A swirl atomizing injector

Abstract

This invention provides a swirl-atomizing urea injector, comprising at least a nozzle needle valve assembly, an injection-molded connector assembly, a solenoid valve assembly, an outer cover, and a sealing ring. The nozzle needle valve assembly includes a filter screen, an upper nozzle body, a spring retaining ring, a needle valve spring, a lower nozzle body, a needle valve, a valve seat, a valve seat mounting plate, and a swirl orifice plate. The swirl orifice plate has several swirl grooves connected to a central countersunk hole and an outer countersunk hole. The long side of the swirl groove is tangent to the outer circle of the outer countersunk hole, and the short side of the swirl groove intersects the outer circle of the outer countersunk hole, with its extension trajectory passing through the center of the outer countersunk hole. The bottom surface of the swirl groove forms a certain angle with the surface of the swirl orifice plate. The width of the swirl groove gradually narrows from the first end to the second end, and the depth gradually decreases. When the urea aqueous solution passes through the swirl groove, it can be further accelerated and form a swirl. This invention has the advantages of reducing spray particle size, improving urea injection atomization effect, and reducing the risk of urea crystallization in diesel engine aftertreatment.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine component technology, specifically to a swirling atomizing injector. Background Technology

[0002] With increasingly stringent emission regulations for diesel engines, the adoption of SCR (Selective Catalytic Reduction) exhaust aftertreatment systems is an essential technology for reducing NOx emissions from modern diesel engines. The urea injector in an SCR system is installed on the diesel engine's exhaust pipe. It injects a measured amount of urea solution into the exhaust pipe at regular intervals, based on the engine's operating conditions, to catalytically reduce NOx in the exhaust, converting it into N2 and H2O, thereby achieving the goal of reducing NOx emissions from diesel engines.

[0003] In practical operation, improving the atomization effect of the urea injector can enhance the contact and mixing between the urea solution and the exhaust gas, thereby improving the conversion efficiency of NOx catalytic reduction. Furthermore, better atomization can reduce the atomized particle size, preventing crystallization or even blockage of the exhaust pipe due to the accumulation of an excessively thick liquid film from the urea solution, which could ultimately lead to worsened emissions or even a decrease in diesel engine power performance due to excessive exhaust back pressure.

[0004] Patent application number 202110561669.8 discloses a bipolar swirling urea injector. It employs a valve seat with oblique holes and swirling grooves, causing the urea aqueous solution to form two-stage swirling flows within the valve seat before converging into the swirling holes and then being ejected through the circular holes of the nozzle plate. This achieves the goal of reducing the atomized particle size and improving the injection atomization effect. However, with increasingly stringent emission regulations, the requirements for the atomized particle size of urea injectors are also becoming more stringent. Because this patented structure uses a single nozzle, it is difficult to further reduce the nozzle diameter to ensure the required total urea injection volume. Therefore, it is difficult to further improve the injection atomization effect and reduce the particle size of the atomized urea by reducing the nozzle size.

[0005] Patent application number 201711425989.0 discloses a urea nozzle that uses a vortex vane with multiple oblique grooves, narrow at one end and wide at the other, connected to the nozzle orifice. The oblique grooves guide the flow, reducing pressure drop and improving atomization. However, this patent uses a straight flow channel formed by the oblique grooves, limiting the resulting swirling effect. Furthermore, it still uses a single nozzle orifice, making it difficult to further reduce the orifice diameter while maintaining the required total urea injection volume, thus hindering further improvement in atomization.

[0006] Patent application number 202210060254.7 discloses an atomizing structure and vehicle. It employs a swirling channel constructed from swirling orifices, secondary swirling grooves, and primary and tertiary swirling grooves, utilizing multi-stage swirling to enhance atomization and reduce the risk of crystallization. While this patented structure uses arc-shaped spiral grooves, the width and depth of these grooves are fixed, making further acceleration of the urea solution impossible. Furthermore, the structure still uses a single nozzle, making it difficult to further improve atomization by reducing the nozzle size while maintaining the required total urea injection volume.

