrogen oxide compounds (NOx), sulfur dioxide (SO2), carbon smoke particles, aldehydes and the like, vehicle emission regulations place increasingly strict requirements on the exhaust emissions of diesel vehicles.

[0021] In order to purify the exhaust gas emitted from a diesel engine so that the exhaust gas emitted from a diesel vehicle can meet the requirements of the emission regulations, embodiments of the present disclosure provide a vehicle, the vehicle having an aftertreatment system that can be connected to an exhaust outlet of the engine and can be used to purify the exhaust gases and to effectively remove harmful substances from the engine exhaust gases so that the exhaust gases emitted from the vehicle can meet the requirements of the emission regulations of the vehicle.

[0022] Since the harmful emissions in diesel engine exhaust are primarily nitrogen oxides (NOx), the aftertreatment system can usually clean up nitrogen oxide compounds. Among some technologies, the aftertreatment system typically uses SCR (Selective Catalytic Reduction) technology to treat nitrogen oxide compounds in the exhaust.

[0023] It should be noted that SCR is a treatment technology for NOx, i.e. under the action of a catalyst, the reducing agent ammonia or urea is injected into the NOx-containing gas and NOx can be reduced to nitrogen (N2) and water (H2O).

[0024] The catalysts used in the above-mentioned SCR generally use titanium dioxide (TiO2) as the base material, vanadium pentoxide (V2O5) as the main active component and tungsten trioxide (WO3) or molybdenum trioxide (MoO3) as the promoter.

[0025] When the aftertreatment system in some technologies uses selective catalytic reduction technology to reduce nitrogen oxide compounds in the exhaust gas, the aftertreatment system generally includes a mixer and a selective catalytic reduction device. A mixing chamber is formed inside the mixer, and a first opening and a second opening are provided that communicate with the mixing chamber. A catalytic space is formed inside the selective catalytic reduction device, and the catalyst is provided with a third opening and a fourth opening that communicate with the catalytic space, the third opening communicating with the second opening.

[0026] The mixing chamber can be used to spray urea solution. The first opening can be used to connect to an engine exhaust outlet. This allows the exhaust gas escaping from the engine to enter the mixing chamber through the first opening.

[0027] Because the temperature of the exhaust gas emitted by the engine is relatively high, the exhaust gas entering the mixing chamber can create a higher-temperature environment within the mixing chamber. This allows the urea solution in the mixing chamber to evaporate and decompose into reducing gas.

[0028] After the reducing gas and the exhaust gas are mixed, the mixed gas can enter the catalytic chamber through the second orifice and the third orifice. At this time, the mixed gas contains ammonia gas, nitrogen oxide compounds (e.g., nitrogen oxide, nitrogen dioxide), and the like.

[0029] The catalytic chamber can be used to accommodate a catalyst. Under the action of the catalyst, ammonia gas and nitrogen oxide compounds (such as nitrogen oxide and nitrogen dioxide) in the mixed gas can undergo a selective catalytic reduction reaction to produce clean nitrogen and water. At this point, the nitrogen oxide compounds in the exhaust gas can be purified by the after-treatment system. During the exhaust gas purification process in the after-treatment system, the urea solution must be sprayed into the mixing chamber of the mixer, and the urea solution evaporates and decomposes in the mixing chamber to form reducing gas. Since the evaporation and decomposition of the aqueous urea solution requires energy absorption, the higher the ambient temperature in the mixing chamber, the better it can meet the evaporation and decomposition conditions of the urea solution.

[0030] To prevent the mixer from dissipating heat, some technologies generally surround the outside of the mixer with a heat-retaining layer. For example, the heat-retaining layer is made of heat-retaining cotton. The heat-retaining layer can effectively prevent heat loss from the mixer, helping to maintain the temperature inside the mixer within a certain range, which has a positive effect on the evaporation and decomposition of the urea solution in the mixing chamber.

[0031] However, during the evaporation and decomposition process in the mixing chamber, the urea solution absorbs the heat in the mixing chamber, and the heat retention layer can only prevent the mixer from dissipating heat and cannot replenish the heat in the mixing chamber, and the ambient temperature in the mixer will still fluctuate greatly, and the evaporation and decomposition effect of the urea solution in the mixing chamber is still poor.

