A dual fuel injector and its nozzle structure

Abstract

The utility model relates to a kind of nozzle structure of dual-fuel injector, including nozzle main body, the both ends of nozzle main body are respectively sealing flange and nozzle head, nozzle head outside is double concave surface structure, including the first inner concave surface of being set around nozzle head outside circumferential and the second inner concave surface of being set in nozzle head end portion;Double concave surface nozzle structure being set on nozzle head, by the first inner concave surface using circumferential annular groove design, the heat exchange surface of radial expansion is formed in nozzle head portion, the second inner concave surface uses end spherical surface structure, by curvature optimization forming progressive temperature transition zone, cooperate the first bevelled conical surface formed by the first inner concave surface, make nozzle head overall thermal inertia promote;It is favorable to reduce the temperature gradient from combustion chamber to nozzle interior, improve nozzle head portion temperature, realized the closed-loop control of pressure stability, heat management optimization, atomization homogenization and durability promotion in fuel injection process, fundamentally solve the problem of low-temperature carbon deposition and high-temperature cracking product generation.

Description

Technical Field

[0001] This utility model belongs to the field of fuel injection technology for internal combustion engines, specifically relating to a dual-fuel injector and its nozzle structure. Background Technology

[0002] The statements herein provide only background information related to this invention and do not necessarily constitute prior art.

[0003] Dual-fuel injectors are an important component of dual-fuel engines. They are injection devices that can handle two different fuels simultaneously, allowing switching between the two fuels or using both fuels at the same time to improve efficiency, reduce emissions, or adapt to different operating conditions.

[0004] Fuel injectors are installed in a fuel injection system to inject high-pressure fuel into an associated combustion cylinder. Each fuel injector includes an injector nozzle with a valve needle, which is typically operated by an actuator to move toward and away from a valve seat. In this way, the valve needle can be moved to control the delivery of fuel into the combustion cylinder through one or more injection orifices or nozzle exits at the end of the injector nozzle. However, in actual operation, dual-fuel injectors must withstand the harsh environment of exhaust gases produced during in-cylinder combustion. Because diesel fuel injection is relatively small, incomplete combustion products tend to adhere to the nozzle orifice, often resulting in carbon buildup and blockage. This blockage hinders normal fuel injection, affecting the efficiency and quality of in-cylinder combustion, and ultimately impacting engine emissions performance. Utility Model Content

[0005] The purpose of this invention is to provide a dual-fuel injector and its nozzle structure. The double concave nozzle structure on the nozzle head helps to increase the surface heat exchange area, increase the nozzle thermal inertia, reduce the temperature gradient from the combustion chamber to the nozzle interior, increase the nozzle head temperature, reduce the combustion of rich mixture on the wall surface with fuel at low temperatures to produce high-temperature cracking products, and at the same time increase diesel fluidity and reduce carbon deposit formation and adhesion.

[0006] To achieve the above objectives, this utility model is implemented through the following technical solution: In a first aspect, embodiments of this utility model provide a nozzle structure for a dual-fuel injector, including a nozzle body. The nozzle body has a sealing flange and a nozzle head at its two ends, respectively. A pressure-stabilizing chamber and a fuel passage with an inlet located within the pressure-stabilizing chamber are provided between the sealing flange and the nozzle head. The outer side of the nozzle head has a double-concave structure, including a first concave curved surface, a second concave curved surface, a first oblique-cut conical surface, and a second oblique-cut conical surface. The first concave curved surface is circumferentially arranged around the outer side of the nozzle head, and the second concave curved surface is located at the end of the nozzle head. The extension line of the first oblique-cut conical surface intersects the extension line of the first concave curved surface with the extension line of the second concave curved surface, and the second oblique-cut conical surface intersects the outer edge line of the nozzle head.

[0007] As a further technical solution, the first concave surface is located above the second concave surface, and the second oblique cone surface is tangent to the extension line of the first concave surface.

[0008] As a further technical solution, the first concave curved surface is provided in the form of an annular groove structure on the nozzle head.

[0009] As a further technical solution, the second concave curved surface is configured as a concave spherical structure on the nozzle head.

[0010] As a further technical solution, the minimum outer diameter of the first concave curved surface is smaller than the maximum outer diameter of the first obliquely shaped conical surface, but larger than the minimum outer diameter of the first obliquely shaped conical surface.

[0011] As a further technical solution, the interior of the nozzle body is a cavity structure, and a volumetric cavity is formed between the side of the cavity structure near the nozzle head and the nozzle head.

