JP2000329030A - Fuel delivery pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorbing shock caused by reflected wave and pulsation pressure of fuel, suppress damping of vibration, and prevent generation of noise by constituting at least one outer wall surface of a communicating pipe with a flexible absorbing surface. SOLUTION: Sockets 3a to 3d for receiving a tip end of an injection nozzle are mounted on a bottom surface of a communicating pipe 11, and two thick and hard brackets 4 for mounting a fuel delivery pipe 10 on an engine main body are mounted. Fuel flows in an arrow direction, and is injected from each fuel flow inlet 13 of the sockets 3a to 3d to each intake passage (an air cylinder). Only upper surface 11a of the communicating pipe 11 is formed of a thin steel plate acted as a flexible absorption surface, and a side surface and the bottom surface 11b are made of a thick and hard member. A fuel supplying pipe 2 is fixed so as to open to the vicinity of a center of the communicating pipe 11. Accordingly, deflection of the absorption surface is the max level at the vicinity of the center, and reflected wave 18 outputted from each socket 4 is canceled near the center.

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 supply passage and a socket (holder) portion 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). Recently, types without a return passage have increased due to cost reduction, but fuel delivery (plunger pump) and fuel delivery due to reflected waves and pulsation pressure caused by collision of the spool of the injector with the counterpart member have been accompanied. Pipes, fuel pipes as related parts, their clamps,
A problem has arisen that the front panel or the like to which the clamp is attached vibrates and emits a strange noise.

[0003] As a countermeasure, a method of mounting a pressure damper immediately before the fuel delivery pipe or supporting a fuel pipe behind the front panel of a vehicle with a plurality of vibration-isolating clamps has been used. Problems such as increase, securing of installation space, and high cost have newly occurred.

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.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to absorb a shock caused by a reflected wave or a pulsating pressure of fuel (absorbing / absorbing).
An object of the present invention is to provide a fuel delivery pipe structure capable of absorbing and suppressing vibration to prevent occurrence of abnormal noise.

[0006]

The above objects of the present invention can be attained by employing a fuel delivery pipe having a structure for reducing or damping a reflected wave and a pulsating pressure of fuel. The basis is that at least one outer wall surface of the communication pipe is formed of a flexible absorbing surface. In addition, the present invention provides a structure in which the fuel supply pipe is opened substantially near the center of the length of the communication pipe in the axial direction.

[0007]

According to the fuel delivery pipe of the present invention, by adopting such a structure, the absorbing surface (damping surface) exhibits the effect of absorbing and buffering the impact energy, so that the communication pipe for the reflected wave from the injector is provided. Generation of abnormal noise due to vibration or pulsation caused by propagation from the fuel pipe to the fuel pipe side can be prevented. Further, in the present invention, since the fuel supply pipe is opened near the center of the length of the communication pipe in the axial direction, that is, near the position where the buffering action by the absorber surface is maximized and the amplitude is maximized, the fuel supply pipe is opened and closed when the fuel injector is opened and closed. Since the impact energy is buffered to the maximum, the pulsating pressure of the fuel is reliably prevented from propagating from the fuel supply pipe to the fuel pipe side, and the generation of abnormal noise can be largely prevented.

In the present invention, when the fuel supply pipe is attached to a surface other than the absorptive surface of the communication tube, the flexibility of the absorptive surface is suppressed, the rigidity is increased, and the buffer capacity is not reduced. In addition, the vibration of the fuel supply pipe itself is reduced, which is advantageous in strength. Further, in the width direction of the communication pipe, it is advantageous to open the fuel supply pipe substantially in the vicinity of the center, since the amplitude of the absorber surface becomes closer to the maximum position.

If there are an even number of sockets, it is advantageous for the fuel supply pipe to be open near the center of the two sockets near the center. If you have an odd number of sockets,
The fuel supply pipe is opened near the center socket, but it is preferable to offset the fuel supply pipe to a position where the reflected wave of the injector from the socket does not directly enter. Specifically, it is preferable to open the fuel supply pipe at a position offset from the axis of the central socket by at least half the width of the communication pipe.

