Needle valve matching part and fuel injector

Abstract

The needle valve matching part comprises a needle valve seat, a needle valve and a nozzle, a mounting cavity and an oil containing groove are formed in the needle valve seat in the axial direction of the needle valve seat, the oil containing groove communicates with the mounting cavity, and a mounting groove is further formed in the side, away from the mounting cavity, of the oil containing groove in the needle valve seat; a clamping opening communicated with the outside of the needle valve seat is formed in one end, deviating from the oil containing groove, of the mounting groove; the needle valve is arranged in the mounting cavity, one end of the needle valve extends to the bottom of the oil containing groove, and the needle valve can axially move along the needle valve seat so that the oil containing groove can communicate with the mounting groove or seal the mounting groove; the nozzle is mounted in the mounting groove, one end of the nozzle is clamped at the clamping port, the nozzle is a micron porous medium nozzle formed by high-temperature sintering of a fiber pressing mold, and a fluid medium flowing into the mounting groove through the oil containing groove is sprayed to the outer side of the needle valve seat through the nozzle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of diesel engine electronic control fuel injection, in particular to a needle valve pair and an oil injector. BACKGROUND

[0002] The thermal efficiency of a diesel propulsion main engine directly determines the endurance and loading capacity of a ship. Theoretical research shows that the indicated thermal efficiency of a diesel engine can be increased to 60% by increasing the isochoric combustion ratio in the combustion process. However, the key bottleneck limiting the controllable isochoric combustion of the diesel of the propulsion main engine is that the in-cylinder fuel is difficult to be quickly atomized and dispersed within the required time, resulting in uncontrollable in-cylinder combustion initiation and cylinder work process. Therefore, optimizing the nozzle structure of the injector needle valve pair, reducing the fuel nozzle diameter, and enhancing the fuel disturbance in the needle valve pair have become one of the core approaches to improve the atomization capacity of the injection system.

[0003] Currently, there are a series of nozzle structures such as umbrella-shaped nozzles, group nozzles, and V-shaped cross nozzles to enhance the fuel atomization performance. However, in order to meet the demand for ultra-fine fuel atomization, a needle valve pair structure with micron-level or even sub-micron-level nozzles needs to be designed. When relying on the traditional needle valve pair processing technology to make ultra-fine atomization structures, there are a series of problems such as high processing difficulty, poor processing consistency, and large injection resistance.

[0004] Based on this, the present application proposes a needle valve pair and an oil injector to solve the above technical problems. SUMMARY

[0005] The present application provides a needle valve pair in the first aspect, comprising:

[0006] A needle valve seat having an installation chamber and an oil tank opened along its axial direction, the oil tank being in communication with the installation chamber, the needle valve seat further having an installation groove opened on the side of the oil tank away from the installation chamber, and the installation groove having a clamping interface communicated with the outside of the needle valve seat opened at the end away from the oil tank;

[0007] A needle valve arranged in the installation chamber and extending to the bottom of the oil tank at one end, the needle valve being configured to move axially along the needle valve seat to communicate or seal the installation groove with the oil tank;

[0008] A nozzle mounted in the installation groove and clamped at one end to the clamping interface, the nozzle being a micron porous medium nozzle made of fiber compression molding high-temperature sintering, and the fluid medium flowing from the oil tank to the installation groove being sprayed to the outside of the needle valve seat through the nozzle.

[0009] Compared with the traditional ultra-fine atomizing nozzle structure, the nozzle of the needle valve assembly of the present invention is independently designed. The fluid medium flowing from the oil tank to the nozzle is sprayed out of the needle valve seat through the nozzle. The independently set nozzle can overcome the limitation of the existing technology where the nozzle is located at the end of the needle valve seat, making it difficult to process micron-level nozzles, and solves the problem of the high difficulty in processing traditional ultra-fine nozzles.

[0010] According to one embodiment of the present invention, the nozzle includes a force-receiving part and a mounting part along the axial direction of the needle valve, and the force-receiving part is recessed towards the mounting part at one end to form a snap-fit ​​arc surface in the direction towards the central axis of the needle valve;

[0011] The locking interface is recessed inward toward the central axis of the needle valve, and the nozzle is locked onto the locking interface at the locking arc surface to connect with the needle valve seat.

[0012] According to one embodiment of the present invention, the circumferential dimension of the mounting portion is smaller than the circumferential dimension of the force-bearing portion extending to the outside of the card interface, the circumferential dimension of the card interface increases in the direction away from the mounting portion, the size of the card interface corresponds to the circumferential dimension of the mounting portion near the end of the force-bearing portion, and the force-bearing portion is located in the mounting groove.

