Ferrule airtightness optimization method and device for fuel cell vehicle-mounted hydrogen system

Abstract

The invention relates to the technical field of fuel cell air tightness detection, in particular to a clamping sleeve air tightness optimization method and device for a fuel cell vehicle-mounted hydrogen system, and the method comprises the steps: shooting the surface microtopography of different brands of front clamping sleeves for testing and the surface microtopography of the interface of a connected valve by using a laser confocal microscope; a vacuum direct-reading spectrometer is used for detecting the metal composition and content of front clamping sleeves and connected valves of different brands, so that the alloy category is judged; and whether the combination is beneficial to hydrogen sealing in an extreme temperature environment or not can be judged by comparing the linear expansion coefficients and the surface microtopographies of the two at different temperatures. According to the method, the high-temperature and low-temperature reliability of the ferrule type metal seal can be effectively judged, the hydrogen leakage rate at the extreme temperature can be effectively reduced, guidance is provided for safety improvement of a hydrogen fuel cell vehicle (FCV), and development, popularization and application of the FCV can be promoted.

Description

Technical Field

[0001] The present application relates to the technical field of fuel cell air tightness detection, and in particular to a method and device for optimizing the air tightness of a ferrule for a fuel cell vehicle-mounted hydrogen system. Background Art

[0002] During the normal operation of FCV, the storage and supply of hydrogen often cause safety problems such as hydrogen leakage due to component failure. As one of the core subsystems of fuel cell vehicles, the on-board hydrogen system, the development of on-board hydrogen system safety performance testing and evaluation is an important task to promote the healthy and orderly development of the fuel cell vehicle industry. In the on-board hydrogen system, the connection between the various components and pipelines often adopts a ferrule connection, in which the ferrule is the core key component of the ferrule joint, which is a high-precision machined thin-walled component. During the installation of the ferrule joint, the ferrule is in contact with the ferrule tube, the joint body, and the nut, generating a force. After installation, the ferrule deforms to form a seal. Taking the double ferrule joint as an example, studies have shown that the shape and size of the front ferrule have a very important influence on the sealing performance; in addition, studies have shown that the deformation degree of the metal surface is different when the stress is the same at different temperatures.

[0003] FCV uses hydrogen as fuel. Hydrogen molecules are small and easily leak through porous materials, assembly surfaces or sealing surfaces. They also have the characteristics of low ignition point, wide explosion range, and large diffusion coefficient. The above characteristics of hydrogen make the safety of on-board hydrogen systems a focus of attention in the use of FCVs, and its safety assurance is an important prerequisite for the large-scale commercialization of FCVs. There are a large number of ferrule-type connections in on-board hydrogen systems, and the airtight reliability of ferrule connections in extreme temperature environments is crucial to the safety of FCVs.

[0004] At present, there are multiple brands of ferrule joints and valves used in on-board hydrogen systems, and the use standards of ferrule joints are still in the process of being improved. Therefore, in order to enhance the airtight reliability of on-board hydrogen systems, it is necessary to strengthen the standardized use of ferrule joints and strengthen the research on related safety technologies and the construction of standard systems. Summary of the invention

[0005] To achieve the above objectives, this application provides the following technical solutions: According to a first aspect of the present invention, the present invention claims a method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle, comprising: The test obtains hydrogen leakage results of a normal temperature leakage test and a high and low temperature leakage test under the assembly of a first front ferrule and a first connected valve of the vehicle-mounted hydrogen system; Photographing and acquiring the surface microscopic morphology of the interface between the first front ferrule and the first connected valve component; Using a vacuum direct reading spectrometer to detect the metal composition and content of the first front ferrule and the first connected valve component, and obtaining an alloy type combination of the first front ferrule and the first connected valve component; According to the alloy type combination of the first front ferrule and the first connected valve member, the linear expansion coefficient at different temperatures is obtained, and the priority of the ferrule air tightness optimization factors is determined in combination with the hydrogen leakage results of the normal temperature leakage test, the hydrogen leakage results of the high and low temperature leakage test and the surface micromorphology; According to the priority of the ferrule air-tightness optimization factors, a combination of a front ferrule and a connected valve component that satisfies the air-tightness optimization of the on-board hydrogen system is selected.

