Valve seat, fuel injector, engine and assembling method

Abstract

The invention provides a valve seat, a fuel injector, an engine and an assembling method.The valve seat is suitable for the fuel injector and comprises a base and a ceramic sealing element, the base is provided with a fuel channel, an assembling part is formed in the fuel channel, and the ceramic sealing element is fixedly arranged on the assembling part; the side, facing the fuel channel, of the ceramic sealing piece is provided with a sealing face, and a valve element of the fuel injector is suitable for being connected with the sealing face in an abutting mode to block the fuel channel or away from the sealing face to open the fuel channel. According to the arrangement, the ceramic material has good corrosion resistance and cannot be damaged by corrosion of methanol, so that sealing connection between the valve seat and the valve element is guaranteed, damage caused by corrosion of methanol in the using process of the methanol fuel injector can be avoided, and normal operation of an engine is guaranteed.

Description

Technical Field

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

[0002] A methanol engine is an internal combustion engine that uses methanol as fuel. Compared with fuel engines, the products of methanol combustion are mainly carbon dioxide and water, which cause less pollution to the atmospheric environment, so its environmental performance is better; in addition, methanol has the characteristics of high anti-knock coefficient, large latent heat of vaporization, and fast combustion speed, which makes the methanol engine have higher thermal efficiency; in addition, methanol is inexpensive and has better economy.

[0003] However, compared with gasoline fuel, methanol also has disadvantages such as strong corrosiveness and poor lubricity, which are particularly prominent in engine moving parts, such as oil pumps, fuel injectors and other components that directly contact methanol.

[0004] Based on the above reasons, the valve seat of the methanol injector in the prior art is easily damaged and fails during use, resulting in poor seal of the injector and engine vibration, which in turn causes engine failure. Based on this, how to prevent the valve seat in the methanol injector from being damaged during use is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] In view of this, the present application provides a valve seat to solve the problem of damage of the valve seat in the methanol fuel injector in the prior art during use. In addition, the present application also provides an injector and an engine including the valve seat, and an assembly method for assembling the valve seat.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] A valve seat, suitable for a fuel injector, comprising:

[0008] A base having a fuel channel, wherein an assembly part is formed inside the fuel channel;

[0009] A ceramic seal is fixedly arranged at the assembly part, and the ceramic seal has a sealing surface on the side facing the fuel channel, and the valve core of the injector is suitable for abutting the sealing surface to block the fuel channel, or moving away from the sealing surface to open the fuel channel.

[0010] Optionally, the cross section of the ceramic seal along its axial direction is an axial cross section, and the length of the intersection line between the axial cross section and the sealing surface is the width of the sealing surface;

[0011] The width of the sealing surface is a, and a≥0.4 mm.

[0012] Optionally, the thermal expansion coefficient of the ceramic seal is b, the thermal expansion coefficient of the base is c, and the difference between the thermal expansion coefficient of the ceramic seal and the thermal expansion coefficient of the base is d;

[0013] Wherein, d≤5%*b, or, d≤5%*c.

[0014] Optionally, the material of the base includes a metal material, and the metal material includes one or more of 9Cr18, 9Cr18MoV, 9Cr18 with coating, ASK-3900, 0Cr17Ni4Cu4Nb and NiCr20TiAl;

[0015] The material of the ceramic seal comprises one or more of zirconium oxide ceramic, aluminum oxide ceramic, titanium oxide ceramic and ceramic polymer.

[0016] Optionally, the ceramic seal is fixedly arranged at an assembly part of the base through a transition piece, and the thermal expansion coefficient of the transition piece is between the thermal expansion coefficient of the base and the thermal expansion coefficient of the ceramic seal.

[0017] Optionally, the base and the ceramic seal are connected by welding, a surface of the ceramic seal connected to the base is a connecting surface, and at least the connecting surface of the ceramic seal has a metal coating.

