JP2003097381A - Fuel delivery pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel delivery pipe used in an electronic fuel injection type automobile engine which prevents generation of vibrations and noise attributable to the reflected wave and the pulsating pressure generated when the fuel is injected. SOLUTION: A communication pipe is formed of a double pipe, and a small space less than each amplitude is maintained between an outer pipe and an inner pipe to form an entirely double wall in the longitudinal direction. A pipe wall part facing a socket out of the communication pipe is formed of an absorbing surface formed of a sheet member. An inner wall is fitted to the absorbing surface with a small space therebetween, and a small space less than each amplitude is maintained therebetween. An absorbing plate formed of a sheet member is added to the inner side of the pipe wall part facing the socket of the communication pipe, and a small space less than each amplitude is maintained therebetween.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention supplies fuel supplied from a fuel pressure pump of an electronically controlled fuel injection type automobile engine to each intake passage or each cylinder of the engine through a fuel injector (injection nozzle). In particular, the present invention relates to an improvement of a fuel delivery pipe for the purpose of connecting a connecting pipe having a fuel supply passage and a socket (holder) portion for receiving a fuel injector.

[0002]

Fuel delivery pipes are widely used in electronically controlled fuel injection systems for gasoline engines, after fuel is delivered from a communicating pipe having a fuel passage to a fuel injector through a plurality of cylindrical sockets. There are a type having a return passage for returning to the fuel tank side and a type having no return passage (returnless). Recently, the number of types that do not have a return passage has increased due to measures to reduce the amount of transpiration gas due to high-temperature return fuel and cost reductions, but due to this, there is a collision with the counterpart member of the fuel pump (plunger pump) or injector spool. Depending on the reflected wave and pulsating pressure, a fuel delivery pipe,
There has been a problem that fuel pipes, clamps and front panels to which the clamps are attached as related parts vibrate and produce a strange noise.

As a countermeasure against this, a pulsation damper is attached immediately before the fuel delivery pipe, or the fuel pipe on the back side of the front panel of the automobile is supported by a plurality of vibration-proof clamps. There were new problems such as increase in installation cost, securing installation space, and high cost.

In Japanese Patent Laid-Open No. 11-2164, "Fuel Delivery", focusing on this problem, the delivery body is manufactured by a sheet metal press in order to reduce the pulsating resonance speed of the fuel piping system to an idle speed or less. It has been proposed to set the rigidity and the internal volume of the to within a certain range. JP 10-2
13046 "Delivery pipe for fuel injection device" and Japanese Patent Laid-Open No. 10-331743 "Fuel distribution structure of internal combustion engine"
Proposes to increase the surface rigidity to prevent the generation of radiated sound.

Japanese Patent Publication No. 3-62904 "Fuel Rail for Internal Combustion Engine" uses a diaphragm to partition the inside of the communication pipe into a socket side and a pipe wall side in order to prevent injectable lap noise, and the diaphragm is flexible. It is proposed to absorb the pulsation and the residual reaction of the injector depending on the sex. JP-A-60-240867, "Fuel supply conduit for fuel injection device for internal combustion engine", proposes that one of the walls of the fuel supply conduit is made elastic to reduce fuel pulsation.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to absorb a shock caused by a reflected wave and a pulsating pressure accompanying opening / closing of a fuel injector, and suppress a vibration (damping). Another object of the present invention is to provide a structure of a fuel delivery pipe capable of preventing the generation of abnormal noise.

[0007]

The above-mentioned object of the present invention is to employ a structure for reducing or buffering the reflected wave and the pulsating pressure from the fuel injector transmitted through the socket by the vibration absorbing ability of the communicating pipe. Achieved by The basic idea is to make the whole or part of the pipe wall portion of the communicating pipe into a double wall, and to maintain a minute gap below each amplitude between them.

The method of forming the double wall is as follows: (1) The communication pipe is formed of a double pipe, and a minute gap having an amplitude equal to or less than each amplitude is maintained between the outer pipe and the inner pipe, and the entire length along the longitudinal direction is maintained. (2) The wall surface of the communication pipe having a double wall is formed by an absorber surface made of a thin plate member facing the socket, and an inner wall is attached to the absorber surface with a minute gap between them. A double wall with a small gap below each amplitude is maintained. (3) An absorber plate made of a thin plate is attached to the inside of the pipe wall portion facing the socket of the communication pipe, and the respective amplitudes are placed between the two. It is possible to use the following method such as forming a double wall with a minute gap maintained.

[0009]

By adopting such a structure, the vibrations can be damped by abutting the mutual vibrations by utilizing the difference in natural frequency between the outer pipe and the inner pipe of the double wall portion. That is, since the double wall portions interfere with each other to cancel out the vibrations, the effect of absorbing and buffering the impact energy emitted from the socket is exerted, so that the reflected wave from the injector travels from the communication pipe to the fuel pipe side. It is possible to prevent generation of abnormal noise due to vibration or pulsation due to propagation. The damping performance by the double wall is described in, for example, Japanese Patent Application Laid-Open No. 2-180400 "Damping Double Metal Pipe".

