Vehicle, engine, fuel injector and valve seat of fuel injector

Abstract

The utility model provides a vehicle, an engine, an oil sprayer and a valve seat of the oil sprayer. The valve seat of the oil injector comprises a valve seat base body which is provided with a contact surface used for being in sealing fit with a valve element of the oil injector. And the protective layer is formed on the contact surface, and the protective layer comprises a carburized layer. The carburized layer has high hardness and good abrasion resistance, the carburized layer serves as an abrasion-resistant coating on the outermost layer of the valve seat and makes contact with a valve element and fuel, the adhesiveness, corrosion resistance and abrasion resistance of the coating of the valve seat can be improved, and the situation that the sealing face leaks due to cavitation of the valve seat is reduced.

Description

Technical Field

[0001] The present application relates to the field of engine technology, and in particular to a vehicle, an engine, an injector and a valve seat thereof. Background Art

[0002] The main problem with the injectors currently used in methanol engines is durability. Due to the characteristics of methanol fuel, when the methanol fuel goes from a high-pressure area to a low-pressure area, the change in pressure will cause cavitation on the valve seat surface, leading to cavitation and peeling of the valve seat sealing area material, poor sealing, increased leakage, poor engine combustion, and decreased power and torque. Utility Model Content

[0003] The present application provides a vehicle, an engine, an injector and a valve seat thereof to solve the problems in the related art.

[0004] In a first aspect, an embodiment of the present application provides a valve seat for a fuel injector, comprising:

[0005] A valve seat base having a contact surface for sealingly cooperating with a valve core of the fuel injector;

[0006] A protective layer is formed on the contact surface, wherein the protective layer comprises a carburized layer.

[0007] Optionally, the valve seat is provided with at least one nozzle hole penetrating the valve seat base and the carburized layer, and a buffer groove is formed at one end of the nozzle hole close to the carburized layer; on the projection plane perpendicular to the axial direction of the nozzle hole, the area of ​​the buffer groove is larger than the area of ​​the nozzle hole.

[0008] Optionally, the thickness of the buffer groove gradually decreases along the direction from the carburized layer to the valve seat substrate.

[0009] Optionally, the buffer grooves are evenly distributed along the axial direction of the corresponding spray holes.

[0010] Optionally, there are multiple spray holes and multiple buffer grooves, and the valve seat is formed with a flow groove between two adjacent buffer grooves, and the two adjacent buffer grooves are respectively connected to the flow grooves.

[0011] Optionally, the thickness of the circulation groove is smaller than the thickness of the buffer groove.

[0012] Optionally, the plurality of spray holes are evenly arranged along the circumference, and two adjacent spray holes are symmetrically arranged relative to the central axis of the valve seat base.

[0013] Optionally, the carburized layer has a thickness ranging from 25 μm to 30 μm.

[0014] Optionally, the valve seat substrate is a steel valve seat, the tensile strength of the steel valve seat is between 1573MPa and 1593MPa, and the yield strength of the steel is between 1465MPa and 1477MPa.

[0015] In a second aspect, an embodiment of the present application provides a fuel injector, comprising the valve seat as described in the first aspect.

[0016] In a third aspect, an embodiment of the present application provides an engine, comprising the injector as described in the second aspect.

[0017] In a fourth aspect, an embodiment of the present application provides a vehicle comprising the engine as described in the third aspect.

[0018] The valve seat of the injector of the present application forms a protective layer on the contact surface of the valve seat, and the protective layer includes a carburized layer. The carburized layer has high hardness and good wear resistance. The carburized layer serves as the outermost wear-resistant coating of the valve seat and is in contact with the valve core and the fuel. The coating adhesion, corrosion resistance and wear resistance of the valve seat can be improved, and the occurrence of sealing surface leakage of the valve seat caused by cavitation can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of a fuel injector provided in one embodiment of the present application.

[0020] Figure 2 yes Figure 1 A magnified schematic diagram of center A.

