WO2003062628A1

WO2003062628A1 - Fuel feeding pipe

Info

Publication number: WO2003062628A1
Application number: PCT/JP2002/000432
Authority: WO
Inventors: Mitsuo Kaishio
Original assignee: Sanoh Kogyo Kabushiki Kaisha
Priority date: 2000-07-17
Filing date: 2002-01-22
Publication date: 2003-07-31
Also published as: JP2002031013A; JP4236799B2

Abstract

A fuel feeding pipe which is enables suppression of the pressure reduction of the fuel effectively while being used like an ordinary piping tube by adding a function to relax the reduction in the internal pressure to the tube itself and which can be arranged with a high degree of piping freedom and has a high reliability. The fuel feeding pipe is connected, when used, to a fuel rail for distributing the fuel to an injector and includes an outer tube (15) made of a flexible material and a bellows-shaped inner tube (16) housed coaxially in the outer tube (15) and forming a fuel passage therein. A sealed space (18) containing a liquid is formed between the outer tube (15) and the inner tube (16).

Description

Description Fuel supply piping technology field

The present invention relates to a fuel supply pipe for supplying fuel to an engine of an automobile, and more particularly to a fuel supply pipe having a function of alleviating a decrease in pressure of fuel generated when an injector is opened and closed. Background technology

In the fuel supply system of an automobile engine, a fuel rail that distributes fuel to the injector is connected to the fuel supply pipe, and an appropriate amount of fuel is injected from an electronically controlled injector to the intake port of the engine. Has been done.

In this type of fuel supply system, when the fuel is injected from the injector, the pressure decreases due to the fluctuation of the fuel volume in the fuel pipe, and the fuel pressure increases when the injector is closed. Pulsating phenomena that increase and decrease alternately appear remarkably. This pulsation of fuel is transmitted as vibration to the vehicle body, causing a problem that noise is transmitted from under the floor of the vehicle body into the vehicle as noise. For this reason, various improvements for reducing fuel pulsation have been conventionally proposed.

Conventionally, a general one is to connect a damping element such as a pulsation damper for absorbing pulsation to a rubber tube in the middle of a fuel pipe. The one disclosed in No. 26561 can be mentioned.

Also, there are known a conventional type in which a pulsation damper is externally mounted on a fuel rail and a conventional type in which a pulsation damper is accommodated inside a fuel rail (for example, US Pat. No. 5,617, 8 227).

However, the type in which the pulsation damper is connected in the middle of the fuel supply pipe has restrictions on the piping layout due to the piping space on the vehicle body side. Parts for connection with piping Products are required separately. Also, when a pulsation damping pipe made of an elastic member capable of expanding and contracting a passage volume is used as a fuel supply pipe, as in the prior art of Japanese Utility Model Application Publication No. Since the effect of absorbing the decrease is inferior to that of the pulsation damper, and the pressure resistance is lower than that of the tubes constituting other fuel supply pipes, there is a problem in reliability.

On the other hand, conventional fuel rails with an external pulsation damper have the disadvantage that the structure is complicated, the number of parts increases, and the cost increases.There is also a type in which the pulsation damper is housed inside. Similarly, a fixed structure and a seal structure for the damper are required, and the cost increases. Disclosure of the invention

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to add a function to alleviate a decrease in internal pressure to the tube itself, so that the tube can be used effectively in the same manner as a normal piping tube. In order to provide a highly reliable fuel supply pipe, which can suppress a decrease in fuel pressure and increase the degree of freedom in pipe routing.

In order to achieve the above object, the invention of the present application is directed to a fuel supply pipe used in connection with a fuel rail for distributing fuel to an injector, comprising: an outer tube made of a flexible material; An inner tube having a deformable bellows-like tube portion accommodated concentrically therein, and between the inside of the inner tube, and the inside of the outer tube and the outside of the inner tube. A sealed space capable of sealing a fluid is formed in any of the spaces, and the sealed space is formed in any of the inside of the inner tube and the space. It is characterized in that a fuel passage is formed on the side where no fuel passage is provided.

In the above invention, the inner tube has a straight tubular portion connected to an end of the bellows-like tube portion.

