JP2001107821A - Fuel delivery pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of vibration and noise due to a reflection wave and a pulsation pressure occurring during injection of fuel, in a fuel delivery pipe used in an engine for an electronic fuel injection type automobile. SOLUTION: An elastic absorbing surface formed of a sheet member is annexed in a state to make contact with the inside end face of a socket or with distance therebetween. A plurality of orifices to effect intercommunication between the internal part of the socket and the internal part of a communication pipe are opened to the periphery of the inside end face of the socket. The surface, positioned facing the socket, of the wall surface of the communication pipe forms a sheet-form elastic absorb surface positioned opposite to the socket, so as to absorb and relax impact energy by the absorbing surface and prevent the generation of noise owing to vibration and pulsation due to propagation of reflection wave, propagated from an injector, to the fuel pipe side through the communication pipe.

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) 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 is 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, in particular, in a returnless type, a method of mounting a pressure damper immediately before a fuel delivery pipe, or supporting a fuel pipe on the back side of a front panel of an automobile with a plurality of vibration isolating clamps has been used. However, problems such as an increase in the number of parts, securing of an installation space, and an increase in 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 viewpoint 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 communication pipe into a socket side and a pipe wall side in order to prevent injector wrap noise. The residual reaction of the injector is absorbed. 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. Japanese Patent Application Laid-Open No. 60-240867 proposes that one of the walls of the fuel supply conduit is elastically configured to reduce fuel pulsation.

[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 are attained by employing a structure which reduces or dampens reflected waves and pulsating pressure of fuel transmitted through a socket when passing through the socket. The basis is to provide a flexible absorbent surface made of a thin plate member in contact with or at an interval on the inner end surface of the socket.
The holes for passing the fuel are formed around the inner end surface of the socket as a plurality of orifice holes for communicating the inside of the socket and the inside of the communication pipe.

[0007]

According to the fuel delivery pipe of the present invention, by adopting such a structure, the distance from the injector to the absorber surface is shortened by providing the absorber surface (damping surface) on the end surface of the socket. The pulsating energy due to the generated impact immediately reaches the absorber surface in a state of high energy density, so that the absorber surface has an effect of absorbing and buffering the impact energy, and the reflected wave from the injector is transmitted from the communication pipe to the fuel pipe side. Generation of abnormal noise due to vibration or pulsation caused by propagation can be effectively prevented. Further, in the present invention, since the holes for passing the fuel are formed around the inner end face of the socket as a plurality of small-diameter orifice holes communicating the inside of the socket and the inside of the communication pipe,
The resistance when passing through the orifice hole has the effect of absorbing and buffering the impact energy, and the impact energy generated when the fuel injector is opened and closed is buffered to the maximum, so that the pulsating pressure of the fuel is reduced. Propagation from the supply pipe to the fuel pipe side can be reliably suppressed, and generation of abnormal noise can be largely prevented.

In the present invention, the orifice hole is formed by a groove formed in the end face of the socket, in addition to a through hole formed by a normal drill, and the absorber surface made of a thin plate member is sealed on each groove. be able to. In this case, the processing of the orifice hole is not a penetrating processing but an end face processing (groove processing), so that there is an advantage that press or forming can be performed and the work becomes easy.

This groove may be formed into a curved shape instead of a straight groove for processing the end face. In this case, the resistance when passing through the curved groove exerts the effect of absorbing and buffering the impact energy, and the effect of the present invention increases.

In another preferred embodiment, if the traveling direction of the wave reflected on the absorbing surface and the central axis of the orifice hole are inclined, the wave proceeds while being reflected on the inner surface of the orifice and is further attenuated. As a result, the resistance at the time of passing through the socket is increased, so that the effect of absorbing and buffering the impact energy is exhibited, and the effect of the present invention is increased.

Further, as another preferred embodiment, when the orifice hole is inclined with respect to the center axis of the socket and the inner peripheral opening is opened on the absorber surface side, the reflected wave of the injector can be reduced. Most of them will collide with the absorber surface and then propagate through the communication pipe to the fuel pipe side, increasing the resistance when passing through the socket, exhibiting the effect of absorbing and buffering impact energy, and according to the present invention. The effect is increased.

