A dual fuel injector elongated nozzle and a dual fuel injector

Abstract

This disclosure relates to an extended nozzle for a dual-fuel injector and a dual-fuel injector, including a nozzle body. Along the axial direction, from top to bottom, the nozzle body comprises a sealing flange and a nozzle head. The nozzle head is an extended conical nozzle structure with an extended volumetric cavity inside. A nozzle orifice communicating with the volumetric cavity is provided on the nozzle head. The wall thickness of the volumetric cavity and the nozzle head gradually decreases towards the apex of the cone, and the portion communicating with the volumetric cavity is higher than the height of the volumetric cavity. Through the synergistic optimization of the extended conical nozzle structure and the gradient thinning design of the volumetric cavity, the surface area of ​​the nozzle head is increased, heat dissipation efficiency is improved, and the nozzle's thermal inertia is increased. This helps reduce the temperature gradient from the combustion chamber to the nozzle interior, increases the nozzle head temperature, and reduces carbon deposit formation and adhesion. Furthermore, it improves fuel atomization uniformity. The nozzle orifice opening is higher than the height of the volumetric cavity, utilizing the gravity settling effect and fluid inertial separation principle to reduce the risk of solid particulate matter adhering to the nozzle orifice.

Description

Technical Field

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

[0002] The statements herein provide only background information in relation to this disclosure 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] Existing nozzles generally employ a constant-diameter straight-through structure. Fuel expands and atomizes instantaneously through the nozzle under high pressure. However, due to the short flow channel and insufficient turbulence intensity, the droplet size distribution is dispersed, resulting in uneven fuel-air mixing. This is especially problematic under low-load conditions, easily creating localized rich-fuel zones and increasing soot emissions. Furthermore, the existing nozzle head structure has significant thermal inertia. The temperature gradient between the high-temperature combustion chamber environment and the low-temperature fuel injection causes thermal stress concentration inside the nozzle. Over long-term operation, carbon deposits easily form at the nozzle edges and on the inner walls of the combustion chamber, causing nozzle blockage. This blockage hinders normal fuel injection, affecting the efficiency and quality of in-cylinder combustion. In severe cases, it can cause injection deviation, atomization deterioration, and ultimately impact engine emissions performance. Utility Model Content

[0005] The purpose of this invention is to provide an extended nozzle for a dual-fuel injector. By extending the conical structure of the nozzle head and thinning the nozzle head wall thickness, the thermal inertia of the nozzle is increased, which helps to reduce the temperature gradient from the combustion chamber to the inside of the nozzle, increase the nozzle head temperature, and reduce carbon deposit formation and adhesion.

[0006] To achieve the above objectives, this utility model is implemented through the following technical solution:

[0007] In a first aspect, an embodiment of this utility model provides an extended nozzle for a dual-fuel injector, comprising a nozzle body, wherein the nozzle body comprises, from top to bottom, a sealing flange and a nozzle head along the axial direction, the nozzle head having a conical structure, the length of the nozzle head along the axial direction being greater than a set value, a volumetric cavity being provided inside the nozzle head, and a spray hole communicating with the volumetric cavity being provided on the nozzle head; the wall thickness relationship between the volumetric cavity and the nozzle head is that it gradually decreases towards the apex of the cone.

[0008] As a further technical solution, the cone height of the nozzle head conical structure is not less than one-third of the diameter of the end section of the nozzle body.

[0009] As a further technical solution, the portion of the nozzle that connects to the volumetric cavity is higher than the height of the volumetric cavity.

[0010] As a further technical solution, the top of the cone-shaped structure of the nozzle head is divided into a spherical surface, and the spherical surface is tangent to the generatrix of the cone structure.

[0011] As a further technical solution, the nozzle body is provided with a pressure stabilizing chamber and a fuel passage with the inlet located in the pressure stabilizing chamber.

[0012] As a further technical solution, the pressure stabilizing chamber and fuel passage are disposed between the sealing flange and the nozzle head.

[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] As a further technical solution, the first fuel channel is a cylindrical hole that penetrates through the nozzle body, and the second fuel channel is a cylindrical through hole that is inclined at an acute angle relative to the axis of the nozzle body.

[0016] Secondly, embodiments of the present invention provide a dual-fuel injector, including the extended nozzle of the dual-fuel injector described in the first aspect.