[0013] According to one embodiment of the present invention, the nozzle is further provided with a locking member on the side of the force-bearing part away from the mounting part. The locking member is threadedly installed in the mounting groove and one end abuts against the force-bearing part. The locking member is used to press the mounting part to fit tightly with the needle valve seat at the card interface.

[0014] According to one embodiment of the present invention, the locking element is a locking nut.

[0015] According to one embodiment of the present invention, the locking member has a cavity in the middle, and the locking member and the needle valve are spaced apart to form a pressure chamber. The fluid medium in the oil tank flows through the pressure chamber and the cavity to the nozzle and is sprayed outward of the needle valve seat through the nozzle.

[0016] According to one embodiment of the present invention, the porosity of the nozzle is calculated using the following formula:

[0017] ;

[0018] Where ε is the porosity of the nozzle; m is the mass of the solid phase inside the nozzle; ρ m V is the average density of the solid medium sampled within the nozzle; nozzle The nozzle volume is [value].

[0019] According to one embodiment of the present invention, the effective flow area of ​​the nozzle outlet is calculated using the following formula:

[0020] ;

[0021] in, σ is the effective flow area of ​​the nozzle outlet; σ is the equivalent orifice flow coefficient; ε is the porosity of the nozzle; and S is the equivalent surface area of ​​the nozzle outlet cross section.

[0022] According to one embodiment of the present invention, the formula for calculating the injection rate of the nozzle is as follows:

[0023] ;

[0024] Where q is the injection rate of the nozzle; ρ is the fuel density; S is the equivalent surface area of ​​the nozzle outlet cross-section; d f ε is the diameter of the solid phase inside the nozzle, and ε is the porosity of the nozzle; ε p α is the cutoff porosity parameter; p is an empirical parameter. rail For high-pressure common rail systems; p out This refers to the pressure inside the cylinder.

[0025] A second aspect of the present invention provides an injector comprising the needle valve assembly as described above.

[0026] According to one embodiment of the present invention, it further includes a control actuator for controlling the needle valve to move upward or downward to open or seal the mounting groove. Attached Figure Description

[0027] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0028] Figure 1 This is a schematic diagram of the structure of an embodiment of the fuel injector of the present invention;

[0029] Figure 2 for Figure 1 Enlarged schematic diagram of part of the fuel injector structure;

[0030] Figure 3 for Figure 1 A schematic diagram of the nozzle surface structure.

[0031] 1. Needle valve seat; 11. Mounting chamber; 12. Oil reservoir; 13. Mounting slot; 131. Snap-fit ​​connector;

[0032] 2. Needle valve;

[0033] 3. Nozzle; 31. Spray hole; 32. Force-bearing part; 33. Mounting part; 34. Snap-fit ​​arc surface; 35. Locking element; 351. Cavity; 36. Pressure chamber;

[0034] 4. Control the execution mechanism. Detailed Implementation

[0035] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0037] The nozzle of a traditional needle valve assembly is directly integrated into the end of the needle valve seat 1. Due to limitations in material hardness, structural shape and processing technology, it is difficult to prepare micron-level nozzles. This results in the fuel in the cylinder not being able to be atomized and dispersed quickly, and it is also prone to problems such as poor processing consistency and high fuel injection resistance, which in turn affects the controllability of the combustion start point and power process.

[0038] Reference Figure 1 and Figure 2 Based on this, this application proposes a needle valve assembly, which includes a needle valve seat 1, a needle valve 2, and a nozzle 3. The needle valve seat 1 has an installation chamber 11 and an oil reservoir 12 along its axial direction. The oil reservoir 12 is connected to the installation chamber 11. The needle valve seat 1 also has an installation groove 13 on the side of the oil reservoir 12 away from the installation chamber 11. The end of the installation groove 13 away from the oil reservoir 12 has a snap-fit ​​interface 131 that communicates with the outside of the needle valve seat 1. The needle valve 2 is located in the mounting chamber 11 and one end extends to the bottom of the oil tank 12. The needle valve 2 is configured to move axially along the needle valve seat 1 to connect the oil tank 12 with the mounting groove 13 or to seal the mounting groove 13. The nozzle 3 is installed in the mounting groove 13 and one end is snapped into the snap-fit ​​interface 131. The nozzle 3 is a micron porous medium nozzle 3 made by high-temperature sintering of fiber compression molding. The fluid medium flowing from the oil tank 12 to the mounting groove 13 is sprayed to the outside of the needle valve seat 1 through the nozzle 3.

