Methanol injector valve seat, preparation method thereof, methanol injector and engine

Abstract

The invention relates to the technical field of engines, in particular to a methanol injector valve seat, a preparation method thereof, a methanol injector and an engine. The invention provides a methanol ejector valve seat. The methanol ejector valve seat comprises a valve seat body and at least one spray hole formed in the valve seat body. A coating is arranged on the inner wall face of the spray hole and comprises a base coat arranged on at least part of the inner wall face of the spray hole and a functional layer arranged on the base coat. Wherein the material of the base layer comprises Si, and the material of the functional layer comprises DLC. The methanol ejector comprises the methanol ejector valve seat. The problem of cavitation of the spraying hole of the methanol injector can be effectively relieved, the corrosion resistance of the spraying hole is improved, then the working stability of the methanol injector can be improved, and the service life of the methanol injector can be prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a methanol injector valve seat and a preparation method thereof, a methanol injector and an engine. Background Art

[0002] The engine is an important part of the car. In recent years, in order to get rid of the dependence on fossil fuels, methanol engines have gradually become a research hotspot in the field of new energy vehicles. Methanol engines use methanol as the main fuel, and have the advantages of clean emissions and good economic performance. At present, methanol vehicles adopt the intake manifold multi-point injection technology solution, which has low methanol injection pressure and poor atomization, resulting in poor fuel economy and emissions. As users have higher and higher requirements for economy and emission regulations are becoming more and more stringent, the technological innovation of the methanol supply system is more urgent. The direct injection technology has been verified in the field of gasoline engines, and has obvious effects on economy and emission improvement. Therefore, the direct injection methanol engine is also a technical route with great development prospects. However, in the high temperature and high pressure working environment of methanol direct injection injectors, due to the physical and chemical characteristics of methanol itself, the saturated vapor pressure is low. During the injection process of the injector, methanol fuel is prone to generate bubbles due to pressure changes. During the collapse of the bubbles, micro-jets and impact force are generated, which cause cavitation to the injector nozzle and destroy its surface characteristics, resulting in abnormal injector flow and spray.

[0003] It can be seen that although the injection of methanol by direct injection injectors significantly improves the engine economy and emissions, and significantly improves the engine cold start performance. However, due to the low saturated vapor pressure of methanol, the high temperature and high pressure working environment of the methanol direct injection injector causes methanol to generate bubbles during the injection process. The bubbles burst with the pressure change, causing cavitation on the injector nozzle, destroying the surface characteristics of the injector nozzle, affecting the flow rate and spray state of the injector (injector), and in severe cases causing the injector to fail.

[0004] Therefore, solving the cavitation problem of the methanol injector's spray hole and improving the working stability of the methanol injector are important topics in the current research on the methanol injector system. Summary of the invention

[0005] In view of this, the present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, the present invention provides a methanol injector valve seat and a preparation method thereof, a methanol injector and an engine, which can effectively alleviate the cavitation problem of the methanol injector spray hole.

[0006] In order to solve the above technical problems, this application is implemented as follows:

[0007] According to one aspect of the present application, an embodiment of the present application provides a methanol injector valve seat, the methanol injector valve seat comprising: a valve seat body and at least one spray hole provided in the valve seat body;

[0008] A coating is provided on the inner wall surface of the spray hole, wherein the coating comprises a primer layer provided on at least a part of the inner wall surface of the spray hole, and a functional layer provided on the primer layer;

[0009] Wherein, the material of the base layer includes Si, and the material of the functional layer includes DLC.

[0010] In addition, the current collector according to the present application may also have the following additional technical features:

[0011] In some embodiments, the thickness of the primer layer is 0.1 μm to 3 μm.

[0012] In some embodiments, the thickness of the functional layer is 1 μm to 6 μm.

[0013] In some embodiments, the hardness of the coating ranges from 2000 HV to 4000 HV.

[0014] In some of the embodiments, the valve seat body is provided with an inner cavity for accommodating a valve ball, and the spray hole is provided on the bottom wall of the inner cavity and penetrates the bottom wall; the bottom wall is used to match the shape of the spherical surface of the valve ball, and the spray hole is used to cooperate with the valve ball to open or close the spray hole.

[0015] According to another aspect of the present application, an embodiment of the present application provides a method for preparing a methanol injector valve seat, the method comprising:

[0016] Providing a valve seat body, wherein the valve seat body is provided with at least one spray hole;

[0017] forming a primer layer on at least a portion of the inner wall surface of the nozzle hole, wherein the material of the primer layer includes Si;

[0018] A functional layer is formed on the surface of the primer layer, and a material of the functional layer includes DLC.

[0019] In some embodiments, the forming of the base layer specifically includes: in an inert gas atmosphere, using Si as a target material, forming the base layer on at least a portion of the inner wall surface of the nozzle through an arc ion plating process; wherein the gas pressure during the arc ion plating process is 0.2Pa~0.7Pa, the bias voltage is 250V~300V, the target current is 60A~80A, the deposition temperature is 240℃~270℃, and the arc ion plating time is 6h~8h.

