Urea metering valve assembly

Abstract

The application discloses a urea metering valve assembly, which comprises a metering valve, an outer bushing, an inner bushing, a sealing sleeve and a cooling water joint; the outer bushing, the inner bushing and the sealing sleeve form an axial annular closed cavity, the metering valve is sleeved into the inner bushing and surrounded by the axial annular closed cavity, and the injection front end of the metering valve is connected with or sleeved with the sealing sleeve, the depth of the sleeve connection is smaller than the length of the sealing sleeve; the cooling water joint is communicated with the axial annular closed cavity and used for passing in cooling water to cool the metering valve. The closed cavity is constructed to surround the whole urea metering valve assembly, the closed cavity is communicated with the cooling water to realize large-area heat exchange, but the urea metering valve is avoided from being directly soaked in the cooling water, meanwhile, the closed cavity prevents the heat of tail gas from entering from the front nozzle of the urea metering valve, and effectively reduces the temperature of the urea injector.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of exhaust treatment of internal combustion engine, and more particularly, to a urea metering valve assembly. BACKGROUND

[0002] In the exhaust treatment process of internal combustion engine, the urea sprayed by the urea injector mixes with the exhaust gas and reacts to purify the polluting components in the exhaust gas, so as to achieve the corresponding emission standard. However, the high-temperature exhaust gas causes the metering valve nozzle of the urea injector to bear high temperature, which easily leads to crystallization failure of the urea injector, affects the exhaust treatment effect, causes air pollution and emission failure, and therefore, a cooling structure is usually arranged to cool the urea injector. In the prior art, such as the metering injector with spliced cooling water jacket disclosed in the announcement No. CN 107701271 A, a water cooling structure is adopted, the metering injection valve is arranged in the cooling water jacket, a sealed cooling cavity is formed between the metering injection valve and the cooling water jacket, circulating cooling water is introduced into the cooling cavity, the cooling water flows around the metering injection valve, and the precise movement part of the injector is wrapped in the cooling water, so as to avoid the uneven temperature field and insufficient cooling caused by one-sided cooling, thereby avoiding the deviation or even failure of the working characteristics of the metering injection valve caused by the temperature boundary condition. However, after the cooling cavity of the prior art is introduced into the cooling water, the outer wall of the metering injection valve is soaked in the cooling water, which has high requirements for the waterproofness of the metering injection valve and the sealingness of the installation, and the front end of the metering injection valve is flat or protruding and directly exposed to the high-temperature exhaust gas, which bears high temperature. Therefore, it is urgent to provide a technical solution for effectively reducing the temperature of the urea injector. SUMMARY

[0003] An object of the present application is to solve at least the above-mentioned drawbacks and to provide at least the advantages that will be mentioned later.

[0004] Another object of the present application is to provide a urea metering valve assembly, which utilizes an outer bushing, an inner bushing and a sealing sleeve to build a sealed cavity to wrap the entire urea metering valve assembly, the sealed cavity is introduced into cooling water to achieve large-area heat exchange but avoid direct soaking of the urea metering valve in the cooling water, and the front end nozzle of the urea metering valve is recessed into the sealing sleeve, which is beneficial to the temperature reduction of the urea injector.

[0005] In order to achieve these objects and other advantages of the present application, the urea metering valve assembly provided by the present application comprises: a metering valve, an outer bushing, an inner bushing, a sealing sleeve and a cooling water joint.

[0006] The outer bushing, the inner bushing and the sealing sleeve form an axial annular closed cavity, the metering valve is sleeved into the inner bushing and surrounded by the axial annular closed cavity, and the injection front end of the metering valve is terminated or sleeved with the sealing sleeve, the sleeving depth is shorter than the length of the sealing sleeve; the cooling water joint is communicated with the axial annular closed cavity and used for passing in cooling water to cool the metering valve.

[0007] Preferably, in the urea metering valve assembly, the cooling water joint comprises an inlet cooling water joint and an outlet cooling water joint, the inlet cooling water joint is connected with the water inlet pipe, and the outlet cooling water joint is connected with the water outlet pipe.

