JP4481250B2 - Pulsation damper - Google Patents

Description

  The present invention relates to a pulsation damper used externally in combination with a fuel injection rail that distributes fuel to a fuel injection device of an automobile engine.

  In the fuel supply system of an automobile, the fuel pulsation phenomenon appears prominently in the pipe every time the injector opens and closes. The vibration caused by the pulsation of the fuel causes a problem that it is transmitted as noise from under the floor of the vehicle body to the inside of the vehicle via the fuel pipe. For this reason, various improvements have been conventionally made to reduce fuel pulsation. For example, it is most widely adopted to connect a pulsation damper for reducing pulsation to a fuel injection rail and attenuate the pulsation with the pulsation damper (for example, Patent Document 1).

  FIG. 4 shows a conventional example of a pulsation damper. In FIG. 4, reference numeral 1 indicates a main body of the fuel injection rail, 2 indicates an injector cup for mounting the injector, and 3 indicates a pulsation damper. The fuel is introduced from the fuel supply pipe 4 into the main body 1 of the fuel injection rail, and is injected from the injector (not shown) attached to the injector cup 3 into the engine cylinder.

  FIG. 5 shows a cross section of the pulsation damper 3. An attenuation chamber 6 is formed in the main body 5 of the pulsation damper, and fuel is introduced into the attenuation chamber 6. The bottom surface of the damping chamber 6 is supported by a spring. The main body 5 of the pulsation damper 3 is fixed to the main body 1 of the fuel injection rail via a stud bolt 8 with a flange. In the pulsation damper 3, a passage 9 is formed in the stud bolt 8 that fixes the main body 5, and fuel enters and exits the damping chamber 7 through the passage 9. The main body 5 of the pulsation damper 3 has a female screw corresponding to the male screw of the stud bolt 8, and is fixed by screwing the main body 5 of the pulsation damper 3 into the stud bolt 8 fixed to the main body 1 of the fuel injection rail. can do.

  According to such a pulsation damper 3, most of the fuel introduced into the main body 1 of the fuel injection rail is sent to the injector without being introduced into the damping chamber 6 of the pulsation damper 3. Therefore, the damping effect of the pulsation damper 3 cannot be sufficiently obtained.

Therefore, in the pulsation damper 3 shown in FIG. 6, the cylindrical member 10 having the introduction chamber 11 is attached between the flange of the stud bolt 8 and the main body 5, and the fuel supply pipe 4 is connected to the cylindrical member 10. All the fuel sent from the supply pipe 4 is once led from the introduction chamber 11 to the attenuation chamber 6. From the damping chamber 6, it flows through the passage 9 of the stud bolt 8 and is led out to the main body 2 of the fuel injection rail.
JP 2000-104636 A

  In the pulsation damper 3 of FIG. 6, since all the fuel passes through the damping chamber 6, the damping function of the damper can be fully utilized. However, on the other hand, the use of the cylindrical member 10 has a drawback that the length is increased in the axial direction and the size is increased. Assembly is also troublesome.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pulsation damper that can solve the problems of the prior art and can fully exhibit a damping function while having a compact configuration of the pulsation damper. .

To achieve the above object, the present invention provides a pulsation damper that is directly attached to a fuel injection rail. A stud bolt for fixing the main body of the motor, and a mounting member for attaching the main body of the pulsation damper to the fuel injection rail. A coaxial first conducting path for guiding fuel from the fuel supply pipe to the damping chamber, and a second conducting path for guiding fuel from the damping chamber into the pipe of the fuel injection rail between the stud bolt and the mounting member. to form the said fuel supply pipe Terminus, in the tube of the fuel injection rail, is characterized in that connected to the stud bolt via a bush which fits into end coaxial with the fuel supply pipe.

  In the present invention, the second conduction path may be formed by a groove that vertically cuts the outer peripheral surface of the stud bolt, or may be formed by a groove that vertically cuts the female thread portion of the mounting member.

  According to the present invention, the stud bolt for fixing the pulsation damper body is used to form the first conduction path and the second conduction path, and all the fuel sent from the fuel supply pipe is guided to the attenuation chamber. After that, since it is guided to the fuel injection rail, the damping function can be sufficiently exhibited while the pulsation damper has a compact configuration.