[0032] On this basis, embodiments of the present disclosure provide an aftertreatment system. As shown in the Fig. 1 and Fig. 2, is Fig. 1 is a first schematic diagram of an aftertreatment system according to some embodiments of the present disclosure, Fig. 2 is a sectional view along AA in Fig. 1, wherein the aftertreatment system 100 may include a heat holding box 1, a mixer 2 and a catalyst 3.

[0033] A heat-retaining space 11 is formed in the heat-retaining box 1, and the heat-retaining box 1 is provided with an air inlet and an air outlet 12 (not shown in the figure) which are in communication with the heat-retaining space 11.

[0034] The mixer 2 is arranged in the heat-retaining chamber 11, and a mixing chamber 21 is formed in the mixer 2. The mixer is provided with a first inlet (not shown in the figure) and a first outlet (not shown in the figure) that communicate with the mixing chamber 21. The first inlet communicates with the air inlet.

[0035] The exhaust gas can enter the mixing chamber 21 of the mixer 2 through the air inlet and the first inlet. The urea solution can be sprayed into the mixing chamber 21. Since the temperature of the exhaust gas is relatively high, the exhaust gas entering the mixing chamber 21 can create a higher-temperature environment in the mixing chamber 21. In this way, the urea solution in the mixing chamber 21 can evaporate and decompose into reducing gas. The reducing gas and the exhaust gas are mixed in the mixing chamber 21 to form a mixed gas. At this time, the mixed gas contains ammonia gas and nitrogen oxide compounds (e.g., nitrogen oxide, nitrogen dioxide, etc.).

[0036] It should be noted that the mixer 2 is also provided with a spray opening (not shown in the figure) communicating with the mixing chamber 21 for spraying the urea solution into the mixing chamber 21. The aftertreatment system 100 may also include a sprayer (not shown in the figure) arranged outside the mixer 2 and opposite the spray opening. The sprayer may be used to hold the urea solution and may spray the urea solution through the spray opening into the mixing chamber 21.

[0037] With further reference to Fig. 2, the catalyst 3 is arranged in the heat-retaining space 11, and a catalytic space 31 is formed inside the catalyst 3. The catalyst 3 is provided with a second inlet (not shown in the figure) and a second outlet (not shown in the figure) communicating with the catalytic space 31. The second inlet communicates with the first outlet (not shown in the figure), and the second outlet communicates with the heat-retaining space 11.

[0038] The mixed gas in the mixing chamber 21 can enter the catalytic chamber 31 through the first outlet and the second inlet. A catalyst can also be placed in the catalytic chamber 31, which can play a catalytic role, accelerating the selective catalytic reduction reaction between ammonia gas and nitrogen oxide compounds in the exhaust gas, thus producing clean nitrogen and water.

[0039] It should be noted that the catalyst placed in the above-mentioned catalytic space 31 generally consists of titanium dioxide (TiO2) as the base material, vanadium pentoxide (V2O5) as the main active component, tungsten trioxide (WO3) or molybdenum trioxide (MoO3) as the promoter.

[0040] At this point, the aftertreatment system 100 provided by the embodiments of the present disclosure can achieve the treatment of nitrogen oxide compounds in the exhaust gas by selective catalytic reduction technology under the action of the mixer 2 and the catalyst 3.

[0041] It should be noted that the urea solution must absorb sufficient heat to evaporate and decompose into ammonia gas, and the reducing gas generated by the evaporation and decomposition of the urea solution in the mixing chamber 21 is small. As the mixed gas flows to the catalyst 3, the reducing gas absorbs heat and gradually decomposes into more ammonia gas until the mixed gas flows into the catalytic space 31, and a large amount of ammonia gas is present in the mixed gas.

[0042] Since the second outlet is connected to the heat-retaining chamber 11, the high-temperature gas in the catalytic chamber 31 can be discharged into the heat-retaining chamber 11 through the second outlet. Since the mixer 2 is arranged in the heat-retaining chamber 11, the high-temperature gas in the heat-retaining chamber 11 can surround the mixer 2.

