VEHICLE AND METHOD THEREOF

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to Korean Patent Application Serial No. 10- 2017-0014649, which was filed February 01 , 2017, and is incorporated by reference in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates to a fuel line assembly and system for conveying hydrogen fuel in a vehicle and method thereof.

BACKGROUND

[0003] This statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Hydrogen fuel cell vehicles (HFCVs) represent one of the most promising alternative to conventional vehicles that use internal combustion engines. In general, HFCVs require hydrogen storage tanks that keep hydrogen as the power source of the HFCVs. The hydrogen storage tanks are located in the rear side of the HFCVs and is connected to a fuel cell by a fuel line assembly and system. Accordingly, hydrogen fuel is conveyed to the fuel cell by the fuel line assembly and system.

[0004] Generally, hydrogen in hydrogen fuel cell vehicle is conveyed through rigid metal pipes because the rigid metal pipes such as a stainless steel are optimized for hydrogen fuel. However, we have discovered that the rigid metal pipes have drawbacks in their installation within limited spaces in the vehicle due to their rigidness. Furthermore, we have found that the rigid metal pipes cannot absorb any vibration occurring to a fuel cell, hydrogen storage tanks and reformer, etc. when the vehicle is running. In further, the rigid metal pipes cannot be expected to absorb any displacement of various parts of related equipment caused by thermal expansion.

SUMMARY

[0005] The present disclosure relates to a fuel line assembly and system for conveying hydrogen in a vehicle and method thereof, which addresses the above- referenced desirable attributes. The fuel line assembly and system in the present disclosure provides a flexibility when it is installed within limited spaces in the vehicle, and allows for absorbing vibrations when the vehicle is running.

[0006] According to one aspect of the present disclosure, a fuel line assembly comprises a rigid metal pipe for conveying hydrogen fuel, a flexible hose connected to the rigid metal pipe, and a coupling for providing a seal in a connected area between the rigid metal pipe and the flexible hose. The coupling may include a guide sleeve and a sealer ring. The guide sleeve is partially inserted in an end of the rigid metal pipe, and contacted to an inner surface of the flexible hose. The sealer ring is fitted around the rigid metal pipe and the fitted sealer ring is configured to press the inner surface of the flexible hose against the rigid metal pipe for improving a sealing effect.

[0007] The guide sleeve may include an insertion-support surface, a tapered surface, a stepped area and a chamfered surface. The insertion-support surface is inserted in the end of the rigid metal pipe and configured to support an inner side of the rigid metal pipe, wherein the sealer ring is fitted around the rigid metal pipe. A longitudinal length of the insertion-support surface is substantially equal to a width of the sealer ring. The tapered surface is configured to reduce frictional resistance when the rigid metal pipe with guide sleeve is axially inserted in the flexible hose. The stepped area is located in which the tapered surface transitions to the insertion-support surface, and configured to limit an extent of the insertion-support surface that is axially inserted into the rigid metal pipe. The chamfered surface is flattened on the tapered surface near the stepped area. Furthermore, the chamfered surface is configured to reduce interference when the rigid metal pipe with the guide sleeve is axially inserted in the flexible hose, and increase a pressure on the inner surface of the flexible hose.

[0008] The sealer ring may include a protruded area and a slant surface. The protruded area is formed along the circumference on the central area of the outside surface of the sealer ring and configured to increase the sealing effect to the inner surface of the flexible hose. The slant surface is laterally formed to both edges form the protruded area and configured to reduce frictional resistance when the rigid metal pipe with the sealer ring is inserted in the flexible hose.

[0009] The coupling further includes a metal collar fitted around the flexible hose. In a connected configuration, the metal collar is configured to provide the sealing effect for a contact area between an end of the flexible hose and the rigid metal pipe.

[0010] According to another aspect of the present disclosure, a fuel line system for conveying hydrogen fuel in a vehicle from a storage tank to a fuel cell comprises a first rigid metal pipe fluidically connected to a storage tank, a second rigid metal pipe fluidically connected to the fuel cell and a flexible connector that fluidically connects the first and second rigid metal pipes. The flexible connector includes a flexible hose and first and second couplings at first and second ends of the flexible hose. The flexible hose is impermeable to hydrogen. Each of the first and second couplings includes a sealer ring fitted around the first or second rigid metal pipe, a guide sleeve inserted in an end of the first or second rigid metal pipe and distal to the sealer ring and a metal collar fitted around the first or second end of the flexible hose. In a connected configuration, the ends of the first and second rigid metal pipes along with the respective sealer rings and guide sleeves of the first and second couplings are fitted inside the flexible hose, and the metal collars are deformed to press the first and second ends of the flexible hose against the first and second rigid metal pipes at a location proximal to the sealer rings and guide sleeves.