[0018] Optionally, the axial cross section of the ceramic seal is approximately triangular, and the assembly part is stepped, including a first table surface and a second table surface, and a vertical surface arranged between the first table surface and the second table surface;

[0019] The vertical surface and the second table surface are respectively connected to different connecting surfaces of the ceramic seal, and welding protrusions are provided on the edge of the first table surface close to the ceramic seal and the edge of the second table surface close to the axis of the fuel channel.

[0020] Optionally, the roughness of the sealing surface is R, and R≤0.8Ra.

[0021] A fuel injector, comprising:

[0022] A valve seat, which is any of the valve seats described above;

[0023] The valve core is arranged in the fuel passage of the valve seat and can move along the extending direction of the fuel passage to open or close the fuel passage.

[0024] Optionally, a spray hole plate is included, wherein the spray hole plate is arranged at the oil outlet end of the fuel channel of the valve seat, and the spray hole is arranged on the spray hole plate.

[0025] Optionally, the valve core includes a sealing ball, which is located at one end of the valve core close to the valve seat, and the sealing ball can abut against the sealing surface to block the fuel channel.

[0026] An engine comprises the fuel injector described in any one of the above items.

[0027] An assembly method, suitable for assembling any of the valve seats described above, comprises the following steps:

[0028] The surface of the ceramic seal is iron plated;

[0029] Welding and fixing the ceramic seal to the assembly part of the base;

[0030] The ceramic seal assembled on the base is turned and polished to a target size and a target surface roughness.

[0031] Optionally, the assembly part has a welding protrusion, and during welding, the welding protrusion is melted to achieve a welding connection between the ceramic seal and the base.

[0032] The valve seat provided in the present application includes a base and a ceramic seal, wherein the ceramic seal is fixedly arranged in an assembly part and forms a surface in the valve seat for sealing connection with the valve core, namely, a sealing surface. Since the ceramic material has good corrosion resistance, it will not be damaged by the corrosion of methanol, thereby ensuring the sealing connection between the valve seat and the valve core. In this way, the damage caused by methanol corrosion during use of the methanol injector can be avoided, thereby ensuring the normal operation of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application 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 application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0034] Figure 1 A schematic diagram of the combined structure of the valve core and the valve seat in an embodiment of the present application;

[0035] Figure 2 for Figure 1 A partial enlarged view of the middle A area;

[0036] Figure 3 for Figure 1 Schematic diagram of the base in area A;

[0037] Figure 4 is the weight loss rate of different materials after being immersed in methanol and formic acid solution;

[0038] Figure 5 This is the dynamic flow rate change diagram of a conventional fuel injector;

[0039] Figure 6 A dynamic flow change diagram of a fuel injector using the valve seat in an embodiment of the present application.

[0040] exist Figure 1-Figure 6 middle:

[0041] 1. Base, 2. Fuel channel, 3. Ceramic seal, 4. Sealing ball, 5. Orifice plate, 6. First weld, 7. Second weld, 8. Vertical surface, 9. First table surface, 10. Welding protrusion, 11. Second table surface, 12. Valve core, 13. Sealing surface. DETAILED DESCRIPTION

[0042] The valve seat in the embodiment of the present application is suitable for a fuel injector, and can cooperate with the valve core of the fuel injector to control the opening or closing of the fuel channel, thereby achieving accurate and efficient injection of the fuel; further, it is particularly suitable for application scenarios in which methanol is used as the injection fuel.

[0043] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0044] The injector is a key component in the engine fuel supply system. Its main function is to atomize the fuel (fuel here includes gasoline, methanol, etc.) and distribute it in the engine combustion chamber to meet the combustion needs. The working principle of the injector is based on the on-off of the solenoid valve. When the solenoid coil is energized, an electromagnetic force is generated, which causes the valve core to be sucked up, thereby opening the fuel channel. The fuel is ejected at high speed through the injection hole at the oil outlet end of the fuel channel to form a mist. This atomized fuel is conducive to full mixing with air and improving combustion efficiency. When the power is off, the electromagnetic force disappears, and the valve core blocks the fuel channel under the action of the return spring, stopping the injection of fuel. The valve seat of the injector is an important part of the valve assembly in the injector. It cooperates with the valve core of the injector to control the opening or closing of the fuel channel, thereby achieving accurate and efficient injection of fuel.