Further, as another preferred embodiment, of the communication tube, the surface facing the socket is constituted by a thin, flexible second absorbing surface, and the first absorbing surface in the socket portion is provided. The reflected wave radiated from the second absorber surface is weakened by colliding with the second absorber surface, so that the synergistic effect of the two absorber surfaces increases the effect of absorbing and buffering impact energy.

When the second absorbing surface is used, when the fuel supply pipe is attached to a surface other than the second absorbing surface on the communication pipe side, the flexibility of the absorbing surface is suppressed and the rigidity is increased. The buffer capacity is not reduced, the vibration of the fuel supply pipe itself is reduced, and the strength is advantageous.

In the present invention, the shape, dimensions, length-to-width ratio, plate thickness, etc. of the thin plate-shaped absorptive surface or orifice hole or communication pipe attached to the socket are values that minimize vibration and pulsation, especially when the engine is idling. Can be determined by experiment or analysis so that 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.

[0015]

1 to 3 show a fuel delivery pipe (top feed type) 10 according to a preferred embodiment of the present invention in a partially exploded overall shape. 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.

Three sockets 3a to 3c for receiving the ends of the injection nozzles are provided at predetermined intervals and angles on one side of the six-cylinder engine on the bottom surface of the communication pipe 11. For a four-cylinder engine, four are mounted at predetermined intervals and angles. Two thick and rigid brackets 4 for attaching the fuel delivery pipe to the engine main body are further laterally bridged over the communication pipe 11. The fuel flows in the direction of the arrow, and the sockets 3a to 3a
The fuel is injected into each intake passage or each cylinder from each fuel inlet 13c through a fuel injector (not shown).

As shown in FIGS. 2 and 3, according to the present invention, the thin plate member 20 is brought into contact with the inner end face 3s of the socket 3.
And a plurality of orifice holes 22 provided around the inner end thereof for communicating between the inside of the socket and the inside of the communication pipe by means of spot welding, projection welding, seam welding, brazing or other methods. Is open. The material of the thin plate member 20 is made of metal or reinforced plastic, and its thickness is, for example, 0.2 to 0.8.
mm.

Further, the wall surfaces 11a, 11b of the communication pipe 11
Of the end caps 11c and 11d, only the upper surface 11a facing the socket 3 is formed of a flexible thin steel plate so as to act as a second absorber surface, and the side and bottom surfaces 11b are thick and solid. Made of components. A hole for communicating the inside of the socket 3 with the inside of the communication pipe 11 is provided with a small-diameter orifice hole 22 around the inner end of the socket 3.
It is formed as.

Thus, according to the embodiment of FIGS.
Since the absorbing surface (damping surface) 20 provided on the end surface of the socket 3 has an effect of absorbing and buffering the impact energy, the vibration caused by the propagation of the reflected wave from the injector from the communication pipe to the fuel pipe side can be reduced. Generation of abnormal noise due to pulsation can be prevented. Further, in the present invention, since the hole 22 for passing the fuel is formed as a small-diameter orifice hole, the resistance at the time of passing through the orifice hole exhibits an effect of absorbing and buffering impact energy, and the fuel injector has The impact energy generated at the time of opening and closing is buffered to the utmost, so that the pulsating pressure of the fuel is reliably suppressed from propagating from the fuel supply pipe to the fuel pipe side, and the generation of abnormal noise is largely prevented. Can be.

FIG. 4 shows another embodiment of the present invention.
In the example of FIG. 4A, the orifice hole 30 is not a through hole formed by a normal drill, but a groove 30 formed in the end face 3s of the socket 3.
, And the absorber surface made of the thin plate member 20 seals the upper part of each groove. This groove 30 is not limited to a straight groove 30 as shown in FIG.
The groove 32 may have a curved shape as shown in FIG.
In this case, the resistance when passing through the curved groove 32 exerts the effect of absorbing and buffering the impact energy, and the effect of the present invention is increased. Further, as shown in FIG. 4D, if the orifice is formed such that the traveling direction of the wave reflected on the absorbing surface and the central axis of the orifice hole 33 are inclined, the wave proceeds while reflecting on the inner surface of the orifice. As a result, the resistance at the time of passing through the socket is increased, thereby exhibiting the effect of absorbing and buffering impact energy, and the effect of the present invention is increased.