[0007] Patent application number 201920410691.0 discloses a urea solution atomizing electromagnetic valve metering injector, employing a multi-orifice structure. Multiple centrifugal turbulence chambers are arranged between the valve seat and the orifice plate, generating high-speed turbulence to improve the atomization effect. While the centrifugal turbulence chambers in this patent structure have an arc-shaped design to guide the urea solution, the depth of the chambers is constant, and the flow area gradually increases along the path towards the spray orifice. Therefore, the urea solution cannot be further accelerated as it flows from the valve seat outlet to the spray orifice, making it difficult to further improve the atomization effect and reduce the particle size of the atomized particles.

[0008] It is evident that although the above-mentioned technical solutions can improve the atomization effect of urea injection to some extent, due to the limitations of the structural design, there are still some difficulties in further improving the atomization effect and reducing the particle size of the atomized particles. Summary of the Invention

[0009] The purpose of this invention is to provide a swirling atomizing injector to solve the problems existing in the prior art.

[0010] The objective of this invention is achieved as follows: a swirling atomizing urea injector, wherein a swirling orifice plate is fixedly connected to the liquid outlet end, facing the liquid channel, and the swirling orifice plate is provided with:

[0011] A circular center countersunk hole;

[0012] Several swirling grooves are circumferentially distributed around the central countersunk hole to form a swirling flow. When viewed from the surface of the swirling orifice plate, the swirling grooves extend outward in an arc shape based on the central countersunk hole, and all the swirling grooves are oriented in the same direction in the circumferential direction.

[0013] Several circular outer countersunk holes that correspond one-to-one with the swirl channels;

[0014] The swirling channel has an inlet end connected to a central submerged hole and an outlet end connected to an outer submerged hole. From the inlet end to the outlet end, the width of the swirling channel gradually narrows to concentrate the water flow. The long side of the swirling channel is tangent to the outer circle of the outer submerged hole, and the short side of the swirling channel intersects the outer circle of the outer submerged hole, with its extension trajectory passing through the center of the outer submerged hole. The center of the outer submerged hole is connected to a jet hole for spraying liquid, and the inner diameter of the jet hole is smaller than the inner diameter of the outer submerged hole.

[0015] Furthermore, the swirl channels and the outer countersunk holes are evenly distributed around the central axis of the swirl orifice plate.

[0016] Furthermore, the swirling orifice plate is configured as a circular plate, and the central axis of the central countersunk hole coincides with the central axis of the swirling orifice plate.

[0017] Furthermore, the inlet end of the jet hole is provided with a chamfer for guiding the flow, so as to concentrate the water flow.

[0018] Furthermore, the number of the swirl channels and the outer countersunk holes is 3 to 6.

[0019] Furthermore, the diameter of the central countersunk hole is 3-4 times the diameter of the outer countersunk hole.

[0020] Furthermore, from the liquid inlet end to the liquid outlet end, the depth of the vortex tank gradually decreases.

[0021] Furthermore, based on the cross-sectional view of the vortex channel, the bottom surface of the vortex channel forms a certain angle with the surface of the vortex orifice plate, and the lowest position point is biased towards the direction of the central countersunk hole.

[0022] Furthermore, the bottom surface of the swirl channel forms an angle of 3° to 5° with the surface of the swirl orifice plate.

[0023] The beneficial effects of this invention are as follows:

[0024] When the urea solution passes through the swirl channel, it can be further accelerated and form a swirling flow. The high-speed swirling urea solution sprayed out of the injection orifice can further reduce the particle size of the spray particles and improve the urea injection atomization effect. At the same time, by using multiple injection orifices for injection control, while ensuring the total amount of urea injected, the diameter of the injection orifice can be further reduced, the particle size of the atomized particles can be reduced, and the atomization quality can be improved. This improves the degree of mixing between the urea solution and the exhaust gas in the exhaust pipe, improves the conversion efficiency of NOx in the exhaust gas, and reduces the risk of urea crystallization in the diesel engine aftertreatment system. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view of the swirl atomizing urea injector assembly according to an embodiment of the present invention;

[0026] Figure 2 This is a cross-sectional view of the nozzle needle valve assembly according to an embodiment of the present invention;

[0027] Figure 3 This is a cross-sectional view of the needle valve according to an embodiment of the present invention;

[0028] Figure 4 This is a cross-sectional view of the valve seat according to an embodiment of the present invention;

[0029] Figure 5 This is an external view of the swirl orifice plate according to an embodiment of the present invention;

[0030] Figure 6 These are cross-sectional and top views of the swirl orifice plate according to an embodiment of the present invention;

[0031] Figure 7 This is a partially enlarged schematic diagram of the swirling groove in the swirling orifice plate according to an embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of the flow field of the vortex orifice plate according to an embodiment of the present invention;

[0033] Figure 9 This is a front view of the flow field of the vortex orifice plate according to an embodiment of the present invention.