[0006] Further, the test obtains the hydrogen leakage result of the normal temperature leakage test under the assembly of the first front ferrule and the first connected valve member of the vehicle-mounted hydrogen system, and also includes: Fixing the assembly torque of the joint of the first front ferrule and the first connected valve member and performing air tightness test under normal temperature environment to ensure that no hydrogen leakage occurs under normal temperature detection conditions; Block the valve outlet, pressurize the valve inlet with hydrogen, maintain the valve at each pressure according to the pressurization steps at room temperature, and then perform hydrogen leakage detection; Block the valve outlet, pressurize the valve inlet with hydrogen, and leave the valve still until the temperature stabilizes. After the pressure maintenance is completed, pressurize and maintain the pressure separately. Detect hydrogen leakage at the inlet and outlet of the valve and record it; Compare the hydrogen leakage results of the room temperature leakage test under different connected valves and different metal ferrule fittings.

[0007] Further, the test obtains the hydrogen leakage result of the high and low temperature leakage test under the assembly of the first front ferrule and the first connected valve member of the vehicle-mounted hydrogen system, and also includes: Fix the assembly torque of the joint of the first front ferrule and the first connected valve member and perform air tightness detection under high and low temperature environments to ensure that no hydrogen leakage occurs under high and low temperature detection conditions; Block the valve outlet, pressurize the valve inlet with hydrogen, maintain the valve at each pressure according to the pressurization steps at high and low temperatures, and then perform hydrogen leakage detection; During the high-temperature leakage test, seal the valve outlet, use hydrogen to pressurize the valve from the air inlet, and place the valve in a high-temperature environment until the temperature stabilizes. After the pressure is maintained, pressurize the valve and detect the hydrogen leakage at the valve inlet and outlet and record it; During the low-temperature leakage test, seal the valve outlet, use hydrogen to pressurize the valve from the air inlet, and place the valve in a low-temperature environment until the temperature stabilizes. After the pressure is maintained, pressurize and maintain the pressure, detect the hydrogen leakage at the valve inlet and outlet and record it; Compare the hydrogen leakage results of high and low temperature leakage tests under different connected valves and different metal ferrule fittings.

[0008] Further, the photographing and obtaining of the surface microscopic morphology at the interface between the first front ferrule and the first connected valve component also includes: The surface microstructure of the front ferrule and the inner conical surface of the connected valve interface used in the test was photographed using a laser confocal microscope and the surface roughness was calculated; Compare the surface micromorphology of different front ferrules, use a magnifying objective to observe the metal surface micromorphology, and determine whether there are obvious processing defects on the metal surface.

[0009] Furthermore, the linear expansion coefficients at different temperatures are obtained based on the alloy type combination of the first front ferrule and the first connected valve member, and the priority of the ferrule air tightness optimization factors is determined by combining the hydrogen leakage results of the room temperature leakage test, the hydrogen leakage results of the high and low temperature leakage test and the surface micromorphology, and further includes: Look up the linear expansion coefficient table of metal materials, and use the linear expansion data of normal temperature and high temperature zone to fit the low temperature curve expansion coefficient; Combined with the low temperature curve expansion coefficient, the normal temperature leakage test hydrogen leakage result, the high and low temperature leakage test hydrogen leakage result and the surface micromorphology, the priority of the optimization factors affecting the sealing performance of the ferrule seal at extreme temperatures is output.

[0010] Furthermore, the method of querying the linear expansion coefficient table of the metal material and fitting the low temperature curve expansion coefficient using the linear expansion data of the normal temperature and high temperature zone also includes: The greater the difference in the slope of the α-T curve between the current ferrule and the alloy of the connected valve, the more unfavorable it is for sealing at extreme temperatures; If the slope of the α-T curve of the front ferrule is greater than the slope of the α-T curve of the connected valve alloy, it is easy to cause hydrogen leakage in low temperature environment and easy to cause strength failure of the connection in high temperature environment; If the slope of the α-T curve of the front ferrule is smaller than the slope of the α-T curve of the connected valve alloy, it is easy to cause hydrogen leakage in a high temperature environment and easy to cause the structural strength failure of the connection in a low temperature environment.

[0011] Furthermore, the method of selecting a front ferrule and a connected valve component combination that satisfies the gas tightness optimization of the vehicle-mounted hydrogen system according to the priority of the ferrule gas tightness optimization factor also includes: Determine whether the alloy material of the front ferrule and the connected valve is the same; If the two materials are different, they should not be used together; If the two materials are the same, then the metal surface micro-morphology of the contact surface between the two is tested; If there are obvious defects on the contact surface of either the front ferrule or the connected valve part, the defective part is replaced with another one, and the alloy material determination and metal surface micromorphology characterization test steps are repeated; If there are no obvious defects in the contact surfaces of the front ferrule or the connected valve part, they can be used in combination.