[0008] The water storage pipe is arranged in the cooling water joint, one end of the water storage pipe is communicated with the water inlet pipe or the water outlet pipe, and the other end of the water storage pipe extends into the closed cavity by a certain depth.

[0009] Preferably, in the urea metering valve assembly, the depth of the water storage pipe extending into the closed cavity is greater than the radius of the closed cavity, and the water storage pipe extending into the closed cavity comprises an arc-shaped pipe segment.

[0010] Preferably, in the urea metering valve assembly, the arc-shaped pipe segment of the water storage pipe extending into the closed cavity is tangent to the inner wall of the closed cavity or is arranged concentrically with the metering valve; or the inlet cooling water joint and the outlet cooling water joint are tangent to the outer bushing.

[0011] Preferably, in the urea metering valve assembly, the inlet cooling water joint and the outlet cooling water joint are arranged at the upper half position of the outer bushing; or the arrangement positions of the inlet cooling water joint and the outlet cooling water joint are at the same height or have a height difference.

[0012] Preferably, in the urea metering valve assembly, the inlet cap is further arranged, the inlet cap covers the top end of the metering valve, and the inlet port is arranged to be communicated to the metering valve, and the metered liquid enters the metering valve through the inlet cap.

[0013] Preferably, in the urea metering valve assembly, the outer bushing and the sealing sleeve are fixedly connected coaxially or are integrally formed; the inner bushing and the sealing sleeve are sealingly connected coaxially or are integrally formed.

[0014] Preferably, in the urea metering valve assembly, after the metering valve is sleeved into the inner bushing, the outer wall of the metering valve is fitted with the inner wall of the inner bushing; and the injection front end of the metering valve is tightly terminated or tightly sleeved with the sealing sleeve.

[0015] Preferably, in the urea metering valve assembly, the closed cavity at least surrounds the metering valve injection front end to the magnet part of the metering valve.

[0016] Preferably, in the urea metering valve assembly, the mounting seat for being fixed to the engine is further arranged, the outer bushing is mounted on the mounting seat, and the metering valve is clamped and matched with the inner bushing.

[0017] The present application at least includes the following advantages:

[0018] 1、The present application can store cooling water in the closed cavity composed of the outer bushing, the inner bushing and the sealing sleeve, realize large capacity water storage, and the closed cavity surrounds the entire urea metering valve assembly. The metering valve assembly only needs to be fitted and centralized, and can be in large-area contact with the cooling water to realize large-area heat exchange, thereby achieving good cooling.

[0019] 2、The urea metering valve of the present application is fitted to the inner bushing, and the sealing sleeve is formed at the front end of the urea metering valve injection, that is, a closed cavity is constructed at the front end of the urea metering valve injection. The front end of the metering valve injection is recessed in the sealing sleeve, that is, the nozzle orifice is directly exposed to the high-temperature tail gas. On the one hand, the front end of the urea metering valve injection is away from the high-temperature tail gas, and on the other hand, the heat of the high-temperature tail gas is taken away by the cooling water in the closed cavity constructed by the sealing sleeve, thereby effectively preventing the heat from being transmitted to the urea metering valve through the sealing sleeve, and facilitating the cooling of the urea metering valve.

[0020] 3、The closed cavity constructed by the outer bushing, the inner bushing and the sealing sleeve can avoid direct contact of the urea metering valve outer wall with the cooling water, avoid soaking of the urea metering valve by the cooling water, and avoid the situation that the cooling water seeps into the urea metering valve to damage the parts. The sealing requirement of the urea metering valve is lower, and the applicability is higher.

[0021] 4、The water storage pipe design of the present application makes the closed cavity always maintain water storage, and solves the problem of water storage when the urea metering valve is installed horizontally.

[0022] 5、The water storage pipe of the present application is arc-shaped or tangent to the closed cavity, or the cooling water joint is tangent to the outer bushing, so that the incoming cooling water rotates in the closed cavity to form turbulent flow, the cooling water speed is increased, and the heat exchange efficiency is increased. The height difference between the inlet cooling water joint and the outlet cooling water joint is set to further increase the cooling effect.