FIG. 5 shows still another embodiment of the present invention, and FIG. 5A shows an example in which a thin plate member 40 is provided with a concentric waveform to improve shock absorption. FIG. 5B shows an example in which the thin plate member 42 is disposed slightly away from the end face 3s of the socket 3 and its outer periphery is bent and fixed to the outer periphery of the socket to improve the shock absorption. FIG. 5C shows an example in which the orifice hole 44 is inclined obliquely with respect to the center axis of the socket, and the inner peripheral opening 44a is opened toward the absorber surface 20.

When the orifice hole is inclined as shown in FIG. 5C, it is reduced that the reflected wave from the injector passes directly to the orifice hole without colliding with the absorber surface, and most of the reflected wave collides with the absorber surface. After passing through the communication pipe, it propagates to the fuel pipe side, so that the resistance at the time of passing through the socket increases, thereby exhibiting the effect of absorbing and buffering impact energy.

The embodiment of FIG. 6 shows a modification of the second absorbing surface in the embodiment of FIGS. 1 to 3, and FIG.
6B shows an example in which the absorbing surface 51a of the communication pipe 51 is corrugated to enhance the shock absorption. FIG.
This is an example in which 1a is formed by bending the entire cross section. FIG. 6B
In the case where the entire side surface of the communication pipe is an absorbing surface as described in (1), it is desirable to attach the fuel supply pipe to the wall surface on the socket 3 side, since the deformation of the second absorbing surface is not hindered.

In the example shown in FIG. 6, the first
Since the reflected wave radiated from the absorptive surface collides with the second absorptive surface and is weakened, the effect of absorbing and buffering the impact energy increases by the synergistic effect of the two absorptive surfaces.

[0025]

As described in detail above, according to the present invention, the flexible absorbing surface (damping surface) of the socket end acts to absorb and buffer impact energy,
It is possible to prevent the generation of abnormal noise due to vibration or pulsation caused by the reflected wave from the injector or the propagation from the communication pipe to the fuel pipe side, and the technical effects are 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 partially broken longitudinal sectional view of a fuel delivery pipe according to the present invention.

FIG. 3 is a longitudinal sectional view taken along line AA of FIG. 2;

FIG. 4 is a sectional view of a socket portion according to another embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a socket portion showing another embodiment of the present invention.

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

[Explanation of symbols]

 2 Fuel supply pipe 3, 3a to 3c Socket 3s Socket end face 4 Bracket 10 Fuel delivery pipe 11, 51, 61 Communication pipe 11a, 51a, 61a Communication pipe wall 13 Fuel inlet 20, 40, 42 Thin plate member 22, 30, 32,33,44 Orifice hole

Claims (5)

[Claims] 1. A communication pipe made of metal having a fuel passage extending linearly therein, a fuel supply pipe fixed to the communication pipe, and a part of the fuel passage protrudingly intersecting with the communication pipe. A fuel delivery pipe for an internal combustion engine, comprising: a plurality of sockets having an open end communicating with the fuel injector end and a thin plate member contacting or spaced apart from an inner end surface of the socket. A flexible absorber surface is attached,
A fuel delivery pipe, wherein a plurality of orifice holes are formed around the inner end face to communicate between the inside of the socket and the inside of the communication pipe. 2. The fuel delivery pipe according to claim 1, wherein said orifice hole is formed of a groove formed in an end face of said socket, and said absorber surface seals over each groove. 3. The fuel delivery pipe according to claim 2, wherein said groove is formed to be curved. 4. The fuel delivery pipe according to claim 1, wherein said orifice hole is obliquely inclined with respect to a central axis of the socket, and an inner peripheral opening thereof is opened to said absorber surface side. 5. The fuel delivery pipe according to claim 1, wherein a surface of said communication pipe facing said socket is formed of a thin plate-shaped flexible absorbing surface.