Further, according to a preferred aspect of the present invention, an absorbing surface made of a thin plate member is provided so as to face the socket, and the portion of this absorbing surface is made into a double wall, so that the reflected wave from the injector is large. After the part collides with the absorber surface, it will pass through the communication pipe and propagate to the fuel pipe side, and the shock energy generated when the fuel injector is opened and closed will be maximally buffered, and the fuel pulsating pressure will be reduced. Propagation from the fuel supply pipe to the fuel pipe side can be surely suppressed, and abnormal noise can be largely prevented.

In the present invention, the gap between the double walls is 10 to 10.
About 150 μm is preferable, and the outer wall and the inner wall may be in local contact with each other. As a method of forming a double wall having a minute gap, in addition to a general method of inserting an inner tube while keeping a gap inside the outer tube, JP-A-2-134236 discloses "a method for producing a double tube". As described above, that is, by forming a coating film on one of the inner surfaces of the facing double walls, and reducing or expanding one to integrate them, and then heating to 400 ° C or higher. For example, a method of treating the coating material to carbonize the coating material to form a uniform interval can be used.

In the present invention, the shape, dimensions, aspect ratio, plate thickness, etc. of the communication pipe having a double wall are determined by experiments and analysis so that vibration and pulsation are minimized, especially when the engine is idling. be able to. Other features and advantages of the present invention will be apparent from the following description with reference to the embodiments of the accompanying drawings.

[0013]

1 to 3 show the overall shape and cross-sectional shape of a fuel delivery pipe (top feed type) 10 according to a first embodiment of the present invention, which is made of a steel pipe having a substantially rectangular cross section. The communication pipe 11 extends along the crankshaft direction, and the fuel supply (introduction) pipe 2 is fixed to the side portion of the communication pipe 11 by brazing or welding. A return pipe for returning to the fuel tank can be provided at the end of the communication pipe, but the returnless fuel delivery pipe in which the pulsating pressure of fuel is a problem does not have a return pipe.

Three sockets 3a to 3c for receiving the ends of the injection nozzles are attached to the bottom surface of the communication pipe 11 for one side of a 6-cylinder engine at predetermined intervals and angles. If it is for a 4-cylinder engine, four of them will be mounted at a predetermined interval and angle. Two thick and solid brackets 4 for attaching the fuel delivery pipe to the engine body are further laid across the communication pipe 11 in the lateral direction. Fuel flows in the direction of the arrow, and the sockets 3a-3
The fuel is injected from each fuel inlet 13 of c through a fuel injector (not shown) to each intake passage or each cylinder.

According to the present invention, the communicating pipe 11 is composed of a double pipe of an outer pipe 21 and an inner pipe 22, and as shown in FIG. 2, all the wall surfaces along the longitudinal direction are formed into double walls. In these figures, the gap S between the double walls is drawn large in order to facilitate understanding, but the actual gap is a minute gap that is equal to or less than the amplitude of each, and is preferably about 10 to 150 μm. In an actual application, the inner pipe and the outer pipe may come into local contact with each other when the double pipe is formed, but if they are locally brought into contact with each other, the effect is not affected.

The fuel delivery pipe 10 of FIG. 3A shows an example in which the communication pipe 11 is formed of double walls 21 and 22 having a substantially quadrangular cross section, and the fuel delivery pipe 30 of FIG. 3B has a communication pipe 31. Double wall 41, 42 with circular cross section
The example shown in FIG.

Since the fuel delivery pipe 10 according to the first embodiment of the present invention is constructed as described above, the double wall portions 21, 22 or 41, 42 interfere with each other to cancel the vibration. It exerts the effect of absorbing and buffering the impact energy emitted from the socket. Thus, it is possible to prevent the generation of abnormal noise due to vibration or pulsation due to the reflected wave from the injector propagating from the communication pipe to the fuel pipe side.

FIGS. 4 and 5 show a fuel delivery pipe 50 according to a second embodiment of the present invention, which is a communication pipe 5.
1 wall surfaces 51a, 51b and end caps 51c, 51d
Among them, only the upper surface 51a facing the socket 3 is made of a flexible thin steel plate so as to act as an absorber surface, and the side surface and the bottom surface 51b are made of a thick and firm member.

Further, an inner wall member 52 is attached to the absorber surface 51a with a minute gap, and the absorber surface has a double wall structure. There may be no gap between the side and bottom surfaces 51b and the inner wall member 52 as shown in the drawing. Thus, most of the reflected waves from the injector will collide with the absorber surface and then propagate through the communication pipe to the fuel piping side, maximally buffering the impact energy generated when the fuel injector is opened and closed. In this case, the pulsating pressure of the fuel can be surely suppressed from propagating from the fuel supply pipe to the fuel pipe side, and the generation of abnormal noise can be largely prevented. In addition, the double wall structure also has the effect of reinforcing the absorber surface.