[0012] As a further technical solution, the first oblique conical surface is provided with a spray hole that communicates with the volume cavity.

[0013] As a further technical solution, the pressure stabilizing chamber includes a first pressure stabilizing chamber and a second pressure stabilizing chamber, with the first pressure stabilizing chamber located above the second pressure stabilizing chamber, both of which are arranged in annular grooves around the nozzle body.

[0014] As a further technical solution, the fuel channel includes a first fuel channel and a second fuel channel, wherein the first fuel channel is disposed in a first pressure stabilizing chamber and the second fuel channel is disposed in a second pressure stabilizing chamber.

[0015] Secondly, embodiments of the present invention provide a dual-fuel injector, including the nozzle structure of the dual-fuel injector described in the first aspect.

[0016] The beneficial effects of one or more of the above technical solutions are as follows: This invention utilizes a double-concave nozzle structure on the nozzle head. The first concave curved surface employs a circumferential annular groove design to form a radially extended heat exchange surface at the nozzle head. The second concave curved surface adopts an end spherical structure, and through curvature optimization, it forms a progressive temperature transition zone. Combined with the first obliquely shaped conical surface formed by the first concave curved surface, this improves the overall thermal inertia of the nozzle head. This helps reduce the temperature gradient from the combustion chamber to the nozzle interior, increases the nozzle head temperature, reduces the combustion of rich air-fuel mixture on the wall surface at low temperatures, and reduces the generation of high-temperature cracking products. At the same time, it increases diesel fluidity and reduces carbon deposit formation and adhesion. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute a limitation thereof.

[0018] Figure 1 This is a front sectional view of the overall structure of the nozzle body in one or more embodiments of the present invention; Figure 2 This is a schematic diagram of the nozzle head structure installation in one or more embodiments of the present invention; Figure 3 This is a schematic diagram of a conventional nozzle head structure in one or more embodiments of the present invention.

[0019] In the figure, 1 is the sealing flange; 2 is the first pressure stabilizing chamber; 3 is the second pressure stabilizing chamber; 4 is the first fuel passage; 5 is the second fuel passage; 6 is the nozzle head; 7 is the first concave curved surface; 8 is the second concave curved surface; 9 is the nozzle orifice; 10 is the volume chamber; 11 is the first oblique cone surface; and 12 is the second oblique cone surface. Detailed Implementation

[0020] It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] Example 1 Existing nozzle structures such as Figure 3 As shown, the following problems exist: When the dual-fuel injector is running, the temperature of the nozzle head 6 is relatively low. At low temperature, the rich mixture on the wall surface burns with the fuel to produce high-temperature cracking products, which are easy to adhere and accumulate on the wall surface.

[0022] In view of the problems existing in the prior art, a typical embodiment of this utility model is as follows: Figures 1-2As shown, this embodiment provides a nozzle structure for a dual-fuel injector, including a nozzle body, with a sealing flange 1 and a nozzle head 6 at both ends, and a pressure stabilizing chamber and a fuel passage with an inlet located in the pressure stabilizing chamber are provided between the sealing flange 1 and the nozzle head 6.

[0023] Specifically, such as Figure 1 As shown, the pressure stabilizing chamber includes a first pressure stabilizing chamber 2 and a second pressure stabilizing chamber 3. The first pressure stabilizing chamber 2 is located above the second pressure stabilizing chamber 3, and both are arranged in annular grooves around the nozzle body. The fuel passage includes a first fuel passage 4 and a second fuel passage 5. The first fuel passage 4 is provided in two sets, which are symmetrically arranged in the first pressure stabilizing chamber 2 with respect to the axis of the nozzle body. The second fuel passage 5 is provided in two sets, which are symmetrically arranged in the second pressure stabilizing chamber 3 with respect to the axis of the nozzle body.

[0024] In addition, the first pressure stabilizing chamber 2 is located above the second pressure stabilizing chamber 3, and the first fuel channel 4 is located above the second fuel channel 5; this not only helps to optimize space utilization, but also ensures efficient fuel delivery.

[0025] The first fuel channel 4 and the second fuel channel 5 are both designed as cylindrical through holes. The first fuel channel 4 runs horizontally through the entire nozzle body. The second fuel channel 5 is inclined at an acute angle relative to the central axis of the nozzle body, with an inclination angle greater than 30 degrees and less than 60 degrees. The inclined design helps to further optimize the fuel mixing and combustion process, thereby improving the efficiency and performance of the entire system. When the injector is opened and closed and the fuel pressure reaches a peak, a pressure stabilizing chamber of a certain volume can be set to absorb instantaneous pressure fluctuations and ensure the accuracy of injection.