[0043] During the process of evaporation and decomposition of the urea solution by absorbing heat in the mixing chamber 21, heat transfer can occur between the high-temperature gas in the heat-holding space 11 and the mixer 2, whereby heat can be transferred to the mixing chamber 21, so that the evaporation and decomposition rate of the urea solution in the mixing chamber 21 is faster, and thus the urea solution in turn evaporates and decomposes more thoroughly in the mixing chamber 21, effectively reducing the risk of crystallization of the urea solution in the mixing chamber 21 and improving the mixing efficiency of the mixer 2. As shown in Fig. 3, is in some embodiments Fig. 3 shows a second schematic diagram of the aftertreatment system 100 according to some embodiments of the present disclosure, wherein the heat retention box 1 may include a top wall 13, a bottom wall 14, and a side wall 15. The bottom wall 14 is opposite the top wall 13 and spaced therefrom. The side wall 15 is annular and is arranged between the top wall 13 and the bottom wall 14 and, together with the top wall 13 and the bottom wall 14, encloses the heat retention space 11 (as in Fig. 2).

[0044] As in Fig. 4 shown, is Fig. 4 is a partial schematic diagram of the aftertreatment system 100 provided by embodiments of the present disclosure, wherein the mixer 2 and the catalyst 3 both extend in a direction perpendicular to the bottom wall 14. The second outlet 32 ​​is arranged towards the bottom wall 14. The air outlet 12 (shown in Fig. 3) is on the upper wall 13 (shown in Fig. 3) or the side wall 15 (shown in Fig. 3). Along the direction perpendicular to the bottom wall 14, the second outlet 32 ​​and the air outlet 12 are located at different heights.

[0045] In this way, the high-temperature gas can flow along the extension direction of the mixer 2 while flowing to the air outlet 12 after the purified high-temperature gas discharged from the second outlet 32 ​​is discharged into the heat-retaining space 11. Therefore, the heat exchange time between the high-temperature exhaust gas and the mixer 2 is relatively long, allowing more heat to be transferred into the mixing chamber 21, thereby further improving the evaporation and decomposition effect of the urea solution in the mixing chamber 21.

[0046] The opening position of the air outlet 12 is not restricted, and for example, the air outlet 12, as shown in Fig. 3, on the side wall 15. The direction of the second inlet can be adjusted according to the actual situation. For example, the second inlet can be provided toward the top wall 13.

[0047] The shape of the mixer 2 can be adjusted according to the actual situation, for example the mixer 2 as shown in Fig. 4, has a mixing side wall 22, wherein the mixing side wall 22 is annular and the mixing chamber 21 (as in Fig. 2) with the first inlet (not shown in the figure) and the first outlet (not shown in the figure). On this basis, in order to facilitate the connection between the first inlet and the air inlet (not shown in the figure), the first inlet can be arranged towards the bottom wall 14, and the first outlet can be arranged towards the top wall 13. The air inlet can be provided on the bottom wall 14. One end of the mixing side wall 22 with the first inlet is connected to the bottom wall 14, and the first inlet is opposite the air inlet.

[0048] In this way, after the mixing side wall 22 is connected to the bottom wall 14, the first inlet can be directly connected to the air inlet on the bottom wall 14, and there is no need to use other connecting pipes between the first inlet and the air inlet, which makes the communication between the two more convenient and makes the structure of the aftertreatment system 100 easier.

[0049] The direction of the first outlet can be adjusted according to the actual situation. For example, the first outlet can be directed toward the top wall 13.

[0050] It will be understood that when the first outlet and the second inlet are both arranged towards the top wall 13, the aftertreatment system 100, in order to achieve communication between the first outlet and the second inlet, further referring to Fig. 4 may also comprise a first communication element 4, wherein the first communication element 4 is arranged on the top wall 13 and, together with the top wall 13, encloses a first communication chamber (not shown in the figure). The first outlet (not shown in the figure) and the second inlet (not shown in the figure) are both connected to the first communication chamber. In this way, the first outlet and the second inlet are connected under the communication function of the first communication element 4.

[0051] With further reference to Fig. 4, the catalyst 3 may, in some embodiments, comprise a main body 33 and a plurality of connecting portions 34. The main body 33 has a main body side wall 331. The main body side wall 331 is annular and encloses the catalytic space 31 with the second inlet (not shown in the figure) and the second outlet 32 ​​(as in Fig. 2). The main body side wall 331 is connected to the upper wall 13. The plurality of connecting portions 34 are located on a side of the main body side wall 331 facing the lower wall 14, and the plurality of connecting portions 34 are spaced apart from each other along the circumferential direction of the second outlet 32. One end of the connecting portion 34 is connected to the main body side wall 331, and the other end is connected to the lower wall 14. An air distribution opening 341 is formed between two adjacent connecting portions 34. The gas in the catalytic space 31 can be discharged into the heat-retaining space 11 through the second outlet 32 ​​and the air distribution opening 341 between two adjacent connecting portions 34.