[0017] The beneficial effects of one or more of the above technical solutions are as follows:

[0018] This disclosure utilizes the synergistic optimization of a long conical nozzle structure and a volumetric cavity gradient thinning design to increase the nozzle head surface area, improve heat dissipation efficiency, and consequently enhance fuel atomization uniformity. Compared to traditional nozzles, the fuel-air mixing efficiency is significantly improved. The nozzle orifice opening is higher than the volumetric cavity height, utilizing gravity settling effect and fluid inertial separation principles to reduce the risk of solid particulate matter adhering to the orifice. The conical apex spherical transition design reduces flow separation, and combined with optimized cavity wall thickness for heat conduction, this increases the nozzle head temperature, reducing carbon deposit formation and orifice clogging. Furthermore, thinning the nozzle head wall thickness helps increase the nozzle's thermal inertia, reducing the temperature gradient from the combustion chamber to the nozzle interior, further increasing the nozzle head temperature and reducing carbon deposit formation and adhesion. This solves the problems of carbon deposit clogging, uneven atomization, and thermal stress concentration inherent in traditional nozzles. Attached Figure Description

[0019] 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.

[0020] Figure 1 This is a front view of the overall structure in one or more embodiments of this disclosure;

[0021] Figure 2 This is a schematic diagram of the nozzle head structure installation in one or more embodiments of this disclosure;

[0022] Figure 3 This is an enlarged view of the extended nozzle head portion in one or more embodiments of this disclosure;

[0023] Figure 4 This is a schematic diagram of a conventional nozzle head structure in one or more embodiments of this disclosure.

[0024] 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 nozzle orifice; and 8 is the volume chamber. Detailed Implementation

[0025] 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.

[0026] Example 1

[0027] Existing nozzle structures such as Figure 4 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 inner wall surface of the volume chamber.

[0028] In view of the problems existing in the prior art, a typical embodiment of this utility model is as follows: Figures 1-3 As shown, this embodiment provides an extended nozzle for a dual-fuel injector, including a nozzle body, which is configured as a sealing flange 1 and a nozzle head 6 from top to bottom along the axial direction.

[0029] like Figure 2 and Figure 3As shown, the nozzle head 6 has a conical structure. The length of the nozzle head 6 along the axial direction is greater than the set value. Specifically, the cone height h of the conical structure is not less than one-third of the diameter D of the nozzle body end section. The conical structure of the nozzle head 6 is provided with an elongated volume cavity 8 in the shape of a conical hole. The generatrix inclination angle α of the conical structure is set at an obtuse angle greater than 100 degrees and less than 130 degrees relative to the diameter D of the nozzle body end section. The generatrix inclination angle β of the conical hole is set at an obtuse angle greater than 90 degrees and less than (α-10) degrees relative to the diameter D of the nozzle body end section section. This ensures that the wall thickness decreases from the nozzle hole to the bottom surface, thus ensuring the effect of increasing thermal inertia.

[0030] Therefore, the wall thickness relationship between the volumetric cavity 8 and the nozzle head 6 is that it gradually decreases towards the cone apex. By lengthening the nozzle design, the nozzle temperature is increased, carbon deposit formation and adhesion are reduced, and the reliability of the dual-fuel injector is improved.

[0031] Specifically, the nozzle head 6 is provided with a spray hole 7 that communicates with the volume chamber 8; the elongated conical nozzle structure helps to improve the atomization effect of fuel, making the fuel and air mix more evenly, thereby improving combustion efficiency and ensuring the stable operation of the engine under various operating conditions.

[0032] Simultaneously, the extended conical nozzle structure effectively increases the surface area of ​​the nozzle head 6. This not only increases the volume of the volume chamber 8 but also ensures that the nozzle 7 is positioned above the volume chamber 8. Since carbon deposits are less likely to adhere to the upper part, the risk of carbon buildup clogging the nozzle 7 is significantly reduced, thereby improving the overall system's operating efficiency and reliability.

[0033] Furthermore, the wall thickness of the volumetric cavity 8 and the nozzle head 6 gradually decreases as it approaches the cone apex. This elongated nozzle design effectively increases the nozzle's operating temperature, thereby reducing carbon buildup and its adhesion to the nozzle, ultimately improving the overall reliability of the dual-fuel injector. Moreover, the elongated volumetric cavity 8 provides a larger cooling space, thus reducing the thermal stress on the nozzle material.

[0034] like Figure 3 As shown, the part of the nozzle 7 that connects to the volume chamber 8 is higher than the height of the volume chamber 8; the top of the cone of the nozzle head 6 is divided into a spherical surface, and the spherical surface is tangent to the generatrix of the cone structure.

[0035] Specifically, the connecting circular hole formed after the connection between the nozzle 7 and the volume chamber 8 is higher than the actual height of the volume chamber 8; the cone apex of the conical structure of the nozzle head 6 is specially designed as a spherical shape, which is perfectly tangent to the generatrix of the conical structure, which helps to reduce the turbulence of the fluid inside the nozzle, thereby making the ejected fluid more uniform and stable, and ensuring that the nozzle will not experience wear and gap increase during long-term use, thus maintaining the consistency of the injection accuracy.

[0036] Specifically, the spherical surface of the nozzle head 6 is tangent to the conical surface of the nozzle head 6, and the center of the spherical surface is located on the central axis of the nozzle head 6. At this time, the radius R of the spherical surface is less than or equal to 1 / 3h, where h is the cone height of the conical structure of the nozzle head 6.