[0026] The vertical arrangement of the first and second pressure-stabilizing chambers 2 and 3 makes the entire nozzle structure more compact. In practical applications, the size and shape of the pressure-stabilizing chambers and fuel passages can be adjusted according to different working conditions and performance requirements. By changing the volume of the pressure-stabilizing chambers, the pre-pressure and injection pressure of the fuel can be affected, thereby adjusting the pressure distribution within the combustion chamber to adapt to different combustion modes and efficiency requirements. Simultaneously, the optimized design of the fuel passages reduces fuel flow resistance, improves fuel supply efficiency, and ensures a stable fuel supply under various operating conditions.

[0027] like Figure 2As shown, the outer side of the nozzle head 6 has a double concave structure, including a first concave curved surface 7, a second concave curved surface 8, a first oblique cone surface 11, and a second oblique cone surface 12. The first concave curved surface 7 is arranged circumferentially around the outer side of the nozzle head 6, and the second concave curved surface 8 is arranged at the end of the nozzle head 6. The first concave curved surface 7 is located above the second concave curved surface 8. The first oblique cone surface 11 and the extension line of the first concave curved surface 7 intersect the extension line of the second concave curved surface 8. The second oblique cone surface 12 intersects the outer edge line of the nozzle head 6.

[0028] Specifically, the first concave curved surface 7 is set in an annular groove structure on the nozzle head 6, and its cross-sectional shape is a concave arc, which helps to enhance the overall strength and stability of the nozzle head 6; the second concave curved surface 8 is set in a concave spherical structure on the nozzle head 6. The spherical structure design allows the flow of liquid or gas to be smoother when the nozzle head 6 is working, thereby effectively improving the spraying efficiency and the uniformity of the sprayed material.

[0029] Furthermore, the first oblique cone surface 11 has an inclination angle of β relative to the second oblique cone surface 12, where the angle of β is between 30 degrees and 90 degrees; the second oblique cone surface 12 has an inclination angle of α relative to the outer edge of the nozzle head 6, where the angle of α is an acute angle less than 90 degrees.

[0030] The first concave surface 7 is tangent to the second obliquely tangent cone surface 12, therefore the radius R of the arc surface 7 of the first concave surface 7 is: L*tan(90°-α) / 2≤R≤L / [2*tan(90°-α)] Where L is the length of the second oblique cone surface 12.

[0031] Furthermore, this double-concave surface design of the nozzle head 6 also offers certain practical advantages. The annular groove structure of the first concave curved surface 7 effectively reduces fluid friction on the surface of the nozzle head 6, thereby reducing energy loss. Simultaneously, this design also helps to disperse pressure, reducing wear on the nozzle head 6 under high-pressure operating environments and extending its service life.

[0032] The spherical structure of the second concave surface 8 provides a smoother transition area for the fluid, which helps reduce turbulence inside the nozzle head 6 and ensures better consistency of the ejected fluid. Furthermore, the spherical structure design allows the nozzle head 6 to maintain consistent ejection performance at different angles and directions, which is particularly important for applications requiring precise control of the ejection direction.

[0033] like Figure 1 and Figure 2As shown, the nozzle body has a hollow cavity structure inside, and a volumetric cavity 10 is formed between the side of the cavity structure near the nozzle head 6 and the nozzle head 6. A spray hole 9 is provided on the first oblique conical surface 11, communicating with multiple volumetric cavities 10. The number of spray holes 9 on the first oblique conical surface 11 is no less than nine, depending on the circumferential length of the first oblique conical surface 11. This design allows the liquid or gas to obtain a uniform flow rate and pressure when passing through the nozzle, thereby ensuring the stability and accuracy of the spray and providing optimal spray effect.

[0034] In addition, the nozzle body is usually made of corrosion-resistant and wear-resistant alloy materials to ensure that the nozzle can maintain stable performance over a long period of time even in harsh environments.

[0035] like Figure 2 As shown, in order to avoid the influence of an excessively large outer diameter of the first concave surface 7, the minimum outer diameter of the first concave surface 7 in this application is smaller than the maximum outer diameter of the first oblique cone surface 11 and larger than the minimum outer diameter of the first oblique cone surface 11. Specifically, the relationship between the minimum outer diameter of the first concave surface 7 and the maximum and minimum outer diameters of the first oblique cone surface 11 is: D1 < D2 < D3, where the outer diameter of the first concave surface 7 is represented by D2, the maximum outer diameter of the first oblique cone surface 11 is represented by D3, and the minimum outer diameter of the first oblique cone surface 11 is represented by D1.