[0020] In some embodiments, the forming of the functional layer specifically includes: using a carbon target as a target material and nitrogen as a protective gas, and forming the functional layer on the surface of the base layer through an arc ion plating process; wherein the flow range of the nitrogen during the arc ion plating process is 300sccm to 600sccm, the target current is 70A to 90A, and the arc ion plating time is 15h to 25h.

[0021] In some of the embodiments, before forming the base layer, the method also includes: performing plasma cleaning on the methanol injector valve seat at least once, and each cleaning time is 20 minutes to 30 minutes; drying the cleaned methanol injector valve seat; placing the coating tooling into the inner cavity of the dried valve seat body, and then placing the coating tooling and the methanol injector valve seat into the coating preparation equipment together.

[0022] According to another aspect of the present application, an embodiment of the present application provides a methanol injector, wherein the methanol injector comprises the methanol injector valve seat as described above or the methanol injector valve seat made according to the above method;

[0023] The methanol injector also includes a valve body, a valve ball and a valve stem;

[0024] The methanol injector valve seat is fixed at one end of the valve body, the valve body is provided with a valve cavity, the methanol injector valve seat is communicated with the valve cavity, the valve ball is connected to one end of the valve stem, and the valve stem and the valve ball are respectively movably arranged in the valve cavity and the inner cavity of the methanol injector valve seat.

[0025] According to still another aspect of the present application, an embodiment of the present application provides an engine, which includes the methanol injector as described above.

[0026] Implementing the technical solution of the present invention has at least the following beneficial effects:

[0027] In the embodiment of the present application, a coating is provided in the spray hole of the provided methanol injector valve seat, and the coating includes a primer layer and a functional layer which are sequentially stacked on at least part of the inner wall surface of the spray hole, wherein the material of the primer layer includes Si (silicon), and the material of the functional layer includes DLC (diamond-like carbon). Thus, by setting the above-mentioned coating at the spray hole, the porosity can be made lower, the density and crystallinity of the inner surface of the spray hole are improved, the internal residual stress of the coating on the inner surface of the spray hole is reduced, and the corrosion resistance of the spray hole is improved, especially the primer layer of Si material, which not only has a strong bonding force with the spray hole substrate, but also has strong corrosion resistance, and the functional layer of DLC material, which not only has the characteristics of low stress, high adhesion, high toughness, and high corrosion resistance, but also has certain corrosion resistance and chemical resistance to aqueous solutions, and has certain lubricity. Thus, by the coordinated setting of the above-mentioned primer layer and the functional layer, the corrosion resistance of the spray hole is improved, the cavitation problem of the spray hole is effectively alleviated, and the durability of the methanol injector can be improved.

[0028] The methanol injector valve seat has been tested on the engine bench for 600 hours, the engine and injector performance are normal, and the injector is disassembled to observe that there is no cavitation phenomenon in the spray hole.

[0029] Additional aspects and advantages of the present application will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a schematic structural diagram of a methanol injector valve seat provided by an embodiment of the present invention;

[0031] Figure 2 Shown is a schematic structural diagram of a coating on a methanol injector valve seat provided by an embodiment of the present invention;

[0032] Figure 3 The figure shows a structural schematic diagram of a methanol injector valve seat and coating tooling provided by an embodiment of the present invention;

[0033] Figure 4 It is a schematic diagram of placing a coating tool and a methanol injector valve seat into a coating device together according to an embodiment of the present invention;

[0034] Figure 5 The figure is a schematic diagram showing the cavitation phenomenon occurring in the spray hole in the valve seat of the methanol injector in the prior art;

[0035] Figure 6 It is a schematic diagram showing that the spray hole in the valve seat of the methanol injector provided by the embodiment of the present application does not have cavitation phenomenon;

[0036] Figure 7Shown is a scanning electron microscope image of a coating on the spray hole surface of a methanol injector valve seat provided by an embodiment of the present invention.

[0037] Description of reference numerals:

[0038] 10-Methanol injector valve seat (valve seat);

[0039] 101-valve seat body;

[0040] 102-spray hole;

[0041] 110-base layer;

[0042] 120-functional layer;

[0043] 20-Coating tooling. DETAILED DESCRIPTION

[0044] The present application is further described below in conjunction with specific embodiments. It should be understood that these embodiments of the present application are only used to illustrate the present application and are not used to limit the scope of the present application.

[0045] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range or the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0046] Hereinafter, the methanol injector valve seat and its preparation method, methanol injector and engine, etc. of the present application are specifically disclosed in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0047] If there is no special description, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution. If there is no special description, all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0048] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0049] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0050] As analyzed in the background technology, direct injection of methanol can significantly improve engine economy and emissions, and significantly improve engine cold start performance. However, due to the low saturated vapor pressure of methanol, the high temperature and high pressure working environment of methanol direct injection injector causes methanol to generate bubbles during injection, and the bubbles burst with pressure changes, causing cavitation on the injector nozzle (such as Figure 5 As shown), the surface features of the injector spray hole are destroyed, affecting the flow rate and spray state of the injector, and in severe cases, causing the injector to fail. At present, there is a blank in the world for methanol direct injection injectors, and it is necessary to develop an injector specifically adapted for in-cylinder methanol direct injection. Therefore, the present invention provides a high-pressure methanol injector valve seat to effectively alleviate the above problems. In view of this, the present application provides a methanol injector valve seat and a preparation method thereof, a methanol injector and an engine, and the present application is described in detail below.