[0021] Figure 3 It is a schematic diagram of the structure of the valve seat surface provided by an embodiment of the present application. DETAILED DESCRIPTION

[0022] Here, the technical solutions in the embodiments (or "implementation methods") of the present application will be described clearly and completely in conjunction with the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0023] If there are terms involving directional indications or positional relationships in the embodiments of the present application (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings); if the specific posture changes, the directional indication or positional relationship will also change accordingly. In addition, the terms "first" and "second" in the embodiments of the present application are only used for the purpose of convenience of description and cannot be understood as indicating or implying relative importance.

[0024] In order to facilitate understanding of the technical solution of the present application, the vehicle, engine, injector and valve seat of the present application are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments and implementations can be combined with each other.

[0025] The embodiment of the present application provides a fuel injector that can be used in a vehicle engine. The working mechanism of the fuel injector is to convert liquid fuel into mist and mix it with air. For a gasoline engine with external injection, the fuel injector sprays the fuel into the intake pipe, which is mixed with air after forming a mist, and then is sucked into the cylinder for combustion during the intake stroke of the engine. For a gasoline engine with in-cylinder injection, the fuel injector directly sprays the atomized fuel into the cylinder, which is ignited by the spark plug after mixing with the air, pushing the piston to do work. In short, the function of the fuel injector is to convert a certain amount of fuel from liquid into mist, and mix it with air to provide the necessary fuel for the combustion process of the engine. Among them, the fuel used can be methanol, or a methanol-mixed fuel.

[0026] See also Figure 1 and Figure 2 As shown, specifically, the injector may include a valve body 10, a valve core 20 and a valve seat 30, wherein the interior of the valve body 10 has a receiving space and an oil outlet end (the bottom end shown in the figure) connected to the receiving space, the valve seat 30 is arranged at the oil outlet end of the valve body 10, that is, the bottom end of the valve body 10, and the valve core 20 is arranged in the receiving space inside the valve body 10. Optionally, the injector is an in-cylinder direct injection methanol injector.

[0027] The valve core 20 may include a support ring 21, a spring 22, a needle valve assembly 23, a valve ball 24, a coil (not shown), etc. The upper end of the needle valve assembly 23 is connected to the support ring 21 and the spring 22, and the lower end of the needle valve assembly 23 is connected to the valve ball 24. The valve ball 24 is sealed with the valve seat 30. A sealing belt is provided between the valve ball 24 and the valve seat 30, and a spray hole for injecting fuel is provided on the valve seat 30. The electromagnetic force generated by the coil drives the needle valve assembly 23 to move. When the coil is energized, the needle valve assembly 23 moves upward, driving the valve ball 25 and the sealing belt to separate from the valve seat, the injector opens, and the high-pressure methanol fuel is sprayed from the spray hole of the valve seat 30 and enters the combustion chamber of the engine for combustion and work. After the coil is de-energized, the needle valve assembly 23 falls back to the valve seat 30. Under the action of high-pressure methanol, the valve ball 24 adheres to the valve seat 30 through the sealing belt and blocks the spray hole, forming a seal to prevent fuel leakage.

[0028] See also Figure 3As shown, the valve seat 30 may include a valve seat base 31 and a protective layer 32. The valve seat base 31 has a contact surface (the upper surface shown in the figure) for sealing with the valve core 20 of the injector. The contact surface refers to the surface that contacts methanol or a high-temperature methanol environment and bears an impact load or a friction load. The surface may be a sealing contact surface between the valve seat and the valve ball of the valve core. The protective layer 32 is formed on the contact surface, and the protective layer 32 includes a carburized layer.

[0029] In practical applications, the valve seat substrate 31 can be made of low-carbon stainless steel, for example, low-carbon stainless steel with a carbon content of less than 0.1%. This type of stainless steel has good corrosion resistance to high-temperature methanol and formic acid. The use of low-carbon stainless steel can prevent carbon precipitation from the valve seat. Before preparing the protective layer, the valve seat substrate 31 can be heat-treated, such as quenching and tempering. After heat treatment, the hardness and strength of the contact surface can be improved, and the toughness can be adjusted. Then, a carburizing process is used to infiltrate carbon atoms into the contact surface to form a carburized layer, thereby obtaining a valve seat with high carbon on the surface and the core still maintaining the original composition.

