JP4449025B2 - Fuel delivery pipe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a fuel delivery system for supplying fuel supplied from a fuel pressurizing pump of an electronically controlled fuel injection type automobile engine into each intake passage or each cylinder of the engine via a fuel injection nozzle (injector). In particular, the present invention relates to a connection structure of a communication pipe having a fuel passage and a socket (holder) portion that receives a fuel injection nozzle.
[0002]
[Prior art]
Fuel delivery pipes are widely used in electronically controlled fuel injection systems for gasoline engines. After fuel is sent from a communication pipe having a fuel passage to a fuel injector through a plurality of cylindrical sockets, the fuel delivery pipe is then sent to the fuel tank side. There are a type having a return path for returning and a type having no return path (returnless). Recently, the type that does not have a return passage has been increasing due to cost reduction. Along with this, the fuel delivery pipe (related to the fuel pump (plunger pump) and the spool of the injector) and the pulsation pressure caused by the reciprocating movement of the spool of the fuel There has been a problem that parts vibrate and generate strange noises.
[0003]
According to the research of the present inventor, it has been found that as the rotational speed of the internal combustion engine increases, the overlap of fuel pressure vibration due to fuel injection at each socket portion increases, and the generation of abnormal noise is promoted. this is,
(A) When fuel is injected, the pressure in the socket directly connected to the injector drops rapidly. (B) The socket has a smaller connection diameter than the communication pipe, but does not cause resistance to pressure propagation ( c) When fuel is injected, the influence of the pressure drop immediately propagates in the communication pipe. (d) Various noises are generated by this pressure propagation.
As a result, it is considered that the pressure drop in the socket is immediately propagated into the communication pipe along with the fuel injection, and various problems are caused by the pressure fluctuation in the fuel flow path.
[0004]
JP-A-11-2164 “Fuel Delivery” pays attention to this problem and manufactures the delivery body with a sheet metal press so that the pulsation resonance rotational speed of the fuel piping system is lower than the idle rotational speed. It is proposed to set the content to a certain range. However, many types of fuel delivery pipes are made using a steel pipe having a circular or square cross section, and there are many problems in adopting the above method due to engine specifications, strength, and cost.
Japanese Patent Publication No. 3-62904 “Fuel Rail for Internal Combustion Engine” uses a diaphragm to divide 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, the arrangement of the flexible diaphragm in the longitudinal direction of the communication pipe requires a sealing member, which complicates the structure and restricts the overall shape, thus supporting a wide variety of engine specifications. There is a disadvantage that it can not.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to suppress pressure fluctuations in the fuel flow path due to fuel injection, suppress vibrations caused by reflected waves of the fuel and pulsation pressure, and prevent occurrence of abnormal noise and various problems. It is to provide a fuel delivery pipe structure capable of.
[0006]
[Means for Solving the Problems]
The above-described object of the present invention is, as a first aspect, a communication pipe having a linearly extending fuel passage, a fuel introduction pipe fixed to an end portion or a side portion of the communication pipe, and the communication pipe. A fuel delivery pipe for an internal combustion engine, comprising: a plurality of sockets that are inserted into a socket receiving hole of the internal combustion engine and communicated with the fuel passage and whose open ends receive the tip of the fuel injection nozzle. A fuel reservoir space comprising a small chamber for absorbing the pulsating pressure of fuel is connected and fixed to a seating surface around the inside of the communication tube, and at least one orifice hole is formed in the wall surface of the small chamber, The outer peripheral shape of the small chamber is formed into a shape that can pass from the outside to the inside of the communication pipe through the socket receiving hole provided in the communication pipe. Fuel the internal volume Morphism is set larger than one injection amount of the nozzle is achieved by the small compartment full Ewell delivery pipe, characterized in that at least one wall is constituted by Absorb plane flexibility.
[0007]
[Action]
By adopting such a structure, according to the fuel delivery pipe of the present invention, the vibration is buffered by the resistance when the fuel passes through the orifice hole, and a part of the injection amount by the injection nozzle is reduced in the compartment. As the fuel pool temporarily accumulates and discharges sequentially, the small chamber acts as a damper, suppressing pressure fluctuations in the fuel flow path, and vibration caused by the reflected wave of the injector and the damping capacity of the communication pipe And generation of abnormal noise due to pulsation can be prevented.
[0008]
The outer peripheral shape of the compartment is designed to be able to enter from the outside to the inside of the communication pipe through the socket receiving hole provided in the communication pipe. At the time of manufacture, the socket and the compartment are brazed or welded. Thus, the fuel delivery pipe can be easily manufactured because it can be inserted and inserted through the socket receiving hole after being connected and fixed together.
The internal volume of the fuel reservoir space in the compartment is set to be equal to or greater than the single fuel injection capacity of the fuel injection nozzle . Even if the pressure in the fuel reservoir space slightly drops during fuel injection, the injection amount, the particle size of the spray particles, the reach distance, and the speed are not significantly affected.