[0012] According to a second aspect of the present invention, the present invention claims protection for a ferrule airtightness optimization device for a fuel cell vehicle-mounted hydrogen system, comprising: one or more processors; A memory having one or more programs stored thereon, when the one or more programs are executed by the one or more processors, the one or more processors implement the method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle.

[0013] The present application relates to the field of fuel cell air tightness detection technology, and in particular to a method and device for optimizing the air tightness of a ferrule for a fuel cell vehicle-mounted hydrogen system. The laser confocal microscope is used to photograph the surface micromorphology of the front ferrules of different brands and the interface of the connected valve parts for the test; a vacuum direct reading spectrometer is used to detect the metal composition and content of the front ferrules of different brands and the connected valve parts to determine the alloy type; by comparing the linear expansion coefficient and surface micromorphology of the two at different temperatures, it can be determined whether their combination is conducive to hydrogen sealing in extreme temperature environments. The present invention can effectively determine the high and low temperature reliability of ferrule-type metal seals, can effectively reduce the hydrogen leakage rate at extreme temperatures, provide guidance for improving the safety of hydrogen fuel cell vehicles (FCVs), and can promote the development and promotion of FCVs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A flowchart of a method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle as claimed in an embodiment of the present application; Figure 2 An example diagram of the microscopic morphology characterization of two front ferrules of a ferrule air tightness optimization method for a fuel cell vehicle hydrogen system as claimed in an embodiment of the present application; Figure 3 An example of characterization of the microscopic morphology of the inner cone surface of the joint of different brands of connected parts at home and abroad for a method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle claimed in an embodiment of the present application; Figure 4 A schematic diagram of the metal composition of front ferrules of different brands for a method for optimizing ferrule air tightness for a hydrogen system on a fuel cell vehicle claimed in an embodiment of the present application; Figure 5A schematic diagram of metal composition of one-way valves of different brands for a method for optimizing ferrule air tightness for a hydrogen system on a fuel cell vehicle as claimed in an embodiment of the present application; Figure 6 A schematic diagram of the metal composition of nuts of different brands for a method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle as claimed in an embodiment of the present application; Figure 7 A schematic diagram of the variation of the linear expansion coefficient of a front ferrule and a connected component made of different materials with temperature in a method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle as claimed in an embodiment of the present application. DETAILED DESCRIPTION

[0015] 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.

[0016] The terms "first", "second" and "third" in this application are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second" and "third" can explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. All directional indications (such as up, down, left, right, front, back...) in the embodiments of this application are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.

[0017] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0018] According to the first embodiment of the present invention, the present invention claims a method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle, referring to Figure 1 ,include: The test obtains hydrogen leakage results of a normal temperature leakage test and a high and low temperature leakage test under the assembly of a first front ferrule and a first connected valve of the vehicle-mounted hydrogen system; Photographing and acquiring the surface microscopic morphology of the interface between the first front ferrule and the first connected valve component; Using a vacuum direct reading spectrometer to detect the metal composition and content of the first front ferrule and the first connected valve component, and obtaining an alloy type combination of the first front ferrule and the first connected valve component; According to the alloy type combination of the first front ferrule and the first connected valve member, the linear expansion coefficient at different temperatures is obtained, and the priority of the ferrule air tightness optimization factors is determined in combination with the hydrogen leakage results of the normal temperature leakage test, the hydrogen leakage results of the high and low temperature leakage test and the surface micromorphology; According to the priority of the ferrule air-tightness optimization factors, a combination of a front ferrule and a connected valve component that satisfies the air-tightness optimization of the on-board hydrogen system is selected.

[0019] Further, the test obtains the hydrogen leakage result of the normal temperature leakage test under the assembly of the first front ferrule and the first connected valve member of the vehicle-mounted hydrogen system, and also includes: Fixing the assembly torque of the joint of the first front ferrule and the first connected valve member and performing air tightness test under normal temperature environment to ensure that no hydrogen leakage occurs under normal temperature detection conditions; Block the valve outlet, pressurize the valve inlet with hydrogen, maintain the valve at each pressure according to the pressurization steps at room temperature, and then perform hydrogen leakage detection; Block the valve outlet, pressurize the valve inlet with hydrogen, and leave the valve still until the temperature stabilizes. After the pressure maintenance is completed, pressurize and maintain the pressure separately. Detect hydrogen leakage at the inlet and outlet of the valve and record it; Compare the hydrogen leakage results of the room temperature leakage test under different connected valves and different metal ferrule fittings.

