JP2003239824A - Fuel delivery pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce shock waves and pulsation pressure following opening/ closing of a fuel injector and secure space for a tool by avoiding interference with other components in regard to a fuel delivery pipe used in an electronic fuel injection type automobile engine. <P>SOLUTION: A body portion of the fuel delivery pipe is composed of a plurality of miniature cases having fuel passages in interiors, and elongated connecting pipes mutually connecting the plurality of miniature cases. A cross section of each miniature case is formed in a substantially flat shape, an outer wall part of each miniature case includes at least one flat or arced flexible absorbing face, and the pulsation pressure and shock wave of fuel flowing into a socket are reduced by sectional area change of the passages through which the fuel passes and deflection of the absorbing face. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injector (injection nozzle) for directly injecting fuel fed from a fuel pressure pump of an electronic fuel injection type automobile engine into each intake passage or cylinder of the engine. The present invention relates to an improvement of a fuel delivery pipe for supplying the fuel in particular, and particularly to a cross-sectional structure and an external structure of a flow path through which fuel passes.

[0002]

Fuel delivery pipes are widely used in electronic fuel injection systems for gasoline engines and, after delivering fuel 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 transpiration gas by high temperature return fuel and cost reduction,
Along with that, the fuel delivery pulsation due to the reflected wave (shock wave) due to the reciprocating motion of the spool that opens and closes the valve for injecting from the injector and the fuel injection pulsation due to the pulsating pressure vibrates and produces a strange noise. There was a problem. In addition, abnormal noise was also generated due to the impact caused by the sitting of the injector spool. In a so-called direct injection type engine that directly injects fuel into the combustion chamber, a high pressure supply pump is provided,
A pulsation damper is provided to absorb the large pulsation, and it is used in some cases even in the case of a normal fuel injection type (MPI) engine, but it is adopted due to space constraints and high cost. Not easy.

Therefore, the inventors of the present invention have disclosed in Japanese Patent Laid-Open No. 2000-32.
As described in No. 9031 “Fuel Delivery Pipe”, it was proposed to make the cross-section of the communication pipe a flat shape as a method of absorbing a vibration by making a part of the wall surface of the communication pipe a flexible absorbing surface. . However, if the entire communication pipe is made flat, there is a risk that it will interfere with or come into contact with piping parts around the engine, and there will be no space for inserting and rotating tools. There was a tendency that it was difficult to adopt the shape.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to prevent interference with other parts while adopting a flat shape sufficient for reducing shock waves and pulsating pressure generated by opening and closing of a fuel injector. The purpose is to provide a new fuel delivery pipe structure that makes it possible to secure space for tools. Another object of the present invention is to provide a fuel delivery pipe with a reservoir portion capable of holding a fixed amount of fuel in order to enable stable supply of fuel.

[0005]

In order to achieve the above-mentioned object, the fuel delivery pipe according to the present invention comprises a plurality of mini-cases each having a fuel flow passage therein and a metal for connecting the plurality of mini-cases to each other. -Made or resin-made elongated connecting pipe, a fuel introduction pipe fixed to at least one end or side of the mini case, at least one in each mini case, and a part of which is provided in the fuel flow path. A plurality of sockets communicating with each other and having an open end for receiving the tip of the fuel injection nozzle. Furthermore, the cross-section of each mini-case is formed into a substantially flat shape, and the outer wall portion of each mini-case includes at least one flat or arc-shaped flexible absorber surface, so that The pulsating pressure and the shock wave are reduced by the change in the cross-sectional area of the passage through which the fuel passes and the bending of the absorber surface.

