JP4159833B2 - Fuel delivery pipe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel delivery pipe used for a fuel supply system of an automobile.
[0002]
[Prior art]
In a fuel supply system in an automobile engine, fuel in a fuel tank is sent to a fuel delivery pipe by a pump, and an appropriate amount of fuel is injected from an injector attached to the fuel delivery pipe into an intake manifold of the engine.
[0003]
FIG. 14 shows a conventional fuel delivery pipe. The main body 10 of the fuel delivery pipe shown in FIG. 14 is composed of two cases, an upper case 10a and a lower case 10b, each formed by pressing a sheet metal, and the upper case 10a is superimposed on the lower case 10b. Both parts are joined together by brazing the overlapping part. The injector cup 17 used for attaching the injector is attached to the lower surface of the lower case 10b. The end of the fuel supply pipe 12 that guides the fuel to the main body 10 of the fuel delivery pipe is connected to the side surface of the lower case 10b.
[0004]
In fuel delivery pipes, fuel pulsations that occur as a result of the opening and closing operation of the injector, and vibrations and abnormal noise caused by reflected waves of shock waves that occur during fuel injection are always a problem.
[0005]
Conventionally, in order to suppress vibration and noise, an external damper is used for the fuel delivery pipe. However, in recent years, a damper means has been built in the fuel delivery pipe, The technical trend is to try to absorb by utilizing its three-dimensional shape. As this type of prior art, for example, one disclosed in Japanese Patent Application Laid-Open No. 2000-283000 can be cited.
[0006]
The fuel delivery pipe according to Japanese Patent Laid-Open No. 2000-283000 has a cross section of the tubular body constituting the main body portion in order to provide a convex portion that forms a gas body reservoir acting as a cushion tank inside the main body of the fuel delivery pipe. L-shaped or T-shaped.
[0007]
[Problems to be solved by the invention]
However, since the fuel delivery pipe of the above prior art is designed such that the air or fuel vapor in the gas body absorbs the pulsation pressure of the fuel, the formation of the gas body pool is insufficient depending on the operating condition of the engine. In such a case, there is a problem that the pulsation pressure cannot be absorbed.
[0008]
In order to add vibration and noise absorbing action to the fuel delivery pipe body itself, it is advantageous that the fuel delivery pipe body is deformed with pressure fluctuation and easily absorbs vibrations. The current situation is that it is difficult to obtain a sufficient absorption performance of vibration and abnormal noise due to the delicate and difficult balance between ensuring the rigidity of the delivery pipe body.
[0009]
Accordingly, an object of the present invention is to solve the problems of the prior art, and a fuel delivery pipe having a shape that effectively absorbs fuel pulsations and vibrations and noise caused by shock waves generated when the injector is opened and closed. Is to provide.
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the invention according to claim 1 has a main body portion in which a plurality of injector cups for mounting an injector are arranged in the length direction, and is pumped from a fuel supply system through a fuel supply pipe. In the fuel delivery pipe for supplying the fuel to the injector, the main body portion of the fuel delivery pipe is formed with two bulging portions that bulge outwardly in a convex shape and deformed by receiving internal pressure. It is characterized by having a Z-shaped cross-sectional shape so as to increase the cross-sectional area change amount of the portion .
[0012]
Furthermore, the invention according to claim 3 has a main body portion in which a plurality of injector cups for mounting the injectors are arranged in the length direction, and supplies fuel pressure-fed from the fuel supply system through the fuel supply pipe to the injector. In the fuel delivery pipe, the area of the wall surface as the damping surface facing the injector cup is expanded by forming a protruding portion that protrudes outward on the side surface of the main body portion of the main body portion of the fuel delivery pipe. It is characterized by.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a fuel delivery pipe according to the present invention will be described with reference to the accompanying drawings.
First Embodiment FIG. 1 is a side view showing a fuel delivery pipe according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view. In FIG. 1, reference numeral 10 indicates a main body portion of the fuel delivery pipe, reference numeral 12 indicates a fuel supply pipe, and these constitute a fuel supply apparatus of a returnless system. The fuel in a fuel tank (not shown) is pumped by a pump and introduced into the fuel delivery pipe through the fuel supply pipe 12.