[0037] like Figure 1 As shown, the nozzle body is also equipped with a pressure stabilizing chamber and a fuel passage with the inlet located in the pressure stabilizing chamber.

[0038] Specifically, the pressure stabilizing chamber and the fuel passage are located between the sealing flange 1 and the nozzle head 6. 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 groove structures around the nozzle body.

[0039] The fuel passage includes a first fuel passage 4 and a second fuel passage 5. The first fuel passage 4 is disposed in the first pressure stabilizing chamber 2, and the second fuel passage 5 is disposed in the second pressure stabilizing chamber 3.

[0040] 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 optimize space utilization but also ensures efficient fuel delivery. Both the first fuel channel 4 and the second fuel channel 5 are designed as cylindrical through-holes. The first fuel channel 4 runs horizontally through the entire nozzle body, while 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. This 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, the pressure-stabilizing chamber of a certain volume can absorb instantaneous pressure fluctuations, ensuring the accuracy of injection.

[0041] Furthermore, the design of the pressure stabilizing chamber and fuel passage takes into account the principles of thermodynamics and fluid mechanics to ensure optimal performance under various operating conditions. The symmetrical layout of the pressure stabilizing chamber helps to distribute pressure evenly, reducing local stress concentration and thus extending the nozzle's service life. At the same time, the cylindrical design of the fuel passage ensures smooth fuel flow, reduces flow resistance, and improves fuel utilization.

[0042] In practical applications, the size and shape of the pressure stabilizing chamber and fuel passage can be adjusted according to different working conditions and performance requirements. By changing the volume of the pressure stabilizing chamber, 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, optimized design of the fuel passage can reduce fuel flow resistance, improve fuel supply efficiency, and ensure a stable fuel supply under various operating conditions.

[0043] This disclosure also extends to a dual-fuel injector that includes the aforementioned extended nozzle for dual-fuel injectors.

[0044] The working principle of this utility model is as follows:

[0045] 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 direction through the inclined second fuel channel. 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, thereby improving injection accuracy.

[0046] The fuel then flows through the elongated conical nozzle. Its upward-extending cavity structure makes the opening of the nozzle 7 higher than the middle of the cavity, using the effect of gravity to reduce the adhesion of solid deposits at the nozzle 7. The thickness of the conical cavity wall gradually decreases along the axial direction (thinnest at the top of the cone). Through material thermal conduction optimization, the temperature gradient at the nozzle head 6 is increased, effectively suppressing the formation of low-temperature carbon deposits. The spherical transition design at the top of the cone (tangent to the generatrix) allows the fuel to form a laminar boundary layer at the injection end, reducing the probability of flow separation and improving the uniformity of atomized particle size distribution.

[0047] While the specific embodiments of this disclosure have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of this disclosure. 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 solutions of this disclosure are still within the scope of protection of this disclosure.

Claims

1. An extended nozzle for a dual-fuel injector, characterized in that, The nozzle body includes a sealing flange and a nozzle head arranged from top to bottom along the axial direction. The nozzle head has a conical structure and its axial length is greater than a set value. A volumetric cavity is provided inside the nozzle head, and a spray hole communicating with the volumetric cavity is provided on the nozzle head. The wall thickness of the volumetric cavity and the nozzle head gradually decreases towards the apex of the cone.

2. The extended nozzle of a dual-fuel injector according to claim 1, characterized in that, The cone height of the nozzle head conical structure is not less than one-third of the diameter of the nozzle body end section.

3. The extended nozzle of a dual-fuel injector according to claim 1, characterized in that, The part of the nozzle that connects to the volume chamber is higher than the height of the volume chamber.

4. The extended nozzle of a dual-fuel injector according to claim 1, characterized in that, The top of the cone-shaped structure of the nozzle head is divided into a spherical surface, which is tangent to the generatrix of the cone structure.

5. The extended nozzle of a dual-fuel injector according to claim 1, characterized in that, The nozzle body is provided with a pressure stabilizing chamber and a fuel passage with the inlet located in the pressure stabilizing chamber.

6. The extended nozzle of a dual-fuel injector according to claim 5, characterized in that, The pressure regulating chamber and fuel passage shown are located between the sealing flange and the nozzle head.

7. The extended nozzle of a dual-fuel injector according to claim 6, 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.

8. The extended nozzle of a dual-fuel injector according to claim 6, 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.

9. The extended nozzle of a dual-fuel injector according to claim 8, characterized in that, The first fuel channel is a cylindrical hole that penetrates the nozzle body, and the second fuel channel is a cylindrical through hole that is inclined at an acute angle relative to the axis of the nozzle body.

10. A dual-fuel injector, characterized in that, Includes an extended nozzle for a dual-fuel injector according to any one of claims 1-9.

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