[0011] Each of the first and second rigid metal pipes includes first and second flanges near the end of the first or second rigid metal pipe. The first flange is formed near the end of the first or second rigid metal pipe in a connected area with the flexible connector and the second flange is formed at a certain distance from the first flange toward the opposing side from the end of the first or second rigid metal pipe. Furthermore, a first diameter of the first flange in the first or second rigid metal pipe is smaller than a second diameter of the second flange in the first or second rigid metal pipe.

[0012] In the connected configuration, a second sectional distance between an inner surface of the first or second rigid metal pipe and the outermost point of the first flange of the first or second rigid metal pipe is smaller than a first sectional distance between an inner surface of the first or second rigid metal pipe and the outermost point of the protruded area of the sealer ring. [0013] Each of the metal collars is placed between the first flange and the second flange of the first or second rigid metal pipe. In further, the metal collar is wrapped around the first or second end of the flexible hose and in contact with the second flange of the first or second rigid metal pipe.

[0014] According to another aspect of the present disclosure, a method provides for the fuel line assembly to convey hydrogen fuel in a vehicle. This method comprises inserting a portion of a guide sleeve into a rigid metal pipe such that a tapered surface thereof projects from the rigid metal pipe. A sealer ring is fitted around the rigid metal pipe between an edge of the rigid metal pipe and the first flange of the rigid metal pipe. A metal collar is fitted around the rigid metal pipe between a first flange and a second flange of the rigid metal pipe. A flexible hose is placed over the guide sleeve and the sealer ring, and between the rigid metal pipe and the metal collar. The metal collar is deformed for sealing. An end of the metal collar is contacted to the second flange of the rigid metal pipe. The method further comprises expanding both ends of the flexible hose.

[0015] According to another aspect of the present disclosure, the method further provides for the fuel line system in the vehicle. The flexible hose has first and second opposing ends, and the first end is placed between the rigid metal pipe and the metal collar described above and further defined herein. The method comprises inserting a portion of a second guide sleeve into a second rigid metal pipe such that a tapered surface thereof projects from the second rigid metal pipe. A second sealer ring is fitted around the second rigid metal pipe between an edge of the second rigid metal pipe and the first flange of the second rigid metal pipe. A second metal collar is fitted around the second rigid metal pipe between a first flange and a second flange of the second rigid metal pipe. The second end of the flexible hose is placed over the second guide sleeve and the second sealer ring and between the second rigid metal pipe and the second metal collar. The second metal collar is also deformed for sealing.

[0016] The first rigid metal pipe is part of a hydrogen storage system and the second rigid metal pipe is a delivery system. In further, the first and second rigid metal pipes are provided and fixed in a vehicle, and thereafter the flexible hose is placed over the first and second rigid metal pipes in the respective placing steps.

[0017] Further areas of applicability will become apparent from the description provided herein. Everyone should understand that the description and specific examples presented herein are for the purpose of illustration only and are not intended to limit the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

[0019] Figure 1 is a perspective view of a fuel line system for conveying hydrogen fuel in a vehicle incorporating a fuel line assembly in accordance with the present disclosure;

[0020] Figure 2 shows an enlarged view of the fuel line assembly including a flexible connector of the present disclosure;

[0021] Figure 3 shows a flexible hose of the present disclosure;

[0022] Figure 4 shows an enlarged view of a coupling of the present disclosure; [0023] Figure 5 shows an enlarged view of a rigid metal pipe of the present disclosure;

[0024] Figure 6 shows a cross section view of a guide sleeve of the present disclosure;

[0025] Figure 7 shows a cross section view of a sealer ring of the present disclosure;

[0026] Figure 8 shows a cross section view of the coupling area of the Figure 4;

[0027] Figures 9A-9F show a method illustrating a coupling assembly including the rigid metal pipe and the flexible hose according to the teachings of the present disclosure; and

[0028] Figure 10 shows an expansion process of the flexible hose of the present disclosure.

[0029] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

[0030] The following description is merely exemplary in nature and is in no way intended to limit the present disclosure or its application or uses. For example, a hydrogen fuel line assembly and system made and used according to the teachings contained herein is described throughout the present disclosure in conjunction with hydrogen fuel cell vehicles (HFCVs), in order to more fully illustrate the composition and the use thereof. The use of this hydrogen fuel line assembly and system in other types of transportation vehicles such as trucks, buses, carts and cycles, as well as on- and off- road hydrogen fuel cell vehicles is contemplated to be within the scope of the present disclosure.

