JP2000320422A - Fuel delivery pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain generation of vibrations to prevent generation of abnormal sound by constructing at least one outer wall surface of a communication pipe of a flexible damping surface, and fixing a flexible end can having an uneven surface portion to at least one end of the communication pipe, so that it is in contact with the damping surface. SOLUTION: In a fuel delivery pipe 10, a fuel lead-in pipe 2 is fixed to the side of a communication pipe 11 via a connector 5, and a socket 3 is mounted to the bottom surface of the pipe 11. the number of the sockets 3 corresponds to the number of cylinders of an engine. Only an upper surface 11a of the pipe 11 is formed of a thin wall steel plate so that functions as a flexible damping surface, while another surface 11b is formed of a thick rigid member. End caps 15, 16 are fixed by brazing or soldering to both ends of the pipe 11. Each of the caps 15, 16 is formed into an outwardly or inwardly recessed shape, and it is preferable that a side thereof to be connected to the damping surface by brazing or soldering be formed with such a thin wall structure as to work in cooperation with bending of the damping surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the supply of fuel supplied from a fuel pressurizing pump of an electronically controlled fuel injection type automobile engine to each intake passage or each cylinder of the engine via a fuel injector (injection nozzle). In particular, the present invention relates to a connection structure between a communication pipe having a fuel passage and a socket (holder) part for receiving a fuel injector.

[0002]

2. Description of the Related Art Fuel delivery pipes are widely used in electronically controlled fuel injection systems of gasoline engines. After fuel is supplied from a communication 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). In recent years, types without return passages have increased due to cost reduction. However, due to reflected waves and pulsation pressure caused by reciprocating motion of the fuel pump (plunger pump) and injector spool, fuel delivery pipes and related A problem has arisen in that parts vibrate and generate unpleasant noises.

Japanese Patent Application Laid-Open No. 11-2164, "Fuel Delivery", pays attention to this problem, and manufactures a delivery main body by a sheet metal press in order to reduce the pulsation resonance rotation speed of the fuel piping system to an idle rotation speed or less. It is proposed to set the rigidity and the internal capacity of each of them in a certain range. However,
In many cases, the body of the fuel delivery pipe is made of a steel pipe having a circular or square cross section, and there are many problems in adopting the above method from the viewpoints of engine specifications, strength, and cost. Japanese Patent Publication No. 3-62904, "Fuel Rail for Internal Combustion Engine", uses a diaphragm to partition the inside of the communicating pipe into a socket side and a pipe wall side in order to prevent noise from the injector, and pulsates due to the flexibility of the diaphragm. And the residual reaction of indiecta. However, arranging a flexible diaphragm in the longitudinal direction of the communication pipe requires a sealing member, which complicates the structure, restricts the overall shape, and supports a wide variety of engine specifications. There is a drawback that you can not.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel delivery pipe structure capable of suppressing vibration caused by a reflected wave or pulsating pressure of fuel and preventing generation of abnormal noise. It is in.

[0005]

The above objects of the present invention can be attained by adopting a structure for reducing or attenuating a reflected wave and a pulsating pressure of fuel in a fuel delivery pipe. The basis is that at least one outer wall surface of the communication pipe is constituted by a flexible damping surface. In addition, in the present invention, a structure in which a flexible end cap having an uneven portion protruding outward and / or inward is fixed to at least one end of the communication pipe so as to be in contact with the damping surface. provide. This is because if a rigid cap (sealing member) is fixed to the end of the communication pipe as in the prior art, the damping surface is restrained and the bending is limited, and further, the brazing or welding at the corner of the cap is performed. This is because stress is concentrated and cracks may occur.

[0006] The end cap is realized in the following three patterns. (A) A flexible end cap having a convex portion protruding outward is fixed to at least one end of the communication tube. (B) A concave portion protruding inward is formed at at least one end of the communication tube. (C) Affix the flexible end cap having at least one of the ends of the communication pipe with the concave and convex portions projecting outward and inward in a wavy manner.

[0007]

According to the fuel delivery pipe of the present invention, by adopting such a structure, the damping surface exhibits the effect of absorbing the impact energy, so that the vibration and pulsation caused by the reflected wave of the injector and the damping ability of the communication pipe are obtained. This can prevent the generation of abnormal noise. Further, in the present invention, by adopting the flexible end cap, the restraint at the end of the damping surface is relaxed, the effect of absorbing impact energy is enhanced, and the stress is dispersed to increase the durability. .
It is understood that the rationale is that the impact energy generated during opening and closing of the fuel injector is absorbed by the cooperative deflection of the damping surface and the end cap.

[0008] In the end cap of the present invention, in order to cooperate with the damping surface, it is preferable that at least a portion connected to the damping surface is made thin. In addition, it is desirable that the concave and convex portions of the end cap have a radius of curvature of 3 mm or more from the viewpoint of elasticity and strength. In the present invention, the shape of the communication pipe, the ratio between the length and width, the thickness of the damping surface and the thickness of the end cap, and the like can be determined by experiments and analysis so that vibration and pulsation are minimized particularly during idling of the engine. .