[0036] This design further prevents the problem that if the minimum outer diameter of the first concave curved surface 7 is too small, the wall thickness is insufficient and the reliability is poor, or if the outer diameter is too large, the spray hole cannot be set on the first oblique cone surface 11, resulting in the spray hole being set on the first concave curved surface 7, thus forming an elliptical outlet. This directly affects the spray direction and atomization of the outermost part of the spray hole, leading to a decrease in spray efficiency and effect.

[0037] This invention also relates to a dual-fuel injector, which includes the aforementioned nozzle structure.

[0038] The working principle of this utility model is as follows: After the fuel enters the nozzle body, it is first diverted to the lower annular pressure stabilizing chamber for initial pressure stabilization and equalization. In the lower second pressure stabilizing chamber, the fuel is guided to the nozzle head 6 through the inclined second fuel channel 5. The inclined flow channel design reduces the impact of fuel on the wall and enhances fuel flowability. After the predetermined fuel injection, excess fuel can be returned and stabilized through the upper first fuel channel 4, thereby improving injection accuracy.

[0039] The fuel then enters the double-concave flow guide structure in the nozzle head 6 region: the first concave curved surface 7 surrounds the outside of the nozzle head 6 with an annular groove structure, dispersing fluid pressure through the concave arc surface and reducing flow resistance and surface friction; the second concave curved surface 8 has an end spherical structure, providing a smooth turning path for the fuel, suppressing turbulence and improving flow uniformity. Simultaneously, the nozzle holes 9 are located on the first oblique conical surface 11 rather than the concave region, avoiding atomization deviation caused by the elliptical outlet, while ensuring the reliability of the nozzle head 6. The fuel is finally ejected through the uniformly distributed nozzle holes 9 on the first oblique conical surface 11: the cavity structure inside the nozzle body and the nozzle head 6 form a volume chamber 10, where the fuel accumulates pressure and then forms a stable conical atomization through multiple nozzle holes.

[0040] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. A nozzle structure for a dual-fuel injector, characterized in that, The nozzle body includes a nozzle body with a sealing flange and a nozzle head at its two ends. A pressure stabilizing chamber and a fuel passage with an inlet located within the pressure stabilizing chamber are provided between the sealing flange and the nozzle head. The outer side of the nozzle head has a double concave structure, including a first concave curved surface, a second concave curved surface, a first oblique cone surface, and a second oblique cone surface. The first concave curved surface is arranged circumferentially around the outer side of the nozzle head, and the second concave curved surface is located at the end of the nozzle head. The extension line of the first oblique cone surface and the first concave curved surface intersects with the extension line of the second concave curved surface, and the second oblique cone surface intersects with the outer edge of the nozzle head.

2. The nozzle structure of a dual-fuel injector according to claim 1, characterized in that, The first concave surface is located above the second concave surface, and the second oblique cone surface is tangent to the extension line of the first concave surface.

3. The nozzle structure of a dual-fuel injector according to claim 1, characterized in that, The first concave curved surface is configured as an annular groove on the nozzle head.

4. The nozzle structure of a dual-fuel injector according to claim 1, characterized in that, The second concave curved surface is configured as a concave spherical structure on the nozzle head.

5. The nozzle structure of a dual-fuel injector according to claim 1, characterized in that, The minimum outer diameter of the first concave curved surface is smaller than the maximum outer diameter of the first obliquely shaped conical surface, but larger than the minimum outer diameter of the first obliquely shaped conical surface.

6. The nozzle structure of a dual-fuel injector according to claim 1, characterized in that, The nozzle body has a hollow structure inside, and a volumetric cavity is formed between the side of the hollow structure near the nozzle head and the nozzle head.

7. The nozzle structure of a dual-fuel injector according to claim 1, characterized in that, The first oblique conical surface is provided with spray holes that communicate with the volume cavity.

8. The nozzle structure of a dual-fuel injector according to claim 1, characterized in that, The pressure stabilizing chamber includes a first pressure stabilizing chamber and a second pressure stabilizing chamber. The first pressure stabilizing chamber is located above the second pressure stabilizing chamber, and both are arranged in annular grooves around the nozzle body.

9. The nozzle structure of a dual-fuel injector according to claim 1, characterized in that, The fuel passage includes a first fuel passage and a second fuel passage, wherein the first fuel passage is disposed in a first pressure regulating chamber and the second fuel passage is disposed in a second pressure regulating chamber.

10. A dual-fuel injector comprising a nozzle structure according to any one of claims 1-9.

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