[0052] The main body 33 is connected to the upper wall 13 and the connecting portion 34 is connected to the lower wall 14, that is, the catalyst 3 is connected to both the upper wall 13 and the lower wall 14, and the connection between the catalyst 3 and the heat-retaining box 1 is stronger, and the positional stability of the catalyst 3 in the heat-retaining space 11 is higher, so that the aftertreatment system 100 has higher reliability in use.

[0053] The number of connecting sections 34 can be adjusted according to the actual conditions. For example, the number of connecting sections 34 is two.

[0054] The connection position between the main body side wall 331 and the top wall 13 is not limited here. For example, the position between the second inlet and the second outlet 32 ​​in the main body side wall 331 is connected to the top wall 13. At this time, the catalytic converter 3 may also include a fixing portion located between the second inlet and the second outlet 32 ​​and located outside the catalytic space 31, which is connected to the main body side wall 331, and the fixing portion is connected to the top wall 13. In this way, the position between the second inlet and the second outlet 32 ​​in the main body side wall 331 is connected to the top wall 13 by the fixing portion.

[0055] To achieve a connection between the first outlet and the second inlet in this case, the first communication element 4 is arranged on the side of the upper wall 13 facing the lower wall 14 and, together with the upper wall 13, encloses a first communication chamber. Both the first outlet and the second inlet communicate with the first communication chamber. In this way, the first outlet and the second inlet can be easily connected to one another under the action of the first communication element.

[0056] Of course, the end of the main body side wall 331 with the second inlet can also be connected to the top wall 13. In this case, in order to enable the communication of the first outlet with the second inlet, the first communication element 4, as shown in Fig. 4, on the side of the upper wall 13 facing away from the lower wall 14. The upper wall 13 is provided with a first communication port (not shown in the figure) and a second communication port (not shown in the figure) communicating with the first communication chamber (not shown in the figure). The first communication port communicates with the first outlet (not shown in the figure), and the second communication port communicates with the second inlet (not shown in the figure).In this way, by arranging the first communication element 4 outside the heat-retaining box 1 and connecting the first outlet to the first communication chamber in the first communication element 4 via the first communication port, the second inlet will be in communication with the first communication chamber in the first communication element 4 via the second communication port, wherein the first outlet and the second inlet can be connected to each other via the first communication chamber.Based on the above-mentioned situation that the first communication element 4 is covered on the side of the top wall 13 facing away from the bottom wall 14 to facilitate communication between the first communication port and the first outlet, one end of the mixing side wall 22 having the first outlet is connected to the top wall 13, and the first outlet and the first communication port are arranged opposite each other. In this way, after the mixing side wall 22 is connected to the top wall 13, the first outlet can communicate with the first communication port on the top wall 13, eliminating the need for other connecting lines to communicate between the first outlet and the first communication port, thereby making the connection between the two more convenient and simplifying the structure of the aftertreatment system 100.

[0057] Of course, in some other embodiments, the catalytic converter 3 comprises only the main body 33. At this time, a gap exists between the second outlet 32 ​​on the main body 33 and the bottom wall 14, and the exhaust gas discharged from the second outlet 32 ​​can be discharged from the gap into the heat-retaining space 11. In this case, the structure of the catalytic converter 3 is relatively simple, and the processing effort is low.

[0058] With further reference to Fig. 4, in some embodiments, the connecting portion 34 includes a vent hole 342. The vent hole 342 is an escape through-hole used to circulate the gas exiting the second outlet 32.In this way, the gas discharged from the second outlet 32 ​​can be discharged not only via the air distribution opening 341 between two adjacent connecting sections 34, but also via the vent hole 342 at connecting sections 34, so that the high-temperature gas discharged from the second outlet 32 ​​can be blown toward the heat-retaining space 11 from different directions, effectively ensuring that each position in the heat-retaining space 11 has a higher temperature, and thus further ensuring that all positions of the heat-retaining space 11 can supply sufficient heat to the mixer 2, further ensuring that the urea solution in the mixer 2 can completely evaporate and decompose.

