Mixer and exhaust system comprising same

Abstract

The utility model relates to a mixer and an exhaust system. Wherein the mixer comprises an air inlet pipe part; the air inlet pipe and the air outlet pipe are arranged in a non-coaxial mode; the cover body is used for limiting a flowing path of exhaust gas from the gas inlet pipe part to the gas outlet pipe part and limiting a mixing space for mixing the exhaust gas and a reducing agent, the cover body comprises a gas inlet part, a gas outlet part and a middle channel part, and the gas inlet part and the gas outlet part are communicated through the middle channel part; the air inlet part is directly connected with the air inlet pipe part; the air outlet part is directly connected with the air outlet pipe part; wherein the middle channel portion of the cover body is provided with an inner wall face, a heat preservation block is arranged on the inner wall face, and the length direction of the heat preservation block extends in the extending direction of the middle channel portion.

Description

Technical Field

[0001] The present application relates to a mixer and an exhaust system including the same. Background Art

[0002] The exhaust system processes the hot exhaust gas generated by the internal combustion engine through various upstream exhaust components to reduce the emission of pollutants. The various upstream exhaust components may include one or more of the following components: pipes, filters, valves, catalysts, mufflers, etc.

[0003] For example, the upstream exhaust component guides the exhaust gas into an exhaust component having an inlet and an outlet and having a diesel oxidation catalyst (DOC) as an exhaust functional part. Downstream of the diesel oxidation catalyst, an exhaust component having a diesel particulate filter (DPF) as an exhaust functional part may be provided. Downstream of the diesel oxidation catalyst and the optional diesel particulate filter is a selective catalytic reduction reactor (SCR) having an inlet and an outlet. The outlet passes the exhaust gas to the downstream exhaust component. The mixer is generally positioned at the outlet of the DOC or downstream of the DPF and upstream of the inlet of the SCR. In the mixer, the exhaust gas is fully mixed with a reducing agent such as a urea aqueous solution injected into the mixer, and discharged to the SCR for a reduction reaction to generate nitrogen and water, so as to reduce the nitrogen oxide emissions of the engine.

[0004] In the mixer, the urea spray injected from the dosing device must be protected from urea crystallization to avoid affecting the mixer's mixing performance and nitrogen oxide treatment performance. This is especially important when the exhaust gas temperature is low.

[0005] In this regard, in existing solutions, it is generally necessary to provide a thicker layer of heat-insulating material on the outer wall of the mixer to ensure sufficient exhaust gas temperature to reduce urea crystallization.

[0006] However, the inventors have found that using a thicker layer of thermal insulation material will increase the size of the mixer and the exhaust system, which is not conducive to the spatial arrangement of the mixer and the exhaust system in vehicles and other occasions.

[0007] Therefore, there is a need in the art for a new mixer and an exhaust system including the same, so as to achieve good thermal insulation performance and reduce crystallization, and make the mixer and the exhaust system easily adaptable to various installation spaces. Utility Model Content

[0008] An object of the present application is to provide a mixer.

[0009] Another object of the present application is to provide an exhaust system.

[0010] A mixer according to one aspect of the present application includes an air inlet pipe portion; an air outlet pipe portion, wherein the air inlet pipe and the air outlet pipe are arranged non-coaxially; and a cover body, wherein the cover body defines a flow path of exhaust gas from the air inlet pipe portion to the air outlet pipe portion, and defines a mixing space for mixing exhaust gas and a reducing agent, the cover body includes an air inlet portion, an air outlet portion and an intermediate channel portion, the air inlet portion and the air outlet portion are connected through the intermediate channel portion; the air inlet portion is directly connected to the air inlet pipe portion; the air outlet portion is directly connected to the air outlet pipe portion; wherein the intermediate channel portion of the cover body has an inner wall surface, on which an insulation block is provided, and the length direction of the insulation block extends along the extension direction of the intermediate channel portion.

[0011] In one or more embodiments of the mixer, an injector mounting seat is provided on the side wall of the air inlet portion of the cover body, and the injector mounting seat defines the injection direction of the injector; and along the injection direction, the protruding height of the insulation block protruding from the inner wall surface increases.

[0012] In one or more embodiments of the mixer, the only communication channel fluidically connecting the air inlet and the air outlet is the middle channel portion; or most of the flow area fluidly connecting the air inlet and the air outlet is provided by the middle channel portion.