[0009]
It is desirable that the size of the orifice hole be narrow enough to allow the previously injected part to pass between the end of the injection and the next injection. This makes it possible to minimize the pressure drop in the fuel reservoir space during injection from propagating into the communication pipe. Thus, the pressure fluctuation in the fuel flow path is kept low, and various noises are reduced.
[0010]
As a theoretical basis for vibration damping by the orifice hole, when a shock wave generated when the fuel injection nozzle is opened and closed passes through the orifice hole,
(A) At the moment of collision with the compartment, the compartment is bent to absorb impact energy and absorb fuel pressure fluctuations. (B) At the moment of passing through the orifice hole provided in the compartment. (C) Absorbs impact energy by absorbing the impact energy by absorbing the impact energy by bending its direction when entering the inside of the communication pipe from the orifice hole. d) It is understood that when passing through the orifice hole and entering the communication pipe, the volume rapidly expands to absorb impact energy and to absorb fuel pressure fluctuations.
[0011]
By constructing at least one outer wall surface of the compartment in the present invention with a flexible absorber surface (damping surface), this absorber surface absorbs impact energy more, and the damping effect can be enhanced. become.
For example, the small chamber can be formed into a loose shape made of a thin steel pipe, or formed by welding or electroforming a disc spring-like thin plate, and this loose shape can be an absorbing surface to absorb the impact.
[0012]
Further, when a shock wave enters the inside of the communication pipe from the orifice hole, the orifice hole can be offset left and right or opened toward the side surface in order to bend the direction as much as possible to enhance the damping effect. In addition, a large number of baffle plates can be placed inside the compartment to turn the vector direction of energy propagation by shock waves in the opposite direction, and a small gap can be provided between the walls to increase the damping effect. desirable.
[0013]
In the present invention, the shape, plate thickness, length, and the like of the compartment can be determined by experiments and analysis so that vibration and pulsation are minimized, particularly when the engine is idling.
[0014]
Since the present invention basically relates to the internal structure of the fuel delivery pipe, 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 with reference to the embodiments of the accompanying drawings.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a basic overall shape of a fuel delivery pipe (top feed type) 10 according to the present invention. A communication pipe 11 made of a steel pipe having a square cross section, a circular cross section, or other cross section is provided in the crankshaft direction. The fuel introduction pipe 2 is fixed to the side portion of the communication pipe 11 via a connector 5 by brazing or welding. Although a return pipe for returning to the fuel tank can be provided at the end of the communication pipe, the return pipe is not provided in the returnless type fuel delivery pipe in which the pulsation pressure of the fuel is particularly problematic.
[0016]
If the socket 3 for receiving the tip of the injection nozzle is a three-cylinder engine, three are attached to the bottom surface of the communication pipe 11 at a predetermined interval and angle. Further, two thick and strong brackets 4 for attaching the fuel delivery pipe to the engine body are bridged across the communication pipe 11 in the lateral direction. The fuel flows in the direction of the arrow, and is injected from the socket 3 into each intake passage or each cylinder via a fuel injector (not shown).
[0017]
FIG. 2 is a cross-sectional view of the fuel delivery pipe 20 according to the first embodiment of the present invention. A fuel passage 21 a extends linearly inside the communication pipe 21. The plurality of sockets 3 have their attachment-side end portions inserted into the socket receiving holes 7 of the communication pipe 21 and open end portions for receiving the tips of the fuel injection nozzles.
In accordance with the present invention, a fuel reservoir space 23 comprising a small chamber 22 for absorbing fuel pressure fluctuations is connected to the seating surface 13 a around the fuel inlet 13 of each socket 3 in the communication pipe 21. . The outer shape of the small chamber 22 is made into a shape that can pass through the socket receiving hole 7 of the communication pipe 21, and in the example of FIG. 2, it is made into a pipe shape having a loose cross section.
Each of the compartments 22 is provided so that its internal volume is larger than the injection amount of fuel injection as much as possible, and an orifice hole 25 is formed at the top. The inside of the small chamber 22 is kept in communication with the inside of the communication pipe 21 through the orifice hole 25.
[0018]
FIG. 3A is a cross-sectional view of the compartment section in the first embodiment, showing the positional relationship between the communication pipe 21 and the compartment 22 having a quadrangular cross section. The compartment 22 is made entirely of a thin-walled steel pipe so that the entire cross-sectional shape, preferably the surface 28 of the socket 3 facing the fuel inlet 13 provides a flexible absorber surface (damping surface). It is made elastically deformable.
[0019]
Thus, the vibration is buffered by the resistance when the fuel passes through the orifice hole 25, and a part of the injection amount of the injection nozzle is temporarily accumulated as the fuel reservoir 23 in the small chamber 22 and sequentially discharged. As a result, the small chamber 22 acts as a damper, suppresses pressure fluctuations in the fuel flow path, and can prevent generation of abnormal noise due to vibration and pulsation caused by the reflected wave of the injector and the damping capacity of the communication pipe. .
