JP2004150368A - High pressure fuel piping for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the fluctuation of fuel injection amount in high pressure fuel piping for an internal combustion engine. <P>SOLUTION: The high pressure fuel piping for distributing fuel supplied from a fuel tank to a plurality of fuel injection devices, comprises a piping main body 100, first and second fuel flow passages 101, 102 divided with a partitioning wall 111 formed integrally with an outer peripheral wall of the piping main body 100 and are formed in approximately parallel to each other in the piping main body 100, a fuel introduction portion 103 which is formed to communicate with the first fuel flow passage 101 and introduces the fuel supplied from the fuel tank, a plurality of inserting portions 104a-104d formed to communicate with the first or second fuel flow passage 101, 102 and into which the fuel injection devices can be inserted, and a plurality of communication portions 105a-105d through which the first and second fuel flow passages 101, 102 communicate with each other. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-pressure fuel pipe for an internal combustion engine, and more particularly to a high-pressure fuel pipe for distributing fuel supplied from a fuel tank to a plurality of fuel injection devices.
[0002]
[Prior art]
In the fuel pipe described in Patent Document 1, the inside of the pipe body is divided into upper and lower fuel flow paths by a partition plate, and the upper and lower fuel flow paths are communicated at both ends, and both ends are connected to the lower to upper fuel flow paths. By supplying the fuel from the fuel injection device, the delay in the recovery of the fuel pressure between the fuel injection devices immediately after the fuel injection is made uniform, and the variation in the fuel injection amount is reduced.
[0003]
The fuel pipe described in Patent Literature 2 divides the inside of the pipe body into upper and lower fuel passages, provides a fuel introduction section in a lower fuel passage, provides a fuel discharge section in an upper fuel passage, and provides a discharge section. The fuel pressure between each fuel injection device immediately after fuel injection is returned by returning the fuel introduced from the lower fuel passage to the fuel tank via the discharge part of the upper fuel passage and the pressure regulator. The recovery delay is made uniform, and the variation in fuel injection amount is reduced.
[0004]
[Patent Document 1]
JP-A-9-296768 (page 3-4, FIG. 1)
[0005]
[Patent Document 2]
JP-A-7-208298 (page 2-3, FIG. 1)
[0006]
[Problems to be solved by the invention]
In a high-pressure fuel pipe of an internal combustion engine, a hoop stress applied to an inner wall by a fuel pressure is represented by the following equation (1).
^{_{σmax = p (r 2 2 +}} r 1 2) / (r 2 2 -r 1 2) ··· (1)
σmax: maximum hoop stress (stress on the pipe due to fuel pressure), p: pipe fuel pressure, r ₁ : pipe inner diameter, r ₂ : pipe outer diameter When the pipe fuel pressure p is high, to reduce variation in injection quantity and pulsation noise. Although it is necessary to increase the piping volume, when the inner diameter r ₁ and the outer diameter r ₂ are increased, the hoop stress increases by the square of Equation (1). For this reason, it is necessary to increase the thickness of the pipe in order to secure the strength of the pipe. However, if the pipe thickness is increased, there is a possibility that the weight, size, and cost of the high-pressure fuel pipe will increase. In addition, the engine layout may not be satisfied due to the large-sized high-pressure fuel pipe.
[0007]
The high-pressure fuel pipe described in Patent Document 1 has a structure in which the pipe is simply divided by a partition plate, and the fuel pressure in the pipe is received only by the pipe wall. It is determined from the inner diameter and the outer diameter, and it is necessary to increase the pipe wall thickness as described above.
[0008]
On the other hand, in the high-pressure fuel pipe described in Patent Literature 2, the wall dividing the pipe main body is formed integrally with the pipe wall to receive the fuel pressure. For this reason, the hoop stress acts on the relation between the inner diameter and the outer diameter in each divided pipe. As described above, the hoop stress acts on the square of the diameter, so that the smaller the diameter of one pipe, the smaller the hoop stress acting on the entire pipe. However, between the fuel injection devices near the both ends and near the center, the distance from the part where the fuel is introduced is different, and the speed of fuel supply is different, so that as the fuel pressure inside the pipe body becomes higher, It is difficult to equalize the delay in fuel pressure recovery between the fuel injection devices, and it is difficult to equalize the fuel injection amount.
[0009]
SUMMARY OF THE INVENTION It is an object of the present invention to reduce a variation in fuel injection amount even under a high fuel pressure in a high-pressure fuel pipe of an internal combustion engine.