Hereinafter, an embodiment of a pulsation damper according to the present invention will be described with reference to the accompanying drawings.
First embodiment
FIG. 1 shows a pulsation damper according to a first embodiment of the present invention. In FIG. 1, reference numeral 2 indicates the main body of the fuel injection rail, and reference numeral 20 indicates the entire pulsation damper.

  A damping chamber 22 into which fuel is introduced is formed in the main body 21 of the pulsation damper 20, and the bottom surface of the damping chamber 22 is supported by a spring. Fuel is sent directly from the fuel supply pipe 23 to the attenuation chamber 22. That is, the end of the fuel supply pipe 23 protrudes into the pipe of the main body 1 of the fuel injection rail and is fitted to the bush 24. A stud bolt 25 is connected to the end of the fuel supply pipe 23 via the bush 24.

The stud bolt 25 is a hollow stud bolt and extends to the damping chamber 22 of the pulsation damper 20. A first conduction path 26 is coaxially formed in the stud bolt 25, and the fuel sent from the fuel supply pipe 23 flows through the first conduction path 26 of the stud bolt 25 and is guided to the damping chamber 22. It has come to be.
In this embodiment, the main body 21 of the pulsation damper 20 is structured to be attached to the main body 1 of the fuel injection rail by utilizing the stud bolt 25. That is, between the main body 1 of the fuel injection rail and the main body 21 of the pulsation damper 20, a disk-shaped boss member 27 having a female screw 27a is provided at the center as an attachment member used in combination with the stud bolt 25. It has been. The boss member 27 is fixed to the end surface of the main body 21 of the pulsation damper 20.

  A stud bolt 25 is screwed into the female screw 27a of the boss member 27, whereby the main body 21 of the pulsation damper 20 can be attached to the side surface of the main body 1 of the fuel injection rail.

  In this embodiment, the stud bolt 25 not only simply fixes the pulsation damper 20 to the side surface of the main body 1 of the fuel injection rail, but also includes a conduction path that leads fuel from the fuel supply pipe 23 to the damping chamber 22, and a damping chamber. A conduction path is formed to return from 22 into the pipe of the fuel injection rail. That is, the coaxial first conduction path 26 passes through the stud bolt 25. As shown in FIG. 2, a plurality of grooves 29 are longitudinally cut in the length direction on the outer peripheral surface of the stud bolt 25. In this embodiment, six grooves 29 extend in parallel at equal intervals. Since the groove 29 extends on the outer peripheral surface of the stud bolt 25 in this way, even when the stud bolt 25 is screwed into the female screw 27a of the boss member 27, fuel is supplied from the damping chamber 22 into the pipe of the fuel injection rail body 1. The second conducting path 30 to be guided is open.

The pulsation damper according to the present embodiment is configured as described above. Next, its operation and effect will be described.
First, the procedure for attaching the pulsation damper 20 to the fuel injection rail will be described.

  In FIG. 1, first, the end of the fuel supply pipe 23 is fixed to the main body 1 of the fuel injection rail by brazing. A bush 24 is attached to the end of the fuel supply pipe 23 projecting into the pipe of the main body 1 of the fuel injection rail or the tip of the stud bolt 25. Then, the bush 24 is sandwiched between the fuel supply pipe 23 and the stud bolt 25. Thereafter, by engaging the female screw 27a of the boss member 27 of the pulsation damper 20 with the stud bolt 25 and screwing together the main body 21 of the pulsation damper 20, the pulsation damper 20 can be easily attached.

  When attaching the pulsation damper 20, unlike the above order, the stud bolt 25 is first screwed into the boss member 27 integrated with the main body 21 of the pulsation damper 20, and the tip of the stud bolt 25 is left as it is. It is also possible to assemble the pulsation damper 20 in such a manner that the boss member 27 is fixed to the main body 1 while abutting against the bush 24 in the fuel injection rail.

