Needle valve for fuel injection nozzle of fuel engine

Abstract

The present invention discloses a needle valve for a fuel engine injector, comprising a valve body and a valve core, wherein a conical sealing portion is provided at the end of the valve core, and a conical sealing surface matching the conical sealing portion is provided at the bottom of the valve body, wherein the conical sealing portion and the conical sealing surface form a conical seal to separate a pressure chamber from the inner bottom end of the valve body, and the surface of the portion where the conical sealing portion contacts the conical sealing surface is evenly distributed with an oil storage tank with a pit structure. Beneficial effects: The oil storage tank of the present invention can store a small amount of fuel before the valve core is seated, effectively reducing the impact load of the valve core on the conical sealing surface of the valve body, reducing impact wear and increasing the service life of the needle valve, and at the same time effectively improving the sealing performance; the oil storage tank can enhance the fuel atomization and mixing performance of the injector. The spoiler pit improves the fuel atomization and mixing quality during the injection process of the injector, ultimately achieving the goal of efficient combustion and low emissions of the engine.

Description

Technical Field

[0001] The invention relates to a component of an engine fuel injection system, in particular to a needle valve of a fuel injection nozzle of a fuel engine, belonging to the technical field of internal combustion engines. Background Art

[0002] The key core component of the engine fuel injection system is the fuel injector. The fuel flow inside the fuel injector plays a decisive role in the quality of fuel atomization and mixing, which directly determines the subsequent combustion and emission performance of the engine. The most core precision component in the fuel injector is the needle valve.

[0003] With the gradual upgrading of emission regulations, near-zero emission of engines has become a future development trend. Taking diesel engines as an example, the main technical means to reduce harmful particulate matter emissions from diesel engines is to use high-pressure common rail fuel injection technology. Existing studies have pointed out that increasing injection pressure is conducive to reducing particulate matter emissions. However, with the continuous increase in injection pressure, especially up to 300MPa, the pressure difference between the upper and lower sealing cone surfaces of the valve core and the needle valve body increases at the end of the injection phase, resulting in an increase in the impact load of the valve core during the seating process, which can easily lead to wear of the valve core and the needle valve body sealing cone surface, thereby affecting the sealing performance and the service life of the needle valve precision parts. In response to the above technical problems, the existing technical solutions mainly adopt some coating treatment at the junction of the valve core and the needle valve body sealing cone surface to reduce the wear of the sealing cone angle, but the existing technology does not fundamentally reduce the impact load to reduce impact wear.

[0004] On the other hand, the atomization and mixing performance of the fuel directly determines the combustion and emission performance of the engine. The existing technical solutions mainly enhance the atomization and mixing quality of the fuel by increasing the injection pressure, thereby achieving the goal of near-zero emission of the engine. Increasing the fuel injection pressure will inevitably consume the power of the engine, thus affecting the power performance and efficiency of the engine. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to address the problems existing in the prior art and to propose a needle valve for a fuel engine injector. The present invention improves the impact load on the sealing cone surface of the needle valve body during the seating process of the injector valve core, reduces impact wear and improves sealing performance. At the same time, it can effectively enhance the turbulent disturbance inside the injector and enhance the fuel atomization mixing quality of the oil storage tank structure. The deep pit structure on the inner wall of the pressure chamber of the injector needle valve body further enhances the turbulent disturbance inside the pressure chamber and improves the fuel atomization mixing quality. Its purpose is to reduce the impact load on the sealing cone surface of the needle valve body during the seating process of the valve core at the end of the injection of the injector, reduce the wear of the cone surface and improve the sealing performance. At the same time, it can enhance the turbulent disturbance intensity of the fuel inside the injector during the injection stage of the injector and improve the fuel atomization mixing quality.

[0006] Technical solution: A needle valve for a fuel engine injector, comprising a valve body and a valve core, wherein a conical sealing portion is provided at the end of the valve core, and a conical sealing surface matching the conical sealing portion is provided at the bottom of the valve body, wherein the conical sealing portion and the conical sealing surface form a conical seal to separate a pressure chamber from the inner bottom end of the valve body, and the surface of the portion where the conical sealing portion contacts the conical sealing surface is evenly covered with oil storage grooves with a pit structure.