[0031] The present disclosure provides a fuel line assembly and system for use in vehicles, such as a hydrogen fuel cell vehicle (HFCV). In particular, the fuel line assembly and system use rigid metal pipes and flexible connectors including a flexible hose with couplings for conveying hydrogen fuel from hydrogen storage tanks to fuel cell in the HFCV. The fuel line assembly and system of the present disclosure can provide for enhanced sealing effect by couplings of the present disclosure. The couplings are installed in the connected areas between the rigid metal pipes and the flexible hose, and each of the couplings prevents hydrogen leakage from the connected area between the rigid metal pipes and the flexible hose.

[0032] Referring in more detail to the drawings, Figures 1 and 2 illustrate a fuel line system 20 for conveying hydrogen in a hydrogen fuel cell vehicle (HFCV). The fuel line system 20 includes a fuel cell 40, a hydrogen storage system 60 and a fuel line assembly 100 including a flexible connector 1 10. The fuel line assembly 100 for conveying hydrogen in the hydrogen fuel line system 20 is formed according to the teachings of the present disclosure. In particular, the fuel line assembly 100 includes a flexible connector 1 10 and two rigid metal pipes 120, 140. When desirable, the fuel line assembly 100 may also incorporate multiple additional flexible connectors, including but not limited to a flexible connector 1 10.

[0033] Referring to Figures 2 and 3, the fuel line assembly 100 for conveying hydrogen fuel in hydrogen fuel cell vehicle according to an embodiment of the present disclosure includes a first rigid metal pipe 120, a second rigid metal pipe 140 and a flexible connector 1 10. The flexible connector 1 10 includes a flexible hose 130, a first coupling 200 and a second coupling 300. The rigid metal pipes 120, 140 are configured for conveying hydrogen that is used as a fuel for hydrogen fuel cell vehicle due to special hydrogen characteristics such as its low in density and light in weight. The rigid metal pipes 120, 140 are made of metallic materials such as a stainless steel for superior durability.

[0034] Generally, if only the rigid metal pipes 120, 140 are used for conveying hydrogen fuel in hydrogen fuel cell vehicle, the leakage of the hydrogen fuel would not occur. Due to their rigidness, however, a lot of vibrations from the vehicle body including the fuel cell 40 are transferred, and cause the rigid metal pipes 120, 140 to be broken by fatigue stress. In addition, when the rigid metal pipes 120, 140 are arranged in the vehicle, it is hard to install them within limited spaces in the vehicle. Accordingly, the flexible connector 1 10 allows for absorbing the vibrations from the vehicle body and changing the fuel line's direction for optimal arrangements of the rigid metal pipes 120, 140. The flexible connector 1 10 between both rigid metal pipes 120, 140 is installed in area where the transportation directions of hydrogen fuel need to be changed. Since the flexible hose 130 in the flexible connector 1 10 has a characteristic of bendability, the direction for conveying hydrogen fuel in the vehicle can be easily changed. The flexible hose 130 is comprised of various materials that are compatible for hydrogen and impermeable to hydrogen. Each of the rigid metal pipes 120, 140 are respectively inserted in a first and second end 134, 136 of the flexible hose 130 and the connected areas between the rigid metal pipes 120, 140 and the flexible hose 130 are sealed by the first and second couplings 200, 300. [0035] Figure 4 illustrates one of the first and second couplings 200, 300 because both couplings have an identical configuration in the present disclosure. Each of the first and second couplings 200, 300 are installed in the connected areas between the first and second rigid metal pipes 120, 140 and the respective first and second ends 134, 136 of the flexible hose 130. Each of the couplings 200, 300 includes a first and second guide sleeve 220, 320, a first and second sealer ring 210, 310 and a first and second metal collar 230, 330 for improving a sealing effect in the connected areas. Each of the guide sleeves 220, 320 is partially inserted in an end of each of the rigid metal pipes 120, 140 along axial direction, and distal to the sealer rings 210, 310. The opposing end of each of the guide sleeves 220, 320 is contacted to an inner surface 132 of the flexible hose 130 and is configured to press tightly the inner surface 132 of the flexible hose 130 for preventing the leakage of hydrogen fuel.