[0045] When methanol is used as an engine fuel, due to its strong corrosiveness and poor lubricity, the valve seat of the injector is easily damaged and fails during use, resulting in poor injector sealing and engine vibration, which in turn causes engine failure. Based on this problem, related technologies use metal surface coating processes for strengthening. However, for smaller parts, especially the injector valve seat sealing surface, the depth and width are both in the millimeter level, which cannot be achieved by the traditional practical physical vapor deposition (PVD) method. The coating technology is limited by many factors such as material performance, structure, and surface finish, and its operability is not strong.

[0046] Based on the above problems, the present application separates the valve seat of the fuel injector into a base 1 and a ceramic seal 3, and uses the ceramic seal 3 to cooperate with the valve core 12 of the fuel injector to control the opening or closing of the fuel channel 2, thereby effectively improving the operability of the scheme and avoiding damage to the valve seat due to corrosion by methanol. Specifically:

[0047] like Figure 1-Figure 3 As shown, the valve seat in the embodiment of the present application includes a base 1 and a ceramic seal 3, wherein the base 1 is the main structure of the valve seat, which has a fuel channel 2 (i.e., a channel for guiding fuel), and an assembly part is formed inside the fuel channel 2 (the assembly part here refers to the part inside the fuel channel 2 for installing the ceramic seal 3, the same below). The ceramic seal 3 is a seal made of ceramic material, which is fixedly arranged in the assembly part and is used to cooperate with the valve core 12 of the injector to realize the opening and closing of the fuel channel 2; specifically, the ceramic seal 3 has a sealing surface 13 on the side facing the fuel channel 2, and the valve core 12 of the injector is suitable for abutting the sealing surface 13 to block the fuel channel 2, or away from the sealing surface 13 to open the fuel channel 2, that is, when the valve core 12 of the injector abuts against the sealing surface 13, the fuel channel 2 can be blocked, and when the valve core 12 of the injector is separated from the sealing surface 13, the fuel channel 2 can be opened, at this time, the fuel inside the fuel channel 2 can be sprayed out through the injection hole and form a mist.

[0048] It should be noted that: Figure 4 The figure shows the test results of the corrosion test on different metal materials and zirconia ceramic materials using methanol formic acid solution, wherein the immersion time of different materials in the above solution is 600 hours, the methanol formic acid solution includes methanol, formic acid and water, and the weight ratio of methanol, formic acid and water is 94:1:5. Figure 4As shown in the figure, different metal materials have a certain degree of weight loss after being immersed in methanol formic acid solution for 600 hours, that is to say, the metal materials will be partially dissolved in the methanol formic acid solution after being immersed in the methanol formic acid solution for 600 hours, which is a direct manifestation of corrosion. In comparison, the immersion weight loss rate of zirconia ceramics is 0, that is to say, zirconia ceramics are not corroded after being immersed in the methanol formic acid solution for 600 hours; obviously, the performance of ceramic materials in resisting corrosion from methanol formic acid solution is much higher than that of metal materials.

[0049] It should also be noted that the ceramic seal 3 can be a ceramic sealing ring, or a ceramic sealing ring covering the entire fuel channel 2 or covering part of the fuel channel 2. In specific implementation, the shape of the ceramic seal 3 can be designed as needed, and it only needs to be able to form the above-mentioned sealing surface 13 to fall within the scope of the ceramic seal 3 in the embodiment of the present application.

[0050] The valve seat mentioned above realizes the on-off control of the fuel channel 2 through the ceramic seal 3 and the valve core 12 of the injector. Since the ceramic material has good corrosion resistance, when it is used in a scenario where methanol is used as fuel, the ceramic seal 3 will not be damaged by the corrosion of methanol, or in other words, the sealing surface 13 in the valve seat will not be damaged by the corrosion of methanol, thereby ensuring the sealing between the sealing surface 13 and the valve core 12 of the injector, avoiding engine jitter caused by loose sealing of the injector, and ensuring the normal use of the engine.