[0013] In one or more embodiments of the mixer, one end of the air inlet pipe is connected to the air inlet of the cover, so that the air inlet is directly connected to the air inlet pipe, wherein a first insulation ring is provided on the inner wall surface of one end of the air inlet pipe.

[0014] In one or more embodiments of the mixer, the air inlet pipe portion is provided with a temperature sensor and / or a pressure sensor, the first thermal insulation ring is arranged at a position adjacent to the temperature sensor and / or pressure sensor in the axial direction, or the first thermal insulation ring is partially annular, and the temperature sensor and / or pressure sensor is arranged in a notch of the partial ring.

[0015] In one or more embodiments of the mixer, one end of the air outlet pipe is connected to the air outlet portion of the cover body, so that the air outlet portion is directly connected to the air outlet pipe, wherein a second insulation ring is provided on the inner wall surface of one end of the air outlet pipe.

[0016] In one or more embodiments of the mixer, the insulation block, the first insulation ring, and the second insulation ring are made of metal, and the surface of the insulation block is smooth; the insulation block is welded to the inner wall surface of the middle channel portion of the cover body, the first insulation ring is welded to the inner wall surface of one end of the air inlet pipe portion, and the second insulation ring is welded to the inner wall surface of one end of the air outlet pipe portion.

[0017] In one or more embodiments of the mixer, the outer wall of the mixer is provided with a thermal insulation material layer, and the minimum thickness of the thermal insulation material layer is 8 mm to 10 mm, wherein the minimum thickness of the thermal insulation material layer corresponding to the outer wall of the air inlet pipe portion and the minimum thickness of the thermal insulation material layer corresponding to the outer wall of the air outlet pipe portion are 8 mm, and the minimum thickness of the thermal insulation material layer corresponding to the outer wall of the cover body is 10 mm.

[0018] According to one aspect of the present application, an exhaust system includes the mixer as described in the first aspect, and an injector, wherein the injector is mounted on an injector mounting seat and injects a reductant into the mixer to form a reductant spray, so that the exhaust gas and the reductant spray form a mixed airflow.

[0019] In one or more embodiments of the exhaust system, the reducing agent liquid is a urea solution, and the exhaust system includes a first part, a second part and the mixer, the first part is connected to the intake pipe part of the mixer, the second part is connected to the outlet pipe part of the mixer, and the first part, the second part and the mixer constitute a U-shaped exhaust after-treatment system.

[0020] The improved effects of the embodiments introduced above include but are not limited to: by arranging an insulation block on the inner wall surface of the middle channel portion of the cover body of the mixer, and / or arranging a second insulation ring on the inner wall surface of one end of the air inlet pipe portion, and / or arranging a second insulation ring on the inner wall surface of one end of the air outlet pipe portion, the insulation performance of the mixer is improved, and the thickness of the insulation material layer is reduced on the basis of reducing crystallization with good insulation performance, so that the mixer and the exhaust system are easy to adapt to various installation spaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other features, properties and advantages of the present application will become more apparent through the following description in conjunction with the accompanying drawings and embodiments. It should be noted that the drawings are only for illustration and are not drawn to scale, and should not be used to limit the actual scope of protection claimed in this application. Among them:

[0022] Figure 1 It is a schematic structural diagram of an exhaust system according to an embodiment.

[0023] Figure 2 It is a structural diagram of a mixer of a comparative scheme.

[0024] Figure 3 1 is a schematic structural diagram of a mixer according to an embodiment.

[0025] Figure 4 It is a structural schematic diagram of a cover body of a mixer according to an embodiment.

[0026] Figure 5 It is a schematic structural diagram of the air intake pipe portion of a mixer according to an embodiment.

[0027] Figure 6 It is a schematic structural diagram of the air outlet pipe portion of a mixer according to one embodiment.

[0028] Figure 7 This is a schematic structural block diagram of an internal combustion engine device according to an embodiment.