[0030] Among them, the heat treatment can specifically include the following steps: first, the valve seat substrate is subjected to solid solution treatment, the valve seat substrate is heated to 925°C in the heat treatment furnace and kept warm for 1 hour, and then the valve seat substrate is taken out of the heat treatment furnace and air-cooled (referring to the process of using air as a cooling medium to cool the hot fluid) to room temperature. Then the valve seat substrate is kept warm at 0°C for 2 hours, and then air-cooled to room temperature. Finally, the valve seat substrate is heated to 540°C and kept warm for 4 hours, and then air-cooled to room temperature. It should be noted that each step of the heat treatment requires that the furnace temperature of the heat treatment furnace reach the set temperature before the parts are placed; after the parts are placed, the furnace temperature must be stabilized to the set temperature before timing; after the insulation time is completed, the parts must be taken out of the furnace and air-cooled, and it is not allowed to cool with the furnace in the furnace, nor is it allowed to only cut off the power or open the furnace door for air cooling.

[0031] The valve seat of the present application forms a protective layer on the contact surface of the valve seat base, and the protective layer includes a carburized layer. The carburized layer has high hardness and good wear resistance. The wear-resistant coating as the outermost layer of the valve seat is in contact with the valve core and the fuel. It can improve the coating adhesion, corrosion resistance and wear resistance of the valve seat, reduce the occurrence of sealing surface leakage caused by cavitation of the valve seat, and enable the valve seat to adapt to the high-temperature methanol corrosion environment. It can be used in various moving parts that contact high-temperature methanol to solve the durability problem of the methanol injector valve seat.

[0032] In some optional embodiments, the valve seat substrate 31 is a steel valve seat, and the tensile strength of the steel valve seat is between 1573MPa and 1593MPa, and the yield strength is between 1465MPa and 1477MPa, which can improve the corrosion resistance and wear resistance of the valve seat surface. It should be noted that the valve seat can also be made of other steels that meet the above performance parameters. Since the aperture of the spray hole of a conventional injector is extremely small, there is no effective surface treatment solution in the industry to strengthen the inside of the spray hole. This application optimizes the material of the valve seat substrate, combines heat treatment technology and carburizing technology, and improves the overall hardness and strength of the valve seat body, improves the corrosion resistance of the valve seat, and significantly improves the cavitation phenomenon of the spray hole through actual bench verification.

[0033] In some optional embodiments, the thickness of the carburized layer 32 ranges from 25 μm to 30 μm, that is, the minimum requirement for the thickness of the carburized layer 32 is 25 μm, and the maximum can be 30 μm. Within this thickness range, the cavitation resistance of the inner surface of the micropores can be fully improved, while the surface hardness of the valve seat substrate 31 can be improved, and the carburizing cost can be limited to a reasonable range. It is also possible to simultaneously improve the wear resistance of the contact surface of the valve seat substrate that bears the impact load and the corrosion resistance of the contact surface, with high hardness and good impact resistance, improve the corrosion resistance of the valve seat, and solve the sealing surface leakage caused by valve seat cavitation. In addition, while taking into account cavitation resistance, the wear resistance of the valve seat is guaranteed to achieve product functions. Preferably, in this embodiment, the thickness of the carburized layer 32 is 28 μm, which can not only ensure the cavitation resistance and surface hardness of the valve seat, but also control the carburizing cost. It should be noted that the carburizing process can be carried out at lower temperatures (approximately 850°C to 900°C), which helps reduce the risk of deformation and oxidation of components and is used to increase the hardness and wear resistance of the material surface while maintaining good toughness and strength in its core.

[0034] In some optional embodiments, the valve seat 30 is provided with at least one spray hole 33 penetrating the valve seat base 31 and the carburized layer 32, and a buffer groove 34 is formed at one end of the spray hole 33 close to the carburized layer 32. On a projection plane perpendicular to the axial direction X of the spray hole 33, the area of ​​the buffer groove 34 is larger than the area of ​​the spray hole 44. It can be understood that the buffer groove 34 can be regarded as a depression formed by the end of the valve seat 30 close to the carburized layer 32 corresponding to the spray hole 33.