[0059] The number of vent holes 342 provided in each connecting portion 34 can be adjusted according to actual conditions. For example, four vent holes 342 may be provided in each connecting portion 34.

[0060] With further reference to Fig. 4, in some embodiments, the vent holes 342 are arranged on at least one connecting section 34 in the direction of the mixer 2. In this way, the high-temperature gas exiting the vent hole 342 can be blown directly to the mixer 2, further ensuring that the urea solution in the mixer 2 can be completely evaporated and decomposed.

[0061] In some embodiments, the number of catalysts 3 is multiple, and the second inlets (not shown in the figure) of the plurality of catalysts 3 are all communicated with the first outlet (not shown in the figure). In this way, the exhaust gas discharged from the first outlet of the mixer 2 can be distributed among a plurality of catalysts 3 and then discharged from the plurality of catalysts 3 into the heat-retaining space 11, so that the refresh rate of the exhaust gas in the heat-retaining space 11 becomes faster, thereby ensuring a higher temperature in the heat-retaining space 11.

[0062] Furthermore, by providing multiple catalysts 3, the exhaust gas encounters less resistance when flowing in the aftertreatment system 100, effectively reducing the exhaust backpressure of the aftertreatment system 100 and reducing engine fuel consumption.

[0063] It should be noted that when the number of catalysts 3 is multiple and the end of the main body side wall 331 having the second inlet is connected to the top wall 13, the number of second communication ports provided on the top wall 13 is also multiple, with one second communication port communicating with the second inlet, that is, a plurality of second communication ports are communicated with the second inlets on the plurality of catalysts 3, respectively.

[0064] The number of catalysts 3 is not limited here and can be adjusted according to the actual needs and the capacity of the heat-holding chamber 11. For example, the number of catalysts 3 is two. At this time, the number of second communication ports on the top wall 13 is also set to two.

[0065] To filter ash and soot in the exhaust gas, as in Fig. 5, is in some embodiments Fig. 5 shows a third schematic diagram of the aftertreatment system 100 according to some embodiments of the present disclosure, wherein the aftertreatment system 100 may also include a particulate filter 5, wherein the particulate filter 5 is located between the bottom wall 14 and the top wall 13, and the particulate filter 5 is located outside the heat retention space 11 (as in Fig. 2) and is connected to the heat-retaining box 1. The particle filter 5 forms a filter chamber 51 (as shown in Fig. 2) with a third inlet (not shown in the figure) and a third outlet (not shown in the figure), the third outlet being connected to the air inlet (not shown in the figure).

[0066] The third inlet allows the exhaust gas to enter the filter chamber 51. The particulate filter 5 can filter the ash and soot in the exhaust gas, thereby removing the ash and soot in the exhaust gas that enters the filter chamber 51. The exhaust gas, freed of ash and soot, can enter the mixer 2 through the third outlet and the air inlet.

[0067] The particulate filter 5 must be maintained at regular intervals, and by disposing the particulate filter 5 outside the heat-retaining room 11, there is no need to enter the heat-retaining room 11 when personnel perform maintenance on the particulate filter 5, and the maintenance or repair can be performed outside the heat-retaining room 11, thereby reducing the difficulty of maintaining the particulate filter 5 in the later period.

[0068] In some embodiments, it is provided that the upper wall 13 is also provided with a third communication port (not shown in the figure), and the lower wall 14 is also provided with a fourth communication port (not shown in the figure). With further reference to Fig. 5, the particulate filter 5 extends in a direction perpendicular to the lower wall 14, with the third inlet (not shown in the figure) arranged toward the upper wall 13, and the third outlet (not shown in the figure) arranged toward the lower wall 14. One end of the particulate filter 5 with a third inlet is connected to the upper wall 13, and the third inlet is opposite the third communication port. One end of the particulate filter 5 with a third outlet is connected to the lower wall 14, and the third outlet and the fourth communication port are arranged opposite each other.