[0020] Further, the test obtains the hydrogen leakage result of the high and low temperature leakage test under the assembly of the first front ferrule and the first connected valve member of the vehicle-mounted hydrogen system, and also includes: Fix the assembly torque of the joint of the first front ferrule and the first connected valve member and perform air tightness detection under high and low temperature environments to ensure that no hydrogen leakage occurs under high and low temperature detection conditions; Block the valve outlet, pressurize the valve inlet with hydrogen, maintain the valve at each pressure according to the pressurization steps at high and low temperatures, and then perform hydrogen leakage detection; During the high-temperature leakage test, seal the valve outlet, use hydrogen to pressurize the valve from the air inlet, and place the valve in a high-temperature environment until the temperature stabilizes. After the pressure is maintained, pressurize the valve and detect the hydrogen leakage at the valve inlet and outlet and record it; During the low-temperature leakage test, seal the valve outlet, use hydrogen to pressurize the valve from the air inlet, and place the valve in a low-temperature environment until the temperature stabilizes. After the pressure is maintained, pressurize and maintain the pressure, detect the hydrogen leakage at the valve inlet and outlet and record it; Compare the hydrogen leakage results of high and low temperature leakage tests under different connected valves and different metal ferrule fittings.

[0021] Among them, in this embodiment, the present invention selects metal ferrule joints of different brands at home and abroad as research objects, the domestic brand is defined as ferrule C1, and the foreign brand is defined as ferrule A.

[0022] The different brands of connected parts, the present invention selects one-way valves for vehicle hydrogen systems of different brands at home and abroad as research objects, the domestic brand is defined as one-way valve C2, and the foreign brand is defined as one-way valve A.

[0023] The room temperature air tightness test method is: block the valve outlet, use hydrogen to pressurize the valve from the air inlet, keep the valve under pressure for more than 1 minute at each pressure according to the pressurization steps at room temperature, and then perform hydrogen leakage detection.

[0024] The pressurization steps are: from low to high pressures of 2 MPa, 5 MPa, 10 MPa, 15 MPa, 20 MPa, 25 MPa, 30 MPa, 35 MPa and 43.8 MPa.

[0025] The room temperature leakage test method is as follows: seal the valve outlet, use hydrogen to pressurize the valve from the air inlet, and leave the valve at 15°C and 2MPa for 1 hour until the temperature stabilizes. After the pressure maintenance is completed, pressurize to 35MPa and 43.8MPa and maintain the pressure for more than 1 minute respectively, detect the hydrogen leakage at the valve inlet, outlet and valve body and record it.

[0026] The high-temperature leakage test method is as follows: seal the valve outlet, use hydrogen to pressurize the valve from the air inlet, and let the valve stand at 85°C and 2MPa for 1 hour until the temperature stabilizes. After the pressure maintenance is completed, pressurize to 35MPa and 43.8MPa and maintain the pressure for more than 1 minute, detect the hydrogen leakage at the valve inlet and outlet and record it.

[0027] The low-temperature leakage test method is as follows: seal the valve outlet, use hydrogen to pressurize the valve from the air inlet, and leave the valve at -40°C and 2MPa pressure for 1 hour until the temperature stabilizes. After the pressure maintenance is completed, pressurize to 35MPa and maintain the pressure for more than 1 minute. Detect hydrogen leakage at the valve inlet and outlet and record it.

[0028] Test 1: Compare the sealing conditions when the ferrule C1 is connected to valve bodies of different brands. For example, Table 1 shows the hydrogen leakage of different brands of one-way valves at home and abroad under different test conditions under the ferrule C1 seal. It can be seen from Table 1 that the low-temperature sealing properties of different brands of one-way valves at home and abroad are different. The sealing properties of the ferrule connection (valve body inlet and outlet) of the one-way valve C2 in a low-temperature environment are lower than those in a normal temperature and high temperature environment, resulting in hydrogen leakage.