[0034] The numbers in the attached diagram are as follows: 1-Inlet sealing ring; 2-Nozzle needle valve assembly; 3-Injection molded connector assembly; 4-Upper nozzle body expansion ring; 5-Solenoid valve assembly; 6-Outer cover; 7-Lower nozzle body sealing ring; 8-Nozzle sealing ring retainer; 9-Nozzle sealing ring; 21-Filter screen; 22-Upper nozzle body; 23-Spring retainer; 24-Needle valve spring; 25-Lower nozzle body; 26-Needle valve; 27-Valve seat; 28-Valve seat mounting plate; 2 9-Swirl orifice plate; 261-Needle valve spring bearing hole; 262-Needle valve inner hole; 263-Needle valve side hole; 264-Needle valve ball head; 2641-Needle valve ball head cross-section; 271-Valve seat sealing cone surface; 272-Valve seat lower center hole; 291-Center countersunk hole; 292-Outer countersunk hole; 293-Swirl groove; 294-Injection hole; 2931-Swirl groove long side; 2932-Swirl groove short side; 2941-Injection hole chamfer. Detailed Implementation

[0035] The following will refer to the appendices in the embodiments of the present invention. Figure 1-9 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] See Figure 1A cross-sectional view of the swirl atomizing urea injector assembly according to an embodiment of the present invention. The swirl atomizing urea injector mainly includes an inlet sealing ring 1, a nozzle needle valve assembly 2, an injection molding plug assembly 3, an upper nozzle body expansion ring 4, a solenoid valve assembly 5, an outer cover 6, a lower nozzle body sealing ring 7, a nozzle sealing ring retainer 8, and a nozzle sealing ring 9.

[0037] Please see Figure 2 The nozzle needle valve assembly includes a filter screen 21, an upper nozzle body 22, a spring retaining ring 23, a needle valve spring 24, a lower nozzle body 25, a needle valve 26, a valve seat 27, a valve seat mounting plate 28, and a swirl orifice plate 29.

[0038] Please see Figure 3 The needle valve 26 includes features such as a needle valve spring bearing hole 261, a needle valve inner hole 262, a needle valve side hole 263, and a needle valve ball head 264. The needle valve ball head 264 is provided with a plurality of needle valve ball head cross-sections 2641 evenly distributed along the needle valve axis.

[0039] Please see Figure 4 The valve seat 27 includes features such as a valve seat sealing cone surface 271 and a central hole 272 at the bottom of the valve seat.

[0040] The lower nozzle body 25 is welded to the upper nozzle body 22. The valve seat 27 is welded to the swirl plate 29 and then to the valve seat mounting plate 28, which is then welded to the lower nozzle body 25. The needle valve spring 24 is placed in the inner hole of the upper nozzle body 22, and its lower end mates with the spring bearing hole 261 above the needle valve 26. The spring retainer ring 23 is placed in the inner hole of the upper nozzle body 22 and mates with the upper end of the needle valve spring 24, providing a limit for the needle valve spring 24. The needle valve 26 is placed in the lower valve body 25 and mates with the valve seat 27. Under the preload of the needle valve spring 24, the needle valve ball head 264 of the needle valve 26 mates with the sealing cone surface 271 of the valve seat 27 for sealing. A clearance is provided between the upper end plane of the needle valve 26 and the lower end plane of the upper nozzle body 22 to form the working stroke of the needle valve 26.

[0041] When the solenoid valve assembly 5 is energized, it generates electromagnetic force, and the needle valve 26 is lifted upwards by overcoming the preload force of the needle valve spring 24 under the action of electromagnetic force. The inner hole 262 of the needle valve communicates with the inner hole of the upper nozzle body 22, and the urea aqueous solution entering from the liquid inlet port above the injector can be transported through the needle valve side hole 263 to the gap between the cross-section of the needle valve ball head 2641 and the valve seat 27.