[0006]

According to the present invention, the main body portion of the fuel delivery pipe is composed of a plurality of mini cases and a connecting pipe, and the bolts and nuts for mounting the fixing bracket are inserted between the mini cases. A space and a space for inserting a tool, wiring, etc. are secured, and a sufficient flat shape can be adopted. In this structure,
Since the fuel alternately passes through the long narrow pipe and the inside of the flat case, the cross-sectional area of the flow passage changes continuously.
As a result, the pulsating pressure and shock wave of the fuel flowing into the socket can be reduced by the change in the cross-sectional area of the passage through which the fuel passes and the bending of the absorber surface. Further, since the mini-case portion acts as a reservoir that always holds a fixed amount of fuel, there is an advantage that a stable supply of fuel is possible.

The theoretical basis of pulsation absorption by the absorber surface is that the shock absorber generated when the fuel injector is opened and closed flows into the fuel inlet of the socket or flows out by a momentary reverse flow, and thus has a flexible absorber. It is understood that shock and pulsation are absorbed by the bending of the surface, and that the thin member having a relatively small spring constant is bent and deformed to change the volume and absorb the fuel pressure fluctuation.

The mini case of the present invention can be formed in a rectangular parallelepiped shape, or a circular or elliptical drum shape. The bracket with a hole for attaching the fuel delivery pipe to the internal combustion engine has conventionally been provided so as to project to the side portion of the fuel delivery pipe, but in the structure of the present invention, it can be arranged between the mini cases. The conventional fuel delivery pipe can be made compact by removing the conventional projections, and the interference with other parts can be further avoided. If each mini case is equipped with a holed bracket, the structure will have increased strength against vibration of the internal combustion engine.

It is preferable that each mini case has one socket, but a mini case having two sockets and a mini case having one socket are combined, or a mini case having two sockets is combined. It is also possible to connect a plurality. The socket hole position and the connection position of the connecting pipe formed in each mini case can be positioned by offsetting from the center position of each mini case in a desired direction, respectively. The flow direction of is changed to the left and right to enhance vibration and shock absorption effects.

Although the socket can be fixed to the bottom of the mini case by projecting as in the conventional case, a recess can be integrally formed on the bottom of the mini case and the socket can be provided in this recess. If the socket is integrally formed with the mini case as described above, there are advantages that the number of parts is reduced and the working process is simplified, and that the height is low and interference with other parts can be further avoided. Adjacent mini cases can be aligned and arranged on the same axis, or the mini cases can be positioned by appropriately offsetting the direction and angle to avoid interference with surrounding parts. Furthermore, the shape and size of the adjacent mini cases can be changed.

In the present invention, the outer shape of the mini case, the plate thickness of the absorber surface, the ratio of the height and width, and the clearance between the socket and the surface facing the fuel inlet are the values at which vibration and pulsation are the smallest, especially during idling of the engine. Can be determined by experiment or analysis. Since the present invention basically relates to the cross-sectional structure of the fuel flow path and the external structure, by maintaining the mounting dimensions of the bracket,
Compatibility with conventional fuel delivery pipes can be maintained. Other features and advantages of the present invention will be apparent from the following description with reference to the embodiments of the accompanying drawings.

[0012]

1 shows a fuel delivery pipe 10 according to a first embodiment of the present invention, FIG. 1A is an overall perspective view, FIG. 1B is a longitudinal sectional view of a socket portion, and FIG.
C is a horizontal sectional view of the socket portion, and FIG. 1D is a perspective view of a modified example. According to the present invention, three mini cases 21, 22, and 23 are arranged along the crankshaft direction, and they are connected to each other by connecting pipes 14 and 15 made of elongated metal. A fuel passage 12 is formed inside each mini-case, and three sockets 3 for receiving the tip of the injection nozzle are attached to the bottom surface of the mini-case, for example, in the case of a 3-cylinder engine, three sockets 3 are attached at predetermined intervals and angles. . Each mini case 21,22,23 has a fuel delivery pipe 10
Brackets 24, 25, 26 having a thick wall and a solid hole for attaching the engine to the engine body are spanned in the longitudinal direction. As shown in FIG. 1C, the end portion in the longitudinal direction of each mini case is hermetically sealed by an end cap 27.

