Erosion-resistant oil nozzle coupling structure

Abstract

The utility model relates to an oil nozzle pair structure of cavitation erosion resistance, including the oil atomizer body and needle valve body of connection, and the needle valve is slidably installed in needle valve body and oil atomizer body, the bottom of needle valve body is equipped with needle valve body sealing surface, pressure chamber from top to bottom in proper order, is equipped with several injection holes to the side of pressure chamber, and the lower part of needle valve is equipped with needle valve sealing surface, and the sealing structure is formed in cooperation with needle valve sealing surface and needle valve body sealing surface, and the plane where the highest point of injection hole is located is lower than the needle valve bottom of needle valve. The utility model can obviously improve the cavitation erosion condition of oil nozzle under superhigh rail pressure, reduce the fatigue damage of oil nozzle injection hole caused by cavitation erosion, prolong the service life of oil nozzle, reduce the replacement frequency of oil nozzle, reduce the risk such as atomization quality deterioration and injection quantity increase caused by injection hole cavitation erosion, and improve the engine performance.

Description

Technical Field

[0001] This utility model belongs to the field of fuel injection and relates to a fuel injector assembly structure that is resistant to cavitation. Background Technology

[0002] The primary goal of developing existing common rail injection systems is to meet pollutant emission regulations. Increasing the injection pressure in electronically controlled high-pressure common rail systems can improve fuel atomization and air-fuel mixing, reducing emissions. However, high rail pressure can also cause injector reliability issues. For example, air bubbles forming in the injector nozzle orifice area can impact the nozzle and needle valve. Under high pressure, these bubbles can burst, causing cavitation in the injection orifice. This leads to changes in fuel injection volume, uneven fuel jet distribution, and poor atomization, ultimately affecting the injector's lifespan. Summary of the Invention

[0003] The purpose of this invention is to provide a cavitation-resistant nozzle assembly structure that can solve the above-mentioned problems and reduce fatigue damage to the nozzle nozzle orifice caused by cavitation.

[0004] According to the technical solution provided by this utility model: a cavitation-resistant nozzle assembly structure includes an injector body and a needle valve body connected together. A needle valve is slidably installed in the needle valve body and the injector body. The bottom of the needle valve body is provided with a needle valve body sealing surface and a pressure chamber from top to bottom. Several spray holes are provided on the side of the pressure chamber. A needle valve sealing surface is provided at the bottom of the needle valve. The needle valve sealing surface and the needle valve body sealing surface cooperate to form a sealing structure. The plane where the highest point of the spray hole is located is lower than the bottom of the needle valve.

[0005] As a further improvement of this utility model, the injector body and the needle valve body are arranged vertically. The injector body has a vertically arranged injector channel. The bottom end of the injector channel is connected to the needle valve body. The side of the injector channel has an oil inlet channel. The middle part of the injector channel is a pressure accumulator chamber, which is connected to the oil inlet channel.

[0006] As a further improvement of this utility model, the accumulator includes a primary accumulator and a secondary accumulator arranged vertically. The primary accumulator is arc-shaped, and the secondary accumulator is cylindrical.

[0007] As a further improvement of this utility model, the oil inlet channel is obliquely arranged on the upper part of the injector body, and the bottom end of the oil inlet channel is connected to the first-stage accumulator chamber.

[0008] As a further improvement of this utility model, the size of the secondary accumulator chamber is smaller than that of the primary accumulator chamber.

[0009] As a further improvement of this utility model, the upper end of the needle valve is a sleeve post, which has a stepped structure.

[0010] As a further improvement of this utility model, the middle part of the needle valve body is a needle valve body guide hole, and the lower part of the needle valve is provided with a matching guide part. The guide part slides in the needle valve body guide hole and a flow structure is provided on the outer periphery of the guide part.

[0011] As a further improvement of this utility model, the guide hole and guide part of the needle valve body are adapted to be cylindrical, and the flow structure is flat.