[0023] Other advantages, objects and features of the present application will be partly embodied by the following description, and partly understood by those skilled in the art through research and practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a vertical sectional structure schematic view of the first embodiment of the urea metering valve assembly described in the present application.

[0025] Figure 2 It is a three-dimensional structure schematic view of the first embodiment of the urea metering valve assembly described in the present application.

[0026] Figure 3 It is a top view structure schematic view of the first embodiment of the urea metering valve assembly described in the present application.

[0027] Figure 4 This is a vertical cross-sectional structural diagram of a second embodiment of the urea metering valve assembly described in this invention.

[0028] Figure 5 This is a vertical cross-sectional structural diagram of the third embodiment of the urea metering valve assembly of the present invention;

[0029] Figure 6 This is a top view of the fourth embodiment of the urea metering valve assembly of the present invention;

[0030] Figure 7 This is a schematic diagram of the cooling water flow principle of the fourth embodiment of the urea metering valve assembly described in this invention;

[0031] Figure 8 This is a vertical cross-sectional structural diagram of the fifth embodiment of the urea metering valve assembly described in this invention;

[0032] Figure 9 This is a schematic diagram of the cooling water flow principle in the fifth embodiment of the urea metering valve assembly described in this invention;

[0033] Figure 10 This is a schematic diagram of the first embodiment of the water storage pipe extending into a sealed cavity according to the present invention.

[0034] Figure 11 This is a schematic diagram of the second embodiment of the water storage pipe of the present invention extending into a sealed cavity.

[0035] In the diagram: 1. Liquid inlet cap; 2. Metering valve; 201. Metering valve spray front end; 202. Metering valve magnet; 3. Outer bushing; 4. Inner bushing; 5. Mounting seat; 6. Sealing sleeve; 7. First sealing ring; 8. Water storage pipe; 9. Cooling water connector; 901. Cooling water inlet connector; 902. Cooling water outlet connector; 10. C-type clamp; 11. Second sealing ring. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, so that those skilled in the art can implement it based on the description.

[0037] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are conventional methods, and the reagents and materials mentioned are commercially available unless otherwise specified. Room temperature refers to 20–25°C.

[0038] like Figures 1-5 As shown, the urea metering valve assembly includes: metering valve 2, outer bushing 3, inner bushing 4, sealing sleeve 6, and cooling water connector 9;

[0039] The outer sleeve 3, the inner sleeve 4 and the sealing sleeve 6 form an axial annular closed cavity, the metering valve 2 is sleeved in the inner sleeve 4 and is surrounded by the axial annular closed cavity, and the injection front end of the metering valve 2 is connected with the sealing sleeve 6, the connection mode includes end connection and sleeve connection, and the sleeve connection depth is shorter than the length of the sealing sleeve, Figure 1 The structure shown is that the injection front end 201 of the metering valve is sleeved to a position 2-3 mm away from the bottom end of the sealing sleeve, Figure 4 The structure shown is that the injection front end 201 of the metering valve is sleeved to a position 2-3 mm away from the bottom end of the sealing sleeve, Figure 5 The structure shown is that the injection front end 201 of the metering valve is sleeved to a position 2-3 mm away from the bottom end of the sealing sleeve, The cooling water joint 9 is connected with the axial annular closed cavity, and the cooling water joint 9 is at least one inlet and one outlet, which is used for passing in cooling water to cool the metering valve 2.