According to the present invention, a double-pipe structure in which fluid is sealed in a sealed space between the bellows-shaped inner tube and the outer tube is provided, so that it can be connected to other pipes in the same manner as a normal pipe tube. Just connect it, and in addition to its original function as a tube, PT / JP02 / 00432

3 It can function as a damper that alleviates the decrease in force and suppresses pulsation. Further, in the above invention, a fuel passage is formed in the space, and the closed space is formed in the inside of the inner tube. According to the present invention, when the internal volume of the fuel supply system is reduced and the pressure balance between the inside and outside of the bellows-shaped inner tube is lost, the inner tube sealed with the fluid is deformed, and the change in the inner volume of the tube is reduced. Absorbed. Therefore, simply by connecting to other piping in the same manner as a normal piping tube, in addition to its original function as a tube, it can exhibit a function as a damper for suppressing pulsation. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an explanatory diagram of a returnless fuel supply device to which a fuel supply pipe according to the present invention is applied.

FIG. 2 is a partially cutaway side view of a fuel supply pipe according to an embodiment of the present invention. FIG. 3 is a sectional view showing a main part of the fuel supply pipe according to the first embodiment of the present invention. FIG. 4 is a sectional view showing a main part of a fuel supply pipe according to a second embodiment of the present invention. FIG. 5 is a partially cutaway side view of a fuel supply pipe according to a third embodiment of the present invention.

FIG. 6 is an explanatory diagram showing the flow of fuel in the fuel supply pipe.

FIG. 7 is an explanatory diagram of a connection example of the fuel supply pipe of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of a fuel supply pipe according to the present invention will be described with reference to the accompanying drawings.

First embodiment

FIG. 1 shows a refueling apparatus of a re-lessless type to which a fuel supply pipe according to the present invention is applied. In FIG. 1, 10 is a fuel rail, and 12 is a fuel supply pipe according to the present embodiment. The upstream side of the fuel supply pipe 12 is connected to a fuel pump (not shown) via a connection tube 11, and the downstream side is connected to a fuel rail 10 via a surrounding rotor 13. Fuel rail 10 is metal The fuel rail 10 may be a known one to which a plurality of injectors are attached.

FIG. 2 is a diagram showing the entire fuel supply pipe 12 according to the present embodiment, in which a part of the tube is cut away. At both ends of the tube body of the fuel supply pipe 12, a female joint, in this embodiment, a socket 14 of a quick joint is connected as an example of the female joint. I have. The socket 14 can be connected to the connection tubes 11 and 13 in Fig. 1 with one touch. The pipe joint connected to both ends of the tube body of the fuel supply pipe 12 is not limited to the quick joint, and a male joint may be used instead of the female joint.

The part of the fuel supply pipe 12 that forms the tube body has a double-tube structure consisting of an outer tube 15 and a bellows-like inner tube 16 housed concentrically inside the outer tube 15. Has become. The inside of the inner tube 16 forms a passage through which fuel flows. The space formed between the inner tube 16 and the outer tube is sealed by sockets 14 fitted to both ends of the tube 11, so that a closed space 1 in which air at a predetermined pressure is sealed. Forming eight.

Here, the air having the predetermined pressure means that the pressure in the closed space 18 is sufficient for deforming the bellows portion 19 with respect to the pressure in the inner tube 16 which is reduced due to the volume change. It suffices if the pressure has a pressure difference, and the pressurized air in the closed space 18 may be, for example, air at approximately one atmospheric pressure. The air at the predetermined pressure may be, for example, air pressurized to 1 or 2 atmospheres.

As the outer tube 15, a resin tube conventionally used as a fuel supply pipe of an automobile can be used. As the inner tube 16 having the bellows portion 19, a resin bellows tube formed by extruding a nylon-based or Teflon-based resin as a material can be used.