[0051] See also Figures 1 to 7 As shown, in some embodiments, the present application provides a methanol injector valve seat 10, which includes: a valve seat body 101 and at least one spray hole 102 arranged on the valve seat body 101; a coating is arranged on the inner wall surface of the spray hole 102, and the coating includes a base layer 110 arranged on at least a portion of the inner wall surface of the spray hole 102, and a functional layer 120 arranged on the base layer 110; wherein the material of the base layer 110 includes Si (silicon), and the material of the functional layer 120 includes DLC (diamond-like carbon).

[0052] In the present application, the methanol injector valve seat 10 includes a valve seat body 101, and the valve seat body 101 is provided with at least one spray hole 102. Preferably, the valve seat body 101 is provided with a plurality of spray holes 102. As an example, a plurality of spray holes 102 can be provided on the bottom wall of the valve seat body 101, and the number of the spray holes 102 can be selected and set according to actual conditions, for example, 4-10 spray holes 102 can be provided, or 6-8 spray holes 102 can be provided. In the embodiment of the present application, six spray holes 102 are evenly provided on the bottom wall of the valve seat body 101 as an example for explanation, but it is not limited thereto, and the number of the spray holes 102 can be designed according to actual needs, and this embodiment does not limit this.

[0053] Under different use conditions, the spray hole 102 is connected or disconnected with the valve cavity of the methanol injector. The spray hole 102 can be connected or disconnected with the valve cavity of the methanol injector by controlling the movement of the valve ball.

[0054] It should be understood that before the methanol injector injects fuel, the spray hole 102 on the injector valve seat is not connected to the injector valve chamber in the injector. When injecting fuel, the spray hole 102 is connected to the injector valve chamber, and the fuel enters the spray hole 102 with a smaller space from the injector chamber with a larger space. The air pressure at the entrance of the spray hole 102 suddenly increases. When the fuel is methanol fuel, the methanol fuel can easily generate bubbles at the entrance of the spray hole 102 accompanied by the bursting of the bubbles. The bursting of the bubbles will cause the spray hole 102 to be subjected to impact force, which will damage the surface features of the injector spray hole 102 and further cause cavitation to the spray hole 102.

[0055] In view of this, the inventor of this application has found through extensive research that conventional methods such as optimizing the valve seat material composition, heat treating the valve seat material surface, and optimizing the valve seat structure in the prior art cannot completely solve the cavitation problem of the injector nozzle 102; more effective technical means are needed to solve this problem. Therefore, the inventor of this application has specially developed a gas coating for the microporous structure to solve the cavitation problem of the nozzle 102 of the methanol injector, in order to fundamentally solve the cavitation problem of the nozzle 102. In detail:

[0056] In the embodiment of the present application, the inner wall surface of the spray hole 102 in the provided methanol injector valve seat 10 is provided with a coating, and the coating includes a base layer 110 and a functional layer 120 which are sequentially stacked on at least part of the inner wall surface of the spray hole 102, wherein the material of the base layer 110 includes Si (silicon), and the material of the functional layer 120 includes DLC (diamond-like carbon), that is, the base layer 110 can be a silicon material layer, and the functional layer 120 can be a diamond-like carbon layer. Among them, the base layer 110 made of Si material not only has a strong bonding force with the substrate of the spray hole 102, but also has strong corrosion resistance, and the functional layer 120 made of DLC material not only has the characteristics of low stress, high adhesion, high toughness, and high corrosion resistance, but also has certain corrosion resistance and chemical resistance to aqueous solutions, and has certain lubricity, which can enhance the corrosion resistance and wear resistance of the coating. Therefore, by coordinating the above-mentioned Si material base layer 110 and the DLC material functional layer 120, the porosity can be reduced, the density and crystallinity of the inner surface of the nozzle 102 can be improved, the internal residual stress of the inner surface coating of the nozzle 102 can be reduced, and the corrosion resistance of the nozzle 102 can be improved.

[0057] Furthermore, by the coordinated arrangement of the Si material base layer 110 and the DLC material functional layer 120, the cavitation problem of the spray hole 102 is effectively alleviated, the durability of the methanol injector can be improved, and the service life of the methanol injector can be extended. Moreover, after experimental verification, after the methanol injector monomer durability test and the engine 600-hour bench durability test, it was found that the methanol injector valve seat 10 has been durable on the engine bench for 600 hours, the engine and the injector have normal performance, and the methanol injector is disassembled to observe that there is no cavitation phenomenon in the spray hole 102, such as Figure 6 As shown, that is, no cavitation failure occurs in the spray hole 102, so the performance of the methanol injector valve seat 10 provided in the present application meets the design requirements and conforms to the use requirements.

[0058] It should be noted that, in the present application, the nozzle hole 102 has an inner wall surface, and the bottom layer 110 is provided on at least part of the inner wall surface of the nozzle hole 102, which means that the bottom layer 110 can cover a part of the inner wall surface of the nozzle hole 102, or the bottom layer 110 can completely cover the entire inner wall surface of the nozzle hole 102; preferably, the bottom layer 110 completely covers the entire inner wall surface of the nozzle hole 102. The functional layer 120 is provided on at least part of the surface of the bottom layer 110, which means that the functional layer 120 can cover a part of the surface of the bottom layer 110, or the functional layer 120 can completely cover the entire surface of the bottom layer 110; preferably, the functional layer 120 completely covers the entire surface of the bottom layer 110.

[0059] It should also be pointed out that in the present application, the methanol injector includes a methanol injector valve seat 10, which is arranged at the end of the methanol injector, and a valve seat body 101 of the methanol injector valve seat 10 is provided with a spray hole 102, and the methanol injector can spray high-pressure fuel spray through the spray hole 102. Although this embodiment is proposed based on the technical defect that bubbles are easily generated during the methanol fuel injection process, which causes damage to the surface characteristics of the injector spray hole 102 and easily causes cavitation of the methanol injector spray hole 102, the methanol injector valve seat 10 of this embodiment can be applied to a methanol in-cylinder direct injection injector, and can also be applied to other injectors using methanol as fuel or injectors using other fuels, and this embodiment does not limit this.

[0060] Optionally, the cross-sectional shape of the spray hole 102 may be circular. Of course, the cross-sectional shape of the spray hole 102 is not limited thereto, and may also be elliptical, square, or other regular or irregular shapes and structures, etc., which is not limited in this embodiment.

[0061] Optionally, the diameter of the nozzle hole 102 may be 0.05 mm to 1.5 mm; further, the diameter of the nozzle hole 102 may be 0.08 mm to 1.2 mm; further, the diameter of the nozzle hole 102 may be 0.1 mm to 1 mm, etc. For example, the diameter of the nozzle hole 102 may be about 0.1 mm. The diameter range of the nozzle hole 102 may be designed according to actual needs, and this embodiment does not limit this.

[0062] Therefore, in view of the fact that the diameter of the spray hole 102 of the methanol injector valve seat 10 is usually relatively small, such as about 0.1 mm, the traditional PVD (physical vapor deposition) and CVD (chemical vapor deposition) coating processes cannot achieve the internal coating of the spray hole 102. The inventors of the present application have specially developed a special gas coating to coat the spray hole 102 of the methanol injector, that is, the above-mentioned Si material base layer 110 and the DLC material functional layer 120, so as to effectively alleviate the cavitation problem of the spray hole 102 of the methanol injector.

[0063] In some embodiments, the valve seat body 101 is provided with an inner cavity for accommodating the valve ball, and the spray hole 102 is provided on the bottom wall of the inner cavity and penetrates the bottom wall; the bottom wall is used to match the shape of the spherical surface of the valve ball, and the spray hole 102 is used to cooperate with the valve ball to open or close the spray hole 102.

[0064] It should be understood that the methanol injector may include the methanol injector valve seat 10 and the valve ball. The methanol injector valve seat 10 and the valve ball are used together, and the valve ball can be used to open or close the spray hole 102.

[0065] The valve seat body 101 may be provided with a side wall and a bottom wall, the bottom end of the side wall being connected to the upper edge of the bottom wall, the side wall and the bottom wall may enclose an inner cavity, which may be used to accommodate a valve ball, and the inner cavity has a sealing surface for cooperating with the valve ball; when the valve ball cooperates with the sealing surface, the valve ball may be used to close the spray hole 102, that is, methanol fuel cannot be sprayed out through the spray hole 102 at this time; when the valve ball is separated from (or away from) the sealing surface, there is a gap between the valve ball and the sealing surface, which may open the spray hole 102, and methanol fuel may be sprayed out through the spray hole 102 at this time.

[0066] The spray hole 102 is arranged on the bottom wall of the inner cavity, for example, a plurality of spray holes 102 are evenly arranged on the bottom wall along the circumferential direction, and the spray hole 102 penetrates the bottom wall, so as to achieve the purpose of spraying fuel. The specific arrangement of the valve seat body 101 and the spray hole 102 can be designed according to actual conditions, and the specific structural shape of the valve seat body 101 is not limited in this application.

[0067] In some embodiments, the thickness of the primer layer 110 is 0.1 μm to 3 μm. As an example, the thickness of the primer layer 110 can be any one of 0.1 μm, 0.2 μm, 0.5 μm, 0.8 μm, 1 μm, 1.2 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, or any range therebetween.

[0068] If the thickness of the primer layer 110 is too thin, it cannot effectively improve the corrosion resistance of the surface of the nozzle hole 102, and the bonding effect between the nozzle hole 102 substrate and the primer layer 110 will be reduced; if the thickness of the primer layer 110 is too thick, it will increase the cost and affect the flow rate or state of the injection. Therefore, by controlling the thickness of the primer layer 110 within the above range, it is not only conducive to processing and cost saving, but also can make the application effect of the primer layer 110 better and meet the anti-cavitation performance.

[0069] In some embodiments, the thickness of the functional layer 120 is 1 μm to 6 μm. As an example, the thickness of the functional layer 120 can be any one of 1 μm, 1.2 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, and 6 μm, or a range between any two of them.

[0070] If the thickness of the functional layer 120 is too thin, it cannot effectively improve the corrosion resistance of the surface of the nozzle hole 102; if the thickness of the functional layer 120 is too thick, it will increase the cost and affect the flow rate or state of the injection, etc. Therefore, by controlling the thickness of the functional layer 120 within the above range, it is not only convenient for processing and cost saving, but also can make the application effect of the functional layer 120 better and meet the anti-cavitation performance.

[0071] In some embodiments, the hardness of the coating ranges from 2000 HV to 4000 HV. As an example, the hardness of the coating can be any one of 2000 HV, 2200 HV, 2500 HV, 2800 HV, 3000 HV, 3500 HV, 3800 HV, 4000 HV, or a range between any two of them.

[0072] The higher the hardness of the coating at the spray hole 102 of the methanol injector valve seat 10, the less likely it is to be damaged when impacted. If the hardness is too high, the surface of the spray hole 102 of the methanol injector valve seat 10 will be more brittle and will be easily damaged when impacted. In addition, too high hardness will also reduce the anti-friction and wear resistance of the coating. Therefore, by making the hardness range of the coating between 2000HV and 4000HV, it is beneficial to make the hardness of the coating moderate, avoid defects caused by too high or too low hardness, and improve the anti-friction and wear resistance of the coating, and improve the durability of the coating.

[0073] Therefore, based on the above settings, the methanol injector valve seat 10 provided by the present invention is provided with a coating structure (such as a Si-DLC coating structure) on the inner wall surface of the spray hole 102, and a Si-based layer 110 and a DLC-based functional layer 120 are used in combination, wherein the thickness of the base layer 110 is 0.1 μm to 3 μm, the thickness of the functional layer 120 is 1 μm to 6 μm, the process temperature is 100 to 250°C, the control valve seat deformation is less than 0.01 mm, the coating hardness is 2000 to 4000 HV, and the coating working temperature is less than 350°C. After experimental verification, the methanol injector valve seat 10 has been tested on the engine bench for 600 hours, and the engine and injector performance are normal, such as Figure 6 As shown, the methanol injector is disassembled and observed that the spray hole 102 has no cavitation phenomenon, so the performance of the methanol injector valve seat 10 provided meets the design requirements and meets the use needs.

[0074] Accordingly, in some embodiments, the present application provides a method for preparing a methanol injector valve seat 10, the method comprising the following steps:

[0075] A valve seat body 101 is provided, wherein the valve seat body 101 is provided with at least one spray hole 102;

[0076] A coating layer 110 is formed on at least a portion of the inner wall surface of the spray hole 102, and the material of the coating layer 110 includes Si;

[0077] The functional layer 120 is formed on the surface of the primer layer 110 , and the material of the functional layer 120 includes DLC.

[0078] The preparation method of the methanol injector valve seat 10 provided in this embodiment can first form a base layer 110 on the inner wall surface of the spray hole 102, and then form a functional layer 120 on the surface of the base layer 110. The preparation method provided in the embodiment of the present invention has simple process, convenient operation, strong feasibility, and is easy to realize industrialization.

[0079] It should be understood that all the features and advantages described above for the “methanol injector valve seat 10” are also applicable to the “method for preparing the methanol injector valve seat 10” and will not be described in detail here.

[0080] In some specific embodiments, the preparation method of the methanol injector valve seat 10 specifically includes the following steps (a) to (d):

[0081] (a) Preprocessing.

[0082] In step (a), before preparing the base layer 110, the methanol injector valve seat 10 is pretreated, specifically including: plasma cleaning the methanol injector valve seat 10 at least once, each cleaning time is 20min to 30min; drying the cleaned methanol injector valve seat 10; placing the coating tooling 20 into the inner cavity of the dried valve seat body 101, and then placing the coating tooling 20 and the methanol injector valve seat 10 into the coating preparation equipment together.

[0083] In the present application, it should be noted that the valve seat body 101 may be provided first, such as the valve seat body 101 may be made of a preset valve seat substrate. The valve seat body 101 may be manufactured by cutting, injection molding, 3D printing, etc., and this embodiment does not limit this. In addition, this embodiment does not limit the specific material of the valve seat body 101, and the valve seat body 101 material commonly used in the relevant field may be used.

[0084] Optionally, in step (a), the methanol injector valve seat 10 is first cleaned, such as by plasma cleaning. As an example, the methanol injector valve seat 10 can be plasma cleaned, and the methanol injector valve seat 10 is placed in a cleaning chamber and plasma cleaned once or multiple times, wherein the plasma collides with the gas molecules in the cleaning chamber to produce a chemical reaction, and the dirt and harmful substances on the inner surface of the spray hole 102 of the valve seat body 101 are completely removed. In this embodiment, the valve seat body 101 is plasma cleaned twice, each time for 20 to 30 minutes, and then dried.

[0085] Optionally, in step (a), after drying, Figure 4As shown, the coating tool 20 is placed in the inner cavity of the dried valve seat body 101, and then the coating tool 20 and the methanol injector valve seat 10 are placed together in a coating preparation device (such as a coating furnace).

[0086] like Figure 3-Figure 4 As shown, by placing the coating tool 20 into the inner cavity of the dried valve seat body 101, it is possible to prevent the coating on the guide surface of the methanol injector valve seat 10 from changing the gap between the valve ball and the guide surface and affecting the movement of the valve ball. That is, by setting the coating tool 20, it is possible to prevent the remaining parts of the valve seat body 101 except the spray hole 102 from being coated, thereby preventing the cooperation between the valve ball and the sealing surface of the inner cavity from being affected, and affecting the sealing effect.

[0087] The coating tool 20 may be provided with a top cover and a mounting portion, the mounting portion being used to install the coating tool 20 into the valve seat body 101, and the top cover being used to shield the coating applied to the inner cavity during the preparation of the methanol injector. The coating tool 20 cooperates with the inner cavity of the valve seat body 101, and the coating tool 20 can be prevented from being applied to the cavity wall of the inner cavity.

[0088] (b) Preparing the base layer 110.

[0089] In step (b), a primer layer 110 is formed on the inner wall surface of the spray hole 102 of the pre-treated valve seat body 101 .

[0090] Optionally, in step (b), before forming the base layer 110, step (b) also includes a vacuuming step, that is, after placing the coating tooling 20 and the methanol injector valve seat 10 together in the coating preparation equipment (such as a coating furnace), vacuuming is required. Specifically, after closing the furnace chamber, turn on the rotary vane vacuum pump, wait for the air pressure in the furnace to drop below 10Pa, start the molecular pump, and further pump the air pressure to the ultimate vacuum degree. Maintain the ultimate vacuum environment for a period of time to maximize the removal of air in the furnace. Vacuuming can increase the density of the coating and reduce the porosity of the coating.

[0091] In the present application, in step (b), a base layer 110 is formed, which specifically includes: in an inert gas atmosphere, using Si as a target material, and forming the base layer 110 on at least a portion of the inner wall surface of the nozzle 102 by an arc ion plating process; wherein, the gas pressure during the arc ion plating process is 0.2Pa~0.7Pa, the bias voltage is 250V~300V, the target current is 60A~80A, the deposition temperature is 240℃~270℃, and the arc ion plating time is 6h~8h.

[0092] Optionally, the inert gas may be argon (Ar). Of course, in other embodiments, other rare gases such as neon and helium may also be used as inert gases, that is, as protective gases.

[0093] In the present application, the preparation method of the base layer 110 is preferably arc ion plating, and the conditions of the arc ion plating include: in an inert gas such as Ar atmosphere, the target (Si target) current is 60A to 80A (such as 60A, 62A, 65A, 68A, 70A, 75A, 78A, 80A, etc.), the process temperature is 240°C to 270°C (such as 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, etc.), and the arc ion plating conditions include: in an inert gas such as Ar atmosphere, the target (Si target) current is 60A to 80A (such as 60A, 62A, 65A, 68A, 70A, 75A, 78A, 80A, etc.), and the process temperature is 240°C to 270°C (such as 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, etc.). ℃, 270℃, etc.), the pressure is 0.2Pa~0.7Pa (such as 0.2Pa, 0.3Pa, 0.4Pa, 0.5Pa, 0.6Pa, 0.7Pa, etc.), which can prevent the coating from being oxidized and nitrided; adjust the bias voltage to 250V~300V, preferably, the bias voltage is reduced to 280V; the arc ion plating treatment time is 6h~8h (such as 6h, 6.5h, 7h, 7.5h, 8h, etc.). Preferably, the thickness of the formed base layer 110 is 0.1μm~3μm.

[0094] It should be pointed out that the specific operation method of preparing the base layer 110 by arc ion plating can adopt the conventional arc ion plating operation method, which will not be described in detail here; except for the arc ion plating operation conditions specified above, the remaining operation conditions can be selected and set according to actual conditions, and this embodiment does not limit this.

[0095] Therefore, by controlling the operating conditions of the arc ion plating within the above range, the prepared base layer 110 can have a strong bonding force with the substrate and the Si coating itself has a strong corrosion resistance, which is beneficial to improving the corrosion resistance of the nozzle 102. In addition, by plating in an Ar atmosphere, the coating can be prevented from being oxidized and nitrided.

[0096] (c) The functional layer 120 is prepared.

[0097] In some embodiments, in step (c), a functional layer 120 is formed, which specifically includes: using a carbon target as a target material and nitrogen (N2) as a protective gas, and forming the functional layer 120 on the surface of the base layer 110 through an arc ion plating process; wherein, the flow range of nitrogen during the arc ion plating process is 300sccm to 600sccm, the target current is 70A to 90A, and the arc ion plating time is 15h to 25h.

[0098] Optionally, the mass purity of the carbon target is not less than 99.9%.

[0099] In the present application, the preparation method of the functional layer 120 is preferably arc ion plating, and the conditions of the arc ion plating include: using a carbon target as a target material, the target (carbon target) current is 70A to 90A (such as 70A, 72A, 75A, 78A, 80A, 85A, 88A, 90A, etc.), the flow rate of the protective gas N2 changes linearly with time in the range of 300sccm to 600sccm (such as 300sccm, 400sccm, 500sccm, 600sccm, etc.), and the processing time of the arc ion plating is 15h to 25h (such as 15h, 16h, 18h, 20h, 22h, 25h, etc.). Preferably, the thickness of the formed functional layer 120 is 1μm to 6μm.

[0100] It should be pointed out that the specific operation method of preparing the functional layer 120 by arc ion plating can adopt the conventional arc ion plating operation method, which will not be described in detail here; except for the arc ion plating operation conditions specified above, the remaining operation conditions can refer to the preparation of the aforementioned base layer 110 or be selected and set according to actual conditions, and this embodiment does not limit this.

[0101] Therefore, by controlling the operating conditions of arc ion plating within the above range, the obtained functional layer 120 can have the characteristics of low stress, high adhesion, high toughness, high corrosion resistance, etc., and has corrosion resistance and chemical resistance to aqueous solutions, and has a certain lubricity.

[0102] In the present invention, the preparation of the functional layer 120 , ie, the diamond-like carbon layer, is preferably performed in a nitrogen atmosphere.

[0103] In the present invention, the hardness of each coating layer such as the primer layer 110 or the functional layer 120 can be adjusted by adjusting the bias voltage, thereby adjusting the hardness of the coating layer.

[0104] (d) Turn off all power supplies, ion sources and gas sources, and the coating preparation is completed.

[0105] Therefore, the coating produced by the above method has low porosity, improves the density and crystallinity of the coating, reduces the internal residual stress of the coating, and improves the corrosion resistance of the coating.

[0106] In some embodiments, the present application provides a methanol injector, which includes the methanol injector valve seat 10 as described above or the methanol injector valve seat 10 manufactured according to the aforementioned method.

[0107] Optionally, the methanol injector may be a methanol direct injection injector.

[0108] The methanol injector provided by the present application solves the problem of easy cavitation of the spray hole 102 in the methanol injector in the related art. Compared with the prior art, the methanol injector provided by the embodiment of the present invention has the same beneficial effects as the methanol injector valve seat 10 of the above embodiment, which will not be described in detail here.

[0109] Further, the methanol injector further includes a valve body, a valve ball and a valve stem (not shown); that is, the methanol injector may include a methanol injector valve seat 10, a valve body, a valve ball and a valve stem. The methanol injector valve seat 10 is fixed to one end of the valve body, the valve body is provided with a valve cavity, the methanol injector valve seat 10 is connected to the valve cavity, the valve ball is connected to one end of the valve stem, and the valve stem and the valve ball are movably arranged in the valve cavity and the inner cavity of the methanol injector valve seat 10, respectively.

[0110] It should be pointed out that the core of the methanol injector is the methanol injector valve seat 10 provided in the embodiment of the present application. The present application does not limit the specific structure and connection settings of the remaining structures in the methanol injector such as the valve body, valve ball, etc., and reference may be made to the relevant prior art.

[0111] As an example, the methanol injector may also include structures such as a return spring and an electromagnetic driver. The methanol injector valve seat 10 is fixed at one end of the valve body, the valve body is provided with a valve cavity, the valve cavity is filled with fuel, the methanol injector valve seat 10 is connected to the valve cavity, the valve stem is movably arranged in the valve cavity, the valve ball is fixed at the end of the valve stem, and the valve ball is movably arranged in the methanol injector valve seat 10. The above-mentioned return spring is fixed in the valve cavity and connected to the top of the valve stem, and the return spring is in a compressed state. The electromagnetic driver is fixed on the valve body and connected to the valve stem, and the valve stem can be driven to move up and down along the valve cavity through the electromagnetic driver.

[0112] Initial position of the valve ball: the valve ball abuts against the bottom wall of the inner cavity of the methanol injector valve seat 10, and cooperates with the spray hole 102 to prevent the fuel from passing through the spray hole 102. When the methanol injector needs to inject fuel, the methanol injector drives the valve stem to move upward along the valve cavity through the electromagnetic drive, and the valve ball moves upward with the valve stem and away from the bottom wall, and the fuel is sprayed into the combustion chamber through the spray hole 102; when the methanol injector does not need to inject fuel, the electromagnetic drive stops working, the return spring stretches and drives the valve stem to move downward along the valve cavity, and the valve ball moves downward with the valve stem until it abuts against the bottom wall and cooperates with the spray hole 102 to prevent the fuel from passing through the spray hole 102.