[0029] Reference numerals:

[0030] 1000-Internal combustion engine equipment

[0031] 100-Exhaust system

[0032] 101-Part 1

[0033] 102-Part 2

[0034] 200-internal combustion engine

[0035] 10,10a-Mixer

[0036] 1-Intake pipe

[0037] 11-One end of the intake pipe

[0038] 110-Axis of the intake pipe

[0039] 111-Inner wall surface of one end of the intake pipe

[0040] 12-First insulation ring

[0041] 121-Gap

[0042] 2- Exhaust pipe

[0043] 21-One end of the exhaust pipe

[0044] 210-Axis of the exhaust pipe

[0045] 211-Inner wall surface of one end of the air outlet pipe

[0046] 22-Second insulation ring

[0047] 3- Cover

[0048] 31-Intake

[0049] 32- Exhaust

[0050] 33-Middle channel

[0051] 331-Inner wall of the middle channel

[0052] 34-Injector Mount

[0053] D1-Spray direction

[0054] H-protrusion height

[0055] 4-Insulation block

[0056] 51-Temperature sensor

[0057] 52-Pressure sensor

[0058] 20-Ejector. DETAILED DESCRIPTION

[0059] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0061] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0062] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0063] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0064] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "install", "connect", "connect", "fix" and so on should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can also be a mechanical connection. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0065] According to some embodiments of the present application, reference Figure 7 As shown, the present application also provides an internal combustion engine device 1000, including an exhaust system 100, which will be described in detail in the following embodiments, and an internal combustion engine 200, wherein the exhaust system 100 is used to process the exhaust gas generated by the internal combustion engine 200.

[0066] The internal combustion engine equipment 1000 includes but is not limited to vehicles that use internal combustion engines as power, such as vehicles, including passenger cars, commercial vehicles, construction machinery, agricultural machinery, rail transit trains, etc. The vehicles can also be, for example, ships and aircraft powered by internal combustion engines. The internal combustion engine equipment also includes power generation systems that use internal combustion engines as power, such as diesel generator systems and biogas generator sets of biogas power stations. In order to meet the requirements of relevant emission regulations for vehicles and power generation systems, an exhaust system is used to treat the exhaust generated by the internal combustion engines of the vehicles and power generation systems.

[0067] refer to Figure 1 As shown, in some embodiments, the exhaust system 100 may include a first portion 101, a second portion 102, and a mixer 10, which will be described in detail in the following embodiments. The first portion 101 is connected to the inlet pipe portion 1 of the mixer, and the second portion 102 is connected to the outlet pipe portion 2 of the mixer. The first portion 1, the second portion 2, and the mixer 10 form a U-shaped exhaust aftertreatment system.

[0068] The first part 101 can be a diesel oxidation catalyst (DOC) or a diesel particulate filter (DPF). The diesel oxidation catalyst and diesel particulate filter introduced above are conventional terms in this field, but are not limited to being used only in the exhaust after-treatment system of diesel engines. For example, for gasoline engines, DOC and DPF can also be set for exhaust after-treatment of gasoline engines in some scenarios.

[0069] The second section 102 may be a selective catalytic reduction (SCR) reactor. Exhaust gas from the internal combustion engine passes through a diesel oxidation catalyst (DOC) to treat unburned hydrocarbons and carbon monoxide in the exhaust, and a diesel particulate filter (DPF) to treat particulate pollutants in the exhaust. The exhaust gas then enters a mixer 10 where it mixes with a spray of a reductant liquid, typically a urea solution, sprayed from an injector 20. This mixture forms a mixed flow, which then flows out of the mixer 10 and into the SCR reactor. The mixed flow undergoes a reduction reaction to produce nitrogen and water, thereby treating nitrogen oxides in the exhaust gas.

[0070] refer to Figure 1 、 Figures 3 to 6 As shown, in some embodiments, the mixer 10 includes an air inlet pipe portion 1 , an air outlet pipe portion 2 and a cover body 3 .

[0071] The air inlet pipe portion 1 is a tubular structure for air intake, and the air outlet pipe portion 2 is a tubular structure for air outlet. The air inlet pipe portion 1 and the air outlet pipe portion 2 are arranged non-coaxially, as shown in FIG. Figure 1 As shown, the axis 110 of the air inlet pipe portion and the axis 210 of the air outlet pipe portion are arranged so as not to overlap, for example Figure 1 Parallel setup shown.

[0072] The cover 3 defines the flow path of the exhaust gas from the intake pipe 1 to the outlet pipe 2, as well as a mixing space where the exhaust gas and the reducing agent mix. The cover 3 includes an intake portion 31, an outlet portion 32, and an intermediate passage 33. The intake portion 31 and the outlet portion 32 are connected through the intermediate passage 33. The intake portion 31 is directly connected to the intake pipe 1, and the outlet portion 32 is directly connected to the outlet pipe 2.