[0040] For easy understanding, Figure 1 In the shown diagram, the inner sleeve 4 and the sealing sleeve 6 are located inside the outer sleeve, and are preferably coaxially arranged, so that the metering valve 2 is uniformly surrounded by the cooling water, but can also be arranged to be different coaxial according to the need, because when being installed to the engine exhaust pipe, the high-temperature conditions of each side of the metering valve assembly are different, and a larger closed space is arranged on the side close to the high-temperature side, so that the cooling effect can be improved. The outer sleeve 3, the inner sleeve 4 and the sealing sleeve 6 can be independent components, and when assembled, the connection is a sealed connection, and the sealed connection mode includes welding or connection through a sealing ring and a sealing gasket, so that the closed cavity does not leak. In the diagram, the connection between the inner sleeve 4 and the sealing sleeve 6 is provided with a first sealing ring 7, and the sealing sleeve 6 is welded and fixed with the outer sleeve 3 at the front end, but the sealing sleeve 6 can also be integrally formed with the inner sleeve 4, and similarly, the sealing sleeve 6 can also be integrally formed with the outer sleeve 3, and according to the processing need or market need, a suitable assembly mode can be selected.

[0041] Figure 1In the structure shown, the inner sleeve 4 has a sleeve space, the metering valve 2 is sleeved into the inner sleeve 4, and is attached to the inner wall of the inner sleeve 4 to exchange heat. The inner sleeve is preferably made of heat-conducting metal, such as steel 304, 316, etc. The injection front end of the metering valve 2 is connected to the inner sleeve 4. The connection mode can be end connection or sleeve connection. In end connection, the injection front end 201 or nozzle of the metering valve 2 is aligned with the central passage of the sealing sleeve 6. In sleeve connection, the injection front end 2 or nozzle of the metering valve 2 is sleeved into the central passage of the sealing sleeve 6. The sleeve connection depth is shorter than the length of the sealing sleeve. When the metering valve assembly is installed at the target installation position such as the engine exhaust pipe, the liquid injected by the metering valve 2 can be injected into the engine exhaust pipe. The inner sleeve 4 is fixedly connected to the outer sleeve 3, including welding, threaded connection, adhesive connection, clamping connection and other common connection structures. Figure 1 In the structure shown, the inner sleeve 4 is fixedly connected to the outer sleeve 3 by welding.

[0042] The shapes of the outer sleeve 3, the inner sleeve 4 and the sealing sleeve 6 are set as needed. Figure 1 In the structure shown, the inner sleeve 4 has a tapered sleeve section, a cylindrical section, an edge and a corner, which are designed according to the shape of the metering valve, the installation and cooperation with the outer sleeve and the sealing sleeve, for easy assembly and improved adaptability. The sealing sleeve 6 is designed as a straight cylindrical sleeve structure to match the inner sleeve 4 and the injection front end of the metering valve 2. The outer sleeve 3 is designed as a sleeve structure with one end large and the other end small to maximize the sealing cavity and cooperate with the mounting seat. These structures can be formed by punching and forming pipe materials, which is beneficial to processing and manufacturing and low in manufacturing cost.

[0043] In this embodiment, the metering valve 2 is directly assembled into the inner sleeve 4, and the circulating cooling water is connected to the closed cavity through the cooling water connector 9. The closed cavity forms a ring-shaped axial wrapping around the metering valve 2, effectively taking away heat and significantly cooling the metering valve 2. The design of the sealing sleeve 6 increases the distance between the metering valve 2 and the engine exhaust, i.e. away from high temperature, so as to avoid direct exposure of the metering valve 2, especially the injection port or nozzle, to high temperature exhaust, effectively preventing crystallization of the metering valve injection front end 2 or nozzle. Due to the blocking of the inner sleeve 4, the cooling water does not soak the metering valve 2, so that even ordinary metering valves without sealing design or waterproof can be directly used. The core parts of the metering valve 2, such as the controller or metering valve magnet 202, which cannot be soaked in water, can be wrapped in the closed cavity, increasing the wrapped area of the metering valve 2 and the heat dissipation area, so that the metering valve can be quickly and effectively cooled.

[0044] Further, in another embodiment, as shown in Figures 1-10 The cooling water connector 9 includes an inlet cooling water connector 901 and an outlet cooling water connector 902. The inlet cooling water connector 901 is connected to the water inlet pipe, and the outlet cooling water connector 902 is connected to the water outlet pipe.

[0045] The cooling water joint is provided with a water storage pipe 8, one end of which is connected to the water inlet pipe or the water outlet pipe, and the other end extends into the sealed cavity to a certain depth.