FIG. 3 is a diagram showing a cross section of a pipe end of the fuel supply pipe 12. The other end of the tube, not shown in FIG. 3, has the same structure as that shown in FIG. 3 with the socket 14 attached. The inner tube 16 is composed of a bellows portion 19 in which rectangular irregularities are continuously formed in a predetermined pitch in a wavy shape, and a straight tube portion 20 forming a tube end. The socket 14 of the quick coupling has a socket body 21, a first press-fit mounting portion 22 at the end on the mounting side, and a second press-fit mounting portion 23 having a larger outer diameter than this. A plurality of uneven ring-shaped steps are continuously formed on the outer peripheral portion of each of the first press-fit mounting portion 22 and the second press-fit mounting portion 23 so as to conform to the function of the press-fit seal. I have. The first press-fit mounting portion 22 is press-fitted into the straight tube portion 20 of the inner tube 16, and the second press-fit mounting portion 23 is press-fitted into the outer tube 15. The outer tube 15 is airtightly adhered to the outer periphery of the second press-fit mounting portion 23 with the uneven ring-shaped step, so that the sealed space between the inner tube 16 and the outer tube 15 is formed. 18 are hermetically sealed.

The main body 21 of the socket 14 is provided with a claw port 26 as a connection port mechanism that is detachable from the tube 24 to be connected. When the tube 24 is inserted into the socket 14, the claw lock portion 26 engages with the flange portion 27 of the tube 24, and restrains the tube 24 from falling out. When the tube 24 is fitted to the socket 14, the gap between the outer peripheral portion of the tube 24 and the inner peripheral portion of the socket 14 is sealed by the O-ring 28. To remove the tube 24 from the socket 14, the claw lock 26 can be opened.

Next, the operation and effect of the first embodiment configured as described above will be described.

In FIG. 1, when fuel discharged from a pump (not shown) is supplied to the fuel rail 10 through a fuel supply pipe 12, the fuel is injected into the engine when an injection is performed. At this time, the internal volume of the fuel supply system including the fuel rail 10 and the fuel supply pipe 12 tends to decrease by the amount of the injected fuel, but the volume change is absorbed as follows.

That is, in FIG. 3, since the sealed space 18 between the outer tube 15 and the inner tube 16 is sealed with air, the internal volume of the fuel supply system is reduced and the inner tube 16 is reduced. If the balance between the air pressure and the fuel pressure is lost inside and outside, the bellows portion 19 of the inner tube 16 is deformed by the expansion and contraction of the inner tube 16 by the air pressure in the sealed space 18 in the fuel supply pipe 12 . As a result, the reduced volume in the pipe of the fuel supply system including the fuel rail 10 and the fuel supply pipe 12 is absorbed. Therefore, according to the fuel supply pipe 12 of the present embodiment, air is supplied to the closed space 18 formed between the outside of the inner tube 16 having the bellows portion 19 and the inside of the outer tube 15. Because of the sealed double-pipe structure, the fuel supply pipe 12 can achieve its original function as a tube simply by connecting it to other pipes in the same way as a normal pipe tube. In addition to the above, it is possible to exhibit a function as a damper that suppresses a pulsation by reducing a pressure decrease due to a change in the internal volume of the fuel supply system including the fuel rail 10 and the fuel supply pipe 12.

In addition, the fuel supply pipe 12 is used for a connection site where flexibility is required from above the pipe connection because the inner tube 16 having the bellows portion 19 formed in a bellows shape has flexibility. You can also demonstrate flexibility. For this reason, the degree of freedom of the piping can be increased even when a desired piping shape, for example, a piping shape that can be bent with a small radius of curvature is required without being restricted by the arrangement shape in drawing the piping. In addition, by combining the outer tube 15 with the inner tube 16, the pressure resistance of the inner tube 16 can be significantly increased as compared with the case where the inner tube 16 is used alone, thereby ensuring reliability.

Further, according to the fuel supply pipe 12 of the present embodiment, in order to seal the sealed space 18, the fuel supply pipe 12 is formed on the outer peripheral portion of the second press-fitting attachment portion 23 which is press-fitted into the outer tube 15. In addition, the use of multiple ring-shaped steps with irregularities enables reliable sealing with a simple configuration without the need for a special sealing structure, and the flexibility provided by the bellows 19 as described above. Excellent connectivity with tube.