[0012] As a further improvement of this utility model, the flow structure is a spiral groove structure.

[0013] As a further improvement of this utility model, the bottom of the needle valve is triangular, frustum-shaped, or arc-shaped.

[0014] The positive and progressive effects of this utility model are as follows: This invention can significantly improve fuel injector cavitation under ultra-high rail pressure, reduce fatigue damage to fuel injector orifices caused by cavitation, extend fuel injector service life, reduce fuel injector replacement frequency, reduce the risks of atomization quality deterioration and increased fuel injection volume caused by orifice cavitation, and improve engine performance. Attached Figure Description

[0015] Figure 1 This is a schematic diagram showing the assembly positional relationship of the needle valve, needle valve body, and injector body of the present invention.

[0016] Figure 2 This is a schematic diagram of the structure of the injector nozzle assembly resistant to cavitation according to the present invention.

[0017] Figure 3 This is a schematic diagram of another embodiment of the present invention, in which the bottom cross section of the needle valve is triangular.

[0018] Figure 4 This is a schematic diagram of another embodiment of the present invention, in which the bottom cross-section of the needle valve is circular.

[0019] Figure 5 This is a velocity flow field diagram at the nozzle, showing the structure where the bottom of the needle valve is lower than the plane where the highest point of the nozzle is located in the prior art.

[0020] Figure 6 The structure of the needle valve bottom being higher than the plane where the highest point of the nozzle is located is designed for this invention. Velocity flow field diagram at the nozzle.

[0021] Figure 7 This is a cloud map of the gas phase volume fraction at the nozzle, showing the structure where the bottom of the needle valve is lower than the plane where the highest point of the nozzle is located in the prior art.

[0022] Figure 8 The structure of the needle valve bottom being higher than the plane where the highest point of the nozzle is located is designed for this invention, and the gas phase volume fraction cloud map at the nozzle is shown.

[0023] Figure 9 This is a schematic diagram showing the flow direction of liquid inside the nozzle when the needle valve is raised, illustrating the structure where the bottom of the needle valve is lower than the plane of the highest point of the nozzle in the prior art.

[0024] Figure 10 The present invention designs a structure in which the bottom of the needle valve is higher than the plane where the highest point of the nozzle is located. The schematic diagram shows the flow direction of the liquid inside the nozzle when the needle valve is raised. Detailed Implementation

[0025] It should be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this utility model described herein. Furthermore, terms such as "comprising" and "having" mean that in addition to those already listed in "comprising" and "having," other unlisted contents may also be included; for example, a process, method, system, product, or device may include a series of steps or units, not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0028] Due to the angle of the drawing, some parts may not be drawn, but their positions and connections can be understood from the text descriptions.

[0029] like Figures 1-2As shown, a cavitation-resistant nozzle assembly structure includes an injector body 3 and a needle valve body 2 connected together. A needle valve 1 is slidably installed in the needle valve body 2 and the injector body 3. The bottom of the needle valve body 2 is provided with a needle valve body sealing surface 21 and a pressure chamber 23 from top to bottom. Several spray holes 22 are provided on the side of the pressure chamber 23. The lower part of the needle valve 1 is provided with a needle valve sealing surface 11. The needle valve sealing surface 11 and the needle valve body sealing surface 21 cooperate to form a sealing structure. The plane 22a where the highest point of the spray hole 22 is located is lower than the bottom 12 of the needle valve of the needle valve 1.

[0030] The injector body 3 and the needle valve body 2 are arranged vertically. The injector body 3 has a vertical injector channel. The bottom end of the injector channel is connected to the needle valve body 2. The side of the injector channel has an oil inlet channel 31. The middle part of the injector channel is a pressure accumulator 32, which is connected to the oil inlet channel 31.