[0029] Table 1 Hydrogen leakage of one-way valves of different brands at home and abroad under different test conditions under ferrule C1 sealing

[0030] Test 2: Comparison of the sealing effect when ferrule A is connected to check valves of different brands. For example, Table 2 shows the hydrogen leakage of check valves of different brands at home and abroad under different test conditions under ferrule A sealing. The results show that the low-temperature sealing performance of check valves of different brands at home and abroad is different. The sealing performance of the ferrule connection (inlet and outlet of the valve body) of the check valve C2 in a low-temperature environment is lower than that in a normal temperature and high temperature environment, and hydrogen leakage occurs.

[0031] Table 2 Hydrogen leakage of one-way valves of different brands at home and abroad under different test conditions under ferrule A seal

[0032] Furthermore, a comprehensive comparison of Table 1 and Table 2 shows that the test results of the one-way valve A used in combination with the two ferrules show that the two combinations have good sealing performance at room temperature, high temperature and low temperature environments, and there is no leakage at the connection; when the one-way valve C2 is used in combination with the two ferrules, no leakage is found under room temperature leak detection (15°C) and high temperature leak detection (85°C), but hydrogen leakage occurs in the low temperature environment.

[0033] Further, the photographing and obtaining of the surface microscopic morphology at the interface between the first front ferrule and the first connected valve component also includes: The surface microstructure of the front ferrule and the inner conical surface of the connected valve interface used in the test was photographed using a laser confocal microscope and the surface roughness was calculated; Compare the surface micromorphology of different front ferrules, use a magnifying objective to observe the metal surface micromorphology, and determine whether there are obvious processing defects on the metal surface.

[0034] Among them, in this embodiment, in order to explore the factors affecting the sealing performance of the ferrule-type seal, the material level characterization method is adopted, including the metal surface micromorphology characterization and the metal element composition analysis of the alloy material to explore the high and low temperature sealing failure mechanism of the ferrule-type seal.

[0035] By comparing the surface micro-morphology of the front ferrules of different brands, it is possible to determine whether the metal surface has obvious processing defects. Using a 10x magnification objective lens, the metal surface micro-morphology can be clearly observed to determine whether the metal surface has obvious processing defects. For example, Figure 2 As shown in the figure, the microscopic morphology of the front ferrule surface and the surface roughness of the corresponding surface of different domestic and foreign brands are shown. It can be seen that the surface of the front ferrule C1 has more pit defects, and the surface of the front ferrule A is more uniform. Because it is difficult to form an effective seal at the defects, it is easy to fail to seal. Therefore, when selecting ferrules, brands with fewer front ferrule processing defects should be preferred.

[0036] The surface roughness of the front ferrules of different brands is compared. The surface roughness can be calculated by taking a picture with a laser confocal microscope. Since the lower the surface roughness, the smoother the surface, and the more conducive to sealing, the ferrules with low surface roughness should be used first if there are no obvious processing defects on the metal surface. For example, Figure 2 As shown in the figure, the surface roughness of the two ferrules are 1.039 μm (front ferrule C1) and 1.088 μm (front ferrule A), respectively. The surface roughness of the two ferrules is basically the same. However, combined with the obvious processing defects on the surface of the front ferrule C1 mentioned in the previous step, the processing technology of the front ferrule C1 is worse than that of the front ferrule A. The friction surface of the material is a rough peak that meshes and collides with each other, which makes it easy for the defective parts to be "released" when the contact stress between the sealing surfaces becomes smaller, resulting in sealing failure.

[0037] Optionally, compare the microscopic morphology of the inner cone surface at the joints of different brands of connected parts to determine whether there are obvious processing defects on the metal surface. Because it is difficult to form an effective seal at the defective part, the seal is prone to failure, so the inner cone surface should be as smooth as possible to avoid processing defects. For example, Figure 3 As shown in the figure, the surface micromorphology of the inner cone test area of ​​the one-way valve joints of different domestic and foreign brands is shown. Both the one-way valve C2 and the one-way valve A have no obvious processing defects.

[0038] By comparing the surface roughness of the inner cone surface of the joint of the connected parts of different brands. The inner cone surface of the joint of the connected part and the front ferrule form a cone seal. The lower and smoother the surface roughness of the inner cone surface, the more conducive to sealing. Under the premise that there are no obvious processing defects on the metal surface, the inner cone surface with low surface roughness is conducive to sealing. For example, Figure 3The figure shows the surface microstructure and corresponding surface roughness of the inner cone test area of ​​one-way valve joints of different brands at home and abroad. The scanning results show that the surface roughness of the two are 2.093 μm (one-way valve C2) and 2.971 μm (one-way valve A), respectively. From the image information and surface roughness scanning results, it can be concluded that the inner cone surface of the one-way valve C2 joint is smoother than that of the one-way valve A joint.