[0010] Further, the fuel supply pipe is more advantageous in strength if it is opened on the surface of the wall of the communication pipe on which the socket is mounted or on the surface on which the bracket for fixing the communication pipe is mounted. is there. Further, it is advantageous that the absorbing surface is provided on the surface facing the socket (the surface on the opposite side) in that the propagation of the reflected wave is weakened.

In the present invention, the shape of the communication pipe, the aspect ratio, the thickness of the absorber surface, and the like can be determined by experiments and analysis so that vibrations and pulsations are minimized particularly when the engine is idling. 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.

[0012]

1 and 2 show a fuel delivery pipe (top feed type) 10 according to a preferred embodiment of the present invention in a partially exploded form as a whole. A communication pipe 11 made of a steel pipe extends along the crankshaft direction, and a fuel supply (introduction) pipe 2 is fixed to a 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. 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 four-cylinder engine, four sockets 3a to 3d for receiving the tips of the injection nozzles are mounted on the bottom surface of the communication pipe 11 at a predetermined angle. The communication pipe 11 further includes a thick and solid bracket 4 for attaching a fuel delivery pipe to the engine body.
Are bridged in the horizontal direction. The fuel flows in the direction of the arrow and is injected from each fuel inlet 13 of each of the sockets 3a to 3d into each intake passage or each cylinder via a fuel injector (not shown).

As shown in FIG. 1, 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 absorbing surface, and the side and bottom surfaces 11b are thick. It is made of solid meat. Further, according to the present invention, the fuel supply pipe 2 is fixed by brazing or welding so as to open substantially near the center of the length of the communication pipe 11 in the axial direction. This is because the flexure of the absorber surface is maximized near the center, and when the number of sockets is even, the reflected waves 18 emitted from each socket cancel each other around the center.

Further, dome-shaped end caps 15 and 16 made of a thin plate are fixed to both ends of the communication pipe 11 by brazing or welding. This is because if a rigid cap (sealing member) is fixed to both ends of the communication pipe as in the conventional case, the absorptive surface is restrained and the bending is limited, and furthermore, stress is applied to the brazing and welding portions of the cap corners. Is concentrated and cracks may occur.

The end caps 15, 16 are made of thin metal,
For example, it can be made from a strip material such as SPCC, SPHC, or SUS by plastic working such as drawing. The end cap can be formed not only in a convex shape but also in a concave or uneven waveform. From the viewpoint of elasticity and strength, the radius of curvature is desirably 3 mm or more.

FIGS. 3A and 3B show an embodiment in which the fuel supply pipe is mounted on another surface. FIG. 3A shows an example in which the fuel supply pipe 2 is mounted on the bottom surface facing the absorber surface 11a.
B shows an embodiment in which the fuel supply pipe 2 is attached to the absorber surface 11a. The fuel supply pipe 2 can be optimally arranged according to the actual engine.

FIG. 4 shows a fuel delivery pipe 20 according to another embodiment, in which the upper surface 21a of the communication pipe 21 constitutes an absorber surface, and the center of the dome-shaped end cap 16 fixed to the end. A fuel supply pipe 22 is attached therethrough. The bottom surface 21b of the communication pipe 21 is made of a solid steel plate. According to the present invention, the fuel supply pipe 22 extends to the center along the axis of the communication pipe, and its inner end 22a opens near the center of the communication pipe 21 in the axial length.

FIG. 5 shows a fuel delivery pipe 30 according to still another embodiment, and the entire surface 31a of the communication pipe 31 having an elliptical cross section constitutes an absorber surface. According to the present invention, the fuel supply pipe 32 extends through the side of the communication pipe 31.
The inner end 32a is opened near the center in the transverse direction of the communication pipe 31. The cross-sectional shape of the communication pipe may be various shapes such as a T-shape, a receiver shape, an inverted eye mask shape, and the like, in addition to the one shown in the drawing, and a flexible absorber surface is provided on all or a part of the wall surface. Can be provided.