[0036] As shown in Figure 4, each of the sealer rings 210, 310 is fitted around the end of the respective rigid metal pipes 120, 140 and is contacted to the inner surface 132 of the flexible hose 130. Each of the sealer rings 210, 310 is also configured to press tightly the inner surface 132 of the flexible hose 130 for improving the sealing effect. In further, each of the metal collars 230, 330 is fitted around the flexible hose 130 near both ends 134, 136 of the flexible hose 130. Each of the metal collars 230, 330 is configured to press the flexible hose 130 tightly for enhancing the sealing effect.

[0037] Figure 5 shows one of the first and second rigid metal pipes 120, 140 because both rigid metal pipes 120, 140 have an identical structure. Each of the first and second rigid metal pipes 120, 140 includes a first flange 122, 142 and a second flange 124, 144. Referring to Figure 5, the first flange 122, 142 is placed near the end of each of the rigid metal pipes 120, 140 and the second flange 124, 144 is placed at a certain distance from the first flange 122, 142 toward the opposing side from the end of each of the rigid metal pipes 120, 140.

[0038] Referring to Figure 8, the first flange 122, 142 may be formed in various shapes such as a circular or polygonal shape with a flat surface, however, other suitable shapes may be implemented. The first flange 122, 142 may be contacted to the inner surface 132 of the flexible hose 130. The second flange 124, 144 is protruded on the outside surface of each of the rigid metal pipes 120, 140, and the second flanges 124, 144 is configured for contacting with both ends 134, 136 of the flexible hose 130. Thus, the configuration and shape of each flange on the rigid metal pipes 120, 140 are configured for preventing the leakage of hydrogen fuel and implementing the sealing effect in the fuel line assembly 100.

[0039] As shown in Figure 8, a first diameter D1 of the first flange 122, 142 and a second diameter D2 of the second flange 124, 144 on each of the rigid metal pipes 120, 140 are defined. The first diameter D1 is smaller than the second diameter D2. The dimension difference of the first and second flanges 122, 124, 142, 144 is configured for facilitating to insert the rigid metal pipes 120, 140 in the flexible hose 130 and enhancing the sealing effect in the contacted areas.

[0040] Figure 6 shows one of the first and second guide sleeves 220, 320 because both guide sleeves 220, 320 have an identical structure. Referring to Figures 6 and 8, each of the first and second guide sleeves 220, 320 includes a tapered surface 224, 324, a chamfered surface 228, 328, a stepped area 226, 326 and an insertion-support surface 222, 322 sequentially from an end of each of the guide sleeves 220, 320 to the other end. [0041] In particular, only the insertion-support surface 222, 322 of each of the guide sleeves 220, 320 is inserted in the respective rigid metal pipes 120, 140. The tapered surface 224, 324 thereof projects from the rigid metal pipes 120, 140. The tapered surface 224, 324 is configured to reduce frictional resistance when each of the rigid metal pipes 120, 140 with the respective guide sleeves 220, 320 is inserted in the flexible hose 130. The slope angle of the tapered surface 224, 324 may not be set at a specific angle. The suitable slope angle may be implemented for corresponding to the geometry of the rigid metal pipes 120, 140 and the flexible hose 130.

[0042] The stepped area 226, 326 is formed on area where the tapered surface 224, 324 transitions to the insertion-support surface 222, 322. When the insertion-support surface 222, 322 is completely inserted axially in each of the rigid metal pipes 120, 140, the stepped area 226, 326 is in contact with an edge of each of the rigid metal pipes 120, 140. In other words, the stepped area 226, 326 is configured to limit the extent that the insertion-support surface 222, 322 inserted axially in each of the rigid metal pipes 120, 140. Since the stepped area 226, 326 is tightly contacted to the edge of the rigid metal pipes 120, 140, the contacted area further enhances the sealing effect in the coupling areas 200, 300.

[0043] Furthermore, the chamfered surface 228, 328 is formed on the uppermost area of the tapered surface 224, 324 near the stepped area 226, 326 as a flat surface. When each of the rigid metal pipes 120, 140 with the respective guide sleeve 220, 320 is inserted axially in the flexible hose 130, the guide sleeve's 220, 320 interference with the flexible hose 130 is decreased due to the chamfered surface 228, 328. In addition, the chamfered surface 228, 328 as the flat surface exert a pressure on the inner surface 132 of the flexible hoses 130. Accordingly, the chamfered surface 228, 328 is configured for increasing the pressure on the inner surface 132 of the flexible hose 130 along their axial direction, and further increasing the sealing effect in the coupling areas 200, 300. Each of the guide sleeves 220, 320 comprises various materials that have a rigidity.

[0044] Figure 7 shows one of the sealer rings 210, 310 because the sealer rings 210, 310 have an identical structure. Referring to Figures 7 and 8, the sealer rings 210, 310 are fitted around each of the rigid metal pipes 120, 140 that are supported against the insertion-support surface 222, 322 of the guide sleeves 220, 320. The sealer rings 210, 310 are placed on an area between the edge of the respective rigid metal pipes 120, 140 and the first flange 122, 142 of the respective rigid metal pipes 120, 140. The sealer rings 210, 310 have an O-ring shape, however, other suitable shapes according to the rigid metal pipes 120, 140 may be implemented. The sealer rings 210, 310 may be formed a plastic material such as an Ethylene Propylene Diene Monomer (EPDM) that endures the -50°C to 150°C.

[0045] The sealer rings 210, 310 include a protruded area 212, 312 and a slant surface 214, 314. The protruded area 212, 312 is formed along the circumference on the central area of the outside surface of each of the sealer rings 210, 310. The protruded area 212, 312 is configured for increasing the sealing effect because the protruded area 212, 312 is directly contacted to the inner surface 132 of the flexible hose 130 and presses the inner surface 132 of the flexible hose 130. In order to increase concentrated pressure on the inner surface 132 of the flexible hose 130, the sectional shape of the protruded area 212, 312 may be formed as a triangular shape. However, other suitable sectional shapes for the protruded area 212, 312 may be implemented. [0046] The slant surface 214, 314 is formed in a downward slope toward both edges of each of the sealer rings 210, 310 from the protruded area 212, 312. The slant surface 214, 314 is configured for preventing the deterioration of the protruded area's function and for supporting the protruded area 212, 312 in lateral direction. In further, the slant surface 214, 314 is configured to reduce frictional resistance and interference between the sealer rings 210, 310 and the flexible hose 130 when each of the rigid metal pipes 120, 140 with the respective sealer rings 210, 310 is inserted in the flexible hose 130. The slope angle of the slant surface 214, 314 may not be set at a specific angle. It may correspond to the geometry of the sealer rings 210, 310.

[0047] Furthermore, each of the sealer rings 210, 310 forms a curved edge area 216, 316 on both edges that correspond to the cutout area of the slant surface 214, 314. The curved edge area 216, 316 is configured to reduce frictional resistance and interference between the sealer rings 210, 310 and the flexible hose 130 when each of the rigid metal pipes 120, 140 with the respective sealer rings 210, 310 is inserted in the flexible hose 130.

[0048] In particular, as shown in Figures 6, 7 and 8, a longitudinal length L of the insertion-support surface 222, 322 in each of the guide sleeves 220, 320 is similar or equal to a width W of each of the sealer rings 210, 310. Each of the rigid metal pipes 120, 140 is supported by the insertion-support surface 222, 322 of each of the guide sleeves 220, 320, and supports the respective sealer rings 210, 310. Since each of the sealer rings 210, 310 is fitted around the area where the insertion-support surface 222, 322 supports the inner side of the respective rigid metal pipes 120, 140, each of the sealer rings 210, 310 presses to the inner surface 132 of the flexible hose 130 toward the outside of the flexible hose 130.

[0049] Referring to Figures 4 and 8, each of the couplings 200, 300 further includes the metal collar 230, 330 on the outside surface of the flexible hose 130 between the first flange 122, 142 and the second flange 124, 144 of the respective rigid metal pipes 120, 140. When each of the rigid metal pipes 120, 140 with the respective guide sleeves 220, 320 and the respective sealer rings 210, 310 is inserted axially in the flexible hose 130, the contact areas between the inner surface 132 of the flexible hose 130 and each of the rigid metal pipes 120, 140 including the respective guide sleeves 220, 320 and sealer rings 210, 310 have the sealing effect. In the connected configuration, however, a gap may occur at the ends 134, 136 of the flexible hose 130. In such a case, if one of the sealer rings 210, 310 deforms, the leakage of hydrogen fuel may occur. For preventing the leakage problem at both ends 134, 136 of the flexible hose 130, each of the metal collars 230, 330 is placed between the first flange 122, 142 and the second flange 124, 144 of the respective rigid metal pipes 120, 140 near a location proximal to the sealer rings 210, 310 and the guide sleeves 220, 320. In further, each of the metal collars 230, 330 are deformed to press both ends 134, 136 of the flexible hose 130 against the respective rigid metal pipes 120, 140. As shown in Figure 9E, the metal collar 230, 330 is tightly deformed by a swaging process or any other suitable manufacturing process.

[0050] In addition, for preventing any opening or leakage between the both ends 134, 136 of the flexible hose 130 and the second flange 124, 144 of each of the rigid metal pipes 120, 140 due to the flexibility of the flexible hose 130, each of the metal collars 230, 330 is in contact with the second flange 124, 144 of the respective rigid metal pipes 120, 140. Thus, each of the metal collars 230, 330 is configured to enhance the sealing effect at both ends 134, 136 of the flexible hose 130 and keep the flexible hose 130 from pull-off.

[0051] Referring to Figure 8, a first sectional distance H1 between the outermost point of the first flange 122, 142 and the inner surface of the rigid metal pipes 120, 140 and a second sectional distance H2 between the outermost point of the protruded area 212, 312 of the sealer rings 210, 310 and the inner surface of the rigid metal pipes 120, 140 are defined. The first sectional distance H1 is smaller than the second sectional distance H2 for providing better sealing effect. In addition, the first sectional distance H1 is similar or equal to a third sectional distance H3 between the inner surface of the rigid metal pipes 120, 140 and the chamfered surface 228, 328 of the guide sleeves 220, 320. The third sectional distance H3 is also smaller than the second sectional distance H2.

[0052] Accordingly, in the connected configuration, the inner surface 132 of the flexible hose 130 has changed its shape such as an arc due to the geometry of the sealer rings 210, 310, the first flange 122, 142 of the rigid metal pipes 120, 140 and the guide sleeves 220, 320. Thus, the inner surface 132 of the flexible hose 130 that is in contact with the sealer ring 210, 310, the first flange 122, 142 and the guide sleeves 220, 320, increases the contact areas along the axial direction of the respective rigid metal pipes 120, 140 and enhances the sealing effect.

[0053] In further, since each of the guide sleeves 220, 320 is configured to transport hydrogen fuel through its inner diameter D3, the inner diameter D3 of the respective guide sleeves 220, 320 can be made as large as possible for minimizing the interference to hydrogen fuel being transported. Each of the guide sleeves 220, 320 may be formed as a body with the respective rigid metal pipes 120, 140 or as a separate part in the present disclosure.

[0054] As shown in Figure 8, each of the couplings 200, 300 is configured to enhance the sealing effect inside and outside the flexible hose 130. Inside the flexible hose 130, the sealing effect is improved because each of the guide sleeves 220, 320, the sealer rings 210, 310 and the first flange 122, 142 of the respective rigid metal pipes 120, 140 are contacted to the inner surface 132 of the flexible hose 130. Outside the flexible hose 130, the sealing effect is also improved because each of the metal collars 230, 330 is contacted to the second flange 124, 144 of the respective rigid metal pipes 120, 140 and tightly presses the flexible hose 130 against the respective rigid metal pipes 120, 140.

[0055] Figures 9A to 9F illustrate a method of the fuel line assembly for conveying hydrogen fuel in a hydrogen fuel cell vehicle. Figure 9A shows an assembly of one of the rigid metal pipes 120, 140 including one of the guide sleeves 220, 320 and one of the sealer rings 210, 310. Figure 9B shows one of the metal collars 230, 330 installed to one of the assembled rigid metal pipes from Figure 9A. Figure 9C illustrates that one of the assembled rigid metal pipes with one of the metal collars 230, 330 is inserted in the flexible hose 130 being held by a jig system. Figure 9D shows the installed flexible hose 130 in one of the assembled rigid metal pipes. Each end 134, 136 of the flexible hose 130 is placed over the guide sleeves 220, 320 and the sealer rings 210, 310, and between the metal collars 230, 330 and the rigid metal pipes 120, 140. Figure 9E shows a swaging process for deforming the metal collars 230, 330, which press the first and second ends 134, 136 of the flexible hose 130 against the first and second rigid metal pipes 120, 140. Figure 9F shows one of the couplings 200, 300 including the deformed metal collars 230, 330.

[0056] Figure 10 shows an expansion process for enlarging both ends 134, 136 of the flexible hose 130. The expansion process is used for facilitating to insert the assembled rigid metal pipes in both ends 134, 136 of the flexible hose 130. The expansion process is performed before placing the flexible hose 130 between the metal collars 230, 330 and the assembled rigid metal pipes.

[0057] The foregoing description of various forms of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precis forms disclosed. Numerous modifications or variations are possible in light of the above teachings. The forms discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various forms and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.