[0073] The middle channel portion 33 of the cover 3 has an inner wall surface 331, on which a heat preservation block 4 is provided. The length direction of the heat preservation block 4 extends along the extension direction of the middle channel portion 33. Figure 3 As shown, the middle channel portion 33 extends from left to right, and the length direction of the heat preservation block 4 extends from left to right.

[0074] The heat-insulating block 4 herein refers to a block structure formed of a material with relatively large thermal inertia. Thermal inertia refers to the fact that when an object is subjected to temperature changes, the surface temperature does not immediately follow the change, but rather has a certain hysteresis effect. Materials with relatively large thermal inertia can be, for example, metals such as cast iron, steel, or ceramics. Preferably, austenitic 304 stainless steel can be used, as it has relatively large thermal inertia and good weldability. The block structure herein should be understood in a broad sense and can be a flat square block structure, or a curved block structure with shapes such as an arc surface or an irregular curved surface, etc.

[0075] The beneficial effect of this is that the inventors found that by setting an insulation block at the key position of the middle channel part 233, it can play a better insulation role for the exhaust gas and the mixed airflow of the exhaust gas and the reducing agent spray, thereby achieving good insulation performance and reducing crystallization, making the mixer and the exhaust system easy to adapt to various installation spaces.

[0076] Specifically, compared with Figure 2 In the comparative embodiment shown, the mixer 10a does not have the heat-insulating block 4. Figure 1 In some embodiments shown, the mixer 4 uses an insulation block 4, and the minimum thickness of the insulation material layer on the outer wall of the mixer 10 can be reduced from 10mm to 20mm to 8mm to 10mm. Specifically, the minimum thickness of the insulation material layer on the outer wall of the inlet pipe portion 1 of the mixer 10 and the outer wall of the outlet pipe portion 2 of the mixer 10 can be reduced from 10mm in the comparative solution to 8mm, and the minimum thickness of the insulation material layer on the outer wall of the cover 3 of the mixer 10 can be reduced from 15mm to 20mm to 10mm. The beneficial effect is that reducing the thickness of the insulation material layer helps the exhaust system adapt to various installation spaces. It can be understood that the thickness values ​​described above allow for certain errors due to factors such as processing and measurement.

[0077] In some embodiments, for example Figure 3 As shown, the only channel fluidically connecting the air inlet 31 and the air outlet 32 ​​is the intermediate channel 33. That is, the air inlet 31 and the air outlet 32 ​​can only communicate through the intermediate channel 33 and cannot be connected through other paths. In this case, the displacement flow path of the mixed flow of exhaust gas and reductant spray is the intermediate channel 33. It can be understood that the majority of the flow area fluidly connecting the air inlet 31 and the air outlet 32 ​​is provided by the intermediate channel 33, for example, 80% to 90% of the flow area is provided by the intermediate channel 33, while only 10% to 20% of the flow area does not pass through the intermediate channel 33. This further optimizes the heat preservation effect of the airflow and reduces the thickness of the thermal insulation material layer.

[0078] Continue to refer Figure 3 、 Figure 4As shown, in some embodiments, an injector mounting seat 34 is provided on the sidewall of the air inlet portion 31 of the cover body 3. The injector mounting seat 34 defines the injector's injection direction D1. Furthermore, along the injection direction D1, the protrusion height H of the insulation block 4 from the inner wall surface 331 increases. This advantageously minimizes the impact of the reductant spray, such as urea solution, injected from the injector on the insulation block 4, preventing urea crystallization on the insulation block 4. It should be understood that the injection direction D1 herein refers to the overall injection direction, such as from left to right in the figure, and does not refer to the direction of each specific spray beam.

[0079] refer to Figure 1 、 Figure 3 、 Figure 5 As shown, in some embodiments, one end 11 of the air inlet pipe portion is connected to the air inlet portion 31 of the cover body 3, so that the air inlet portion 31 is directly connected to the air inlet pipe portion 1, wherein the inner wall surface 111 of the one end 11 of the air inlet pipe portion is provided with a first insulation ring 12. The beneficial effect of this is that the provision of the first insulation ring 12 can further optimize the heat insulation effect of the mixer on the air flow and reduce the thickness of the insulation material layer. However, the inventors have found that the heat insulation effect of providing the first insulation ring 12 at the one end 11 of the air inlet pipe portion is not as good as that of providing the insulation block 4 on the inner wall surface 331 of the middle channel portion 33.

[0080] Continue to refer Figure 1 、 Figure 3 、 Figure 5 As shown, in some embodiments, the axial position of the first insulation ring 12 can be such that the air intake pipe portion 1 is provided with a temperature sensor 51 and / or a pressure sensor 52, and the first insulation ring 12 is provided at a position adjacent to the temperature sensor 51 and / or the pressure sensor 52 in the axial direction, or the first insulation ring 12 is partially annular, and the temperature sensor 51 and / or the pressure sensor 52 is provided in the notch 121 of the partially annular portion. In this way, the temperature sensed by the temperature sensor 51 and / or the pressure sensor 52 can be closer to the actual temperature / pressure, thereby improving the sensing accuracy of the sensor. In addition, the structure of the first insulation ring 12 in the mixer 10 can be made compact.

[0081] refer to Figure 1 、 Figure 3 、 Figure 6As shown, in some embodiments, one end 21 of the air outlet pipe portion is connected to the air outlet portion 32 of the cover body 3, so that the air outlet portion 32 is directly connected to the air outlet pipe portion 2, wherein the inner wall surface 111 of the one end 21 of the air outlet pipe portion is provided with a second insulation ring 22. The beneficial effect of this is that the provision of the second insulation ring 22 can further optimize the heat preservation effect of the mixer on the air flow and reduce the thickness of the insulation material layer. However, the inventors found that the heat preservation effect of providing the second insulation ring 22 at the one end 21 of the air outlet pipe portion is not as good as that of providing the insulation block 4 on the inner wall surface 331 of the middle channel portion 33.

[0082] It can be understood that the structures of the first insulation ring 12 and the second insulation ring 22 introduced above can be split semi-rings as shown in the figure, with gaps between the semi-rings, but this is not a limitation, for example, they can also be full rings.

[0083] The inventors found that the insulation block 4, the first insulation ring 12, and the second insulation ring 22 have a significantly greater insulation effect on exhaust gas than the first insulation ring 12 and the second insulation ring 22. If it is necessary to divide the proportion of the effects, the inventors found that when the insulation block 4, the first insulation ring 12, and the second insulation ring 22 are jointly arranged in the mixer, the insulation block 4 plays a 70% to 90% insulation role.

[0084] As described above, the material with large thermal inertia used for the insulation block 4, the first insulation ring 12, and the second insulation ring 22 can be metal, such as austenitic 304 stainless steel. The insulation block 4 is welded to the inner wall surface 331 of the middle channel portion 33 of the cover body 3, the first insulation ring 12 is welded to the inner wall surface 111 of one end 11 of the air inlet pipe portion, and the second insulation ring 22 is welded to the inner wall surface 211 of one end 21 of the air outlet pipe portion. In addition, the surface of the insulation block 4 generally needs to be smooth, which can prevent the urea spray from adhering to the surface of the insulation block 4 and reduce urea crystallization. In addition, the use of metal, especially austenitic 304 stainless steel, is easy to weld, so that the fixed structure of the insulation block 4, the first insulation ring 12, and the second insulation ring 22 is stable and reliable.

[0085] As can be seen from the above, the beneficial effects of the mixer and exhaust system introduced in the above embodiments include but are not limited to, by arranging an insulation block on the inner wall surface of the middle channel portion of the cover body of the mixer, and / or arranging a second insulation ring on the inner wall surface of one end of the air inlet pipe portion, and / or arranging a second insulation ring on the inner wall surface of one end of the air outlet pipe portion, so that the insulation performance of the mixer is good, and the thickness of the insulation material layer is reduced on the basis of reducing crystallization with good insulation performance, so that the mixer and the exhaust system are easy to adapt to various installation spaces.

[0086] Although the present application is disclosed above with reference to the above embodiments, they are not intended to limit the present application. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modifications, equivalent variations, and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application shall fall within the scope of protection defined by the claims of the present application.

