JPH08261097A - Fuel pressure pulsation damper - Google Patents

Abstract

PURPOSE: To eliminate the reduction of reliability due to assembling and prevent the occurrence of spatial disadvantage in a fuel pressure pulsation damper. CONSTITUTION: A nipple 14 having a connection port 13 is fusion fitted in one end of a housing 12 of a fuel delivery pipe 11. The housing 12 has a fuel passage 16 which is extended along the longitudinal direction and a pressure pulsation damping mechanism 21 is arranged and fixed on the connection port 13 side in the housing 12. The pressure pulsation damping mechanism 21 has a case 22, a spacer 23, filters 24, 25, a cap 26, and an orifice 28, and consists of an elastic body 27 having closed cells. Pressure pulsation transmitted to fuel inside the mechanism 21 can be damped by the pressure pulsation damping mechanism 21. Since the pressure pulsation damping mechanism 21 is fixed in the housing 12, it is integrated with the fuel delivery pipe 11 of the pressure pulsation damping mechanism 21, and the reduction of reliability of performance due to separate body assembling can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel delivery pipe for use in an engine having a plurality of fuel injection valves and for distributing fuel to each fuel injection valve, and more specifically, to a fuel delivery pipe that may occur during fuel injection. The present invention relates to a fuel pressure pulsation damping device for damping fuel pressure pulsations.

[0002]

2. Description of the Related Art Conventionally, as one of fuel supply mechanisms for a multi-cylinder engine, there is one in which a plurality of fuel injection valves are arranged in an intake passage and fuel is injected from each fuel injection valve to a corresponding cylinder. . In this mechanism, a fuel delivery pipe is usually used to distribute the fuel from the fuel pump to each fuel injection valve. For example, as shown in FIG. 6, a fuel passage (not shown) is provided through the housing 52 of the fuel delivery pipe 51, and a socket portion 54 for mounting the fuel injection valve 53 is provided at a plurality of locations along the passage. Has been formed. Then, during operation of the engine to which the fuel delivery pipe 51 is attached, the fuel from the fuel pump is introduced into the fuel passage from one end of the housing 52 and flows through the passage. During this passage, the fuel is injected into each fuel injection valve 5
It is divided into three parts and is injected into each cylinder of the engine from here. Excess fuel is discharged from the other end of the housing 52 and returned to the fuel tank via the return pipe 55.

In such a conventional technique, a pressure regulator 56 for keeping the fuel pressure substantially constant is provided downstream of the fuel delivery pipe 51.
Further, a pulsation damper 57 for damping the fuel pressure pulsation is provided on the upstream side of the fuel delivery pipe 51. That is, the pulsation damper 57
As shown in FIG. 7, the moving body 58 and the diaphragm 5 are
9, a spring 60, a cap 61 and the like.
Then, the pulsation damper 57 causes the diaphragm 59 and the movable body 5 to move when the fuel pressure maintained by the pressure regulator 56 is pulsated by the fuel injection from the fuel injection valve 53.
The vibration of 8 plays a role of attenuating the pulsation.

[0004]

However, in the above prior art, the pulsation damper 57 is provided separately from the fuel delivery pipe 51, so that the pressure pulsation is damped. For this reason, the reliability of the performance due to the mutual assembly is not always reliable.

Further, since the pulsation damper 57 has to be provided so as to project outward from the housing 52 of the fuel delivery pipe 51, a significant space disadvantage is brought about. As a result, for example, another member cannot be installed at the installation location of the pulsation damper 57.

The present invention has been made to solve the above problems, and an object thereof is to provide a device for attenuating fuel pressure pulsation, which is integrated with a fuel delivery pipe so as to improve reliability by assembly. SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel pressure pulsation damping device capable of eliminating the decrease in fuel pressure and preventing a space disadvantage.

[0007]

In order to achieve the above object, in the invention described in claim 1, a fuel for introducing fuel into a housing and distributing the fuel to a plurality of fuel injection valves. A fuel delivery pipe having a passage; and a pressure pulsation damping mechanism having an elastic body, which is disposed and fixed on the fuel introduction side in the housing of the fuel delivery pipe, and has an orifice for passing the fuel. The fuel pressure pulsation damping device is the main point.

The invention according to claim 2 is characterized in that, in the fuel pressure pulsation damping device according to claim 1, the elastic body has independent air bubbles inside.

[0009]

According to the invention described in claim 1, the fuel is introduced into the fuel passage with the fuel injection valve attached to the housing of the fuel delivery pipe, and the fuel is distributed to each fuel injection valve in the process of flowing through the fuel passage. To be done. Here, pulsation may occur in the fuel pressure with the fuel injection from the fuel injection valve or with the introduction of the fuel into the fuel passage from the fuel pump or the like. However, according to the present invention, the pressure transmitted to the fuel inside the housing is fixed by the pressure pulsation damping mechanism having the elastic body which is arranged and fixed on the fuel introduction side in the housing and has the orifice for passing the fuel. Pulsations can be dampened. More specifically, waves based on pressure pulsations can be damped by passing through the orifice.
Further, when the wave hits the elastic body, the elastic body is deformed, and its energy can be attenuated and absorbed.