The fuel introduction pipe 2 is fixed to the side end of the central mini case 22 by brazing or welding via a connector (not shown). A return pipe for returning to the fuel tank can be provided at either end of the mini case,
In returnless type fuel delivery pipe,
No return pipe is provided. Fuel is the mini case 2 in the center
It flows from 2 to the left and right mini cases 21 and 23 in the direction of the arrow, and is directly injected from the socket 3 into each intake passage or the cylinder through a fuel injector (not shown).

As shown in FIGS. 1B and 1C, in this example, each of the mini-cases 21, 22, and 23 has a flat elliptical cross section formed by crushing a low carbon steel or stainless steel pipe having a circular cross section. The inner lower surface of the portion faces the fuel inlet 13 (FIG. 1B) of the socket 3. The cross-sectional dimensions of each mini case can be set, for example, as a flat plate having a plate thickness of 1.2 mm, a height H of 6.4 mm, and a width W of 32 mm. FIG. 1D shows a modification in which the connecting pipes 14 and 15 are integrally formed, and a hole 20 through which the fuel flows toward the inside of the mini case 22 is provided on the side surface thereof. According to the invention,
Almost the entire outer wall of the mini-case having a flat elliptical cross section provides a flexible absorbing surface, and the flat portions 21a, 22a and 23a facing the fuel inlet 13 are mainly used as the main absorbing surface due to their span length. To work.

Thus, the pulsating pressure and the shock wave of the fuel flowing into the socket are reduced by the change in the sectional area of the passage through which the fuel passes and the deflection of the absorber surface.
Conventionally, the bracket 4 with holes has been provided so as to project to the side portion of the fuel delivery pipe, but in the structure of FIG. 1, it is possible to arrange it in the space between the mini-cases 21, 22 and 23. By removing the protrusions, the entire fuel delivery pipe is slim and compact, and interference with other parts can be further avoided.

2A and 2B show a fuel delivery pipe 30 of a second embodiment in which various modifications are made to the example of FIG. (A) The connecting pipes 28, 29 are made of resin rather than metal. (B) The center of the hole of the socket 3 is arranged in the mini cases 21, 22, 2
(C) The connecting positions of the connecting pipes 28 and 29 offset from the central portion of the
22 and 23 are alternately offset in opposite directions from each other (d) The fixed positions of the brackets 25 and 26 with holes are offset from the central portions of the mini-cases 22 and 23 in opposite directions respectively (e) Ends The position of the holed bracket 24 was changed to the side part (f) The position of the fuel introducing pipe 2 was changed from the side part to the end part. By making various corrections and deformations in this way, the pressure, cross-sectional area, and flow direction of the fuel change as it flows through the flow path, and the effect of absorbing shock and pulsation is further enhanced. .

FIG. 3 shows the mini case 2 in the example of FIG.
2, 23 are integrated to form a large size mini case 33, so that the mini cases 21 having different sizes can be formed.
Fuel delivery pipe 3 whose main body is composed of 33
4 is represented. In this case, the number of connecting pipes is one and the number of brackets with holes is two, which greatly simplifies the configuration.

FIG. 4 shows the mini case 2 in the example of FIG.
1 and 22 are integrated, and two mini cases 23 are connected to each other to form large size mini cases 36 and 37, respectively.
Shows a fuel delivery pipe 38 that is configured as a main body part and can be used for a four-cylinder engine. Compared to the case where four mini cases are connected for a 4-cylinder engine, the number of connecting pipes and brackets with holes is reduced, and the configuration is greatly simplified.

5A and 5B show a fuel delivery pipe 40 according to the fifth embodiment of the present invention, which is characterized in that the mini cases 41, 42 and 43 are formed in a circular drum shape. Similar to the example of FIG. 1, mini cases 41, 42, 4
3 are connected to each other by elongated metal connecting pipes 14 and 15. A fuel passage 12 is formed inside each mini case, and a socket 3 is attached to the bottom surface of the fuel passage 12. Thick, rigid holed brackets 24, 25, 26 for attaching the fuel delivery pipe 40 to the engine body are bridged in the mini-cases 41, 42, 43 in the longitudinal direction.