[0046] In the present embodiment, as shown in Figure 1 , the water storage pipe 8 extends into the sealed cavity to a certain distance (without contacting the intermediate metering valve 2), and in fact, the depth of the water storage pipe 8 extending into the sealed cavity is set according to the water storage requirement of the sealed cavity. When the urea metering valve assembly is installed to the engine exhaust pipe (target installation position) of different mechanical equipment, such as tractors, agricultural machines, transport vehicles, etc., there are usually vertical, inclined or horizontal installation methods, therefore, through the design of the water storage pipe 8, the urea metering valve assembly can maintain water storage under different installation methods, which can effectively improve its applicability and is very important for the market promotion of the product. Figure 1 or 5 or 6, is the vertical installation state of the urea metering valve assembly; the cooling water joint and the cooling water outlet joint are arranged on the upper half of the sealed cavity as shown in Figure 2 , so as to achieve the purpose of maximizing the water storage of the sealed cavity. Even if the installation position is as shown in Figure 8 and 9 , a certain amount of water can be maintained in the sealed cavity, which is beneficial to the cooling of the urea metering valve assembly.

[0047] When the metering valve assembly is installed in an inclined or horizontal manner, the water storage pipe 8 is inserted into the sealed cavity to a certain depth, which can also avoid the complete outflow of the cooling water in the sealed cavity and maintain water storage. Water storage is beneficial to the cooling of the metering valve and avoids overheating. As shown in Figure 10 and 11 , are structural schematic diagrams of the metering valve assembly installed in a horizontal manner, at this time, the water storage pipe 8 extends into the sealed cavity, the depth of the extension reaches more than half of the radius of the sealed cavity, or even reaches or approaches the diameter of the sealed cavity, thereby increasing the water storage capacity of the sealed cavity.

[0048] Further, in another embodiment, as a preference, the depth of the water storage pipe 8 extending into the sealed cavity is more than the radius of the sealed cavity. As shown in Figure 10 , the depth of the water storage pipe 8 extending into the sealed cavity approaches the diameter of the sealed cavity, and as shown in Figure 11 , the depth of the water storage pipe 8 extending into the sealed cavity is the radius of the sealed cavity. When the metering valve 1 is installed in a horizontal manner, such a setting can maintain the water storage capacity of the sealed cavity, which can generally reach more than the volume of the sealed cavity.

[0049] Further, in another embodiment, as shown in Figure 10 and 11 , the part of the water storage pipe 8 extending into the sealed cavity has an arc-shaped pipe section, that is, the water storage pipe can be an arc-shaped structure as a whole or partially.

[0050] Further, in another embodiment, as shown in Figure 10 and 11 the arc-shaped pipe section of the water storage pipe extending into the closed cavity is tangent to the inner wall of the closed cavity or is arranged concentrically around the metering valve; or the inlet cooling water joint and the outlet cooling water joint are tangent to the outer sleeve.

[0051] The above-mentioned arc-shaped arrangement and tangent arrangement are both for the purpose of spiral acceleration of the cooling water in the closed cavity to form turbulent flow and improve the heat dissipation and cooling effect.

[0052] Figure 10 and 11 In the structure shown in Figure 6 and 7 the tangent arrangement can also make the cooling water rotate and accelerate, and improve the heat exchange efficiency.

[0053] Further, in another embodiment, as shown in Figure 2 the inlet cooling water joint 901 and the outlet cooling water joint 902 are both arranged at the upper half position of the outer sleeve 3.

[0054] Alternatively, the inlet cooling water joint and the outlet cooling water joint are arranged at the same height.

[0055] Alternatively, as shown in Figure 8 and 9 the inlet cooling water joint and the outlet cooling water joint are arranged at different heights.

[0056] Alternatively, the arrangement of the inlet water pipe and the outlet water pipe, or the arrangement of the inlet cooling water joint and the outlet cooling water joint is not limited to the arrangement forms of being in the same direction, forming a certain angle, being opposite to each other, or being tangent to the outer sleeve.

[0057] In the present embodiment, the inlet cooling water joint 901 and the outlet cooling water joint 902 are both arranged at the upper half position of the outer sleeve 3, so that in the vertical installation state, the water storage of the closed cavity is maximized; and the arrangement of the inlet cooling water joint 901 and the outlet cooling water joint 902 at different heights can promote the full circulation of the cooling water and improve the cooling effect.

[0058] Further, in another embodiment, as shown in Figure 1As shown, the liquid inlet cap 1 covers the top end of the metering valve 2 and is provided with a liquid inlet communicating with the metering valve 2, and the liquid to be metered (urea) enters the metering valve 2 through the liquid inlet cap 1. In the legend, the liquid inlet cap 1 completely covers the top end of the metering valve inside, together with the sealed cavity, to wrap the metering valve, and the bottom end of the liquid inlet cap 1 is fixed with the inner bushing 4 or the outer bushing 3 by welding or the like, and the second sealing ring 11 is arranged inside the liquid inlet cap 1, which seals the gap between the liquid inlet cap 1 and the metering valve, preventing liquid leakage.

[0059] Further, in another embodiment, the outer bushing is coaxially fixedly connected with the sealing sleeve or integrally formed; the inner bushing is coaxially sealingly connected with the sealing sleeve or integrally formed. According to the needs, a suitable processing method can be selected.

[0060] Further, in another embodiment, as shown, Figure 1 after the metering valve 2 is sleeved into the inner bushing 4, the outer wall of the metering valve is in close contact with the inner wall of the inner bushing; and the injection front end of the metering valve is tightly terminated or tightly sleeved with the sealing sleeve 6.

[0061] Further, in another embodiment, as shown, Figure 1 the sealed cavity at least wraps around the metering valve injection front end to the metering valve magnet 202 part.

[0062] Further, in another embodiment, as shown, Figure 1 the mounting seat 5 for fixing to the engine is further included, the outer bushing 3 is mounted on the mounting seat, and the metering valve 2 is clamped and matched with the inner bushing 4. In the legend, the metering valve 2 is fixed on the inner bushing 4 through the C-shaped clamping plate.

[0063] Example 1

[0064] As shown, Figures 1-11As shown, a urea metering valve assembly, wherein the outer sleeve 3, the inner sleeve 4, the sealing sleeve 6, the three form a large area of axial annular closed cavity, cooling water joint 9, can be divided into one in and one out, engine cooling water can be through the cooling water joint 9 into the closed cavity cooling water into the closed cavity, form cooling water circulation, for urea metering valve 2, urea metering valve 2 is located in the cavity surrounded by closed cavity, in the cavity, the magnet of urea metering valve 2 and the inner wall of the inner sleeve are attached, the front nozzle of urea metering valve 2 and the inner wall of sealing sleeve 6 are attached (the inner sleeve and the sealing sleeve can be designed as a whole), forming a large capacity of cooling water to urea metering valve 2 for overall surrounding package, so as to realize the large area, high efficiency heat dissipation cooling of urea metering valve. The urea metering valve 2 has a clamping groove, and the urea metering valve 2 is fixed on the inner sleeve 4 through the c-shaped clamping plate 10. The liquid inlet cap 1 is connected with the urea metering valve 2, and the liquid enters the urea metering valve 2 through the liquid inlet cap 1. The urea metering valve 2 performs quantitative injection. The water storage pipe 8 is located in the cooling water joint 9 at one end and in the closed cavity at the other end. The maximum distance of the water storage pipe 8 extending into the closed cavity is preferably more than the radius of the closed cavity, so that the closed cavity always keeps water storage when the urea metering valve is installed horizontally. The part of the water storage pipe 8 extending into the closed cavity can be arc-shaped or straight, or a combination of the two. The water storage pipe 8 does not contact the metering valve 2.