[0035] In this way, when the needle valve assembly 23 moves upward, driving the valve ball 25 and the sealing belt to separate from the valve seat 30, the high-pressure fuel will first enter the buffer groove 34 when passing through the spray hole 33 quickly, which can reduce the flow rate of the fuel at the edge of the spray hole 33. After buffering, it will enter the spray hole 33, which can inhibit the formation of bubbles near the spray hole 33.

[0036] In some optional embodiments, along the direction of the carburized layer 32 toward the valve seat substrate 31, that is, Figure 3 From top to bottom, the thickness of the buffer groove 34 gradually decreases until it is aligned with the aperture of the spray hole 33, presenting a trumpet shape with a large opening and a small bottom. When the fuel passes through, it gradually flows from the area with a larger space at the opening to the area with a smaller space, which can achieve a better buffering effect.

[0037] Furthermore, the trumpet shape formed by the buffer groove 34 is evenly distributed along the axial direction of the spray hole 33. It can be understood that the axial direction of the buffer groove 34 and the corresponding axial direction of the spray hole 33 are overlapped. The shape of the buffer groove 34 can be determined according to the oil beam design and arrangement, and it is sufficient to ensure that the spray hole 33 is in the shape center of the buffer groove 34. The pressure of the fuel in the buffer groove 34 entering the spray hole 33 in all directions is relatively balanced, forming a buffer pressure-stabilizing chamber, balancing the pressure difference around the spray hole at the initial stage of injection, reducing the flow rate at the edge of the spray hole, and inhibiting the formation of bubbles near the spray hole.

[0038] Combination Figure 2 and Figure 3 As shown, taking the buffer groove 34 formed on the top surface of the valve seat 30 and the carburized layer 32 also formed on the top surface of the valve seat base 31 as an example, the spray hole 33 includes a first hole portion 331 and a second hole portion 332 that are interconnected, the first hole portion 331 being closer to the carburized layer 32 than the second hole portion 332, and the aperture of the first hole portion 331 being smaller than the aperture of the second hole portion 332. After being buffered by the buffer groove 34, the fuel enters the first hole portion 331 evenly, and then enters the second hole portion 332 with a larger aperture to be sprayed outward.

[0039] In some optional embodiments, the spray hole 33 and the buffer groove 34 are both multiple, and the valve seat 30 is formed with a flow groove 35 between two adjacent buffer grooves 34, and the two adjacent buffer grooves 34 are respectively connected to the flow groove 35 located in the middle. The flow groove 35 can play a role in drainage. After the fuel enters the buffer groove 34, the fuel can flow to other buffer grooves 34 through the flow groove 35, so that all the buffer grooves 34 can be filled up faster.

[0040] Furthermore, the thickness of the circulation groove 35 is smaller than the thickness of the buffer groove 34, that is, the concave degree of the circulation groove 35 is smaller than the concave degree of the buffer groove 34. Figure 3As shown in the cross-sectional view, the two adjacent buffer grooves 34 and the flow groove 35 in the middle form a groove structure similar to the ω-shaped structure, which can make the pressure of the fuel in the buffer groove 34 relatively balanced in all directions when entering the spray hole 33, forming a buffer pressure stabilizing cavity, balancing the pressure difference around the spray hole at the initial stage of injection, reducing the flow rate at the edge of the spray hole, and inhibiting the formation of bubbles near the spray hole. The internal fluid pressure and flow rate conditions are improved, the occurrence of methanol gasification is inhibited from the source, and the possibility of cavitation is reduced.

[0041] In some optional embodiments, the plurality of spray holes 33 are evenly arranged along the circumference, and two adjacent spray holes 33 are symmetrically arranged relative to the central axis of the valve seat base 31. Correspondingly, the buffer grooves 34 are also evenly arranged along the circumference, and two adjacent buffer grooves 34 are also symmetrically arranged relative to the central axis of the valve seat base 31. In this way, the fuel can evenly enter the buffer grooves 34 and the spray holes 33, so that the pressure of the fuel in all directions is relatively balanced.