[0039] The nozzle 3 of this application employs a micron-sized porous media sintering process, which enables the stable fabrication of micron-sized nozzles that are difficult to achieve using traditional processing methods. Furthermore, the interconnected porous media nozzle 3 with its interconnected nozzles increases the fuel atomization and dispersion area, enhances the fuel-air mixing efficiency, and reduces fuel flow resistance, thus avoiding the drawbacks of traditional ultra-fine nozzles, such as high processing difficulty, poor consistency, and high injection resistance. For details, please refer to...Figure 3 , Figure 3 The surface structure of the micron-sized porous medium nozzle 3 is shown. It is a highly flowable porous medium with uniform micron-sized pore distribution and normalized pore size distribution, that is, the nozzle holes 31 cover the entire surface and interior of the nozzle 3.

[0040] Moreover, the snap-fit ​​independent installation method of nozzle 3 and needle valve seat 1 not only simplifies the assembly process, but also allows for individual disassembly and replacement when nozzle 3 is worn or nozzle hole 31 is blocked, without the need to replace the entire needle valve seat 1, thereby significantly reducing maintenance costs and equipment downtime.

[0041] Furthermore, the fabrication process and control difficulty of the micron-sized porous media nozzle 3 are lower than those of traditional orifice nozzles, which is conducive to the engineering realization of the ultrafine atomizing nozzle 31 structure.

[0042] Optionally, the nozzle 3 can be a micron-porous media ceramic nozzle made by high-temperature sintering of fiber compression molding, which can ensure the structural reliability of the nozzle 3 under high injection pressure.

[0043] Specifically, the nozzle 3 includes a force-receiving part 32 and a mounting part 33 along the axial direction of the needle valve 2. The end of the force-receiving part 32 facing the mounting part 33 is recessed inward in the direction towards the central axis of the needle valve 2 to form a snap-fit ​​arc surface 34. The snap-fit ​​interface 131 is recessed inward in the direction towards the central axis of the needle valve 2. The nozzle 3 is snapped into the snap-fit ​​interface 131 at the snap-fit ​​arc surface 34 to connect with the needle valve seat 1.

[0044] It should be noted that the force-bearing part 32 and the mounting part 33 of this application are integrally formed, and the snap-fit ​​arc surface 34 provided between the force-bearing part 32 and the mounting part 33 facilitates a tight fit between the nozzle 3 and the needle valve seat 1.

[0045] In one embodiment, the circumferential dimension of the mounting portion 33 is larger than that of the force-bearing portion 32, and the mounting portion 33 extends to the outside of the card interface 131, while the force-bearing portion 32 is accommodated in the mounting groove 13.

[0046] The snap-fit ​​arc surface 34 increases in circumferential dimension in the direction away from the mounting part 33, so that when the nozzle 3 is installed, the nozzle 3 will not come off the snap-fit ​​interface 131 due to the restriction of the snap-fit ​​arc surface 34.

[0047] Furthermore, the snap-fit ​​arc surface 34 forms a surface seal between the snap-fit ​​interface 131 and the needle valve seat 1, thereby increasing the sealing area between the mounting part 33 and the needle valve seat 1. This can counteract the axial impact force of high-pressure fuel on the nozzle 3, prevent the nozzle 3 from having an installation gap with the needle valve seat 1, improve the sealing effect, reduce the risk of high-pressure fuel leakage, and thus reduce fuel waste.

[0048] In other words, the nozzle 3 of this application relies on snap-fit ​​installation and does not require special tools, which can greatly reduce the operation threshold during mass production. Moreover, with the snap-fit ​​arc surface 34, when the fluid medium in the mounting groove 13 is sprayed, it will only improve the sealing between the nozzle 3 and the needle valve seat 1, thus completely avoiding the formation of gaps between the nozzle 3 and the needle valve seat 1 and oil leakage.

[0049] Furthermore, the nozzle 3 is provided with a locking member 35 on the side of the force-bearing part 32 away from the mounting part 33. The locking member 35 is threaded in the mounting groove 13 and one end abuts against the force-bearing part 32. The locking member 35 is used to press the mounting part 33 to fit tightly with the needle valve seat 1 at the locking interface 131.

[0050] When installing the nozzle 3, first install the nozzle 3 into the locking interface 131, so that the locking arc surface 34 of the nozzle 3 locks into the locking interface 131 to form a pre-position. Because the circumferential dimension of the force-bearing part 32 is larger than the dimension of the locking interface 131, the nozzle 3 will not detach from the mounting groove 13 from the locking interface 131. However, the end of the nozzle 3 away from the locking interface 131 is in a free state. Therefore, this application provides a locking member 35 on the side of the nozzle 3 away from the locking interface 131. The locking member 35 limits the nozzle 3 to the locking interface 131 and applies a certain pre-tightening force to the nozzle 3. This allows the nozzle 3 to be stably locked into the locking interface 131, thereby preventing the nozzle 3 from shaking and affecting the spray direction and spray stability of the nozzle 3.