Further, since the pressure pulsation damping mechanism is fixed in the housing of the fuel delivery pipe, unlike the prior art in which a pulsation damper must be provided outside, the fuel pulsation damping mechanism fuel delivery pipe. Can be integrated with. Furthermore, the pressure pulsation damping mechanism does not project outside the housing of the fuel delivery pipe.

Further, according to the invention of claim 2,
In addition to the action of the invention described in claim 1, since the elastic body has independent bubbles inside, when the pressure of the fuel fluctuates, the independent bubbles contract or expand. As a result, fluctuations in pressure are absorbed. Therefore, the waves based on the pressure pulsation are more easily attenuated and absorbed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the fuel pressure pulsation damping device of the present invention will be described below with reference to FIGS.

As shown in FIGS. 1 and 2, in this embodiment, a fuel pressure pulsation damping device is mainly constituted by the fuel delivery pipe 11. The housing 12 of the fuel delivery pipe 11 is formed in a long shape by a fiber reinforced resin (for example, a composite material made of polyamide resin and glass fiber) having excellent heat resistance and high rigidity. The housing 12 has a connection port 13 at one end (the left end in the figure) for connecting a fuel pipe.
A nipple 14 made of the same material as that of No. 2 is fitted through an O-ring 15 and the housing 12
Is heat-sealed against. The other end (the right end in the figure) is simply a wall. That is, as the fuel delivery pipe 11 in this embodiment, what is called a returnless type is adopted. However, the return pipe may be separately connected to return the surplus fuel to the fuel pump.

The housing 12 has a fuel passage 16 extending along the longitudinal direction. One end (left end in FIGS. 1 and 2) of the fuel passage 16 is open to the connection port 13 of the nipple 14. The fuel for operating the engine flows into the fuel passage 16 through the fuel pump, the fuel pipe (none of which is shown), and the connection port 13.

In the housing 12, in the middle of the fuel passage 16, as many socket portions 17 as there are cylinders of the engine (four in the figure) are formed in a state of being separated from each other. Each socket portion 17 has a substantially cylindrical shape, and a fuel injection valve 18 is attached thereto. Each fuel injection valve 18 is an electromagnetic valve that opens by energization to inject fuel.

In this embodiment, the pressure pulsation damping mechanism 21 is fixedly arranged on the side of the connection port 13 in the housing 12 of the fuel delivery pipe 11. The pressure pulsation damping mechanism 21 includes a bottomed cylindrical case 22, a cylindrical spacer 23 housed inside the case 22, filters 24 and 25 provided at both ends of the spacer 23, and a cap for closing the case 22. 26 and an elastic body 27 circumferentially fixed to the inside of the spacer 23. The case 22, the spacer 23 and the cap 26 are, for example,
It is made of polyamide resin. Also, case 2
Through holes 22a and 26a are formed in the bottom portion of 2 and the central portion of the cap 26, respectively.

The elastic body 27 is made of, for example, foamed rubber and has a large number of independent air bubbles inside. Further, the elastic body 27 is thick in the middle portion thereof, and the thick portion forms a portion (orifice) 28 in which the fuel passage is narrow.

Further, in this embodiment, the case 22 is used.
Is housed in a housing space having an enlarged diameter inside the housing 12, and its movement is restricted by the presence of the step portion.

Next, the operation and effect of the fuel pressure pulsation device constructed as above will be described. The fuel pumped from the fuel pump is connected to the fuel pipe and the connection port 1.
3 through the pressure pulsation damping mechanism 21 and flow into the fuel passage 16 of the fuel delivery pipe 11. Then, in the process of flowing through the fuel passage 16, it is distributed to each fuel injection valve 18. Here, as fuel is injected from the fuel injection valve 18 or fuel is introduced into the fuel passage 16 from a fuel pump or the like, pulsation may occur in the fuel pressure. However, in this embodiment, the pressure pulsation damping mechanism 21 having the elastic body 27 and the like can damp the pressure pulsation transmitted to the fuel inside. More specifically, the waves due to pressure pulsation can be damped by passing through the orifice 28 formed by the elastic body 27. In addition, when the wave hits the elastic body 27, the elastic body 27 is deformed, and the energy thereof can be attenuated and absorbed.

For example, pulsation may occur in the fuel pressure inside the housing 12 due to the fuel injection from the fuel injection valve 18. Then, the wave resulting from the pulsation is first attenuated by the so-called orifice effect when passing through the orifice 28 (diffusion effect in which the wave rapidly expands after passing through the orifice 28), as shown in FIG. . Also,
Most of the waves hit the slope of the elastic body 27 on the right side of the figure, and the elastic body 27 is deformed as shown in the figure. afterwards,
Along with the vibration of the elastic body 27, the wave can be attenuated.
On the contrary, when the fuel pressure inside the housing 12 pulsates due to the introduction of fuel into the fuel passage 16 from the fuel pump or the like, as shown in FIG. It is damped by the so-called orifice effect. Most of the waves hit the slope on the left side of the elastic body 27, and the elastic body 27 is deformed as shown in the figure. Then, as the elastic body 27 vibrates, the wave can be attenuated.