[0069] The aftertreatment system 100 may also include a second communication element 6, wherein the second communication element 6 is located on the side of the lower wall 14 facing away from the upper wall 13 and, together with the lower wall 14, encloses a second communication chamber (not shown in the figure). Both the fourth communication port and the air inlet (not shown in the figure) are connected to the second communication chamber.

[0070] In this way, the exhaust gas with the ash and soot removed by the particulate filter 5 can enter the second communication chamber of the second communication element 6 through the third outlet and the fourth communication port and then enter the mixer 2 through the air inlet.

[0071] The second communication element 6 is provided on the side of the lower wall 14 facing away from the upper wall 13, wherein the second communication element 6 does not occupy the space between the upper wall 13 and the lower wall 14, whereby the volume of the heat retention space 11 can be set larger and thus more catalysts 3 can be installed in the heat retention space 11, wherein the exhaust back pressure of the aftertreatment system 100 is reduced more effectively and the fuel consumption of the engine is further reduced.

[0072] Of course, in other embodiments, the third outlet of the particulate filter 5 is arranged toward the bottom wall 14, and a certain gap exists between the third outlet and the bottom wall 14. The air inlet is provided on the side wall 15 and connected to the first inlet. The aftertreatment system 100 may also include a communication pipe (not shown in the figure) located between the top wall 13 and the bottom wall 14, with one end connected to the air inlet and the other end connected to the third outlet. At this time, the exhaust gas from which ash and soot have been removed by the particulate filter 5 can enter the mixer 2 through the third outlet, the connecting pipe, and the air inlet.

[0073] In order to further facilitate the subsequent maintenance of the particle filter 5 for the user, in some embodiments, as in Fig. 6 shown, Fig. 6 shows a fourth schematic diagram of the aftertreatment system 100 according to some embodiments of the present disclosure, wherein the particulate filter 5 is detachably connected to the bottom wall 14 and the top wall 13. In this way, when the particulate filter 5 needs to be serviced later, the user can disassemble the particulate filter 5 from the bottom wall 14 and the top wall 13, thus allowing the particulate filter 5 to be serviced more conveniently.

[0074] To remove hydrocarbons (HC) in the exhaust gas, the aftertreatment system 100 may, in some embodiments, as shown in Fig. 4, may also include an oxidation catalyst 7 (diesel oxidation catalyst, DOC). The oxidation catalyst 7 is located on the side of the upper wall 13 facing away from the lower wall 14 and is connected to the upper wall 13. An oxidation chamber (not shown in the figure) is formed in the oxidation catalyst 7, and a fourth inlet (not shown in the figure) and a fourth outlet (not shown in the figure) connected to the oxidation chamber are provided. The fourth outlet is connected to the third communication port (not shown in the figure).

[0075] Through the fourth inlet, the exhaust gas can enter the oxidation chamber of the oxidation catalyst 7. The oxidation catalyst 7 can oxidize the hydrocarbons in the exhaust gas and thereby remove the hydrocarbons in the exhaust gas.

[0076] The exhaust gas freed from hydrocarbons can enter the particulate filter 5 through the fourth outlet, the third communication port and the third inlet.

[0077] As in Fig. 7, is in some embodiments Fig. 7 shows a fifth schematic diagram of the aftertreatment system 100 according to some embodiments of the present disclosure. The aftertreatment system 100 may also include a gas collection hood 8, wherein the gas collection hood 8 is located on the side defined by the bottom wall 14 (in Fig. 6) opposite side of the upper wall 13 (in Fig. 6) and encloses a gas collection chamber (not shown in the figure) with the upper wall 13. The oxidation catalyst 7 (in Fig. 4) and the first communication element 4 (in Fig. 4) are both located in the gas collection chamber, and the fourth inlet (not shown in the figure) is connected to the gas collection chamber. The gas collection hood 8 is provided with an exhaust gas inlet 81 that communicates with the gas collection chamber.

[0078] In this way, as in Fig. 8, which is a sectional view at BB in Fig. 7, the exhaust gas from the exhaust inlet 81 (shown in Fig. 7) enter the gas collection chamber 82. Since the fourth inlet (not shown in the figure) is connected to the gas collection chamber 82, the exhaust gas in the gas collection chamber 82 can enter the oxidation catalyst 7 through the fourth inlet.

[0079] Since the first communication element 4 is located in the gas collection chamber 82, the high-temperature exhaust gas filled in the gas collection chamber 82 can surround the first communication element 4, so that the first communication chamber 41 also has a higher temperature, and thus the urea solution can in turn also evaporate and decompose in the first communication chamber 41 to form ammonia gas, which further improves the evaporation and decomposition effect of the urea solution.

[0080] The above only illustrates specific embodiments of the present disclosure, but the scope of the present disclosure is not limited thereto. Anyone familiar with the technical field can easily imagine modifications or substitutions within the technical scope disclosed in the present disclosure, and these should be covered by the scope of the present disclosure. Therefore, the scope of the present disclosure should be subject to the scope of the claims. Reference symbol: 100 aftertreatment system 1 heat-retaining box 2 mixers 3 Catalyst 4 First communication element 5 particle filters 6 Second communication element 7 Oxidation catalyst 8 Gas collection hood 11 Heat retention room 12 Air outlet 13 Upper wall 14 Lower wall 15 Side wall 21 Mixing chamber 22 Mixing side wall 31 catalytic space 32 Second outlet 33 main bodies 34 connecting section 331 Main body side wall 341 Air distribution opening 342 vent hole 51 Filter chamber 81 Exhaust inlet 82 Gas collection chamber 41 First Communications Chamber

Claims

[1] Aftertreatment system comprising: a heat-retaining box in which a heat-retaining space is formed, and wherein the heat-retaining box is provided with an air inlet and an air outlet communicating with the heat-retaining space; a mixer arranged in the heat-retaining space, wherein a mixing chamber is formed in the mixer, and wherein the mixer is provided with a first inlet and a first outlet communicating with the mixing chamber, the first inlet communicating with the air inlet; and a catalyst disposed in the heat retention space, wherein a catalytic space is formed in the catalyst, and wherein the catalyst is provided with a second inlet and a second outlet communicating with the catalytic space, the second inlet communicating with the first outlet, the second outlet communicating with the heat retention space. [2] The aftertreatment system of claim 1, wherein the heat retention box comprises: an upper wall; a lower wall opposite and spaced from the upper wall; and a side wall which is annular and arranged between the top wall and the bottom wall and which, together with the top wall and the bottom wall, encloses the heat-retaining space; wherein the mixer and the catalyst both extend in a direction perpendicular to the bottom wall; wherein the second outlet is arranged towards the bottom wall; wherein the air outlet is provided on the top wall or the side wall; wherein along the direction perpendicular to the bottom wall, the second outlet and the air outlet are at different heights. [3] Aftertreatment system according to claim 2, the catalyst comprises: a main body having a main body side wall; wherein the main body side wall is annular and encloses the catalytic space with the second inlet and the second outlet; wherein the main body side wall is connected to the top wall; and a plurality of connecting portions disposed on the side of the main body side wall facing the bottom wall, the plurality of connecting portions being provided spaced apart along the circumferential direction of the second outlet; one end of the connecting portion being connected to the main body side wall and the other end of the connecting portion being connected to the bottom wall; an air distribution opening being formed between two adjacent connecting portions. [4] The aftertreatment system according to claim 3, wherein the connecting portion has a vent hole; wherein the vent hole is an alternate through-hole used to circulate the gas exiting from the second outlet. [5] Aftertreatment system according to claim 4, wherein the vent hole is arranged at at least one connecting portion towards the mixer. [6] The aftertreatment system of claim 2, wherein the catalyst is provided in a plurality; wherein the second inlets of the plurality of catalysts are all in communication with the first outlet. [7] Aftertreatment system according to claim 6, further comprising: a first communication element arranged on the top wall and enclosing a first communication chamber with the top wall; wherein the first outlet and the plurality of second inlets are all in communication with the first communication chamber. [8] The aftertreatment system of claim 7, wherein the first communication element is mounted on a side of the top wall remote from the bottom wall; wherein a first communication port and a plurality of second communication ports are provided on the top wall and are in communication with the first communication chamber; wherein the first communication port is connected to the first outlet; wherein one of the second communication ports is in communication with the second inlet. [9] Aftertreatment system according to claim 2, further comprising: a particulate filter located between the bottom wall and the top wall and outside the heat-retaining space and connected to the heat-retaining box; wherein the particulate filter forms a filter chamber having a third inlet and a third outlet, the third outlet being in communication with the air inlet.

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