[0051] Optionally, the locking element 35 is a locking nut.

[0052] That is, the locking element 35 is threaded into the mounting groove 13. Using a locking nut for the locking element 35 improves operation and maintenance efficiency. During subsequent maintenance, the nozzle 3 can be removed simply by loosening the locking nut in the reverse direction, without damaging the needle valve seat 1 or the nozzle 3. Furthermore, the locking nut allows for flexible adjustment of the preload, preventing insufficient preload from causing seal failure or excessive preload from causing nozzle 3 deformation.

[0053] In one implementation, please continue to refer to Figure 1 and Figure 2 The locking member 35 has a cavity 351 in the middle, and the locking member 35 and the needle valve 2 are spaced apart to form a pressure chamber 36. The fluid medium in the oil tank 12 flows to the nozzle 3 through the pressure chamber 36 and the cavity 351 and is sprayed to the outside of the needle valve seat 1 through the nozzle 3.

[0054] It can be seen that the setting of pressure chamber 36 can effectively buffer the pulse fluctuations of high-pressure fuel and avoid uneven fuel output from nozzle 3 orifice 31 due to sudden pressure rise and fall. At the same time, the pressure-stabilized fuel enters nozzle 3 at a uniform speed along cavity 351, thereby ensuring uniform fuel flow rate in the micron-porous medium.

[0055] The nozzle 3 proposed in this application has completely different structural features from traditional orifice nozzles. When designing the micron-sized porous media nozzle 3, it is necessary to evaluate the porosity. Porosity is defined as the proportion of pore volume in the total volume of the nozzle 3.

[0056] Specifically, porosity can be calculated based on the amount of solid material used in the nozzle, using the following formula:

[0057] ;

[0058] Where ε is the porosity of the nozzle; m is the mass of the solid phase inside the nozzle; ρ m V is the average density of the solid phase inside the nozzle. nozzle This refers to the nozzle volume.

[0059] Based on the porosity, the effective flow area at the nozzle outlet can be calculated using the following formula:

[0060] ;

[0061] in, σ is the effective flow area at the nozzle outlet; σ is the equivalent orifice flow coefficient; ε is the nozzle porosity; S is the equivalent surface area of ​​the nozzle outlet section. The nozzle outlet is the sum of all orifices on the portion of the nozzle extending beyond the needle valve seat.

[0062] The injection rate of the nozzle can be calculated based on the effective flow area of ​​the nozzle orifice. Specifically, it can be determined using Darcy's law combined with the Tomadakis-Robertson method, as shown in the following formula:

[0063] ;

[0064] Where q is the injection rate of the nozzle; ρ is the fuel density; S is the equivalent surface area of ​​the nozzle outlet section; d f Let ε be the diameter of the solid phase inside the nozzle, and ε be the porosity of the nozzle; p To cut off the porosity parameter, it is taken as 0.11 in the Tomadakis-Robertson method; α is an empirical parameter, for example, for micron-sized porous materials formed by compression molding of 9.2 μm diameter fibers, its value is taken as 0.521; p rail For high-pressure common rail systems; p out This refers to the pressure inside the cylinder.

[0065] As mentioned above, the nozzle 3 proposed in this application can reduce the diameter of the nozzle 31 to the micrometer scale compared with the traditional ultra-fine atomization technology. This effectively reduces the diameter of the fuel jet, which in turn helps to increase the contact area between the broken fuel droplets and the high-temperature gas in the cylinder. This ensures that the fuel and the gas in the cylinder mix quickly, thereby increasing the proportion of isochoric combustion in the diesel engine combustion process and helping to increase the thermal efficiency of the diesel propulsion main engine.

[0066] This application uses micron-level porous media nozzles 31 instead of the traditional cylindrical nozzle structure. While further reducing the diameter of the nozzles 31, it increases the number of nozzles 31 per unit area. This reduces the fuel jet diameter while ensuring that the nozzles 31 have a high effective flow area and low flow resistance. Moreover, the internal pores of the nozzle 3 are interconnected, thereby enhancing the disturbance of fuel flow inside the needle valve assembly and facilitating the atomization and fragmentation of fuel in the cylinder.

[0067] The present invention also proposes an injector comprising the above-described needle valve assembly.

[0068] In one embodiment, the injector further includes a control actuator 4 for controlling the needle valve 2 to move up or down to open or seal the mounting groove 13.