[0065] The cooling water pipe connected with the cooling water joint 9 is divided into an inlet pipe and an outlet pipe, which can be arranged in the following ways: ① as shown in Figure 2 , the inlet pipe and the outlet pipe are located at the upper half of the outer sleeve, realizing maximum water storage of the closed cavity; ② as shown in Figure 8 and 9 , the inlet pipe and the outlet pipe form a height difference, and a turbulent flow is formed in the closed cavity, which, in combination with the large area contact of the urea metering valve 2 with the cooling water, realizes large area heat exchange; ③ as shown in Figure 6 and 7 , the inlet pipe and the outlet pipe are tangent to the outer sleeve, and the cooling water forms a turbulent flow in the closed cavity, the cooling water speed is accelerated, and a large amount of cooling is realized; ④ in addition, the arrangement of the inlet pipe and the outlet pipe is not limited to the arrangement forms of the same direction, a certain angle, opposite, and tangent to the outer sleeve.

[0066] The mounting seat 5 is arranged on the outer sleeve 3, and the urea metering valve 2 is fixed on the engine through the mounting seat 5 to realize injection. The first sealing ring 7 and the second sealing ring 11 play a sealing role.

[0067] Although the embodiments of the present application have been disclosed as above, they are not limited to the application listed in the specification and the embodiments. They can be fully applied to various fields suitable for the present application. Those skilled in the art can easily make other modifications.

Claims

1. A urea metering valve assembly, characterized in that, include: Metering valve, outer bushing, inner bushing, sealing sleeve, and cooling water connector; The outer bushing, inner bushing, and sealing sleeve form an axially annular sealed cavity. The metering valve is fitted into the inner bushing and surrounded by the axially annular sealed cavity. The injection tip of the metering valve is connected to or sleeved with the sealing sleeve, and the sleeve depth is shorter than the length of the sealing sleeve. The cooling water connector is connected to the axially annular sealed cavity and is used to introduce cooling water to dissipate heat and cool the metering valve. The cooling water connector includes an inlet cooling water connector and an outlet cooling water connector. The inlet cooling water connector is connected to the inlet pipe, and the outlet cooling water connector is connected to the outlet pipe. The cooling water connector is equipped with a water storage pipe. One end of the water storage pipe is connected to the inlet pipe or the outlet pipe, and the other end extends into the sealed cavity to a certain depth. The depth to which the water storage pipe extends into the sealed cavity is equal to or greater than the radius of the sealed cavity, and the portion of the water storage pipe extending into the sealed cavity includes an arc-shaped pipe section. The arc-shaped section of the water storage pipe extending into the sealed cavity is tangent to the inner wall of the sealed cavity or is concentric with the metering valve; or the inlet and outlet cooling water connectors are tangent to the outer bushing.

2. The urea metering valve assembly as described in claim 1, characterized in that, Both the inlet and outlet cooling water connectors are located in the upper half of the outer bushing; or the inlet and outlet cooling water connectors are located at the same height or have a height difference.

3. The urea metering valve assembly as described in claim 1, characterized in that, It also includes a liquid inlet cap, which covers the top of the metering valve and has an inlet port connected to the metering valve. The liquid to be metered enters the metering valve through the liquid inlet cap. A sealing ring is provided inside the liquid inlet cap, which seals the gap between the inner wall of the liquid inlet cap and the metering valve.

4. The urea metering valve assembly as described in claim 1, characterized in that, The outer bushing is coaxially fixedly connected to the sealing sleeve or integrally formed; the inner bushing is coaxially sealed to the sealing sleeve or integrally formed.

5. The urea metering valve assembly as described in claim 1, characterized in that, After the metering valve is fitted into the inner liner, the outer wall of the metering valve fits snugly against the inner wall of the inner liner; the injection tip of the metering valve is tightly connected to or tightly fitted into the sealing sleeve.

6. The urea metering valve assembly as described in claim 1, characterized in that, The sealed cavity at least surrounds and encloses the area from the injection tip of the metering valve to the magnet of the metering valve.

7. The urea metering valve assembly as described in claim 1, characterized in that, It also includes a mounting base with mounting holes, the mounting base being fixed to the engine through the mounting holes, the outer bushing being mounted on the mounting base, and the metering valve engaging with the inner bushing.

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