[0042] Please see Figure 5 , Figure 6 and Figure 7The swirling orifice plate 29 includes a central countersunk hole 291, outer countersunk holes 292, swirling grooves 293, injection holes 294, a long side 2931 of the swirling grooves, a short side 2932 of the swirling grooves, and a chamfered injection hole 2941. The number of outer countersunk holes 292 corresponds to the number of swirling grooves 293, ranging from 3 to 6, and they are evenly distributed around the centerline of the swirling orifice plate 299. An injection hole 294 is located at the center of each outer countersunk hole 292, and the injection hole 294 has a chamfered injection hole 2941 for guiding the flow. The first end of the swirling groove 293 is connected to the central countersunk hole 291, and the second end is connected to the outer countersunk hole 292. The second end of the long side 2931 of the swirling groove is tangent to the outer circle of the outer countersunk hole 292, and the second end of the short side 2932 of the swirling groove intersects the outer circle of the outer countersunk hole 292, with the extension trajectory of the short side 2932 passing through the center of the outer countersunk hole 292. The bottom surface of the swirl channel 293 forms an angle of 3°-5° with the upper and lower end faces of the swirl orifice plate 29. The width of the swirl channel 293 gradually narrows from the first end to the second end, while the depth gradually decreases. The diameter of the central countersunk hole 291 of the swirl orifice plate 29 is 3 to 4 times the diameter of the outer countersunk hole 292, and the central countersunk hole 291 communicates with the lower central hole 272 of the valve seat 27.

[0043] Please see Figure 8 and Figure 9 The schematic diagram of the flow domain of the vortex orifice plate 29 shown illustrates that, due to the structural characteristics of the designed vortex channel 293, which narrows in width and shallows in depth from the first end to the second end, the flow domain of the vortex orifice plate 29 exhibits a characteristic of narrowing in width and thinning in thickness from the central countersunk hole 291 to the outer countersunk hole 292. When the urea aqueous solution flows from the first end to the second end of the vortex channel 293, it is further accelerated due to the continuously decreasing flow area. Furthermore, since the second end of the long side 2931 of the vortex channel is tangent to the outer circle of the outer countersunk hole 292, and the second end of the short side 2932 of the vortex channel intersects with the outer circle of the outer countersunk hole 292, and the extension trajectory of the short side 2932 of the vortex channel coincides with the center of the outer countersunk hole 292, the vortex channel 293 possesses a vortex guiding function. Therefore, when the urea aqueous solution flows from the first end to the second end of the vortex channel 293, a counterclockwise vortex from the outside to the inside is formed at the outer countersunk hole 292.

[0044] The working principle of the swirl atomizing urea injector provided by the present invention is as follows: When the swirl atomizing urea injector is working, the urea aqueous solution with a certain pressure from the SCR aftertreatment system enters the inner channel of the upper nozzle body through the liquid inlet port above the injector, and flows through the gap between the needle valve inner hole 262 and the needle valve ball head cross-section 2641 and the valve seat 27 to the lower central hole 272 of the valve seat 27.

[0045] When the injector is not injecting, under the spring preload of the needle valve spring 24, the needle valve ball head 264 of the needle valve 26 cooperates with the sealing cone surface 271 of the valve seat 27 to seal, closing the lower central hole 272 of the valve seat 27.

[0046] When the injector sprays, the solenoid valve assembly 5 is energized to generate electromagnetic force, which attracts the needle valve 26 to lift up and open the valve seat 27. The urea solution can flow through the valve seat 27 to the center countersunk hole 291 of the swirl plate 29, and then through the swirl groove 293 to the outer countersunk hole 292. Finally, it is sprayed into the exhaust pipe through the injection hole 294 that communicates with the outer countersunk hole 292.