[0031] The accumulator chamber 32 includes a primary accumulator chamber 321 and a secondary accumulator chamber 322 arranged vertically. The primary accumulator chamber 321 is arc-shaped, and the secondary accumulator chamber 322 is cylindrical. The oil inlet channel 31 is obliquely arranged on the upper part of the injector body 3. The bottom end of the oil inlet channel 31 is connected to the primary accumulator chamber 321. The arc-shaped inner wall of the primary accumulator chamber 321 buffers and slows down the high-pressure liquid in the oil inlet channel 31. The secondary accumulator chamber 322 is smaller than the primary accumulator chamber 321, so that the oil buffered in the primary accumulator chamber 321 is reduced again in the secondary accumulator chamber 322, reducing the oil pressure fluctuation inside the injector and making the high-pressure liquid more stable inside the injector.

[0032] The upper end of the needle valve 1 is a mounting post 15, which is a stepped structure used to install parts such as springs and piston sleeves. The stepped structure effectively reduces the processing difficulty compared to the multi-step structure.

[0033] The needle valve body 2 has a needle valve body guide hole 24 in the middle, and the lower part of the needle valve 1 is provided with a matching guide part 14. The guide part 14 slides in the needle valve body guide hole 24 to realize the overall positioning of the needle valve 1, which facilitates the positioning accuracy of the needle valve 1 during the lifting and lowering process.

[0034] To ensure smooth liquid flow, a flow structure 13 is provided on the outer periphery of the guide part 14. The flow structure 13 makes the needle valve 1 and the pressure chamber 23 at the bottom of the injector body 3 form an oil outlet channel, ensuring that there is a gap between the needle valve body 2 needle valve body guide hole 24 and the needle valve 1 to allow high-pressure oil to pass through, thereby realizing liquid injection.

[0035] In this embodiment, the needle valve body guide hole 24 and guide portion 14 are adapted cylindrical shapes, and the flow structure 13 is a flat part. The number of flat parts is set according to the working requirements, and can be 3 or 4, etc. In other embodiments, the flow structure 13 is a spiral groove structure.

[0036] Multiple nozzles 22 are evenly distributed in a horizontal ring on the side wall of the pressure chamber 23. The multiple nozzles 22 can be evenly distributed in a ring on different horizontal planes. The plane 22a where the highest point of the nozzle 22 is located is lower than the bottom 12 of the needle valve 1.

[0037] like Figure 3 , Figure 4 The needle valve bottom 12 of the needle valve 1 is triangular, frustum-shaped, or arc-shaped. Different shapes of needle valve bottom 12 will result in different volumes of pressure chamber 23. The smaller the volume, the less pressure is lost during transmission, and the better the spray effect of the liquid discharged from the nozzle 22.

[0038] The working process of this utility model is as follows: When the solenoid valve is energized, creating a pressure difference in the injector's volume chamber, the needle valve 1 rises under hydraulic pressure. Liquid flows through the gap between the needle valve 1 and the needle valve body 2 into the pressure chamber 23, and then is ejected through the nozzle 22. When the bottom 12 of the needle valve 1 is lower than the plane 22a where the highest point of the nozzle 22 is located, the cross-section at the inlet of the nozzle 22 changes continuously as the needle valve 1 moves up and down. The flow velocity of the liquid flowing into the pressure chamber 23 also changes accordingly. This changing flow velocity alters the local hydrostatic pressure. When the pressure is lower than the saturated vapor pressure of the cavitation bubble, the cavitation bubble will grow and rapidly expand based on the existing gas nuclei, thus producing cavitation. Figure 9 As shown, when the bottom 12 of the needle valve 1 is lower than the plane 22a where the highest point of the nozzle 22 is located, the liquid will experience backflow in the pressure chamber 23. That is, after the liquid flows into the pressure chamber 23, it first flows to a position below the nozzle 22, and then flows upward into the nozzle 22. This upward-flowing liquid will collide with the downward-flowing liquid at the inlet of the nozzle 22, thereby generating more bubbles. The shock wave generated by the bursting of bubbles will cause impact damage to the surrounding wall material, ultimately causing the nozzle 22 and the bottom 12 of the needle valve to fail due to cavitation deformation. Figure 6 As shown in the gas phase volume fraction cloud diagram, cavitation is more pronounced in the lower part of nozzle 22.