Claims

1. A mixer (10) for an exhaust system (100), characterized in that: The mixer (10) comprises: Intake pipe part (1); An air outlet pipe portion (2), wherein the air inlet pipe portion (1) and the air outlet pipe portion (2) are arranged non-coaxially; and a cover body (3), the cover body (3) defining a flow path of exhaust gas from the air inlet pipe portion (1) to the air outlet pipe portion (2), and defining a mixing space for mixing exhaust gas and reducing agent, the cover body (3) comprising an air inlet portion (31), an air outlet portion (32), and an intermediate channel portion (33), the air inlet portion (31) and the air outlet portion (32) being in communication with each other through the intermediate channel portion (33); The air inlet portion (31) is directly connected to the air inlet pipe portion (1); the air outlet portion (32) is directly connected to the air outlet pipe portion (2); The middle channel portion (33) of the cover body (3) has an inner wall surface (331), and a heat preservation block (4) is provided on the inner wall surface (331). The length direction of the heat preservation block (4) extends along the extension direction of the middle channel portion (33).

2. The mixer (10) according to claim 1, characterized in that An injector mounting seat (34) is provided on the side wall of the air inlet portion (31) of the cover body (3), and the injector mounting seat (34) defines the injection direction of the injector; and along the injection direction, the protruding height of the heat-insulating block (4) protruding from the inner wall surface (331) increases.

3. The mixer (10) according to claim 1, characterized in that The only communication channel that fluidically connects the air inlet (31) and the air outlet (32) is the intermediate channel (33); or most of the flow area that fluidly connects the air inlet (31) and the air outlet (32) is provided by the intermediate channel (33).

4. The mixer (10) according to claim 1, characterized in that One end of the air intake pipe is connected to the air intake portion (31) of the cover body (3), so that the air intake portion (31) is directly connected to the air intake pipe (1), wherein a first heat preservation ring (12) is provided on the inner wall surface of one end of the air intake pipe.

5. The mixer (10) according to claim 4, characterized in that The air intake pipe portion (1) is provided with a temperature sensor (51) and / or a pressure sensor (52); the first heat-insulating ring (12) is provided at a position adjacent to the temperature sensor (51) and / or the pressure sensor (52) in the axial direction; or the first heat-insulating ring (12) is partially annular, and the temperature sensor (51) and / or the pressure sensor (52) is provided in a notch (121) of the partially annular shape.

6. The mixer (10) according to claim 1, characterized in that One end of the air outlet pipe is connected to the air outlet portion (32) of the cover body (3), so that the air outlet portion (32) is directly connected to the air outlet pipe (2), wherein a second heat preservation ring (22) is provided on the inner wall surface of one end of the air outlet pipe.

7. The mixer (10) according to any one of claims 1, 4 to 6, characterized in that: The heat-insulating block (4), the first heat-insulating ring (12), and the second heat-insulating ring (22) are made of metal materials, and the surface of the heat-insulating block (4) is smooth; the heat-insulating block (4) is welded to the inner wall surface (331) of the middle channel portion (33) of the cover body (3), the first heat-insulating ring (12) is welded to the inner wall surface of one end of the air inlet pipe portion, and the second heat-insulating ring (22) is welded to the inner wall surface of one end of the air outlet pipe portion.

8. The mixer (10) according to any one of claims 1, 4 to 6, characterized in that: The outer wall of the mixer (10) is provided with a heat-insulating material layer, and the minimum thickness of the heat-insulating material layer is 8 mm to 10 mm, wherein the minimum thickness of the heat-insulating material layer corresponding to the outer wall of the air inlet pipe portion (1) and the minimum thickness of the heat-insulating material layer corresponding to the outer wall of the air outlet pipe portion (2) are 8 mm, and the minimum thickness of the heat-insulating material layer corresponding to the outer wall of the cover body (3) is 10 mm.

9. An exhaust system (100), characterized in that: The invention comprises a mixer (10) as described in any one of claims 1 to 8, and an injector (20), wherein the injector (20) is mounted on an injector mounting seat (34), and injects a reducing agent into the mixer (10) to form a reducing agent spray, so that the exhaust gas and the reducing agent spray form a mixed airflow.

10. The exhaust system (100) according to claim 9, characterized in that The reducing agent is a urea solution. The exhaust system (100) comprises a first part (101), a second part (102) and the mixer (10). The first part (101) is connected to an air inlet pipe (1) of the mixer, and the second part (102) is connected to an air outlet pipe (2) of the mixer. The first part (101), the second part (102) and the mixer (10) form an exhaust after-treatment system with a U-shaped structure.

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