[0069] Optionally, the actuator can be an electromagnetically driven structure. In non-injection conditions, the solenoid valve coil of the electromagnetically driven structure is not energized, and the lower end of the needle valve 2 is tightly fitted to the inlet of the oil reservoir 12, blocking the flow of fuel. When injection is required, the solenoid valve coil generates electromagnetic attraction to attract the armature, causing the needle valve 2 to move upward and open the mounting groove 13. As a result, the fuel in the oil reservoir 12 flows through the mounting groove 13 to the nozzle 3, and is then injected through the nozzle 3 onto the outside of the needle valve seat 1.

[0070] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation", "connection", "joining", and "fixing" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can also refer to mechanical connections. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0071] This application uses specific terms to describe embodiments of the application. Terms such as "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0072] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A needle valve assembly, characterized in that, include: The needle valve seat has an installation chamber and an oil reservoir inside along its axial direction. The oil reservoir is connected to the installation chamber. The needle valve seat also has an installation groove on the side of the oil reservoir away from the installation chamber. The end of the installation groove away from the oil reservoir has a snap-fit ​​interface that communicates with the outside of the needle valve seat. A needle valve is disposed in the mounting chamber and extends at one end to the bottom of the oil tank. The needle valve is configured to be axially movable along the needle valve seat to communicate with the oil tank or seal the mounting groove. The nozzle is installed in the mounting groove and one end is snapped into the snap-fit ​​interface. The nozzle is a micron porous medium nozzle made by high-temperature sintering of fiber compression molding. The fluid medium flowing from the oil tank into the mounting groove is sprayed to the outside of the needle valve seat through the nozzle.

2. The needle valve assembly according to claim 1, characterized in that, The nozzle includes a force-receiving part and a mounting part along the axial direction of the needle valve. The force-receiving part is recessed towards the mounting part at one end in the direction towards the central axis of the needle valve to form a snap-fit ​​arc surface. The locking interface is recessed inward toward the central axis of the needle valve, and the nozzle is locked onto the locking interface at the locking arc surface to connect with the needle valve seat.

3. The needle valve assembly according to claim 2, characterized in that, The circumferential dimension of the mounting part is smaller than the circumferential dimension of the force-bearing part, extending to the outside of the card interface. The circumferential dimension of the card-attaching arc surface increases in the direction away from the mounting part. The size of the card interface corresponds to the circumferential dimension of the mounting part near the end of the force-bearing part. The force-bearing part is located in the mounting groove.

4. The needle valve assembly according to claim 2, characterized in that, The nozzle is further provided with a locking member on the side of the force-bearing part away from the mounting part. The locking member is threaded into the mounting groove and one end abuts against the force-bearing part. The locking member is used to press the mounting part to fit tightly with the needle valve seat at the card interface.

5. The needle valve assembly according to claim 4, characterized in that, The locking component is a lock nut.

6. The needle valve assembly according to claim 4, characterized in that, The locking member has a cavity in the middle, and the locking member and the needle valve are spaced apart to form a pressure chamber. The fluid medium in the oil tank flows through the pressure chamber and the cavity to the nozzle and is sprayed outward of the needle valve seat through the nozzle.

7. The needle valve assembly according to claim 1, characterized in that, The formula for calculating the porosity of the nozzle is as follows: ； Where ε is the porosity of the nozzle; m is the mass of the solid phase inside the nozzle; ρ m V is the average density of the solid phase inside the nozzle; nozzle The nozzle volume is [value].

8. The needle valve assembly according to claim 7, characterized in that, The formula for calculating the effective flow area at the nozzle outlet is as follows: ； in, σ is the effective flow area of ​​the nozzle outlet; σ is the equivalent orifice flow coefficient; ε is the porosity of the nozzle; and S is the equivalent surface area of ​​the nozzle outlet cross section.

9. The needle valve assembly according to claim 8, characterized in that, The formula for calculating the injection rate of the nozzle is as follows: ； Where q is the injection rate of the nozzle; ρ is the fuel density; S is the equivalent surface area of ​​the nozzle outlet cross-section; d f ε is the diameter of the solid phase inside the nozzle, and ε is the porosity of the nozzle; ε p α is the cutoff porosity parameter; p is an empirical parameter. rail For high-pressure common rail systems; p out This refers to the pressure inside the cylinder.

10. A fuel injector, characterized in that, Includes the needle valve assembly as described in any one of claims 1 to 9.

11. The injector according to claim 10, characterized in that, It also includes a control actuator for controlling the needle valve to move up or down to open or seal the mounting groove.

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