[0014]
The main body 10 of the fuel delivery pipe is composed of an upper case 13 and a lower case 14 each having an L-shaped cross-sectional shape, which are overlapped and joined by brazing. A first bulging portion 13 a that bulges outward is formed in a portion of the upper case 13 that is closer to one side. The remaining portion of the upper surface is a flat surface and is used as a damping surface 13b that absorbs pulsation pressure and the like as will be described later.
[0015]
In the same manner, on the bottom surface of the lower case 14, a second bulging portion 14 a bulging outward is formed in a portion that is closer to one side, and the remaining portion is a flat surface. A required number of fuel supply ports are formed on the flat surface of the lower surface of the lower case 14, and injector cups 17 for attaching injectors (not shown) are arranged in a longitudinal direction at predetermined intervals. . The injector cup 17 can be mounted by press-fitting an injector (not shown).
[0016]
As shown in FIG. 2, the first bulging portion 13 a and the second bulging portion 14 a are in a relationship of approximately 180 ° with respect to the center of the main body portion 10 of the fuel delivery pipe. The cross-sectional shape is Z-shaped as a whole.
[0017]
The end of the fuel supply pipe 12 is connected by brazing to the upstream end of the main body 10 of the fuel delivery pipe.
[0018]
The fuel delivery pipe according to the present embodiment is configured as described above. Next, its operation and effect will be described.
While the engine is operating, the interior of the main body 10 of the fuel delivery pipe is filled with fuel pumped through the fuel supply pipe 12, and the fuel is distributed and supplied to each injector. .
[0019]
When the injector is repeatedly opened and closed and fuel is injected by being opened, the pressure of the fuel suddenly decreases. Further, when the injector is closed, the fuel pressure rapidly rises and pulsation pressure is generated. These pressure fluctuations become shock waves and cause vibrations and abnormal noise.
[0020]
In the present embodiment, the main body portion 10 of the fuel delivery pipe is composed of an upper case 13 having a first bulge portion 13a and a lower case 14 having a second bulge portion 14a. The tube structure is a Z-shaped cross section.
[0021]
This Z-shaped tube structure is useful for making the three-dimensional shape of the main body 10 of the fuel delivery pipe itself a flexible structure having a larger absorption function with respect to pulsation pressure. That is, the amount of change in the cross-sectional area of the Z-shaped cross section of the main body portion 10 when subjected to pressure fluctuation due to the generation of pulsation pressure increases, thereby increasing the effect of reducing pulsation.
[0022]
In addition, since the surface rigidity of the flat upper surface portion other than the first bulging portion 13a of the upper case 13 does not increase, it functions as a damping surface 13b, and enhances the damping effect of vibration caused by shock waves and pulsations when the injector is opened and closed. it can.
[0023]
It has been found that the height h and the width w of the first bulging portion 13a and the second bulging portion 14a are related to enhance the effects of pulsation absorption and vibration damping. In relation to the width W of the main body 10, the height h is preferably as high as possible within a range of 1/2 of the width W, and the width w is preferably as narrow as possible. In processing into such a shape, it is advantageous to divide the main body portion 10 into an upper case 13 and a lower case 14 and to process each of them as in this embodiment because the degree of design freedom is high.
[0024]
Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS.
[0025]
In the second embodiment, the main body 10 of the fuel delivery pipe is an elongated box-shaped case, and is composed of an upper case 20 having a U-shaped cross section and a lower case 21. Among these, the upper surface part of the upper case 20 is a wall surface facing the injector cup 17, and an uneven thickness part 22 whose thickness is unevenly thinner than other parts is formed. This uneven thickness part is formed with the breadth which covers the arrangement range of all the injector cups 17 at least. Other components are the same as those in the first embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted.
[0026]
Next, the operation and effect of the second embodiment as described above will be described.
By adopting a tubular structure in which the uneven thickness portion 22 is formed on the upper surface portion of the upper case 20, the surface rigidity of the upper surface portion where the uneven thickness portion 22 exists can be made suitable for absorbing pulsation and vibration. Specifically, when the pressure fluctuation due to the generation of the pulsation pressure is received, the displacement amount of the uneven thickness portion 22 increases, and the increase amount of the cross-sectional area change amount of the main body portion 10 increases, and these dynamics are increased. Based on various characteristic changes, the effect of reducing pulsation and vibration is enhanced. Moreover, it is thought that the internal volume of the main-body part 10 increasing by the uneven thickness part 22 also contributes to a reduction effect.