FIG. 6 shows a fuel delivery pipe 40 in an embodiment having an odd number of sockets. When there are an odd number of the sockets 3a to 3c, the fuel supply pipe 2 opens near the center socket 3b, but it is desirable to offset the fuel supply pipe 2 to a position where the reflected wave of the injector from the socket does not directly enter. That is, in FIG. 6, the fuel supply pipe 2 is offset from the axis of the central socket 3b by a length S, and the offset amount S is desirably at least half the width of the communication pipe. This is because it is considered advantageous that the reflected wave 18 is offset to the outside of the diameter of the largest circle formed on the absorbing surface 41a of the communication pipe 41 because the reflected wave is buffered.

[0021]

As described above in detail, according to the present invention, the flexible absorbing surface (damping surface) acts to absorb and buffer impact energy, and the position of the fuel supply pipe is determined by the absorbing surface. By selecting a position near the position where the buffering action is maximized and the amplitude is maximized, it is possible to prevent the generation of abnormal noise due to vibration and pulsation caused by reflected waves from the injector and propagation from the communication pipe to the fuel pipe side. Some of the technical effects are extremely remarkable.

[Brief description of the drawings]

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

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

FIG. 3 is a sectional view of a socket portion showing an embodiment in which a position of a fuel supply pipe is changed.

FIG. 4 is a longitudinal sectional view showing an embodiment in which the position of a fuel supply pipe is changed.

FIG. 5 is a sectional view of a fuel supply pipe portion showing an embodiment in which an absorbing surface is elliptical.

FIG. 6 is a longitudinal sectional view showing an embodiment having an odd number of sockets.

[Explanation of symbols]

 2, 22, 32 Fuel supply pipe 3a to 3d Socket 4 Bracket 10, 20, 30, 40 Fuel delivery pipe 11, 21, 31, 41 Communication pipe 11a, 21a, 31a, 41a Absorbing surface 13 Fuel inlet 15, 16 End cap 18 reflected wave

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 37/00 321 F02M 37/00 321A 321B

Claims (7)

[Claims] 1. A communication pipe made of metal having a fuel passage extending in a straight line therein, a fuel supply pipe fixed to an end or a side portion of the communication pipe, and a projection intersecting the communication pipe. A fuel delivery pipe for an internal combustion engine, the plurality of sockets having a part communicating with the fuel passage and an open end receiving a tip of a fuel injection nozzle, wherein at least one outer wall surface of the communication pipe is flexible. A fuel delivery pipe comprising: a fuel supply pipe formed substantially at the center of an axial length of a communication pipe. 2. The fuel delivery pipe according to claim 1, wherein the fuel supply pipe is attached to a surface other than an absorbing surface of the communication pipe. 3. The fuel delivery pipe according to claim 1, wherein the fuel supply pipe is opened substantially at the center of the width of the communication pipe. 4. The fuel delivery pipe according to claim 1, wherein an even number of sockets are attached to the communication pipe, and the fuel supply pipe is opened near the center of the two sockets near the center. . 5. The communication pipe according to claim 1, wherein an odd number of sockets are attached to the communication pipe, and the fuel supply pipe is opened at a position offset from the axis of the central socket by at least half the width of the communication pipe. Fuel delivery pipe described in Crab. 6. The fuel supply pipe according to claim 1, wherein the fuel supply pipe is mounted on a surface of the wall of the communication pipe on which the socket is mounted or a surface on which a bracket for fixing the communication pipe is mounted. Fuel delivery pipe described in Crab. 7. The fuel delivery pipe according to claim 1, wherein the absorbing surface is provided on a surface facing the socket.