Since the present invention basically relates to the structure of the communication pipe itself, compatibility with the conventional fuel delivery pipe can be maintained. Other features and advantages of the present invention will become apparent from the following description in which reference is made to the embodiments of the accompanying drawings.

[0010]

1 and 2 show a fuel delivery pipe (top feed type) 10 according to the present invention.
The communication pipe 11 formed of a steel pipe having a square cross section extends along the crankshaft direction, and the fuel introduction pipe 2 is connected to the side of the communication pipe 11 via the connector 5. It is fixed by attaching and welding. A return pipe for returning to the fuel tank can be provided at the end of the communication pipe. However, a return pipe is not provided in a returnless type fuel delivery pipe in which pulsation pressure of fuel is a problem.

In the case of a three-cylinder engine, three sockets 3 for receiving the tip of the injection nozzle are mounted on the bottom surface of the communication pipe 11 at a predetermined angle. Communication pipe 11
Further, two thick and rigid brackets 4 for attaching the fuel delivery pipe to the engine body are laid horizontally. Fuel flows in the direction of the arrow,
The fuel is injected from the fuel inlet 13 of the socket 3 into each intake passage or each cylinder via a fuel injector (not shown).

As shown in FIGS. 2A and 2B, according to the present invention,
Of the cross section of the communication pipe 11, only the upper surface 11a is formed of a thin steel plate so as to act as a flexible damping surface, and the other surface 11b is formed of a thick solid member.
Further, according to the present invention, end caps 15, 16 are fixed to both ends of the communication pipe 11 by brazing or welding. The end caps 15 and 16 are made of thin metal such as SPCC,
It can be made from a strip material such as SPHC or SUS by plastic working such as drawing.

FIG. 3 shows the shape of three patterns of end caps according to the present invention, and FIG.
B is an inward concave shape, and FIG. 3C is a corrugated uneven shape in which the outward and inward are combined. These end caps, at least on the side connected to the damping surface 11a by brazing or welding, preferably have a structure in which the whole is thin and cooperates with the bending of the damping surface. The radius of curvature of the concave and convex portion of the end cap is 3 mm.
It is desirable that this is the case.

FIGS. 4A to 4E show that the end cap according to the present invention can be applied to the case where the communicating pipe and its damping surface adopt various shapes. In FIG. 4A, only the side 21a of the communication tube 21 provides a damping surface, while the other surface 21b is made of a rigid steel tube. The end cap 25 is fixed to one end or both ends of the communication pipe 21. In FIG. 4B, the entire surface 31a of the communication tube 31 provides an oval damping surface, and the end cap 35 is entirely thin and is fixed to one or both ends of the communication tube 31.

In FIG. 4C, the entire surface 41a of the communication tube 41 provides a receiver-shaped damping surface, and the end cap 45 is fixed to one or both ends of the communication tube 41. In FIG. 4D, the entire surface 51a of the communication tube 51 provides an inverted eye mask-shaped damping surface, and the end cap 55 is fixed to one or both ends of the communication tube 51. In FIG. 5E, the entire surface 61 a of the communication pipe 61 provides a T-shaped damping surface, and the end cap 65 is fixed to one or both ends of the communication pipe 61.

[0016]

As described in detail above, according to the present invention, the flexible damping surface and the end cap cooperate to absorb the impact energy, thereby reflecting the reflected wave of the injector and the communication pipe. It is possible to prevent the generation of abnormal noise due to vibration or pulsation due to the damping ability of the horn, and its technical effect is extremely remarkable.

[Brief description of the drawings]

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

FIG. 2 is a left side view of the fuel delivery pipe of FIG. 1 and a cross-sectional view taken along line BB.

FIG. 3 is a cross-sectional view illustrating three patterns of end caps.

FIG. 4 is a sectional view of a socket portion showing a damping surface and an end cap in communication pipes of various shapes.

[Explanation of symbols]

 Reference Signs List 2 Fuel introduction pipe 3 Socket 10 Fuel delivery pipe 11, 21, 31, 41, 51, 61 Communication pipe 11a, 21a, 31a Damping surface 13 Fuel inlet 15, 16, 17, 18 End cap 25, 35, 45 , 55, 65 End cap 41a, 51a, 61a Damping surface

Claims (3)

[Claims] 1. A communication pipe made of metal having a fuel passage extending in a straight line therein, a fuel introduction pipe fixed to an end or a side of the communication pipe, and a projection intersecting the communication pipe. A fuel delivery pipe for an internal combustion engine, comprising a plurality of sockets partially communicating with the fuel passage and having an open end receiving a tip of a fuel injection nozzle, wherein at least one outer wall surface of the communication pipe is flexible The damping surface of at least one end of the communication pipe,
A fuel delivery pipe, wherein a flexible end cap having an uneven portion protruding outward and / or inward is fixed so as to be in contact with the damping surface. 2. The fuel delivery pipe according to claim 1, wherein at least a portion of the end cap connected to the damping surface is made thin. 3. The fuel delivery pipe according to claim 1, wherein the concave / convex portion of the end cap has a radius of curvature of 3 mm or more.