In accordance with the invention, the outer wall of each circular drum-shaped mini-case provides a generally flexible absorbing surface, particularly flat portions 41a, 42a facing the fuel inlet 13 and having curved perimeters. , 43a act as a main absorber surface because of their diameter. As described above, by forming the mini case in the shape of a circular drum, the free bending of the absorber surface is expanded, and the cross-sectional area of the fuel flow path is further expanded to enhance the shock absorbing effect.

FIG. 6 shows a structure in which a circular drum-shaped mini case 45 similar to that of FIG. 5 is divided into an upper case 46 and a lower case 47, and a recess is formed on the lower surface of the lower case 47 by deep drawing. In this embodiment, the function of the socket 48 is provided. The flat surface 45a having the curved peripheral edge of the upper case 46 provides a main absorption surface. According to this embodiment, it is not necessary to manufacture the socket as a separate part, the welding and brazing process steps are omitted, and the cost can be significantly reduced, and the height is lowered to prevent interference with other parts. This can be avoided even further, and the degree of freedom in installing fuel delivery pipes can be further improved.

In FIG. 7, the socket 3, the connecting pipe 60 and the fuel introducing pipe 2 are attached to the lower surfaces of the lower cases 57, 58 and 59 of the upper and lower drum-shaped mini cases 51, 52 and 53, respectively. This shows an embodiment in which a space around the mini case is secured. The flat surfaces 51a, 52a, 53a of the upper cases 54, 55, 56 provide the main absorption surface.
Illustration of the bracket with holes is omitted. Similar to the example of FIG. 5, by forming the mini case into a circular drum shape,
The free bending of the absorber surface is expanded, and the cross-sectional area of the fuel flow path is further expanded to enhance the impact absorbing effect.

FIGS. 8A and 8B are characterized in that an upper case 63 of a drum-shaped mini case 62 similar to the example of FIG. 6 is press-molded so that its cross section becomes a corrugated diaphragm shape. An example is shown. By forming the corrugations in this way, it becomes possible to secure a greater degree of bending of the main absorber surface 62a.

In FIG. 9, each of the mini cases 71, 72, 73 is formed in an elliptical drum shape, and the upper surface thereof is formed as main absorption surfaces 71a, 72a, 73a, and the connecting pipes 74, 7 are formed.
5 shows an embodiment in which 5 is formed of a bellows-shaped flexible tube. By using the flexible tube, there are advantages that a mounting range is ensured within an allowable range and interference with surrounding parts can be avoided. In addition, the flexible tube has the effect of absorbing the vibration and shock of the entire fuel delivery pipe.

FIGS. 10A and 10B show mini cases 81 and 8 respectively.
This is an embodiment in which 2,83 are formed in a bent mountain shape and the entire surface thereof is provided with the absorber surfaces 81a, 82a, 83a. By attaching the mini cases 81, 82, 83 with their directions and angles offset from each other,
It is possible to avoid interference with surrounding parts. Figure 10
B represents the cross-sectional shape at the position of the connecting pipe 15.

FIG. 11 shows a fuel delivery pipe 90 for a 4-cylinder engine. Each mini case 91,9
2, 93 and 94 are formed in a circular drum shape, and the upper surfaces thereof provide main absorber surfaces 91a, 92a, 93a and 94a. Connecting pipes 95, 96, 97 between the mini cases
Has a bent shape to absorb vibration.
The sockets 3 are arranged at positions offset from the center in each mini case, but all the sockets 3 are aligned in the same line corresponding to the engine side. The bracket with holes is not shown. It is also possible to adopt such a special shape in order to avoid interference with surrounding parts, and the bent connecting pipe has an effect of absorbing vibration and impact of the entire fuel delivery pipe. The fuel delivery pipe according to the present invention can be configured in various different shapes in relation to the shapes and arrangements of the surrounding parts, thus achieving both the vibration reduction effect and the interference prevention effect.