[0020]
Further, since the shock wave passing through the fuel inlet 13 immediately after fuel injection collides with the absorber surface 28 at the moment when it flows into the compartment 22, the absorber surface 28 is bent, and at the same time, the loose-shaped compartment 22 is also bent. In addition to absorbing impact energy, the volume rapidly expands and changes its direction when passing through the orifice hole 25 and entering the communication pipe 21 to absorb impact energy and absorb fuel pressure fluctuations. Understood.
[0021]
FIG. 3B shows a modified example of the communication pipe and the compartment. In this fuel delivery pipe 30, a small compartment 32 having a loose cross section is accommodated inside a communication pipe 31 having a circular cross section. Similarly to the example of FIG. 3A, shock absorption is similarly achieved by providing an orifice hole 35 at the top of the compartment 32 and configuring the entire surface of the absorber surface 38 and the compartment 32 with a flexible absorber surface. The effect can be enhanced.
[0022]
FIG. 4 shows another modification of the compartment. In this fuel delivery pipe 40, a cylindrical compartment 42 is accommodated inside a communication pipe 41 having a rectangular cross section, and a plurality of baffle plates are contained therein. 46 is arranged in a labyrinth (maze). This is because, as described above, when the shock wave passes through the socket and enters the inside of the communication pipe from the orifice hole, the passing direction is bent as much as possible and the passing distance is increased to enhance the damping effect. That is, fuel passes through the orifice hole 45 through the small gap 49 between the baffle plate 46 and the wall surface, and the shock wave bypasses the baffle plate 46 while reversing the energy propagation direction and the small gap 49. The shock absorbing effect is enhanced by passing through the orifice hole 45 having a small diameter.
In this example as well, the impact absorbing effect can be further enhanced by configuring the entire wall surface of the compartment 42 or only the top plate 48 with a flexible absorber surface.
[0023]
5A and 5B show still another modified example, and this fuel delivery pipe 50 shows another modified example of the compartment, and the horizontal cross section has an elliptical shape inside the communication pipe 51 having a quadrangular cross section. A cylindrical small compartment 52 is accommodated. The orifice hole 55 is formed not on the top but on the side surface so as to enhance the damping effect. In this example as well, the impact absorbing effect can be similarly enhanced by configuring the entire wall surface of the small chamber 52 or only the cap 58 with a flexible absorber surface.
In this embodiment, the cap 58 is made from a thin metal, for example, a strip plate material such as SPCC, SPHC, SUS, or the like by plastic working such as drawing, and is fixed to the top of the compartment 52 to thereby form the compartment 52. It is easy to bend up to the end portion of the lens, and the impact absorbing effect is enhanced.
[0024]
【The invention's effect】
As described above in detail, according to the fuel delivery pipe of the present invention, the vibration is buffered by the resistance when the fuel passes through the orifice hole, and the shock wave bypasses the small gap while passing through the small gap. The shock absorption effect is exhibited by changing the passing direction, etc., and a part of the injection amount by the injection nozzle is temporarily accumulated as a fuel reservoir in the small chamber and discharged sequentially, acting as a damper, and the fuel flow The technical effect is that the fluctuation of pressure in the road can be suppressed to prevent the generation of abnormal noise and various problems due to vibration and pulsation caused by the reflected wave of the injector and the damping capacity of the communication pipe. Some are very prominent.
[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 longitudinal sectional view of a first embodiment of a fuel delivery pipe.
3 is a cross-sectional view of a socket portion of the fuel delivery pipe of FIG.
FIG. 4 is a longitudinal sectional view of a fuel delivery pipe according to another embodiment.
FIG. 5 is a longitudinal sectional view of a fuel delivery pipe according to another embodiment.
[Explanation of symbols]
2 Fuel introduction pipe 3 Socket 7 Socket receiving holes 10, 20, 30, 40, 50 Fuel delivery pipes 11, 21, 31, 41, 51 Communication pipe 13 Fuel inlet 13a Seating surface 21a Fuel passages 22, 32, 42, 52 Compartment 25, 35, 45, 55 Orifice hole 46 Baffle plate

Claims (1)

A communication pipe having a fuel passage extending in a straight line, a fuel introduction pipe fixed to an end portion or a side portion of the communication pipe, a socket receiving hole of the communication pipe, and communicating with the fuel passage; In a fuel delivery pipe for an internal combustion engine, the open end comprising a plurality of sockets for receiving the tip of the fuel injection nozzle,
A fuel reservoir space comprising a small chamber for absorbing fuel pulsation pressure is connected and fixed to a seating surface around the fuel inlet of the socket, and at least one orifice hole is formed in the wall surface of the small chamber. The outer peripheral shape of the small chamber is made to be able to enter the inside of the communication pipe from the outside through the socket receiving hole provided in the communication pipe. ,
The inner volume of the small chamber is set to be larger than a single injection amount of the fuel injection nozzle,
A fuel delivery pipe, wherein at least one wall surface of the small compartment is formed of a flexible absorber surface .

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