[0047] This invention provides a swirl-flow atomizing urea injector, in which the swirl groove 293 of the swirl plate 29 connects the central countersunk hole 291 and the outer countersunk hole 292. The width of the swirl groove 293 gradually narrows from the first end connected to the central countersunk hole 291 to the second end connected to the outer countersunk hole 292, while the depth gradually decreases. When the urea aqueous solution flows from the central countersunk hole 291 through the swirl groove 293 to the outer countersunk hole 292, it is further accelerated due to the gradually decreasing flow area. Under the guiding effect of the swirl structure of the swirl groove 293, a high-speed swirl is formed at the outer countersunk hole 292. Finally, when the high-speed swirling urea aqueous solution is sprayed out through the injection hole 294, it can produce smaller spray particle sizes, resulting in better atomization and mixing quality.

[0048] Furthermore, since the swirl atomizing injector provided by this invention uses a swirl orifice plate 29 with multiple injection holes 294, while ensuring the total amount of urea injected, a smaller injection hole diameter can be selected compared to the single injection hole scheme, and the spray particle size can be further reduced, thereby improving the spray quality.

[0049] Because of the above technical solutions, the swirl atomizing injector provided by this invention can further reduce the spray particle size of urea aqueous solution, improve the urea injection atomization effect, increase the degree of mixing between urea aqueous solution and exhaust gas in the diesel engine exhaust pipe, improve the conversion efficiency of NOx in exhaust gas, and at the same time reduce the risk of urea crystallization in the diesel engine aftertreatment system during operation.

[0050] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. In this invention, it should also be noted that the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, an integrally formed connection, a mechanical connection, or an indirect connection through intermediate connecting parts. The specific meaning of the terms in this utility model can be understood according to the specific circumstances.

[0051] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0052] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A swirl-atomizing urea injector, characterized in that, Its outlet end is fixedly connected to a swirl orifice plate (29) facing the liquid channel, and the swirl orifice plate (29) is provided with: A circular central countersunk hole (291); A number of swirling grooves (293) are circumferentially distributed around the central countersunk hole (291). When viewed from the plate surface of the swirling hole plate (29), the swirling grooves (293) extend outward in an arc shape based on the central countersunk hole (291), and all the swirling grooves (293) are oriented in the same direction in the circumferential direction. Several circular outer countersunk holes (292) that correspond one-to-one with the swirl channel (293); The swirling channel (293) has its inlet end connected to the central counterbore (291) and its outlet end connected to the outer counterbore (292). From the inlet end to the outlet end, the width of the swirling channel (293) gradually narrows. The long side of the swirling channel (293) is tangent to the outer circle of the outer counterbore (292), and the short side of the swirling channel (293) intersects the outer circle of the outer counterbore (292) and its extension trajectory passes through the center of the outer counterbore (292). The center of the outer counterbore (292) is connected to a jet hole (294) for jetting liquid. The inner diameter of the jet hole (294) is smaller than the inner diameter of the outer counterbore (292).

2. The swirl atomizing urea injector according to claim 1, characterized in that, The swirl grooves (293) and the outer countersunk holes (292) are evenly distributed around the central axis of the swirl orifice plate (29).

3. The swirl atomizing urea injector according to claim 1, characterized in that, The swirling orifice plate (29) is a circular plate, and the central axis of the central countersunk hole (291) coincides with the central axis of the swirling orifice plate (29).

4. The swirl atomizing urea injector according to claim 1, characterized in that, The inlet end of the jet hole (294) is provided with a jet hole chamfer (2941) for guiding the flow.

5. A swirl-atomizing urea injector according to claim 2, characterized in that, The number of the swirl grooves (293) and the outer countersunk holes (292) is 3 to 6.

6. A swirl-atomizing urea injector according to claim 3, characterized in that, The diameter of the central countersunk hole (291) is 3-4 times the diameter of the outer countersunk hole (292).

7. A swirl-atomizing urea injector according to claim 1, characterized in that, From the liquid inlet end to the liquid outlet end, the depth of the vortex tank (293) decreases from deep to shallow.

8. A swirl-atomizing urea injector according to claim 7, characterized in that, From the perspective of the cross-section of the swirling channel (293), the bottom surface of the swirling channel (293) forms a certain angle with the surface of the swirling orifice plate (29), and the lowest position point is biased towards the direction of the central countersunk hole (291).

9. A swirl-atomizing urea injector according to claim 8, characterized in that, The bottom surface of the swirling groove (293) forms an angle of 3° to 5° with the surface of the swirling perforated plate (29).

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