FIG. 6 shows a fuel delivery pipe 60 according to a third embodiment of the present invention, in which the entire wall surface of the communicating pipe 61 is made of a flexible thin steel plate so as to act as an absorbing surface. . Furthermore, this absorber surface 6
A thin inner wall member 62 is provided at a position facing the socket 3 of No. 1 with a minute gap, and the absorber surface facing the socket has a double wall structure. Thus, most of the reflected waves from the injector will collide with the absorber surface and then propagate through the communication pipe to the fuel piping side, maximally buffering the impact energy generated when the fuel injector is opened and closed. In this case, the pulsating pressure of the fuel can be surely suppressed from propagating from the fuel supply pipe to the fuel pipe side, and the generation of abnormal noise can be largely prevented.

FIG. 7 shows a fuel delivery pipe 70 according to a fourth embodiment of the present invention. A communication pipe 71 is composed of upper and lower channel members 71a and 71b and both end caps (not shown). ing. Further, below the upper channel member 71a, an absorbing surface formed of a flexible thin inner wall member 72 is attached with a minute gap, and the absorbing surface facing the socket has a double wall structure. Thus, most of the reflected waves from the injector will collide with the absorber surface and then propagate through the communication pipe to the fuel piping side, maximally buffering the impact energy generated when the fuel injector is opened and closed. In this case, the pulsating pressure of the fuel can be surely suppressed from propagating from the fuel supply pipe to the fuel pipe side, and the generation of abnormal noise can be largely prevented.

[0022]

As described in detail above, according to the present invention, the double wall portions of the communication pipe interfere with each other to cancel out the vibration, and absorb the impact energy emitted from the socket. Also, since the effect of buffering is exhibited, it is possible to prevent the generation of abnormal noise due to vibration or pulsation due to the reflected wave from the injector propagating from the communication pipe to the fuel pipe side. Further, the effect is further enhanced by providing an absorber surface made of a thin plate member facing the socket to form a double wall, and the technical effect is extremely remarkable.

[Brief description of drawings]

FIG. 1 is a front view showing the entire fuel delivery pipe according to the present invention.

FIG. 2 is a vertical cross-sectional view of a fuel delivery pipe according to the present invention.

3 is a vertical cross-sectional view taken along the line XX of FIG.

FIG. 4 is a partially cutaway vertical sectional view showing another embodiment of the present invention.

5 is a vertical cross-sectional view taken along the line YY of FIG.

FIG. 6 is a longitudinal sectional view of a socket portion showing another embodiment of the present invention.

FIG. 7 is a vertical sectional view of a socket portion showing another embodiment of the present invention.

[Explanation of symbols]

2 Fuel supply pipe 3 Socket 10, 30, 50, 60, 70 Fuel delivery pipe 11, 31, 51, 61, 71 Communication pipe 13 Fuel inlet 21, 41 Outer pipe 22, 42 Inner pipe 51a Thin plate member 52, 62 , 72 Inner wall member

Claims (3)

[Claims] 1. A metal communication pipe having a linearly extending fuel passage therein, a fuel supply pipe fixed to an end portion or a side portion of the communication pipe, and a projection provided so as to intersect with the communication pipe. A fuel delivery pipe for an internal combustion engine, comprising a plurality of sockets, a part of which communicates with the fuel passage and an open end of which receives a tip of a fuel injection nozzle, wherein the communication pipe is a double pipe and an outer pipe. A fuel delivery pipe characterized in that a minute gap of less than each amplitude is maintained between the inner pipe and the inner pipe, and the entire wall surface along the longitudinal direction is a double wall. 2. A metal communication pipe having a linearly extending fuel passage therein, a fuel supply pipe fixed to an end portion or a side portion of the communication pipe, and a projection provided so as to intersect with the communication pipe. A fuel delivery pipe for an internal combustion engine, comprising: a plurality of sockets, a part of which communicates with the fuel passage and an open end of which receives a tip of a fuel injection nozzle, wherein a pipe wall portion of the communication pipe facing the socket. Is formed by an absorber surface made of a thin plate member, and an inner wall is attached to the absorber surface with a minute gap, and a double wall is formed in which a minute gap of less than each amplitude is maintained between them. Fuel delivery pipe. 3. A metal communication pipe having a linearly extending fuel passage therein, a fuel supply pipe fixed to an end portion or a side portion of the communication pipe, and a projection provided so as to intersect with the communication pipe. A fuel delivery pipe for an internal combustion engine, comprising: a plurality of sockets, a part of which communicates with the fuel passage and an open end of which receives a tip of a fuel injection nozzle, wherein a pipe wall portion of the communication pipe facing the socket. A fuel delivery pipe characterized in that an absorber plate made of a thin plate member is attached to the inside of the double wall, and a double wall is formed between the two to maintain a minute gap of less than the amplitude of each.