[0039] Combining the surface roughness of the inner conical surfaces of the two connected joints and the test results of the above test, it was found that under the same brand ferrule sealing conditions, the one-way valve A with a higher surface roughness has better low-temperature sealing performance than the one-way valve C2, which shows that the surface roughness of the contact surface is not a decisive factor affecting the sealing performance of the ferrule seal at extreme temperatures.

[0040] Furthermore, the linear expansion coefficients at different temperatures are obtained based on the alloy type combination of the first front ferrule and the first connected valve member, and the priority of the ferrule air tightness optimization factors is determined by combining the hydrogen leakage results of the room temperature leakage test, the hydrogen leakage results of the high and low temperature leakage test and the surface micromorphology, and further includes: Look up the linear expansion coefficient table of metal materials, and use the linear expansion data of normal temperature and high temperature zone to fit the low temperature curve expansion coefficient; Combined with the low temperature curve expansion coefficient, the normal temperature leakage test hydrogen leakage result, the high and low temperature leakage test hydrogen leakage result and the surface micromorphology, the priority of the optimization factors affecting the sealing performance of the ferrule seal at extreme temperatures is output.

[0041] In this embodiment, a vacuum direct reading spectrometer is used to detect the metal composition and content of the front ferrules and the connected valve parts of different brands to determine the alloy type. Figure 4-6 shown.

[0042] Depend on Figure 4 It can be seen that the front ferrules of both brands are SS316, but the metal composition is slightly different: front ferrule A contains multiple metals such as Ag, W, Cu, V, and Ti.

[0043] Depend on Figure 5 From the Ni content and Cr content of the check valve C2, it can be seen that the valve body material of the check valve C2 is Nitronic50, while the valve body material of the check valve A is SS316. It is reported that Nitronic50 has better corrosion resistance than SS316, 316L, etc. and has a yield strength at room temperature that is twice that of SS316 and 316L.

[0044] Depend on Figure 6 It can be seen that both nuts are made of SS316, and the influence of nut material on the sealing of the ferrule connection in this study can be ruled out.

[0045] Furthermore, the method of querying the linear expansion coefficient table of the metal material and fitting the low temperature curve expansion coefficient using the linear expansion data of the normal temperature and high temperature zone also includes: The greater the difference in the slope of the α-T curve between the current ferrule and the alloy of the connected valve, the more unfavorable it is for sealing at extreme temperatures; If the slope of the α-T curve of the front ferrule is greater than the slope of the α-T curve of the connected valve alloy, it is easy to cause hydrogen leakage in low temperature environment and easy to cause the structural strength failure of the connection in high temperature environment; If the slope of the α-T curve of the front ferrule is smaller than the slope of the α-T curve of the connected valve alloy, it is easy to cause hydrogen leakage in a high temperature environment and easy to cause the structural strength failure of the connection in a low temperature environment.

[0046] Among them, in this embodiment, if Figure 7 As shown in the figure, if the slope of the α-T curve of the front ferrule material is greater than the slope of the α-T curve of the one-way valve material, as the temperature decreases, the shrinkage of the one-way valve interface will be lower than the shrinkage of the front ferrule, which will cause the contact stress between the contact surfaces to decrease. When the contact stress is lower than the critical sealing value, hydrogen leakage will occur. As the temperature increases, the expansion at the one-way valve interface will be lower than the expansion of the front ferrule, which will cause the contact stress between the contact surfaces to increase. When the contact stress is greater than the yield strength of the material, it will cause plastic deformation of the joint or ferrule, which is also not conducive to sealing.

[0047] Furthermore, the method of selecting a front ferrule and a connected valve component combination that satisfies the gas tightness optimization of the vehicle-mounted hydrogen system according to the priority of the ferrule gas tightness optimization factor also includes: Determine whether the alloy material of the front ferrule and the connected valve is the same; If the two materials are different, they should not be used together; If the two materials are the same, then the metal surface micro-morphology of the contact surface between the two is tested; If there are obvious defects on the contact surface of either the front ferrule or the connected valve part, the defective part is replaced with another one, and the alloy material determination and metal surface micromorphology characterization test steps are repeated; If there are no obvious defects in the contact surfaces of the front ferrule or the connected valve part, they can be used in combination.