[0113] In some embodiments, the present application also provides an engine, which includes the methanol injector as described above.

[0114] It should be understood that, in addition to the aforementioned methanol injector, the engine also includes other conventional structural components. The embodiment of the present application does not limit the remaining structure of the engine and its connection settings, etc. For details, please refer to the prior art and will not be repeated here.

[0115] The methanol injector valve seat, the method for preparing the methanol injector valve seat, the methanol injector and the engine provided by the embodiments of the present invention are suitable for methanol fuel, which can not only improve the corrosion resistance and wear resistance of the methanol injector valve seat, but also help to improve the reliability of the methanol injector and the engine.

[0116] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0117] The basic principle of the present invention is described above in conjunction with specific embodiments. However, it should be pointed out that the advantages, strengths, effects, etc. mentioned in the present invention are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. must be possessed by each embodiment of the present invention. In addition, the specific details disclosed above are only for the purpose of illustration and facilitation of understanding, rather than limitation, and the above details do not limit the present invention to being implemented by adopting the above specific details.

[0118] It should be noted that the term "and / or" or " / " used in this document is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The singular forms of "a", "the" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0119] In the detailed description and claims, a list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms may mean any combination of the listed items. For example, if items A, B are listed, the phrase "at least one of A, B" means only A; only B; or A and B. In another example, if items A, B, C are listed, the phrase "at least one of A, B, C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may include a single element or multiple elements. Item B may include a single element or multiple elements. Item C may include a single element or multiple elements.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A methanol injector valve seat, characterized in that: The methanol injector valve seat comprises: a valve seat body and at least one spray hole arranged on the valve seat body; A coating is provided on the inner wall surface of the spray hole, wherein the coating comprises a primer layer provided on at least a part of the inner wall surface of the spray hole, and a functional layer provided on the primer layer; Wherein, the material of the base layer includes Si, and the material of the functional layer includes DLC.

2. The methanol injector valve seat according to claim 1, characterized in that: The thickness of the primer layer is 0.1 μm to 3 μm; And / or, the thickness of the functional layer is 1 μm to 6 μm.

3. The methanol injector valve seat according to claim 1, characterized in that: The hardness of the coating ranges from 2000 HV to 4000 HV.

4. The methanol injector valve seat according to any one of claims 1 to 3, characterized in that: The valve seat body is provided with an inner cavity for accommodating the valve ball, and the spray hole is provided on the bottom wall of the inner cavity and penetrates the bottom wall; The bottom wall is used to match the shape of the spherical surface of the valve ball, and the spray hole is used to cooperate with the valve ball to open or close the spray hole.

5. A method for preparing a methanol injector valve seat, characterized in that: The method comprises: Providing a valve seat body, wherein the valve seat body is provided with at least one spray hole; forming a primer layer on at least a portion of the inner wall surface of the nozzle hole, wherein the material of the primer layer includes Si; A functional layer is formed on the surface of the primer layer, and a material of the functional layer includes DLC.

6. The method for preparing a methanol injector valve seat according to claim 5, characterized in that: The forming of the bottom layer specifically includes: In an inert gas atmosphere, Si is used as a target material to form a primer layer on at least a portion of the inner wall surface of the nozzle hole by an arc ion plating process; The gas pressure during the arc ion plating process is 0.2Pa-0.7Pa, the bias voltage is 250V-300V, the target current is 60A-80A, the deposition temperature is 240°C-270°C, and the arc ion plating time is 6h-8h.

7. The method for preparing a methanol injector valve seat according to claim 5, characterized in that: The forming of the functional layer specifically includes: Using a carbon target as a target material and nitrogen as a protective gas, a functional layer is formed on the surface of the primer layer by an arc ion plating process; Wherein, when implementing the arc ion plating process, the flow range of the nitrogen gas is 300 sccm to 600 sccm, the target current is 70A to 90A, and the arc ion plating time is 15h to 25h.

8. The method for preparing a methanol injector valve seat according to any one of claims 5 to 7, characterized in that: Before forming the base layer, the method further comprises: Perform plasma cleaning on the methanol injector valve seat at least once, with each cleaning time lasting 20 to 30 minutes; Dry the cleaned methanol injector valve seat; Place the coating tooling into the inner cavity of the dried valve seat body, and then place the coating tooling and the methanol injector valve seat into the coating preparation equipment together.

9. A methanol injector, characterized in that: The methanol injector comprises the methanol injector valve seat according to any one of claims 1 to 4 or the methanol injector valve seat made according to the method according to any one of claims 6 to 8; The methanol injector also includes a valve body, a valve ball and a valve stem; The methanol injector valve seat is fixed at one end of the valve body, the valve body is provided with a valve cavity, the methanol injector valve seat is communicated with the valve cavity, the valve ball is connected to one end of the valve stem, and the valve stem and the valve ball are respectively movably arranged in the valve cavity and the inner cavity of the methanol injector valve seat.

10. An engine, characterized in that: The engine includes the methanol injector of claim 9.

Images