[0042] The embodiment of the present application also provides an engine, including the injector described in the above embodiment and implementation mode. The injector adopts the valve seat described in the above embodiment and implementation mode. The valve seat forms a protective layer on the contact surface of the valve seat substrate. The protective layer includes a carburized layer. The carburized layer has high hardness and good wear resistance. As the outermost wear-resistant coating of the valve seat, it contacts the valve core and the fuel, which can improve the coating adhesion, corrosion resistance and wear resistance of the valve seat, reduce the occurrence of sealing surface leakage caused by cavitation of the valve seat, and enable the valve seat to adapt to the high-temperature methanol corrosion environment. It can be used in various moving parts that contact high-temperature methanol, and solve the durability problem of the methanol injector valve seat. In addition, while taking into account cavitation resistance, the wear resistance of the valve seat is guaranteed, the product function is realized, and the service life of the engine is increased.

[0043] The present application also provides a vehicle, including an engine as described in the above embodiments and implementation methods. The vehicle adopts the engine as described in the above embodiments and implementation methods, and the valve seat of the injector forms a protective layer on the contact surface of the valve seat substrate, and the protective layer includes a carburized layer. The carburized layer has a high hardness and good wear resistance. As the outermost wear-resistant coating of the valve seat, it contacts the valve core and the fuel, which can improve the coating adhesion, corrosion resistance and wear resistance of the valve seat, reduce the occurrence of sealing surface leakage caused by cavitation of the valve seat, and enable the valve seat to adapt to the high-temperature methanol corrosion environment. It can be applied to various moving parts that contact high-temperature methanol, and solve the durability problem of the methanol injector valve seat. In addition, while taking into account cavitation resistance, the wear resistance of the valve seat is guaranteed, the product function is realized, and the service life of the vehicle engine is increased.

[0044] It should be noted that the technical solutions or technical features described in the above embodiments can be combined or supplemented with each other without causing conflicts. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the drawings; all modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A valve seat for a fuel injector, characterized in that: include: A valve seat base having a contact surface for sealingly cooperating with a valve core of the fuel injector; a protective layer formed on the contact surface, the protective layer comprising a carburized layer; The valve seat is provided with at least one nozzle hole penetrating the valve seat substrate and the carburized layer, and a buffer groove is formed at one end of the nozzle hole close to the carburized layer; on a projection plane perpendicular to the axial direction of the nozzle hole, an area of ​​the buffer groove is larger than an area of ​​the nozzle hole.

2. The valve seat of the fuel injector according to claim 1, characterized in that: Along the direction from the carburized layer to the valve seat substrate, the thickness of the buffer groove gradually decreases.

3. The valve seat of the fuel injector according to claim 1, characterized in that: The buffer grooves are evenly distributed along the axial direction of the corresponding spray holes.

4. The valve seat of the fuel injector according to claim 1, characterized in that: There are multiple spray holes and multiple buffer grooves. The valve seat forms a flow groove between two adjacent buffer grooves. The two adjacent buffer grooves are respectively connected to the flow grooves.

5. The valve seat of the fuel injector according to claim 4, characterized in that: The thickness of the flow groove is smaller than the thickness of the buffer groove.

6. The valve seat of the fuel injector according to claim 1, characterized in that: The thickness of the carburized layer ranges from 25 μm to 30 μm.

7. The valve seat of the fuel injector according to claim 1, characterized in that: The valve seat substrate is a steel valve seat, the tensile strength of the steel valve seat is between 1573MPa and 1593MPa, and the yield strength of the steel is between 1465MPa and 1477MPa.

8. A fuel injector, characterized in that: Comprising the valve seat according to any one of claims 1 to 7.

9. An engine, characterized in that: Comprising the fuel injector as claimed in claim 8.

10. A vehicle, characterized in that: Comprising the engine as claimed in claim 9.

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