Furthermore, according to the present embodiment, in addition to the above-mentioned action, the elastic body 27 has independent air bubbles inside thereof, so that when the pressure of the fuel fluctuates, it becomes independent. Pressure fluctuations are absorbed as the bubbles contract and expand. Therefore, the waves based on the pressure pulsation are more easily attenuated and absorbed.

At the same time, the through holes 22a and 26 are incidentally provided.
The orifice effect of a and the presence of the filters 24, 25 can also attenuate the waves due to pressure pulsations. Thus, in this embodiment, the pressure pulsation damping mechanism 21 provided in the fuel delivery pipe 11 can sufficiently damp the pressure pulsation. As a result, it is possible to avoid problems such as variations in fuel injection amount due to pressure pulsation. Further, since the pressure pulsation damping mechanism 21 is fixed inside the housing 12 of the fuel delivery pipe 11, unlike the conventional technique in which a pulsation damper must be provided outside, the fuel pulsation damping mechanism 21 has a fuel delivery function. It is possible to achieve integration with the pipe 11. Therefore, in the present embodiment, it is possible to eliminate the deterioration in reliability of the performance caused by assembling each member separately.

Further, since the pressure pulsation damping mechanism 21 does not project outside the housing 12 of the fuel delivery pipe 11, it is possible to prevent a space disadvantage. That is, it is possible to effectively utilize the space in the portion where the pulsation damper is conventionally provided.

In addition, in this embodiment, since the elastic body 27 constituting the pressure pulsation damping mechanism 21 is housed in the case 22, when the elastic body 27 is likely to deteriorate, The portion of the case 22 can be used as a cartridge and can be easily replaced as appropriate.

The present invention is not limited to the above embodiment, but may be configured as follows, for example. (1) In the above-described embodiment, the thick portion is provided only at one location in the middle portion of the elastic body 27 to form one orifice 28. However, as shown in FIG. 5, the orifice is provided at two locations. You may make it provide the elastic body 33 which has 31,32. With such a configuration, the pressure pulsation can be attenuated more efficiently.

(2) In the above embodiment, the housing 12,
Nipple 14, case 22, spacer 23, cap 2
All of 6 and the like are made of a resin material, but the material is not limited at all, and may be made of, for example, a resin material other than that or a metal material such as an aluminum alloy. Further, the material of the elastic body 27 is not limited to the foamed rubber, and may be a deformable elastic material such as a foamed resin material. Further, it can be embodied when it does not have independent bubbles.

(3) The pressure pulsation damping mechanism 21 is not limited to the structure of the above embodiment, and for example, at least one of the case 22, the spacer 23, the filters 24 and 25, and the cap 26 is omitted. You can also
Therefore, for example, the elastic body 27 may be directly joined to the inner wall of the housing 12.

(4) A so-called side feed type pipe may be used as the fuel delivery pipe. Although the respective embodiments of the present invention have been described above, technical ideas other than the claims that can be understood from the respective embodiments will be described below together with their effects.

(A) In the fuel pressure pulsation damping device according to claim 1 or 2, the elastic body is housed in a case that can be taken out from the housing. With such a configuration, the case can be easily replaced, and the life of the product can be extended by this replacement.

[0030]

As described above in detail, according to the fuel pressure pulsation damping device of the present invention, not only the pressure pulsation can be efficiently damped, but also by integration with the fuel delivery pipe, This has an excellent effect that it is possible to prevent deterioration of reliability due to assembly and prevent a disadvantage in space.

In particular, according to the second aspect of the invention, there is an excellent effect that the pressure pulsation can be damped more efficiently.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a main part of a fuel pressure pulsation damping device.

FIG. 2 is a cross-sectional view showing a fuel delivery pipe and the like.

FIG. 3 is a partial cross-sectional view showing the operation of the fuel pressure pulsation damping device.

FIG. 4 is a partial cross-sectional view showing the operation of the fuel pressure pulsation damping device.

FIG. 5 is a partial cross-sectional view showing a fuel pressure pulsation damping device in another example.

FIG. 6 is a perspective view showing a fuel delivery pipe and the like in the prior art.

FIG. 7 is a sectional view showing a pulsation damper according to a conventional technique.

[Explanation of symbols]

11 ... Fuel delivery pipe, 12 ... Housing, 16 ...
Fuel passage, 18 ... Fuel injection valve, 21 ... Pressure pulsation damping mechanism, 27, 33 ... Elastic body, 28, 31, 32 ... Orifice.

Claims (2)

[Claims] 1. Introducing fuel into the housing (12),
A fuel delivery pipe (1) having a fuel passage (16) for distributing the same fuel to a plurality of fuel injection valves (18).
1) and a housing (12) for the fuel delivery pipe (11)
And a pressure pulsation damping mechanism (21) having an elastic body (27, 33) formed and fixed on the fuel introduction side and having orifices (28, 31, 32) for passing the fuel. A fuel pressure pulsation damping device characterized by being provided. 2. The fuel pressure pulsation damping device according to claim 1, wherein the elastic body (27, 33) has independent air bubbles inside.