Next, the pulsation damping action of the pulsation damper 20 will be described.
The fuel sent from the fuel supply pipe 23 is first sent to the damping chamber 22 through the passage of the bush 24 and the first conduction path 26 of the stud bolt 25 before reaching the fuel injection rail. And it passes through the 2nd conduction path 30, and is supplied in the pipe | tube of the main body 1 of a fuel injection rail.

  Thus, according to the pulsation damper 20 of the present embodiment, the structure is such that all the fuel is once introduced into the damping chamber 22, and is introduced into the fuel injection rail 2 as in the conventional example shown in FIG. Most of the generated fuel is not introduced into the damping chamber 6 of the pulsation damper 4 and is sent to the injector, so that the damping effect of the pulsation damper 20 is fully exhibited. be able to.

  Moreover, in the pulsation damper 20, all the fuel sent from the fuel supply pipe 23 is formed by forming the first conduction path 26 and the second conduction path 30 using the stud bolt 25 that fixes the main body 21. Is guided to the damping chamber 22 and then to the fuel injection rail. For this reason, as in the conventional pulsation damper 3 shown in FIG. 6, the fuel supply pipe 4 is connected to the cylindrical member 10, and all the fuel sent from the fuel supply pipe 4 is once supplied from the introduction chamber 11 to the attenuation chamber. Compared with the structure that leads to 6 and is further fed into the pipe of the fuel injection rail through the stud bolt 8, the structure can be greatly reduced in size and size in that the cylindrical member 10 that forms the introduction chamber 11 is not required. Moreover, since the attachment is only screwed in the stud bolt 25 as described above, the assembly is very easy.

Second embodiment
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 3 shows a boss member 27 for attaching the pulsation damper 20 to the main body 1 of the fuel injection rail. In the first embodiment, the second conduction path 30 for guiding the fuel from the damping chamber 22 to the fuel injection rail is formed using the groove 29 that vertically cuts the outer peripheral surface of the stud bolt 25 shown in FIG. In the embodiment, the second conduction path 30 is formed by using a groove 32 that vertically cuts the female screw 2 7a of the boss portion 27. Along with this, stud bolts 25 without grooves are used on the outer peripheral surface.
In the above 2nd Embodiment, since an effect is the same as that of 1st Embodiment, description is abbreviate | omitted.

The longitudinal cross-sectional view which shows one Embodiment of the pulsation damper by this invention. The perspective view of the stud bolt used for the pulsation damper. The perspective view which shows the boss | hub member used for other embodiment of this invention. The perspective view which shows a pulsation damper. The longitudinal cross-sectional view which shows the conventional pulsation damper. The longitudinal cross-sectional view of the pulsation damper by other examples of the past.

Explanation of symbols

1 Fuel Injection Rail Main Body 20 Pulsation Damper 21 Pulsation Damper Main Body 22 Damping Chamber 23 Fuel Supply Pipe 24 Bush 25 Stud Bolt 26 First Conducting Path 27 Boss Member (Mounting Member)
27a Female thread 29 Groove 30 Second conducting path 32 Groove

Claims (4)

In the pulsation damper that can be directly attached to the fuel injection rail,
A body of the pulsation damper having an attenuation chamber formed therein;
A stud bolt for fixing the main body of the pulsation damper to the fuel injection rail;
An internal thread portion threadably engaged with the stud bolt; and an attachment member for attaching the main body of the pulsation damper to the fuel injection rail.
The stud bolt has a coaxial first conduction path that guides fuel from a fuel supply pipe to the damping chamber, and guides fuel from the damping chamber to a pipe of a fuel injection rail between the stud bolt and the mounting member. A second conduction path is formed , and the end of the fuel supply pipe is connected to the stud bolt via a bush fitted coaxially with the end of the fuel supply pipe in the pipe of the fuel injection rail. A pulsation damper.   2. The pulsation damper according to claim 1, wherein the second conduction path is formed by a groove that vertically cuts an outer peripheral surface of the stud bolt.   2. The pulsation damper according to claim 1, wherein the second conduction path is formed by a groove that vertically cuts the female thread portion of the mounting member.   The pulsation damper according to claim 1, wherein the attachment member is a disc-shaped boss member.

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