[0007] The oil storage tank of the present invention can store a small amount of fuel before the valve core is seated. When the valve core is seated, the fuel in the oil storage tank is squeezed to produce hydraulic damping, effectively reducing the impact load of the valve core on the conical sealing surface of the valve body, reducing impact wear and increasing the service life of the needle valve. At the same time, due to the squeezing of the fuel in the oil storage tank to produce a high-pressure area, it can also effectively improve the sealing performance. During the injection process of the fuel injector, the oil storage tank of the conical sealing part will actively destroy the flow boundary layer to enhance the turbulent disturbance intensity during the fuel flow process inside the fuel injector, thereby enhancing the fuel atomization mixing performance of the fuel injector.

[0008] Preferably, in order to effectively reduce the impact load of the valve core on the conical sealing surface of the valve body, the diameter of the oil storage tank is 150 μm to 250 μm, and the depth is 2 μm to 7 μm. The oil storage tank structure is designed to store a suitable amount of oil for effective lubrication.

[0009] Preferably, in order to further effectively reduce the impact load of the valve core on the conical sealing surface of the valve body, the area of ​​the oil storage groove distributed on the surface of the conical sealing portion accounts for 2%-10% of the contact area between the conical sealing portion and the conical sealing surface. The design of the number of oil storage grooves can effectively lubricate within the conical sealing area.

[0010] Preferably, in order to improve the quality of fuel atomization and mixing, the surface of the pressure chamber is uniformly distributed with spoiler pits. During the process of fuel injection by the injector, when the high-pressure fuel flows through the pressure chamber of the valve body, the spoiler pit structure opened on the inner wall of the pressure chamber will actively destroy the flow boundary layer, thereby enhancing the turbulent disturbance inside the pressure chamber, improving the quality of fuel atomization and mixing, and ultimately achieving the goal of efficient combustion and low emissions of the engine.

[0011] Preferably, in order to improve the turbulent disturbance effect of the fuel, the diameter of the spoiler pit is 50μm to 120μm, and the depth is 10μm to 20μm. When the structural parameters of the spoiler pit are within the above range, the boundary layer in the fuel flow process can be effectively and actively destroyed, the turbulent disturbance in the fuel flow process can be improved, and the atomization mixing quality can be enhanced.

[0012] Preferably, in order to further improve the turbulent disturbance effect of the fuel, the cross-sectional area of ​​the intersection of the spoiler pit and the inner surface of the pressure chamber accounts for 5%-20% of the theoretical surface area of ​​the inner surface of the pressure chamber. When the coverage area of ​​the spoiler pit is within the above range, the boundary layer in the fuel flow process can be more effectively destroyed, the turbulent disturbance in the fuel flow process can be improved, and the atomization mixing quality can be enhanced.

[0013] Preferably, in order to improve the adaptability of the needle valve, the cross-section shape of the intersection of the oil storage tank and the surface of the conical sealing portion is circular, elliptical or polygonal. The design of the oil storage tank structure can meet the sealing and atomization requirements of various fuel injection systems.

[0014] Beneficial effects: The oil storage tank of the present invention can store a small amount of fuel before the valve core is seated. When the valve core is seated, the fuel in the oil storage tank is squeezed to produce hydraulic damping, effectively reducing the impact load of the valve core on the conical sealing surface of the valve body, reducing impact wear and increasing the service life of the needle valve. At the same time, due to the squeezing of the fuel in the oil storage tank to produce a high-pressure area, it can also effectively improve the sealing performance. During the fuel injection process of the fuel injector, the oil storage tank of the conical sealing part will actively destroy the flow boundary layer and enhance the turbulent disturbance intensity during the fuel flow process inside the fuel injector, thereby enhancing the fuel atomization mixing performance of the fuel injector. During the fuel injection process of the fuel injector, when the high-pressure fuel flows through the valve body pressure chamber, the spoiler pit structure opened on the inner wall of the pressure chamber will actively destroy the flow boundary layer, thereby enhancing the turbulent disturbance inside the pressure chamber, improving the fuel atomization mixing quality, and ultimately achieving the goals of efficient engine combustion and low emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0017] Figure 2 It is a schematic diagram of the local structure of the valve core of the present invention;

[0018] Figure 3 It is a partial enlarged view of the oil storage tank of the present invention;

[0019] Figure 4 It is a schematic diagram of the partial structure of the valve body of the present invention;

[0020] Figure 5 It is a partial enlarged view of the spoiler pit of the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0024] Embodiment 1

[0025] like Figure 1 , 2 As shown in Figure 3, a needle valve for a fuel engine injector comprises a valve body 1 and a valve core 2, wherein a conical sealing portion 21 is provided at the end of the valve core 2, and a conical sealing surface 11 matching the conical sealing portion 21 is provided at the bottom of the valve body 1, wherein the conical sealing portion 21 and the conical sealing surface 11 form a conical seal to separate a pressure chamber 12 from the inner bottom end of the valve body 1, and the surface of the portion where the conical sealing portion 21 contacts the conical sealing surface 11 is evenly distributed with oil storage grooves 22 with a pit structure.

[0026] The oil storage tank 22 of the present invention can store a small amount of fuel before the valve core 2 is seated. When the valve core 2 is seated, the fuel in the oil storage tank 22 is squeezed to produce hydraulic damping, effectively reducing the impact load of the valve core 2 on the conical sealing surface 11 of the valve body 1, reducing impact wear and increasing the service life of the needle valve. At the same time, due to the squeezing of the fuel in the oil storage tank 22 to produce a high-pressure area, the sealing performance can also be effectively improved. During the injection process of the fuel injector, the oil storage tank 22 of the conical sealing portion 21 will actively destroy the flow boundary layer and enhance the turbulent disturbance intensity during the fuel flow process inside the fuel injector, thereby enhancing the fuel atomization and mixing performance of the fuel injector.

[0027] like Figure 2 and 3 As shown, in order to effectively reduce the impact load of the valve core 2 on the conical sealing surface 11 of the valve body 1, the diameter of the oil storage tank 22 is 150μm-250μm and the depth is 2μm-7μm. The design of the structure of the oil storage tank 22 can store a suitable amount of oil for effective lubrication.

[0028] In order to improve the adaptability of the needle valve, the cross-section shape of the intersection of the oil storage tank 13 and the surface of the conical sealing portion 11 is circular, elliptical or polygonal. The design of the oil storage tank 13 structure can meet the sealing and atomization requirements of various fuel injection systems.

[0029] In order to further effectively reduce the impact load of the valve core 2 on the conical sealing surface 11 of the valve body 1, the area of ​​the oil storage groove 22 distributed on the surface of the conical sealing portion 21 accounts for 2%-10% of the contact area between the conical sealing portion 21 and the conical sealing surface 11. The design of the number of oil storage grooves 22 can effectively lubricate within the conical sealing area.

[0030] like Figure 4 and 5 As shown, in order to improve the quality of fuel atomization and mixing, the inner surface of the pressure chamber 12 is uniformly distributed with spoiler pits 13. During the process of fuel injection by the injector, when the high-pressure fuel flows through the valve body pressure chamber 12, the spoiler pits 13 structure opened on the inner wall of the pressure chamber 12 will actively destroy the flow boundary layer, thereby enhancing the turbulent disturbance inside the pressure chamber 12, improving the quality of fuel atomization and mixing, and finally achieving the goal of efficient combustion and low emissions of the engine.

[0031] In order to improve the turbulent disturbance effect of the fuel, the diameter of the spoiler pit 13 is 50μm to 120μm, and the depth is 10μm to 20μm. When the structural parameters of the spoiler pit 13 are within the above range, the boundary layer in the fuel flow process can be effectively and actively destroyed, the turbulent disturbance in the fuel flow process can be improved, and the atomization mixing quality can be enhanced.

[0032] In order to further improve the turbulent disturbance effect of the fuel, the cross-sectional area of ​​the intersection of the spoiler pit 13 and the inner surface of the pressure chamber 12 accounts for 5%-20% of the theoretical surface area of ​​the inner surface of the pressure chamber 12. When the coverage area of ​​the spoiler pit 13 is within the above range, the boundary layer in the fuel flow process can be more effectively and actively destroyed, the turbulent disturbance in the fuel flow process can be improved, and the atomization mixing quality can be enhanced.

[0033] Embodiment 2

[0034] A needle valve for a fuel injection nozzle of a fuel engine comprises a valve body 1 and a valve core 2, wherein the end of the valve core 2 is provided with a conical sealing portion 21, and the bottom of the valve body 1 is provided with a conical sealing surface 11 matching the conical sealing portion 21, wherein the conical sealing portion 21 and the conical sealing surface 11 form a conical seal to separate a pressure chamber 12 from the bottom end of the inner side of the valve body 1,

[0035] The surface of the conical sealing part 21 that contacts the conical sealing surface 11 is uniformly distributed with oil storage grooves 22 of a pit structure. The diameter of the oil storage grooves 22 is 150 μm to 250 μm, and the depth is 2 μm to 7 μm. The area of ​​the oil storage grooves 22 distributed on the surface of the conical sealing part 21 accounts for 2% to 10% of the contact area between the conical sealing part 21 and the conical sealing surface 11.

[0036] The inner surface of the pressure chamber 12 is uniformly distributed with spoiler pits 13. The diameter of the spoiler pits 13 is 50 μm to 120 μm, and the depth is 10 μm to 20 μm. The cross-sectional area of ​​the spoiler pits 13 intersecting with the inner surface of the pressure chamber 12 accounts for 5% to 20% of the theoretical surface area of ​​the inner surface of the pressure chamber 12.

[0037] The impact load of the valve core 2 on the conical sealing surface 11 of the valve body 1 is reduced during the seating of the valve core 2 at the end of the injection stage of the fuel injector, and the wear is reduced. The high-pressure area generated by the squeezed fuel in the fuel storage tank 22 also improves the sealing performance. At the same time, it also meets the goal of enhancing the turbulent disturbance of the fuel inside the fuel injector during the injection process of the fuel injector and improving the atomization and mixing quality of the fuel. It can also extend the service life of the precision couple valve core 2 and the valve body 1 of the fuel injector.

[0038] The area of ​​the oil storage tank 22 distributed on the surface of the conical sealing part 21 accounts for 2%-10% of the contact area between the conical sealing part 21 and the conical sealing surface 11. When the above conditions are met, the impact load of the valve core 2 on the conical sealing surface 11 is reduced during the seating of the valve core 2 at the end of the fuel injection of the fuel injector, and the wear is reduced. The oil storage tank 22 destroys the boundary layer of the fuel flowing inside the fuel injector during the fuel injection process of the fuel injector, enhances the turbulent disturbance of the fuel inside the fuel injector, and improves the atomization and mixing quality of the fuel. For example, if the area of ​​the oil storage tank 22 distributed on the surface of the conical sealing portion 21 accounts for a contact area between the conical sealing portion 21 and the conical sealing surface 11 that is less than the above range, a good hydraulic damping effect cannot be generated during the seating process of the valve core 2, and the impact load cannot be reduced; if the area occupancy rate is greater than the above range, the hydraulic damping force generated is too large, the valve core 2 and the valve body 1 cannot be seated well and quickly, and oil leakage problems will occur; on the other hand, if the depth H1 of the oil storage tank 22 is greater than the above range, the fuel flow performance inside the fuel injector will be reduced; if the diameter of the oil storage tank 22 is too large, it will affect the sealing performance between the needle valve sealing cone surface (40) and the conical sealing surface 11, and if the diameter D1 of the oil storage tank 22 is too small, it will not produce an effective hydraulic damping effect. Therefore, the parameters of the oil storage tank 22 must be within the above-mentioned range in order to simultaneously meet the requirements of reducing the impact load and wear of the valve core 2 on the conical sealing surface 11 during the seating process of the valve core 2 at the end of fuel injection of the injector, destroying the boundary layer of the fuel flowing inside the injector during fuel injection of the injector, enhancing the turbulent disturbance of the fuel inside the injector, improving the fuel atomization mixing quality, and taking into account the fuel flow performance inside the injector.

[0039] In an exemplary embodiment, the area of ​​the oil storage tank 22 distributed on the surface of the conical sealing portion 21 accounts for 5% of the contact area between the conical sealing portion 21 and the conical sealing surface 11. The diameter D1 of the oil storage tank 22 is 200 μm, and the depth H1 of the oil storage tank 22 is 4 μm. This can effectively reduce the impact load and wear of the valve core 2 on the conical sealing surface 11, while enhancing the turbulent disturbance of the fuel inside the fuel injector, improving the quality of fuel atomization mixing, and taking into account the fuel flow performance inside the fuel injector.

[0040] Only when the spoiler pit 13 on the inner surface of the pressure chamber 12 has a cross-sectional area occupancy rate of 5% to 20% of the theoretical surface area of ​​the entire inner surface of the pressure chamber 12, the diameter D2 of the spoiler pit 13 is 50μm to 120μm, and the depth H2 of the spoiler pit 13 is 10μm to 20μm. The spoiler pit 13 parameters are within the above range to more effectively and actively destroy the boundary layer in the fuel flow process, improve the turbulent disturbance in the fuel flow process, and then enhance the atomization mixing quality. On the contrary, outside the above range, for example, the depth H2 of the spoiler pit 13 is too large, which will destroy the overall strength of the injector valve body 1; in addition, when the area occupancy rate is too large, the turbulent structure generated in the pressure chamber 12 increases, which will affect the flow performance of the fuel inside the injector nozzle and have an adverse effect on the engine performance. Therefore, only when the structural parameters of the spoiler pit 13 are within the above range can the turbulence disturbance intensity of the fuel inside the injector be improved to improve the fuel atomization mixing quality, the fuel flow performance inside the injector, and the reliability of the injector valve body 1 be taken into consideration at the same time.

[0041] In an exemplary embodiment, the spoiler pit 13 is provided on the inner surface of the pressure chamber 12 of the fuel injector, and the cross-sectional area of ​​the intersection with the inner surface of the pressure chamber 12 occupies 10% of the theoretical surface area of ​​the entire inner surface of the pressure chamber 12, the diameter D2 of the spoiler pit 13 is 80 μm, and the depth H2 of the spoiler pit 13 is 15 μm. Providing the spoiler pit 13 on the inner surface of the pressure chamber 12 can effectively destroy the flow boundary layer during the fuel injection process of the fuel injector, enhance the turbulent disturbance intensity of the fuel flowing inside the nozzle, and improve the fuel atomization mixing quality, while also taking into account the overall flow performance of the fuel inside the fuel injector and the reliability of the valve body 1.

[0042] Under the combined effect of the oil storage tank 22 and the spoiler pit 13, the impact load and wear of the valve core 2 on the conical sealing surface 11 can be effectively reduced, while the turbulent disturbance of the fuel inside the fuel injector can be enhanced, the fuel atomization mixing quality can be improved, and the effect of the fuel flow performance inside the fuel injector can be taken into account.

[0043] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0044] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined in this specification may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A needle valve for a fuel engine injection nozzle, comprising a valve body (1) and a valve core (2), wherein the end of the valve core (2) is provided with a conical sealing portion (21), and the bottom of the valve body (1) is provided with a conical sealing surface (11) matching the conical sealing portion (21), wherein the conical sealing portion (21) and the conical sealing surface (11) form a conical seal to separate a pressure chamber (12) from the inner bottom end of the valve body (1), characterized in that: The portion of the surface of the conical sealing portion (21) that contacts the conical sealing surface (11) is uniformly distributed with oil storage grooves (22) having a pit structure; the inner surface of the pressure chamber (12) is uniformly distributed with flow-turbulating pits (13); The oil storage tank (22) has a diameter of 150 μm to 250 μm and a depth of 2 μm to 7 μm; The flow-disturbing pit (13) has a diameter of 50 μm to 120 μm and a depth of 10 μm to 20 μm.

2. The needle valve of the fuel injection nozzle of the fuel engine according to claim 1, characterized in that: The area of ​​the oil storage groove (22) distributed on the surface of the conical sealing portion (21) accounts for 2%-10% of the contact area between the conical sealing portion (21) and the conical sealing surface (11).

3. The needle valve of the fuel injection nozzle of a fuel engine according to claim 1, characterized in that: The cross-sectional area where the spoiler pit (13) intersects with the inner surface of the pressure chamber (12) accounts for 5% to 20% of the theoretical surface area of ​​the inner surface of the pressure chamber (12).

4. The needle valve of the fuel injection nozzle of a fuel engine according to claim 1, characterized in that: The cross-sectional shape of the intersection of the oil storage groove (22) and the surface of the conical sealing portion (21) is circular, elliptical or polygonal.

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