[0027]

As described above in detail, according to the present invention, the shock wave generated by the seating of the spool when the fuel injector is opened / closed ・ When flowing into the fuel inlet of the socket or flowing out by the instantaneous backflow Pulsating pressure generated is reduced by the bending of the absorbing surface of the flat mini-case, and the presence of the space between the mini-cases makes it possible to avoid interference with other parts.
The technical effect is extremely remarkable, for example, the space for tools is secured, and the mini-case portion acts as a reservoir for always holding a fixed amount of fuel to enable stable fuel supply.

[Brief description of drawings]

FIG. 1 is a perspective view of an entire fuel delivery pipe according to the present invention, a vertical sectional view and a horizontal sectional view of a socket portion, and a perspective view of a modified example.

FIG. 2 is a perspective view of the entire fuel delivery pipe and a vertical sectional view of a socket portion according to another embodiment.

FIG. 3 is a perspective view of an entire fuel delivery pipe according to another embodiment.

FIG. 4 is a perspective view of an entire fuel delivery pipe according to another embodiment.

FIG. 5 is a perspective view of the entire fuel delivery pipe according to another embodiment and a vertical sectional view of a socket portion.

FIG. 6 is a vertical cross-sectional view showing an embodiment in which a socket is integrally formed with a mini case.

FIG. 7 is a vertical cross-sectional view showing an embodiment in which a fuel introducing pipe and a connecting pipe are arranged on the lower side.

8A and 8B are a vertical cross-sectional view and a plan view showing an embodiment in which the upper surface of a mini case is formed in a corrugated shape.

FIG. 9 is a plan view of the entire fuel delivery pipe according to another embodiment.

FIG. 10 is a perspective view of the entire fuel delivery pipe according to another embodiment and a vertical sectional view of a connecting pipe portion.

FIG. 11 is a plan view of the entire fuel delivery pipe according to another embodiment.

[Explanation of symbols]

2 Fuel introduction pipe 3 Socket 4 Fixing bracket 10, 30, 34, 38, 40 Fuel delivery pipe 13 Fuel inlet 14, 15, 28, 29 Connecting pipe 21, 22, 23, 33, 36, 37 Mini case 21a , 41a, 42a, 43a Absorbing surface

Claims (6)

[Claims] 1. A plurality of mini-cases having a fuel flow passage therein, an elongated connecting pipe made of metal or resin for mutually connecting the plurality of mini-cases, and at least one end or side of the mini-case. And a plurality of sockets, at least one of which is provided in each of the mini cases, a part of which communicates with the fuel passage and an open end of which receives the tip of the fuel injection nozzle. A fuel delivery pipe for an internal combustion engine, wherein each of the mini-cases has a substantially flat cross-section, and the outer wall of each mini-case has at least one flat or arc-shaped flexible absorber surface. The pulsation pressure and the shock wave of the fuel flowing into the socket are reduced by the change in the cross-sectional area of the passage through which the fuel passes and the deflection of the absorber surface. That full Ewell delivery pipe. 2. The fuel delivery pipe according to claim 1, wherein each of the mini cases is formed in a rectangular parallelepiped shape, or a circular or elliptical drum shape. 3. The fuel delivery pipe according to claim 1, wherein a bracket with a hole for attachment to an internal combustion engine is fixed to each of the mini cases. 4. The fuel delivery pipe according to claim 1, wherein the socket hole formed in each mini case and / or the connection position of the connecting pipe are positioned offset from the center position of each mini case. . 5. The fuel delivery pipe according to claim 1, wherein a recess is integrally formed on the bottom surface of each mini case, and the recess provides a socket. 6. The fuel delivery pipe according to claim 1, wherein the orientation and / or the angle of the adjacent mini-cases are offset.