[0048] Among them, in this embodiment, the use of the joint should give priority to the use of the front ferrule and the connected part with the same alloy type of ferrule, such as SS316, and secondly, the front ferrule with fewer metal surface defects and lower surface roughness. It is worth emphasizing that the surface uniformity of the front ferrule should be higher than the priority of roughness, that is, when the surface roughness of a front ferrule is lower, but there are obvious defects such as pits or protrusions on its surface, another front ferrule with slightly higher surface roughness but few obvious defects such as pits or protrusions should be preferred.

[0049] The test results of this embodiment show that the front ferrule A and the front ferrule C1 are not compatible with the one-way valve C2.

[0050] Furthermore, the compatibility of the front ferrule A, the front ferrule C and the one-way valve A can be judged by the following steps: if the two materials are the same, the metal surface micromorphology of the contact surface of the two is characterized.

[0051] Figure 2 , Figure 3 The metal surface micromorphology of the contact surface between the two ferrules and the one-way valve A is shown respectively. Figure 2 It can be seen that the surface of the front ferrule C has obvious processing defects, while the surface of the front ferrule A has no obvious processing defects, and the inner cone surface of the one-way valve A interface has no obvious processing defects.

[0052] Furthermore, through the step, if there is an obvious defect in the contact surface of one of the front ferrule or the connected part, the judgment method of replacing the defective part and selecting other brands for replacement can be used. It can be known that compared with the front ferrule C1, the matching seal of the front ferrule A and the one-way valve A is the most preferred.

[0053] According to a second embodiment of the present invention, the present invention claims protection for a ferrule airtightness optimization device for a fuel cell vehicle-mounted hydrogen system, comprising: one or more processors; A memory having one or more programs stored thereon, when the one or more programs are executed by the one or more processors, the one or more processors implement the method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle.

[0054] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0055] In addition, each functional unit in each embodiment of the present application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of software functional units. The above is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the specification and drawings of this application, or directly or indirectly used in other related technical fields, is also included in the patent protection scope of the present application.

[0056] The specific implementation methods of the invention are described in detail above, but they are only examples, and the present application is not limited to the specific implementation methods described above. For those skilled in the art, any equivalent modification or substitution of the invention is also within the scope of the present application, and therefore, the equalization, modification, and improvement made without departing from the spirit and principle of the present application should be included in the scope of the present application.

Claims

1. A method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle, characterized in that: include: The test obtains hydrogen leakage results of a normal temperature leakage test and a high and low temperature leakage test under the assembly of a first front ferrule and a first connected valve of the vehicle-mounted hydrogen system; Photographing and acquiring the surface microscopic morphology of the interface between the first front ferrule and the first connected valve component; Using a vacuum direct reading spectrometer to detect the metal composition and content of the first front ferrule and the first connected valve component, and obtaining an alloy type combination of the first front ferrule and the first connected valve component; According to the alloy type combination of the first front ferrule and the first connected valve member, the linear expansion coefficient at different temperatures is obtained, and the priority of the ferrule air tightness optimization factors is determined by combining the hydrogen leakage results of the normal temperature leakage test, the hydrogen leakage results of the high and low temperature leakage test and the surface micromorphology; According to the priority of the ferrule air-tightness optimization factors, a combination of a front ferrule and a connected valve component that satisfies the air-tightness optimization of the on-board hydrogen system is selected.

2. A method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle as claimed in claim 1, characterized in that: The test obtains hydrogen leakage results of a normal temperature leakage test under the assembly of a first front ferrule and a first connected valve member of the vehicle-mounted hydrogen system, and also includes: Fixing the assembly torque of the joint of the first front ferrule and the first connected valve member and performing air tightness test under normal temperature environment to ensure that no hydrogen leakage occurs under normal temperature detection conditions; Block the valve outlet, pressurize the valve inlet with hydrogen, maintain the valve at each pressure according to the pressurization steps at room temperature, and then perform hydrogen leakage detection; Block the valve outlet, pressurize the valve inlet with hydrogen, and leave the valve still until the temperature stabilizes. After the pressure is maintained, pressurize and maintain the pressure separately. Detect hydrogen leakage at the inlet and outlet of the valve and record it; Compare the hydrogen leakage results of the room temperature leakage test under different connected valves and different metal ferrule fittings.