[0051] The ceramic seal 3 is along its axial direction (the axial direction of the ceramic seal 3 can be specifically referred to in the appendix of the specification). Figure 1 ) is an axial cross section, and the length of the intersection line of the axial cross section and the sealing surface 13 is the width of the sealing surface 13. Figure 2 As shown, in some embodiments, the width of the sealing surface 13 is a, and a≥0.4 mm, for example: the width of the sealing surface 13 can be 0.4 mm, 0.6 mm or 0.7 mm, etc.; in this way, after the valve core 12 abuts against the sealing surface 13, the cooperation between the two can effectively block the fuel channel 2, so as to avoid engine jitter caused by loose sealing of the injector.

[0052] It should be noted that the part of the valve core 12 that abuts the sealing surface 13 is a sealing part, and the shape of the sealing surface 13 can be set to a curved surface that matches the surface shape of the sealing part. For example, when the surface of the sealing part (hereinafter referred to as the abutting surface) is a spherical surface (for details, please refer to the attached manual). Figure 1), the sealing surface 13 can be set to an inner concave spherical arc surface that matches the above-mentioned spherical surface, but under the above-mentioned setting mode, there is surface contact between the ceramic seal 3 and the valve core 12. In order to ensure the sealing performance, it is necessary to ensure that the sealing surface 13 and the abutting surface have extremely high processing accuracy and assembly accuracy. At the same time, the fuel cannot contain any granular impurities, otherwise there will be a gap between the ceramic seal 3 and the valve core 12, affecting the sealing performance between the two, which undoubtedly increases the processing cost and processing difficulty, and increases the probability that the injector cannot work normally; Based on the above problems, in some preferred embodiments, the sealing surface 13 is set to a shape similar to the side of a truncated cone. At this time, the intersection line of the axial section of the ceramic seal 3 and the sealing surface 13 is a straight line, and the ceramic seal 3 and the valve core 12 are in line contact, which can effectively reduce the probability of the above-mentioned sealing problems. Of course, in some other embodiments, the sealing surface 13 can also be set to an outer convex spherical arc surface.

[0053] In some embodiments, the thermal expansion coefficient of the ceramic seal 3 is b, the thermal expansion coefficient of the base 1 is c, and the difference between the thermal expansion coefficient of the ceramic seal 3 and the thermal expansion coefficient of the base 1 is d; wherein, d≤5%*b, or, d≤5%*c. That is, the difference between the thermal expansion coefficient of the ceramic seal 3 and the thermal expansion coefficient of the base 1 is less than or equal to 5% of the thermal expansion coefficient of the ceramic seal 3, or, the difference between the thermal expansion coefficient of the ceramic seal 3 and the thermal expansion coefficient of the base 1 is less than or equal to 5% of the thermal expansion coefficient of the base 1. It can be understood that the temperature of the injector will change during use. In addition, in some application scenarios, the base 1 and the ceramic seal 3 are connected by welding. Based on this, the present embodiment limits the difference between the thermal expansion coefficient of the ceramic seal 3 and the thermal expansion coefficient of the base 1, which can avoid the connection failure between the ceramic seal 3 and the base 1 due to the large difference between the thermal expansion coefficients of the ceramic seal 3 and the base 1, thereby ensuring the connection strength between the ceramic seal 3 and the base 1 and the service life of the injector.

[0054] Further, in some embodiments, the material of the base 1 includes a metal material, for example: one or more of 9Cr18, 9Cr18MoV, 9Cr18 with coating, ASK-3900, 0Cr17Ni4Cu4Nb and NiCr20TiAl and other metal materials. In the specific implementation, adaptive selection can be made as needed. The material of the ceramic seal 3 includes one or more of zirconia ceramics, alumina ceramics, titanium oxide ceramics and ceramic polymers. Under this setting, the base 1 is prepared by metal material, and its molding process is more mature, which is more conducive to reducing production costs. Of course, in some other embodiments, the base 1 can also be prepared by ceramic material (it should be noted that: at this time, the base 1 and the ceramic seal 3 can be integrally formed), or partially prepared by ceramic material.