[0027]
By the way, if the size of the uneven thickness portion 22 of the upper case 20 changes, it is expected that the effect of reducing pulsation and the like will also change.
[0028]
Therefore, about the result of simulating how the shape of the main body portion 10 of the fuel delivery pipe is modeled and how the cross-sectional area change amount, the maximum displacement amount, and the internal capacity change when the width of the uneven thickness portion 22 is changed. explain.
[0029]
FIG. 6 shows a model for the fuel delivery pipe used for the simulation. This is modeled under the following conditions.
[0030]
・ Material SP steel plate thickness 1.2mm
Young's modulus 21000 [kgf / mm ² ]
Poisson's ratio 0.3
・ Dimensions Total length 300mm
Width 30mm
30mm height
Overlap 4mm
・ Pressure condition Internal pressure 350 [kPa]
-Uneven thickness portion shape As shown in Fig. 7, maximum depth 0.2mm, width X1,
A curved surface with a curvature X of length 250 is used.
[0031]
・ Section area change ΔS
S0 is the cross-sectional area of the central portion in the axial direction when no internal pressure is applied, and S1 is the cross-sectional area when deformed by receiving the internal pressure.
ΔS = S1 / S0 × 100 (%)
Maximum amount of displacement Maximum amount of displacement at the center of uneven thickness part (mm)
Internal volume V
Internal volume (cc) without internal pressure
Next, FIG. 8 shows the result of simulation by changing the width X1 dimension of the uneven thickness portion.
When the width X1 of the uneven thickness portion is gradually increased, the cross-sectional area change amount, the maximum displacement amount, and the internal volume tend to increase in direct proportion. From this, the width X1 of the uneven thickness portion 22 is A wider one is expected to have a higher effect of reducing pulsation and the like.
[0032]
However, if the ratio of the width X1 of the uneven thickness portion 22 to the width of the main body portion 10 exceeds 60%, the cross-sectional area change amount, the maximum displacement amount, and the internal volume are only slightly increased uniformly. This means that even if the width X1 of the uneven thickness portion 22 is increased, an improvement in the effect of reducing pulsation or the like cannot be expected, but the negative side due to a decrease in rigidity is rather increased. Therefore, the width X1 of the uneven thickness portion 22 can be expected to have the maximum effect when the ratio to the width of the main body portion 10 is about 60%, and is preferably within 60%.
[0033]
Third Embodiment Next, a third embodiment of the present invention is shown in FIG.
In the third embodiment, the main body portion 10 of the fuel delivery pipe is composed of the lower case 14 having the bulging portion 14a in the first embodiment and the upper case 20 having the uneven thickness portion 22 in the second embodiment. Yes.
[0034]
Also according to the third embodiment as described above, the effect of pulsation damping and vibration absorption can be enhanced by utilizing the solid shape itself of the main body 10 of the fuel delivery pipe. Further, it is advantageous to divide the main body portion 10 into an upper case 20 and a lower case 14 and to process each of them because of a high degree of design freedom.
[0035]
Fourth Embodiment Next, a fourth embodiment of the present invention will be described with reference to FIG.
In the fourth embodiment, an elongated box-shaped case is adopted for the upper case 30 and the lower case 31 that constitute the main body portion 10 of the fuel delivery pipe, but a part of the side surface of the main body portion 10 is used. A protruding portion 32 that protrudes outward is formed. In this embodiment, the shape of the protrusion 32 is a triangle having an acute apex angle.
[0036]
The presence of such a protrusion 32 serves to expand the area of the wall surface facing the injector cup 17, in this case, the upper surface portion of the upper case 30, and accordingly, this upper surface portion serves as a damping surface that receives pulsating pressure. In addition, it is possible to increase the effect of absorbing vibrations caused by shock waves and pulsation pressures, and increase the internal volume of the main body 10.
[0037]
In the fourth embodiment described above, the connection position of the fuel supply pipe 12 is the upstream end of the main body 10, but the end of the fuel supply pipe 12 is connected to the protrusion 32 as shown in FIG. 11. May be.