Second embodiment

Next, a second embodiment of the fuel supply pipe of the present invention will be described with reference to FIG. Note that the same components as those of the first embodiment in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

The difference between the fuel supply pipe 30 according to the second embodiment and the first embodiment is the sealing structure of the sealed space 18. In addition, the socket 14 of the quick coupling has a press-fit mounting portion 22, and the second press-fit mounting portion 23 in FIG. 3 is not formed. A plurality of ring-shaped steps having irregularities are continuously formed on the outer peripheral portion of the press-fit mounting portion 22 so as to conform to the function of the press-fit seal. The straight tube portion 20 of the inner tube 16 is formed so as to extend outward from the end of the outer tube 15, and the press-fit mounting portion 22 of the quick fitting socket 14 is formed of the inner tube 16. It is press-fitted into the straight pipe section 20 of the pipe 16. A cylindrical end plug member 32 is inserted and fixed between the outer side of the straight tube portion 20 of the inner tube 16 and the inner end of the outer tube 15. The sealed space 18 between the inner tube 16 and the outer tube 15 is hermetically sealed by the member 32. In this case, the end plug member 32 is a resin sleeve having an O-ring 33 and is attached to the straight pipe portion 20 and the outer tube 15 by press-fitting.

The main functions and effects of the fuel supply pipe 30 according to the second embodiment are similar to those of the first embodiment. The fuel supply pipe 30 according to the second embodiment is suitable to be configured as a pipe tube in which the length of the bellows portion 19 of the inner tube 16 is relatively short. The bellows-shaped inner tube 16 is formed by arranging a bellows mold for forming the bellows portion 19 and a straight tube mold for forming the straight tube portion 20 in series. In this case, each of the bellows mold and the straight pipe mold has a certain appropriate length, and in order to form a bellows-like inner tube 16 of a desired length, the bellows mold and the straight pipe mold are used. And are arranged in the length direction as many as necessary to form the entire type. Therefore, it is possible to easily change the length of the inner tube 16 without manufacturing a new mold.

Third embodiment

Next, a third embodiment of the fuel supply pipe according to the present invention will be described with reference to FIG.

In the fuel supply pipe 40 according to the third embodiment, the outer tube 41 made of a flexible tube, for example, a resin tube, is formed concentrically inside the outer tube 41. The double tube structure with the bellows-shaped inner tube 42 accommodated in the second embodiment is the same as in the first embodiment and the second embodiment. The main difference of the third embodiment is that the space between the outer tube 41 and the inner tube 42 is a fuel passage 43 through which fuel flows, and air is generated inside the bellows-like inner tube 42. It is a sealed point. Both ends of the inner tube 42 are sealed by end plug members 44, 44 for sealing the inside of the inner tube 42. At both ends of the outer tube 41, in this embodiment, male fittings 4 5 The socket 46 of the quick fitting is attached as a female pipe fitting. A tube 47 is connected to the pipe fitting 45, and a socket 48 of a quick fitting is attached to a pipe end of the tube 47.

As shown in FIG. 6, the end plug member 44 has a plurality of, for example, four notches 50 in a portion protruding from the inner tube 42 in an axially symmetrical position with respect to the axis. It will be formed. The portion where the cut groove 50 is formed is adapted to fit into the inner diameter of the fitting 45 and the socket 46, and the inner tube 42 is firmly fitted to the fitting 45 and the socket 46. It is connected. The flow passages inside the pipe joint 45 and the socket 46 and the fuel passage 43 communicate with each other through a cut groove 50.

In the fuel supply pipe 40 according to the third embodiment, when fuel is injected from the injector, the internal volume of the fuel supply system decreases and the pressure balance between the inside and outside of the bellows-like inner tube 42 is reduced. If this happens, the bellows-shaped inner tube 42 in which air is sealed expands and contracts and is deformed, thereby absorbing the change in the inner volume of the tube. Therefore, simply by connecting to other pipes in the same manner as a normal pipe tube, in addition to the original function as a tube, the function as a damper for suppressing pulsation can be exhibited. Thus, the fuel supply pipe 40 can have both functions as a tube and as a damper.

Also, as shown in Fig. 7 for an example of connection to the fuel rail 10, the fuel supply pipe 40 is treated as a single tube that can be handled independently, and the inner tube 42 has the inherent flexibility of the bellows. Therefore, the fuel supply pipe 40 can be used instead of the tube requiring flexibility.

In addition, as shown in Fig. 7, the quick connection socket 48 can be connected to the fuel rail 10 via the tube 47 with a one-touch switch, so connection is easy and piping flexibility is high. Is the same as in the first and second embodiments. The connection may be made such that socket 46 is directly connected to fuel rail 10. In addition, the combination of the joints can be arbitrarily combined, for example, to install the socket 46 instead of the joint 45, or to install the joint 45 instead of the socket 46 so as to facilitate piping.