[0055] In other embodiments, the ceramic seal 3 is fixedly arranged at the assembly part of the base 1 through a transition piece, and the thermal expansion coefficient of the transition piece is between the thermal expansion coefficient of the base 1 and the thermal expansion coefficient of the ceramic seal 3. That is to say, in this embodiment, the ceramic seal 3 and the base 1 are not directly connected, but are connected through a transition piece. In this arrangement, since the ceramic seal 3 and the base 1 are not directly connected, the allowable range of the difference between the thermal expansion coefficient of the ceramic seal 3 and the thermal expansion coefficient of the base 1 can be increased, thereby making the material selection of the ceramic seal 3 and the base 1 more diversified.

[0056] It should be noted that the transition piece can be an integral structural piece, that is, the transition piece is formed in one piece using one material or multiple materials, and the thermal expansion coefficients of the part of the transition piece connected to the ceramic seal 3 and the part of the transition piece connected to the base 1 are consistent; under this setting, the manufacturing cost of the transition piece is lower. In addition, the transition piece can also be a layered structure, and different layers of the transition piece are made of materials with different thermal expansion coefficients; this setting is conducive to further increasing the allowable range of the difference between the thermal expansion coefficient of the ceramic seal 3 and the thermal expansion coefficient of the base 1.

[0057] In some embodiments, the base 1 and the ceramic seal 3 are connected by welding, and the surface of the ceramic seal 3 connected to the base 1 is the connection surface, and at least the connection surface of the ceramic seal 3 has a metal coating. It can be understood that during the welding process, the metal coating can improve the wettability of the connection surface of the ceramic seal 3, so that the metal solder can spread and penetrate more easily on the connection surface during the welding process, thereby increasing the welding area and improving the firmness of the connection. Specifically, in an exemplary embodiment, the base 1 is a 9Cr18 metal material, the ceramic seal 3 is a zirconia ceramic material, and the connection surface of the zirconia ceramic material has an iron coating to enhance the connection between the base 1 and the ceramic seal 3.

[0058] It should be understood that welding connection is only an exemplary connection method between the base 1 and the ceramic seal 3, but the present application is not limited thereto. For example, the base 1 and the ceramic seal 3 can also be connected by interference fit, or the base 1 and the ceramic seal 3 can also be connected to the fuel channel 2 of the base 1 by two axial limiting structures. Of course, in the specific implementation, no matter what connection method is used, it is necessary to ensure the sealing between the base 1 and the ceramic seal 3.

[0059] Further, such as Figure 2 and Figure 3As shown, in some embodiments, the axial cross-section of the ceramic seal 3 is nearly triangular, and the assembly part is stepped, including a first table 9 and a second table 11, and a vertical surface 8 arranged between the first table 9 and the second table 11; wherein the vertical surface 8 and the second table 11 are respectively connected to different connecting surfaces of the ceramic seal 3, and the edge of the first table 9 close to the ceramic seal 3 and the edge of the second table 11 close to the axis of the fuel channel 2 are both provided with welding protrusions 10. The welding protrusions 10 serve as a material storage structure for filling the weld. During the welding process, the welding protrusions 10 are melted using welding equipment (such as a laser welder). The molten material generated after the melting of the welding protrusions 10 can effectively fill the weld (the weld here includes Figure 2 The first weld 6 and the second weld 7 in the ceramic seal 3 can not only achieve a high-strength connection between the ceramic seal 3 and the base 1, but also improve the sealing between the ceramic seal 3 and the base 1. In addition, it can be understood that in order to avoid interference between the first table 9 and the valve core 12, after the ceramic seal 3 is assembled to the base 1, the height of the first table 9 should not exceed the ceramic seal 3. Similarly, in the axial direction of the fuel channel 2, the extension length of the second table 11 should not exceed the ceramic seal 3. At the same time, since the second table 11 is provided with a welding protrusion 10, this means that after the ceramic seal 3 is placed in the assembly position, it must be higher than the second table 11. Combined with the small size of the valve seat itself, during the welding process, the welding heat must pass through the ceramic seal 3 to be transferred to the welding protrusion 10. On this basis, in this embodiment, the axial cross-section of the ceramic seal 3 is set to a nearly triangular shape, and the welding protrusion 10 is set at the edge of the first table 9 close to the ceramic seal 3 and the edge of the second table 11 close to the axis of the fuel channel 2. With this arrangement, the heat transfer path to the welding protrusion 10 is shorter, thereby effectively reducing the difficulty of welding.

[0060] It should be understood that the nearly triangular axial cross-section of the ceramic seal 3 described above is only an exemplary shape structure of the ceramic seal 3, but the present application is not limited to this. For example, the shape of the axial cross-section of the ceramic seal 3 can also be trapezoidal, fan-shaped or irregular.

[0061] Further, in some embodiments, the roughness of the sealing surface 13 is R, and R≤0.8Ra. This is conducive to enhancing the sealing between the sealing surface 13 and the valve core 12 of the injector, thereby increasing the service life of the injector. Exemplarily, in some embodiments, the surface roughness of the sealing surface 13 is 0.2Ra. In other embodiments, the surface roughness of the sealing surface 13 is 0.4Ra. In other embodiments, the surface roughness of the sealing surface 13 is 0.8Ra.

[0062] Example

[0063] The beneficial effects of the valve seat in the embodiment of the present application are described in more detail below by taking the case where the base 1 is made of 9Cr18 metal material and the ceramic seal 3 is made of zirconia ceramic material.

[0064] Specifically, Figure 1 As shown, in this embodiment, the ceramic seal 3 is a ceramic sealing ring, and the axial section of the ceramic seal 3 is a right triangle, and the surface corresponding to the hypotenuse of the right triangle is a sealing surface 13, and the width of the sealing surface 13 is 0.6 mm or the length of the hypotenuse of the above right triangle is 0.6 mm. In addition, the surface roughness of the sealing surface 13 is 0.6Ra; a fuel channel 2 is provided at the axial position of the base 1, and the inner wall of the fuel channel 2 has a stepped assembly part, the assembly part includes a first table top 9 and a second table top 11, and a vertical surface 8 arranged between the first table top 9 and the second table top 11, the ceramic seal 3 is welded and fixed to the above assembly part, and different connecting surfaces of the ceramic seal 3 (i.e., the two surfaces corresponding to the two right-angled sides of the above right triangle) are respectively connected to the vertical surface 8 and the second table top 11 of the assembly part.

[0065] Figure 5 The figure shows the dynamic flow rate change of the fuel injector in the related art (i.e., the conventional fuel injector, the fuel injector is made of metal material as a whole); Figure 6 The figure shows the dynamic flow rate change of the fuel injector using the valve seat in this embodiment under the same test conditions (i.e., the fuel injector in the related art and the fuel injector using the valve seat in this embodiment are tested under the same working conditions). The dynamic flow rate of the fuel injector refers to the amount of fuel injected during the dynamic process of the fuel channel 2 opening and closing under specific working conditions. Correspondingly, the dynamic flow rate change of the fuel injector refers to the change in the amount of fuel injected during the dynamic process of the fuel channel 2 opening and closing under specific working conditions. Figure 5 As shown in the figure, during the test of the fuel injector in the related art, as the number of tests increases, the dynamic flow rate change of the fuel injector increases significantly, and after 600 million durability tests, the dynamic flow rate change of the fuel injector is generally above 3.5%. Figure 6 As shown, during the test of the fuel injector using the valve seat in this embodiment, as the number of tests increases, the dynamic flow rate change of the fuel injector does not increase significantly, and after 600 million durability tests, the dynamic flow rate change of the fuel injector is generally below 0.5%. It can be seen that compared with the fuel injector in the related art, the performance of the fuel injector using the valve seat in this embodiment is significantly better, that is, the fuel injector using the valve seat in this embodiment is less likely to be damaged by methanol corrosion during use, thereby ensuring the normal operation of the engine.

[0066] The embodiment of the present application also discloses a fuel injector, which includes a valve seat and a valve core 12, wherein the valve seat is the valve seat mentioned above, and the valve core 12 is arranged in the fuel channel 2 of the valve seat and can move along the extension direction of the fuel channel 2 to open or close the fuel channel 2. It should be noted that: since the fuel injector in the embodiment of the present application includes the valve seat mentioned above, the beneficial effects of the fuel injector brought by the valve seat are discussed in detail above, and the present application will not repeat them here.

[0067] Furthermore, in some embodiments, the fuel injector further includes a spray hole plate 5, which is arranged at the oil outlet end of the fuel channel 2 of the valve seat, and the spray hole plate 5 is provided with a fuel injection hole connected to the fuel channel 2. In this arrangement, the structure forming the fuel injection hole in the fuel injector is arranged separately from the valve seat, which is more conducive to the processing of the fuel channel 2 in the valve seat, thereby improving the processing efficiency.

[0068] It should be noted that the number, size and shape of the fuel injection holes on the nozzle plate 5 can be adaptively designed according to needs, and this application does not limit this, but it needs to be ensured that the fuel can be atomized after being sprayed through the nozzle. Exemplarily, the number of fuel injection holes can be 1 to 7, the size range of the fuel injection holes can be 0.1mm to 0.6mm, and the shape can be triangular, circular, rectangular or irregular. More specifically, in some embodiments, a circular fuel injection hole is provided on the nozzle plate 5 of the fuel injector, and the size of the fuel injection hole is 0.45mm. In other embodiments, two irregular fuel injection holes are provided on the nozzle plate 5 of the fuel injector, and the size of the fuel injection hole is 0.3mm.

[0069] In addition, if Figure 1 As shown, the valve core 12 includes a sealing ball 4, which is located at one end of the valve core 12 close to the valve seat, and the sealing ball 4 can abut against the sealing surface 13 to block the fuel channel 2. The part of the valve core 12 that cooperates with the sealing surface 13 is set to be spherical, which is more conducive to improving the sealing between the valve core 12 and the valve seat.

[0070] Furthermore, in some embodiments, the surface of the sealing ball 4 is strengthened. Specifically, a ceramic layer can be formed on the surface of the sealing ball 4 to improve its corrosion resistance. The ceramic layer can be a zirconium oxide ceramic layer, an aluminum oxide ceramic layer, etc., and can be adaptively designed according to needs during specific implementation.

[0071] The embodiment of the present application also discloses an engine, which includes the above-mentioned fuel injector. It should be noted here that: since the engine includes the above-mentioned fuel injector, the beneficial effects brought by the fuel injector to the engine are discussed in detail above, and the present application will not repeat them here.

[0072] In addition, the embodiment of the present application also discloses an assembly method, which is suitable for assembling the valve seat mentioned above, and more specifically, suitable for assembling the ceramic seal 3 in the valve seat on the base 1. The assembly method comprises the following steps:

[0073] The surface of the ceramic seal 3 is iron-plated to enhance the welding effect between the ceramic seal ring and the metal base 1. It should be noted that the specific treatment method of the iron-plating treatment can refer to the prior art and will not be repeated in this application.

[0074] The ceramic seal 3 is welded and fixed to the assembly part of the base 1; in specific implementation, the ceramic seal 3 is pressed into the base 1 at the position for assembling the ceramic seal 3 after positioning by the tooling, and then the protrusion 10 is welded using a laser device to form a molten material. The molten material is filled into the weld between the ceramic seal 3 and the base 1 under the action of factors such as gravity, thereby realizing the welding connection between the ceramic seal 3 and the base 1 and strengthening the sealing effect between the two.

[0075] The ceramic seal 3 assembled on the base 1 is turned and polished to a target size and a target surface roughness; the target size here refers to the size that can achieve a sealed connection between the valve core 12 and the ceramic seal 3, and the target surface roughness specifically refers to a surface roughness ≤ 0.8Ra. Further, in some other embodiments, other areas in the fuel channel 2 can also be turned and polished simultaneously, such as the area around the ceramic seal 3.

[0076] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0077] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0078] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0079] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0080] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solution and cannot be used to limit the scope of protection of the present application.

[0081] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A valve seat, suitable for a fuel injector, characterized in that: The valve seat comprises: A base having a fuel channel, wherein an assembly part is formed inside the fuel channel; A ceramic seal is fixedly arranged at the assembly part, and the ceramic seal has a sealing surface on the side facing the fuel channel, and the valve core of the injector is suitable for abutting the sealing surface to block the fuel channel, or moving away from the sealing surface to open the fuel channel.

2. The valve seat according to claim 1, characterized in that: The cross section of the ceramic seal along its axial direction is an axial cross section, and the length of the intersection line between the axial cross section and the sealing surface is the width of the sealing surface; The width of the sealing surface is a, and a≥0.4 mm.

3. The valve seat according to claim 2, characterized in that: The thermal expansion coefficient of the ceramic seal is b, the thermal expansion coefficient of the base is c, and the difference between the thermal expansion coefficient of the ceramic seal and the thermal expansion coefficient of the base is d; Wherein, d≤5%*b, or, d≤5%*c.

4. The valve seat according to any one of claims 1 to 3, characterized in that: The material of the base includes a metal material, and the metal material includes one or more of 9Cr18, 9Cr18MoV, 9Cr18 with coating, ASK-3900, 0Cr17Ni4Cu4Nb and NiCr20TiAl; The material of the ceramic seal comprises one or more of zirconium oxide ceramic, aluminum oxide ceramic, titanium oxide ceramic and ceramic polymer.

5. The valve seat according to any one of claims 2, characterized in that: The ceramic seal is fixedly arranged on the assembly part of the base through a transition piece, and the thermal expansion coefficient of the transition piece is between the thermal expansion coefficient of the base and the thermal expansion coefficient of the ceramic seal.

6. The valve seat according to any one of claims 1 to 3, characterized in that: The base and the ceramic seal are connected by welding, the surface of the ceramic seal connected to the base is a connection surface, and at least the connection surface of the ceramic seal has a metal coating.

7. The valve seat according to claim 6, characterized in that The axial cross section of the ceramic seal is nearly triangular, and the assembly part is stepped, including a first table surface, a second table surface, and a vertical surface arranged between the first table surface and the second table surface; The vertical surface and the second table surface are respectively connected to different connecting surfaces of the ceramic seal, and welding protrusions are provided on the edge of the first table surface close to the ceramic seal and the edge of the second table surface close to the axis of the fuel channel.

8. The valve seat according to any one of claims 1 to 3, characterized in that: The roughness of the sealing surface is R, and R≤0.8Ra.

9. A fuel injector, characterized in that: include: The valve seat is the valve seat according to any one of claims 1 to 8; The valve core is arranged in the fuel passage of the valve seat and can move along the extending direction of the fuel passage to open or close the fuel passage.

10. The fuel injector according to claim 9, characterized in that: It comprises a spray hole plate, which is arranged at the oil outlet end of the fuel channel of the valve seat and is provided with oil spray holes.

11. The fuel injector according to claim 9 or 10, characterized in that: The valve core comprises a sealing ball, which is located at one end of the valve core close to the valve seat, and the sealing ball can abut against the sealing surface to block the fuel channel.

12. An engine, characterized in that: A fuel injector comprising any one of claims 9 to 11.

13. An assembly method, characterized in that: A valve seat suitable for assembling any one of claims 1 to 8, comprising the following steps: The surface of the ceramic seal is iron plated; Welding and fixing the ceramic seal to the assembly part of the base; The ceramic seal assembled on the base is turned and polished to a target size and a target surface roughness.

14. The assembly method according to claim 13, characterized in that: The assembly part has a welding protrusion, and during welding, the welding protrusion is melted to achieve the welding connection between the ceramic sealing component and the base.

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