[0010]
Another object of the present invention is to easily manufacture a high-pressure fuel pipe of an internal combustion engine that can reduce the variation in the fuel injection amount under a high fuel pressure, and to reduce the cost.
[0011]
[Means for Solving the Problems]
A high-pressure fuel pipe according to the present invention is a high-pressure fuel pipe for distributing fuel supplied from a fuel tank to a plurality of fuel injection devices, and includes a pipe main body, first and second fuel flow paths, and a fuel introduction pipe. And a plurality of insertion sections and a plurality of communication sections. The pipe main body has an outer peripheral wall and a partition wall formed integrally with the outer peripheral wall. The first and second fuel passages are separated by a partition wall of the pipe main body, and are formed substantially parallel to each other inside the pipe main body. The fuel introduction unit is formed in communication with the first fuel flow path, and introduces fuel supplied from the fuel tank. The plurality of insertion portions are formed so as to communicate with the fuel flow path of the first or second fuel flow path, and can insert the fuel injection device. The plurality of communicating portions communicate the first and second fuel flow paths with each other.
[0012]
In this high-pressure fuel pipe, high-pressure fuel from a fuel tank is introduced from a fuel introduction part, and fuel is supplied to the first and second fuel flow paths through a plurality of communication parts. Thereby, the fuel is filled in the pipe main body, the fuel pressure is adjusted, and the fuel is injected from the fuel injection device. Also, immediately after fuel injection under a high fuel pressure, fuel is quickly supplied to the insertion portion via the plurality of communication portions, and the fuel pressure between the fuel injection devices is quickly recovered.
[0013]
【The invention's effect】
According to the present invention, in the high-pressure fuel pipe under the high fuel pressure, the fuel is promptly supplied to each fuel injection device from the plurality of communication portions immediately after the fuel injection, so that the delay in the recovery of the fuel pressure between the fuel injection devices is made uniform. And the variation of the fuel injection amount can be reduced.
[0014]
Further, according to the present invention, in a high-pressure fuel pipe under a high fuel pressure, necessary hoop stress can be reduced by dispersing hoop stress by a plurality of fuel flow paths, and the pipe wall thickness can be reduced. This makes it possible to reduce the weight, size, and cost of the high-pressure fuel pipe.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
(1) First Embodiment (1-1) Configuration [Fuel Supply System]
FIG. 1 is a block diagram of a fuel supply system to which a high-pressure pipe of an internal combustion engine according to the present invention is applied. This fuel supply system mainly includes a common rail 1000 as a high-pressure pipe of an internal combustion engine, a fuel injection device 2, and a fuel tank 10.
[0016]
The common rail 1000 includes a pipe main body 100, a partition wall 111, a first fuel flow path 101, a second fuel flow path 102, a fuel introduction section 103, insertion sections 104a to 104d, and communication sections 105a to 105d. Have. The first fuel passage 101 and the second fuel passage 102 are formed by dividing the inside of the pipe main body 100 into upper and lower parts by a partition wall 111, and are formed as hollow spaces arranged substantially in parallel with each other. The fuel introduction section 103 is provided at one end of the first fuel flow path 101 and is connected to the high-pressure supply pipe 3. Here, the fuel introduction section 103 is formed at the left end of the first fuel flow path 101, but may be appropriately changed according to the engine layout. For example, the fuel introduction section 103 may be formed at the right end of the first fuel flow path 101, may be formed at any end of the second fuel flow path 102, or may be formed at the first fuel flow path 102. It may be formed in the middle of the first fuel passage 101 or the second fuel passage 102. The insertion portions 104a to 104d have openings for inserting the fuel injection devices 2a to 2d corresponding to the respective cylinders. The communication portions 105a to 105d make the first fuel flow path 101 and the second fuel flow path 102 communicate with each other. Here, the number of communication sections 105a to 105d is the same as the number of insertion sections 104a to 104d, but may be smaller than the number of insertion sections 104a to 104d. The first fuel passage 101 is provided with a fuel pressure sensor 5 for detecting the fuel pressure inside the pipe main body 100.
[0017]
The fuel injection devices 2a to 2d are inserted into the insertion portions 104a to 104d, respectively. The input side is disposed on the fuel flow path 102 side, and the output side is inserted into the cylinder of each cylinder. Inject into the cylinder of each cylinder.
[0018]
The fuel tank 10 stores fuel, and the stored fuel is sent to the pressure regulator 11 by the low-pressure pump 9. The pressure regulator 11 is connected to the high-pressure pump 6 via the low-pressure supply pipe 7, and adjusts the pressure of the fuel sent from the low-pressure pump 9 to send the fuel to the high-pressure pump 6. A low-pressure return pipe 12 is connected to the pressure regulator 11. The pressure regulator 11 returns excess fuel to the fuel tank 10 through the low-pressure return pipe 12, so that the fuel whose fuel pressure has been adjusted is supplied to the low-pressure pump 6. Send out. The high-pressure pump 6 is connected to the first fuel flow path 101 via the high-pressure supply pipe 3 and the fuel introduction unit 103, and pressurizes the fuel sent from the pressure regulator 11 and sends the fuel to the first fuel flow path 101.
[0019]
Further, a relief valve 4 is provided in the first fuel flow path 101, and the relief valve 4 is connected to the fuel tank 10 via a return pipe 8. The relief valve 4 is opened when the detection value of the fuel pressure sensor 5 becomes equal to or more than a predetermined value, and returns the fuel in the pipe main body 100 to the fuel tank 10 so that the fuel pressure in the pipe main body 100 does not exceed the predetermined value. Like that. Here, the relief valve 4 is provided above the first fuel flow path 101, but may be appropriately changed according to the engine layout. For example, the relief valve 4 may be disposed at one end of the first fuel passage 101 or the second fuel passage 102, or may be provided in the middle of the first fuel passage 101 or the second fuel passage 102. It may be arranged.
[0020]
[Common rail]
FIG. 2 is a perspective view of the common rail 1000, and FIG. 3 is a cross-sectional view of the common rail 1000 taken along iii-iii '. 2 and 3, the same reference numerals as those in FIG. 1 indicate the same components.
[0021]
The common rail 1000 is manufactured by using an aluminum die casting method. Specifically, the first fuel flow path 101 and the second fuel flow path 102, the insertion portions 104a to 104d, and the communication portions 105a to 105d are formed by using a core inserted from the left and right and a core inserted from the up and down direction. The opening of the fuel discharge unit 106 and the opening of the sensor mounting unit 107 are formed.
[0022]
The partition wall 111 is formed integrally with the outer peripheral wall 112 of the pipe main body 100 when the first fuel flow path 101 and the second fuel flow path 102 are formed by a core during casting. The first fuel passage 101 and the second fuel passage 102 are partitioned by a partition wall 111 inside the pipe main body 100 and are formed substantially parallel to each other. The left end of the first fuel flow path 101 has an opening 103 that opens in the longitudinal direction, and the opening 103 forms a fuel introduction section 103. On the right end side of the first fuel passage 101, a fuel discharge portion 106 extending upward and integrally formed is provided. The fuel discharge portion 106 has an opening, and this opening communicates with the first fuel flow path 101 and opens upward. The relief valve 4 is attached to this opening. On the left end side of the first fuel flow path 101, a sensor mounting portion 107 extending upward and integrally formed is provided. The sensor mounting portion 107 has an opening, and this opening communicates with the first fuel flow path 101 and opens upward. The fuel pressure sensor 5 is attached to this opening. The second fuel flow path 102 has an opening 108 that opens in the longitudinal direction at the right end, and a plug 109 is fitted into the opening 108 and closed. The second fuel flow path 102 is provided with insertion portions 104a to 104d extending downward and integrally formed. The insertion portions 104a to 104d have openings, and these openings communicate with the second fuel flow path 102 and open downward. The fuel injection devices 2a to 2d are inserted into these openings.
[0023]
The communication portions 105a to 105d communicate the first fuel flow path 101 and the second fuel flow path 102. The communication parts 105a to 105d are arranged at positions corresponding to the insertion parts 104a to 104d, and when viewed from the insertion direction of the insertion parts 104a to 104d (the direction of the arrow in FIGS. 2 and 3), the communication parts 105a to 105d are formed. Are included in the opening ranges of the insertion portions 104a to 104d.
[0024]
FIG. 4 is a diagram illustrating the relationship between the insertion portion 104a and the communication portion 105a viewed from the direction of the arrows in FIGS. Here, the relationship between the insertion section 104a and the communication section 105a is shown as an example. The same applies to the relationship between the other insertion portions 104b to 104d and the communication portions 105b to 105d. FIG. 5A shows a case where the axes of the openings of the insertion portion 104a and the communication portion 105a are coaxial, and the opening of the communication portion 105a is smaller than the insertion portion 104a. FIG. 2B shows a case where the axes of the openings of the insertion portion 104a and the communication portion 105a are not coaxial, and the opening of the communication portion 105a is smaller than the opening of the insertion portion 104a. FIG. 3C shows a case where the opening of the insertion portion 104a and the opening of the communication portion 105a are coaxial and have the same diameter. The openings of the communicating portions 105a to 105d are formed in any size or positional relationship shown in FIGS.
[0025]
As described above, the openings of the communication portions 105a to 105d are formed so as to be included in the opening range of the insertion portions 104a to 104d. Therefore, when the common rail 1000 is manufactured by the aluminum die-casting method, the common cores are formed by using a common core. The communication portions 105a to 105d and the insertion portions 104a to 104d are formed at the same time. When the openings of the communication portions 105a to 105d and the insertion portions 104a to 104d are coaxial and have the same diameter, formation of the core is simple. After the casting process, the insertion portions 104a to 104d may be opened by a cutting drill, and then the communication portions 105a to 105d may be opened by a cutting drill through the openings. When the openings of the communication portions 105a to 105d and the insertion portions 104a to 104d are coaxial and have the same diameter, the openings of the communication portions 105a to 105d and the insertion portions 104a to 104d can be formed simultaneously by one opening operation.
[0026]
Further, main body mounting portions 110a to 110d extending in the vertical direction are provided on side surfaces of the piping main body 100, and the main body mounting portions 110a to 110d have through holes penetrating in the vertical direction. When mounting the common rail 1000, bolts are passed through the through holes of the main body mounting portions 110a to 110d, and the bolts are tightened to the cylinder block to fix the piping main body 100. At this time, the fuel injection devices 2a to 2d inserted into the insertion portions 104a to 104d are fixed by being sandwiched from above and below by the upper pipe main body 100 and the lower cylinder.
[0027]
(1-2) Operation In the common rail 1000 according to this embodiment, the fuel from the fuel tank 10 is introduced from the fuel introduction unit 103, and the first fuel flow path 101 and the second fuel flow are communicated through the communication units 105a to 105d. The road 102 is filled. When fuel is accumulated in the first fuel flow path 101 and the second fuel flow path 102 and the fuel pressure sensor 5 reaches a desired value, the fuel is injected from the fuel injection devices 2a to 2d to the cylinders of each cylinder. Immediately after fuel injection, fuel is quickly supplied to the fuel injection devices 2a to 2d via the communication portions 105a to 105d located directly above the fuel injection devices 2a to 2d.
[0028]
When the fuel pressure exceeds a predetermined value, the relief valve 4 is opened to return the fuel in the pipe main body 100 to the fuel tank 10 to prevent the fuel pressure in the pipe main body 100 from exceeding a predetermined value.
[0029]
Further, two fuel flow paths of the first fuel flow path 101 and the second fuel flow path 102 are provided to disperse the hoop stress applied to the inner wall of the pipe main body 100. In order to secure the same volume with one fuel flow path as in the related art and to secure the strength of the pipe, a pipe wall thickness of 5.5 mm is required. In the present embodiment, however, two fuel flow paths are used. The required strength was reduced by dispersing the hoop stress, and the pipe thickness was set to 4 mm. Thus, the weight, size, and cost of the common rail 1000 can be reduced.
[0030]
(1-3) Effects According to the common rail 1000 according to the present embodiment, even if the fuel pressure near the insertion portions 104a to 104d is reduced by the fuel injection, the communication portions 105a to 105d within the opening range of the insertion portions 104a to 104d. , Fuel is quickly supplied to the insertion portions 104a to 104d. As a result, the delay in fuel pressure recovery between the fuel injection devices 2a to 2d immediately after the fuel injection can be made uniform, and the variation in the fuel injection amount can be reduced.
[0031]
Further, since the high-pressure supply pipe 3 and the return pipe 8 communicate with the first fuel flow path 101, pulsation caused by fuel injection is reduced in the second fuel flow path 102 and the partition wall 111, and the first fuel flow The pulsation transmitted to the high-pressure supply pipe 3 and the return pipe 8 via the path can be reduced.
[0032]
In addition, according to the common rail 1000 according to the present embodiment, the variation of the fuel injection amount among the fuel injection devices 2a to 2d can be reduced by the plurality of communication portions 105a to 105d. There is no need to separately provide such components, so that the number of components can be reduced and cost can be reduced.
[0033]
Further, according to the common rail 1000 according to the present embodiment, the pipe strength required for dispersing the hoop stress by the plurality of fuel flow paths (the first fuel flow path 101 and the second fuel flow path 102) can be reduced, and the pipe wall thickness can be reduced. The thickness can be reduced. Thereby, the weight, size, and cost of the common rail 1000 can be reduced. In addition, the downsizing of the common rail 1000 makes it less likely to be affected by engine layout conditions, and secures a sufficient volume for reducing pulsating noise. As a result, it is not necessary to separately provide a soundproof protector for countermeasures for pulsating noise, and the number of parts and cost can be reduced. Further, when the common rail 1000 is manufactured by the aluminum die-casting method, if the thickness of the pipe body 100 is large, shrinkage cavities and variations in density may occur. 100 can be made thinner and shrinkage cavities and variations in density can be prevented.
[0034]
In addition, according to the common rail 1000 according to the present embodiment, since the partition wall 111 is formed integrally with the outer peripheral wall 112, the number of components can be reduced, the manufacturing process can be simplified, and the cost can be reduced.
[0035]
In the common rail 1000 according to the present embodiment, the openings of the communication portions 105a to 105d are formed so as to be included in the opening ranges of the insertion portions 104a to 104d. And the insertion portions 104a to 104d can be simultaneously cast. Alternatively, after the casting step, by opening the insertion portions 104a to 104d and the communication portions 105a to 105d with a cutting drill, the communication portions 105a to 105d and the insertion portions 104a to 104d can be easily formed. Thereby, the manufacturing process can be simplified and the cost can be reduced.
(2) Second Embodiment (2-1) Configuration FIG. 5 is a perspective view of a common rail 2000 according to the second embodiment, and FIG. 6 is a cross-sectional view taken along a line vi-vi ′. In the present embodiment, the communication portions 205a to 205d are formed not at positions corresponding to the insertion portions 204a to 204d but at positions shifted from the insertion portions 204a to 204d.
[0036]
(2-2) Effects In the common rail 2000 according to the present embodiment, since the communication portions 205a to 205d are not disposed right above the insertion portions 204a to 204d, they are generated near the insertion portions 204a to 204 immediately after fuel injection. The pressure pulsation can be reduced by irregular reflection on the partition wall 211. As a result, the pressure pulsation is transmitted to the high-pressure supply pipe 3 and the return pipe 8 via the communication portions 205a to 205d, thereby preventing generation of abnormal noise.
(3) Third Embodiment (3-1) Configuration FIG. 7 is a perspective view of a common rail 3000 according to the third embodiment, and FIG. 8 is a cross-sectional view along viii-viii ′. In the present embodiment, the second fuel flow path 302 does not have the fuel discharge portions 106 and 206 formed upward from the first fuel flow path 301 and the second fuel flow path 302 does not have the openings 108 and 208 at the right end thereof. An opening 308 is formed at the left end of the fuel flow path 302. The opening 303 is a fuel introduction section 303, the opening 308 is a fuel discharge section 308, the high pressure supply pipe 3 is connected to the fuel introduction section 303, and the relief valve 4 is arranged in the fuel discharge section 308. Conversely, the opening 303 is a fuel discharge section 303, the opening 308 is a fuel introduction section 308, the relief valve 4 is disposed in the fuel discharge section 303, and the high pressure supply pipe 3 is connected to the fuel introduction section 308. May be.
[0037]
(3-2) Function and Effect According to the common rail 3000 according to the present embodiment, the fuel introduction part 303 and the fuel discharge part 308 can be formed at the same time when the first fuel passage 301 and the second fuel passage 302 are formed. it can. Further, it is not necessary to separately form the fuel introduction portions 106 and 206. This simplifies the manufacturing process and reduces costs.
(4) Fourth Embodiment (4-1) Configuration FIG. 9 is a perspective view of a common rail 4000 according to a fourth embodiment, and FIG. 10 is a cross-sectional view taken along line xx ′. In the present embodiment, the number of communication portions 405a to 405c is smaller than the number of insertion portions 404a to 404d. Here, the communication portions 405a to 405c are arranged at substantially the middle of the insertion portions 404a to 404d along the longitudinal direction of the pipe main body 400.
[0038]
(4-2) Effects In the common rail 4000 according to the present embodiment, the number of the communication portions 405a to 405c is smaller than the number of the insertion portions 404a to 404d. Compared with the case of supplying, the plurality of communication portions 405a to 405c arranged near the insertion portions 404a to 404d can reduce the variation in the fuel pressure recovery of the fuel injection devices 2a to 2d, and achieve a uniform fuel injection amount. be able to.
(5) Other Embodiments In the above embodiment, two fuel flow paths are provided. However, three or more fuel flow paths are provided, and a fuel introduction portion is formed so as to communicate with any one of the fuel flow paths. The portion may be formed to communicate with any one of the fuel flow paths, and the fuel flow paths adjacent to each other may be connected by a plurality of communication portions. In this case, the hoop stress applied to the inner wall of the common rail can be further dispersed, and the wall thickness of the pipe can be reduced.
[Brief description of the drawings]
FIG. 1 is a fuel supply system to which a high-pressure pipe of an internal combustion engine according to the present invention is applied.
FIG. 2 is a perspective view of a common rail according to the first embodiment.
FIG. 3 is a sectional view taken along iii-iii ′ of FIG. 2;
FIG. 4 is a view for explaining the relationship between a communication unit and an insertion unit.
FIG. 5 is a perspective view of a common rail according to a second embodiment.
FIG. 6 is a sectional view taken along line vi-vi ′ of FIG. 5;
FIG. 7 is a perspective view of a common rail according to a third embodiment.
FIG. 8 is a sectional view taken along viii-viii ′ of FIG. 7;
FIG. 9 is a perspective view of a common rail according to a fourth embodiment.
FIG. 10 is a sectional view taken along line xx ′ of FIG. 9;
[Explanation of symbols]
1000, 2000, 3000, 4000 Common rail 2 fuel injection device (fuel injector)
3 High pressure supply pipe 4 Relief valve 5 Fuel pressure sensor 6 High pressure pump 7 Low pressure supply pipe 8 Return pipe 9 Low pressure pump 10 Fuel tank 11 Pressure regulator 12 Low pressure return pipe 100, 200, 300, 400 Main body 101, 102, 201, 202, 301 , 302, 401, 402 Fuel passages 103, 108, 203, 208, 303, 308, 403, 408 Openings 104a-d, 204a-d, 304a-d, 404a-d Insertions 105a-d, 205a-d , 305a-d, 405a-c Communication parts 106, 206, 406 Fuel discharge parts 107, 207, 307, 407 Sensor mounting parts 109, 209, 409 Plugs 110a-d, 210a-d, 310a-d, 410a-d Main body Mounting parts 111, 211, 311, 411 Partition wall

Claims (8)

A high-pressure fuel pipe for distributing fuel supplied from a fuel tank to a plurality of fuel injection devices,
A pipe main body having an outer peripheral wall and a partition wall formed integrally with the outer peripheral wall,
First and second fuel flow paths separated by a partition wall of the pipe main body and formed substantially parallel to each other inside the pipe main body;
A fuel introduction unit formed in communication with the first fuel flow path and configured to introduce fuel supplied from the fuel tank;
A plurality of insertion portions formed in communication with the first or second fuel flow passage and capable of inserting the fuel injection device;
A plurality of communicating portions that communicate the first and second fuel flow paths with each other;
A high-pressure fuel pipe. The plurality of communication portions are arranged at positions corresponding to the plurality of insertion portions so that the opening of the communication portion is included in an opening range of the insertion portion when viewed from an insertion direction of the insertion portion. Item 2. A high-pressure fuel pipe according to item 1. 3. The high-pressure fuel pipe according to claim 2, wherein the plurality of communication sections are arranged coaxially with the corresponding insertion section at a position corresponding to any of the plurality of insertion sections. 4. The high-pressure fuel pipe according to claim 2, wherein the number of the communication portions is the same as the number of the insertion portions. 2. The high-pressure fuel pipe according to claim 1, wherein the plurality of communication sections are arranged along the longitudinal direction of the pipe main body so as to be shifted from any of the plurality of insertion sections. 3. The high-pressure fuel pipe according to claim 2, wherein the number of the communication portions is smaller than the number of the insertion portions. The high-pressure fuel pipe according to any one of claims 1 to 6, wherein the plurality of insertion portions are formed to communicate with the second fuel flow path. 8. The fuel cell system according to claim 1, further comprising at least one fuel flow path arranged substantially parallel to the first and second fuel flow paths and communicating with one of the two fuel flow paths. 9. High pressure fuel piping.

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