3. A method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle as claimed in claim 1, characterized in that: The test obtains the hydrogen leakage result of the high and low temperature leakage test under the assembly of the first front ferrule and the first connected valve of the vehicle-mounted hydrogen system, and also includes: Fix the assembly torque of the joint of the first front ferrule and the first connected valve member and perform air tightness detection under high and low temperature environments to ensure that no hydrogen leakage occurs under high and low temperature detection conditions; Block the valve outlet, pressurize the valve inlet with hydrogen, maintain the valve at each pressure according to the pressurization steps at high and low temperatures, and then perform hydrogen leakage detection; During the high-temperature leakage test, seal the valve outlet, use hydrogen to pressurize the valve from the air inlet, and place the valve in a high-temperature environment until the temperature stabilizes. After the pressure is maintained, pressurize the valve and detect the hydrogen leakage at the valve inlet and outlet and record it; During the low-temperature leakage test, seal the valve outlet, use hydrogen to pressurize the valve from the air inlet, and place the valve in a low-temperature environment until the temperature stabilizes. After the pressure is maintained, pressurize and maintain the pressure, detect the hydrogen leakage at the valve inlet and outlet and record it; Compare the hydrogen leakage results of high and low temperature leakage tests under different connected valves and different metal ferrule fittings.

4. A method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle as claimed in claim 1, characterized in that: The photographing and obtaining of the surface microscopic morphology at the interface between the first front ferrule and the first connected valve member also includes: The surface microstructure of the front ferrule and the inner conical surface of the connected valve interface used in the test was photographed using a laser confocal microscope and the surface roughness was calculated; Compare the surface micromorphology of different front ferrules, use a magnifying objective to observe the metal surface micromorphology, and determine whether there are obvious processing defects on the metal surface.

5. A method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle as claimed in claim 1, characterized in that: The step of obtaining the linear expansion coefficient at different temperatures based on the alloy type combination of the first front ferrule and the first connected valve member, and determining the priority of the ferrule air tightness optimization factors in combination with the hydrogen leakage results of the room temperature leakage test, the hydrogen leakage results of the high and low temperature leakage test, and the surface micromorphology, further includes: Look up the linear expansion coefficient table of metal materials, and use the linear expansion data of normal temperature and high temperature zone to fit the low temperature curve expansion coefficient; Combined with the low temperature curve expansion coefficient, the normal temperature leakage test hydrogen leakage result, the high and low temperature leakage test hydrogen leakage result and the surface micromorphology, the priority of the optimization factors affecting the sealing performance of the ferrule seal at extreme temperatures is output.

6. A method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle as claimed in claim 5, characterized in that: The method of querying the linear expansion coefficient table of the metal material and fitting the low temperature curve expansion coefficient using the linear expansion data of the normal temperature and high temperature zone also includes: The greater the difference in the slope of the α-T curve between the current ferrule and the alloy of the connected valve, the more unfavorable it is for sealing at extreme temperatures; If the slope of the α-T curve of the front ferrule is greater than the slope of the α-T curve of the connected valve alloy, it is easy to cause hydrogen leakage in low temperature environment and easy to cause strength failure of the connection in high temperature environment; If the slope of the α-T curve of the front ferrule is smaller than the slope of the α-T curve of the connected valve alloy, it is easy to cause hydrogen leakage in a high temperature environment and easy to cause the structural strength failure of the connection in a low temperature environment.

7. A method for optimizing the air tightness of a ferrule for a hydrogen system on a fuel cell vehicle as claimed in claim 1, characterized in that: The method further comprises selecting a front ferrule and a connected valve component combination that satisfies the gas tightness optimization of the vehicle-mounted hydrogen system according to the priority of the ferrule gas tightness optimization factor, and further comprising: Determine whether the alloy material of the front ferrule and the connected valve is the same; If the two materials are different, they should not be used together; If the two materials are the same, then the metal surface micro-morphology of the contact surface between the two is tested; If there is an obvious defect on the contact surface of either the front ferrule or the connected valve part, the defective part is replaced with another one, and the alloy material determination and metal surface micromorphology characterization test steps are repeated; If there are no obvious defects in the contact surfaces of the front ferrule or the connected valve part, they can be used in combination.

8. A ferrule air tightness optimization device for a fuel cell vehicle hydrogen system, characterized in that: include: one or more processors; A memory having one or more programs stored thereon, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement a ferrule air tightness optimization method for a fuel cell vehicle-mounted hydrogen system according to any one of claims 1 to 7.

Images