[0038]
By connecting the fuel supply pipe 12 to the protrusion 32, the flow rate is lowered when the fuel pumped from the fuel supply pipe 12 flows into the protrusion, and energy is lost at that time, which is advantageous in reducing pulsation. It is.
[0039]
Fifth Embodiment Next, FIG. 12 shows a fifth embodiment of the present invention.
[0040]
In the fifth embodiment, the main body portion 10 of the fuel delivery pipe basically includes a tubular case 50 in which a first bulging portion 13a and a second bulging portion 14a are formed in the length direction. Both ends are closed with caps 51a and 51b, respectively. Other components are basically the same as those in the first embodiment.
[0041]
Next, in FIG. 13, in the tubular case 52, as in the second embodiment, the wall thickness portion 22 is formed on the wall surface facing the injector cup 17 so as to be thinned over a predetermined range. Is an embodiment closed with caps 53a and 53b.
[0042]
As in the embodiments shown in FIGS. 12 to 13, there is no problem even if a tubular case is used, and the effects of pulsation damping and vibration absorption can be enhanced using the solid shape itself.
[0043]
【The invention's effect】
As is clear from the above description, according to the present invention, the three-dimensional shape of the fuel delivery pipe itself effectively absorbs fuel pulsations and vibrations and noise caused by shock waves generated when the injector is opened and closed. be able to.
[Brief description of the drawings]
FIG. 1 is a side view of a fuel delivery pipe according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the fuel delivery pipe of FIG.
FIG. 3 is a side view of a fuel delivery pipe according to a second embodiment of the present invention.
FIG. 4 is a cross-sectional view of a fuel delivery pipe according to a second embodiment of the present invention.
FIG. 5 is a plan view of a fuel delivery pipe according to a second embodiment of the present invention.
6A and 6B are views showing a model of a fuel delivery pipe used for simulation, in which FIG. 6A is a side view and FIG. 6B is a front view.
FIG. 7 is a diagram showing a model shape of the uneven thickness portion in simulation.
FIG. 8 is a graph showing the result of simulation with varying the width of the uneven thickness portion.
FIG. 9 is a cross-sectional view of a fuel delivery pipe according to a third embodiment of the present invention.
10A and 10B show a fuel delivery pipe according to a fourth embodiment of the present invention, in which FIG. 10A is a plan view and FIG. 10B is a cross-sectional view.
11A and 11B show a modification of the fuel delivery pipe according to the fourth embodiment of the present invention, in which FIG. 11A is a plan view and FIG. 11B is a cross-sectional view.
FIG. 12 is a side view of a fuel delivery pipe according to a fifth embodiment of the present invention.
FIG. 13 is a side view of another modification of the fuel delivery pipe according to the fifth embodiment of the present invention.
FIG. 14 is a side view of a conventional fuel delivery pipe.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Main part of fuel delivery pipe 12 Fuel supply pipe 13 Upper case 13a First bulging part 14 Lower case 14a Second bulging part 17 Injector cup 20 Upper case 21 Lower case 22 Uneven part

Claims (5)

In a fuel delivery pipe that has a main body part in which a plurality of injector cups for mounting an injector are arranged in the length direction and supplies fuel that is pumped from a fuel supply system through a fuel supply pipe to the injector,
Two bulges that bulge in a convex shape toward the outside are formed in the main body of the fuel delivery pipe so that the amount of change in the cross-sectional area of the main body when deformed by receiving internal pressure increases. A fuel delivery pipe with a cross-sectional shape.   2. The fuel delivery pipe according to claim 1, wherein a height of the bulging portion is ½ or less of a width of the main body portion. In a fuel delivery pipe that has a main body part in which a plurality of injector cups for mounting an injector are arranged in the length direction and supplies fuel that is pumped from a fuel supply system through a fuel supply pipe to the injector,
The fuel is characterized in that the surface area of the wall as a damping surface facing the injector cup is expanded by forming a protruding portion protruding outward on the side surface of the main body portion of the main body portion of the fuel delivery pipe. Delivery pipe. The fuel delivery pipe according to claim 3 , wherein a terminal of the fuel supply pipe is connected to the protrusion. Main body of the fuel delivery pipe, the fuel delivery pipe according to any one of claims 1 to 4, characterized in that formed by joining the upper case and lower case.

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