[0039] This invention designs the bottom 12 of the needle valve to be higher than the plane 22a where the highest point of the nozzle 22 is located. During the up-and-down movement of the needle valve 1, because there is no abrupt change in the cross-section at the inlet of the nozzle 22, the flow velocity of the liquid into the pressure chamber 23 will not change abruptly. Figure 6 The velocity flow field diagram shown and Figure 10 As shown in the schematic diagram of the liquid flow direction inside the pressure chamber 23, backflow is eliminated, greatly improving the turbulent state of the liquid in the pressure chamber 23. This makes the liquid ejected from the nozzle 22 more smoothly, thereby improving the cavitation effect of the nozzle 22. Figure 8 As shown in the gas phase volume fraction cloud diagram, the cavitation phenomenon at the inlet of nozzle 22 is significantly improved.

[0040] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of this utility model, and the utility model is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of this utility model, and these modifications and improvements are also considered to be within the protection scope of this utility model.

Claims

1. A cavitation-resistant nozzle assembly structure, comprising an injector body (3) and a needle valve body (2) connected together, wherein a needle valve (1) is slidably installed in the needle valve body (2) and the injector body (3), the bottom of the needle valve body (2) is provided with a needle valve body sealing surface (21) and a pressure chamber (23) from top to bottom, the side of the pressure chamber (23) is provided with several spray holes (22), the lower part of the needle valve (1) is provided with a needle valve sealing surface (11), the needle valve sealing surface (11) and the needle valve body sealing surface (21) cooperate to form a sealing structure, characterized in that, The plane (22a) where the highest point of the nozzle (22) is located is lower than the bottom (12) of the needle valve (1).

2. The cavitation-resistant nozzle assembly structure as described in claim 1, characterized in that, The injector body (3) and the needle valve body (2) are arranged vertically. The injector body (3) has a vertical injector channel. The bottom end of the injector channel is connected to the needle valve body (2). The side of the injector channel has an oil inlet channel (31). The middle part of the injector channel is a pressure accumulator (32). The pressure accumulator (32) is connected to the oil inlet channel (31).

3. The cavitation-resistant nozzle assembly structure as described in claim 1, characterized in that, The accumulator (32) includes a primary accumulator (321) and a secondary accumulator (322) arranged vertically. The primary accumulator (321) is arc-shaped, and the secondary accumulator (322) is cylindrical.

4. The cavitation-resistant nozzle assembly structure as described in claim 3, characterized in that, The oil inlet channel (31) is obliquely arranged on the upper part of the injector body (3), and the bottom end of the oil inlet channel (31) is connected to the first-stage accumulator chamber (321).

5. The cavitation-resistant nozzle assembly structure as described in claim 3, characterized in that, The secondary accumulator (322) is smaller than the primary accumulator (321).

6. The cavitation-resistant nozzle assembly structure as described in claim 1, characterized in that, The upper end of the needle valve (1) is a sleeve post (15), which is a stepped structure.

7. The cavitation-resistant nozzle assembly structure as described in claim 1, characterized in that, The needle valve body (2) has a needle valve body guide hole (24) in the middle. The lower part of the needle valve (1) is provided with a matching guide part (14). The guide part (14) slides in the needle valve body guide hole (24). The outer periphery of the guide part (14) is provided with a flow structure (13).

8. The cavitation-resistant nozzle assembly structure as described in claim 7, characterized in that, The needle valve body guide hole (24) and guide part (14) are adapted cylindrical, and the flow structure (13) is flat.

9. The cavitation-resistant nozzle assembly structure as described in claim 7, characterized in that, The flow structure (13) is a spiral groove structure.

10. The cavitation-resistant nozzle assembly structure as described in claim 1, characterized in that, The bottom (12) of the needle valve (1) is triangular, frustum-shaped, or arc-shaped.

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