As is clear from the above description, according to the present invention, the internal pressure is applied to the tube itself. A structure that suppresses fluctuations can be added, and a decrease in fuel pressure can be effectively alleviated. In addition, a highly reliable fuel supply pipe can be provided with a high degree of freedom in pipe routing.

In the above description, the fluid sealed in the sealed space is air, but may be another fluid such as a liquid.

Claims

The scope of the claims

1. In the fuel supply pipe used in connection with the fuel rail that distributes fuel to the injector,

An outer tube made of a flexible material;

An inner tube having a deformable bellows-like tube portion accommodated concentrically inside the outer tube,

A sealed space capable of sealing fluid is formed in one of the inside of the inner tube and a space between the inside of the outer tube and the outside of the inner tube,

A fuel passage is formed on one of the inside of the inner tube and the space, on the side where the closed space is not formed.

A fuel supply pipe characterized by the above-mentioned.

2. The closed space is formed in the space,

A fuel passage is formed in the inside of the inner tube.

The fuel supply pipe according to claim 1, wherein:

3. The inner tube has a straight tubular portion connected to an end of the bellows-like tube portion.

3. The fuel supply pipe according to claim 2, wherein:

4. Fittings at the ends,

The pipe fitting,

A first press-fit mounting portion press-fitted into the straight pipe portion,

A second press-fit mounting portion press-fit into the outer tube;

Has,

The second press-fit mounting portion can also be used as sealing means for sealing the closed space.

4. The fuel supply pipe according to claim 3, wherein:

5. An irregular ring-shaped step is formed on the outer peripheral portion of each of the first press-fit mounting portion and the second press-fit mounting portion. 5. The fuel supply pipe according to claim 4, wherein:

6. The pipe joint is attached to both ends of the outer tube, and the second press-fitting attachment portions are press-fitted at both ends of the outer tube.

5. The fuel supply pipe according to claim 4, wherein:

7. The straight tube portion extends from an end of the outer tube,

An end plug member that is inserted and mounted between the inner end portion of the outer tube and the outer side of the straight pipe portion and seals the sealed space portion;

4. The fuel supply pipe according to claim 3, wherein:

8. Fittings at the ends,

The pipe fitting,

It has a press-fit mounting part that is press-fitted into the straight pipe part.

8. The fuel supply pipe according to claim 7, wherein:

9. The fuel supply pipe according to claim 8, wherein an uneven ring-shaped step is formed on an outer peripheral portion of the press-fit mounting portion.

10. The end plug member is attached at both ends,

The pipe joint is attached to the straight pipe portion on both ends,

The press-fit mounting portion is press-fit at both ends of the outer tube.

9. The fuel supply pipe according to claim 8, wherein:

1 1. A fuel passage is formed in the space,

The closed space is formed in the inside of the inner tube.

The fuel supply pipe according to claim 1, wherein:

12. A fitting which is attached to an end of the outer tube,

An end plug member for sealing an end of the inner tube,

The end plug member is formed so that a flow path in the pipe joint can communicate with the fuel passage.

The fuel supply pipe according to claim 11, wherein:

13. The end plug member has a cut groove formed therein so that a flow path in the pipe joint can communicate with the fuel passage.

The fuel supply pipe according to claim 12, wherein:

14. The end plug member has a plurality of the cut grooves formed at positions symmetrical with respect to an axis.

14. The fuel supply pipe according to claim 13, wherein:

15. The plurality of kerfs are the four kerfs

15. The fuel supply pipe according to claim 14, wherein:

16. The pipe joint is attached to both ends of the outer tube, and the end plug member is provided so as to seal both ends of the inner tube. 2. The fuel supply pipe described in 2.

17. The end of the end plug member, which is on the side opposite to the side that seals the end of the inner tube, is fitted with the pipe joint.

The fuel supply pipe according to claim 12, wherein:

18. The fuel supply pipe according to claim 17, wherein the end of the end plug member is fitted with an inner diameter of the pipe joint.

1 9. The inner tube is made of flexible material

The fuel supply pipe according to claim 1, wherein: