JP2002106438A - Pulsation absorbing system of fuel piping system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent abnormal noise transmitted from a body to a cabin from occurring by suppressing an pressure fluctuation in a fuel passage with fuel injection and suppressing vibration resultant from a reflected wave and pulsation pressure of fuel. SOLUTION: A pulsation absorbing container made of metallic, synthetic rubber or synthetic resin is inserted on way of fuel piping, the pulsation absorbing container has an outer wall containing at least a flat or arc elastic absorbing face, a pulsation pressure and shock wave of fuel in the fuel piping are reduced a deflection of an absorbed face of the pulsation absorbing container and a change in inside volume. The pulsation absorbing container prevents the abnormal noise from occurring resultant from vibration and pulsation due to reflected wave of injector, pressure fluctuation by high pressure supply pump, damping capacity of communicating tube and also absorbs the vibration transmitted to the cabin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel delivery pipe for supplying fuel to each intake passage or each cylinder of an electronic fuel injection type automobile engine via a fuel injector, a fuel tank, and the fuel tank. The present invention relates to a system for absorbing pulsation in a fuel piping system including a fuel pipe connecting a delivery pipe to a fuel tank.

[0002]

2. Description of the Related Art As shown in FIG. 8, a fuel pipe 13 extending from a fuel tank 12 to an engine 10 of a car 11 (gasoline-powered vehicle) equipped with an electronic fuel injection type engine 10 has a number of about several to several tens. It is supported under the front panel and body floor by using a clip 14. The fuel delivery pipe 15 attached to the engine 10 has a return passage for sending fuel from a communication pipe having a fuel passage to a fuel injector via a plurality of cylindrical sockets, and then returning to a fuel tank side. There is a type and a type without a return passage (returnless). Recently, the type without a return passage has been increasing to prevent the fuel temperature in the tank from rising. However, the reflected wave (shock wave) and the pulsation pressure caused by the reciprocating motion of the fuel pump (plunger pump) and the spool of the injector have been increased. As a result, the fuel pipe and related parts vibrate, and this vibration is transmitted to the front panel and the body floor through the clip 14 to vibrate them, thereby causing a problem that a strange noise is transmitted to the driver. Have been.

[0003] In order to prevent such vibrations, recently, a clip with an anti-vibration function made of an elastic body or resin is provided in the underfloor piping. In a so-called direct injection type engine that directly injects fuel into a combustion chamber, a high-pressure supply pump is provided, and a pulsation damper is provided to absorb the large pulsation. However, there has been a problem that pulsations which cannot be completely absorbed remain even when these are used.

Japanese Patent Application Laid-Open No. 60-240867, entitled "Fuel Supply Pipe for Fuel Injection System for Internal Combustion Engine", relates to an improvement of a fuel delivery pipe, and at least one wall of the fuel supply pipe is used to reduce pulsation of fuel. It is elastically configured to attenuate. Similarly, JP-A-8-326622, "Fuel pressure pulsation damping device" and JP-A-11-37380, "Delivery pipe", also show devices for improving pulsation by improving a fuel delivery pipe.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to suppress pressure fluctuations in a fuel flow path due to fuel injection, suppress vibrations caused by fuel reflected waves and pulsating pressure, and reduce It is an object of the present invention to provide a pulsation absorbing system for a fuel piping system, which can prevent generation of abnormal noise and various problems transmitted to the fuel cell system.

[0006]

A pulsation absorbing system according to the present invention comprises a fuel delivery pipe for supplying fuel to each intake passage or each cylinder of an electronic fuel injection type automobile engine via a fuel injector, and a fuel delivery pipe. A system for absorbing pulsation of a fuel piping system including a tank and a fuel pipe connecting the fuel delivery pipe to the fuel tank, wherein a metal, synthetic rubber, or synthetic resin made in the middle of the fuel pipe. A pulsation absorbing container is inserted, the pulsation absorbing container having at least one flat or arcuate flexible absorbing surface on its outer wall to reduce the pulsating pressure and shock wave of the fuel in the fuel pipe. It is characterized in that it is reduced by bending of the absorber surface of the absorption container and change in the internal volume. The cross-sectional shape of the metal pulsation absorption container can take various shapes according to the shape on the vehicle body side, the fuel pressure, the pressure fluctuation width, and the like. When synthetic rubber or synthetic resin is used, the shape of the pulsation absorbing container can be made relatively simple.

[0007]

By adopting such a structure, in the case of a normal fuel injection type (MPI) engine, this pulsation absorbing container can generate abnormal noise due to vibration or pulsation caused by the reflected wave of the injector or the damping ability of the communication pipe. It has been found that generation can be prevented and vibration transmitted to the vehicle body can be absorbed. The theoretical basis is that when a shock wave generated when opening and closing the fuel injector flows into the fuel inlet of the socket or flows out due to instantaneous backflow, the shock wave due to the deflection of the flexible absorber surface of the pulsation absorbing container It is understood that the pulsation is absorbed and the thin member having a relatively small spring constant is bent and deformed to change the volume and absorb the fuel pressure fluctuation. In the case of a direct injection (DI) engine, vibrations and pulsations also occur due to fuel pressure fluctuations from the high-pressure supply pump to the pump suction port synchronized with high-pressure fuel pumping. By this effect, generation of abnormal noise can be prevented, and vibration transmitted to the vehicle body can be absorbed.

In the present invention, the material of the pulsation absorbing container, the ratio of the plate thickness to the length and width of each part, and the like can be determined by experiments and analysis so as to minimize vibration and pulsation, particularly when the engine is idling. Since the present invention inserts a pulsation absorbing container into the passage of the fuel supply pipe, it can be applied to existing vehicles. 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.

[0009]

FIG. 1 shows an entire pulsation absorbing system 20 of a fuel piping system according to a first embodiment of the present invention. The fuel from a fuel tank 12 to an engine 10a according to the features of the present invention. The pulsation absorbing container 21 is inserted into the piping system 26. The fuel pipe system 26 includes a metal or resin pipe 22 extending from the fuel delivery pipe 15 attached to the engine 10a, a rubber or resin hose 23 connected to the pipe 22, and a pulsation absorbing vessel 21.
And a hose 24 made of rubber or resin and a relatively long fuel pipe 13 for connecting the fuel tank 12 with the fuel tank 12. These fuel pipes are supported under the front panel and the body floor by using several to several tens of clips 14. In this example, the fuel delivery pipe 15 is not provided with a return pipe for returning to the fuel tank 12.

FIG. 2 shows an entire fuel pipe pulsation absorbing system 30 according to a second embodiment of the present invention. An engine 10b is a direct-injection gasoline engine, and a high pressure gas is applied to the side of the engine. A supply pump 28 is provided. A pulsation absorbing container 21 is inserted into a fuel piping system 40 extending from the fuel tank 12 to the engine 10b based on the features of the present invention. The fuel piping system 40 includes a metal or resin pipe 2 extending from the fuel delivery pipe 15 attached to the engine 10b to the high-pressure supply pump 28.
2. A metal or resin pipe 25 extending from the high-pressure supply pump 28 to the fuel tank side, a rubber or resin hose 23 connected to the pipe 25, a pulsation absorbing vessel 21
And a hose 24 made of rubber or resin and a relatively long fuel pipe 13 for connecting the fuel tank 12 with the fuel tank 12. These fuel pipes are supported under the front panel and the body floor by using several to several tens of clips 14. Also in this example, the fuel delivery pipe 15 is not provided with a return pipe for returning to the fuel tank 12.

3A and 3B show the external appearance of the metal pulsation absorbing container 21 and the cross-sectional shape of the central portion thereof. Pipes 21 for connecting pipes are provided at both end surfaces of the main body portion 21a having an oval cross section.
b and 21c are integrally fixed by brazing, welding, or the like. The thickness of the main body portion 21a is desirably set to about 0.4 to 1.5 mm, and in this shape, the portion having an elliptical cross section acts as an absorption surface for absorbing pulsation, and the fuel pressure is changed due to the fluctuation of the fuel pressure. When the fuel pressure rises, the elliptical shape is deformed to become circular, and when the fuel pressure drops, it deforms to further flatten, whereby the internal volume changes and the pulsation can be absorbed.

4A to 4G show modified examples of the cross-sectional shape of the main body portion 21a of the metal pulsation absorbing container 21. FIG. In any case, a shape that enhances flexibility is intended so that it can be selected according to the shape of the vehicle body, the fuel pressure, the pressure fluctuation width, and the like. FIG. 4A shows an example in which an oval cross section is used.
For example, the plate thickness is 0.8 mm, the height H is 10 mm, and the width W is 5 mm.
It can be set to 0 mm. FIG. 4B is an example in which a flat portion having flat portions having arc-shaped portions at both ends and a flat plate are combined to form a flat shape. For example, the plate thickness can be set to 1.0 mm, the height H to 8 mm, and the width W to 80 mm. 4C is an example of an inverted eye mask shape cross section, FIG. 4D is an example of a dumbbell shape cross section, FIG. 4E is an example of a waveform cross section, FIG. 4F is a rectangular cross section, FIG. 4G is a T-shaped cross section, and A to G are the same. Combined, welded and united with thick materials, the entire cross section provides an absorbing surface. FIG. 4H shows an example in which a thin plate 47 is welded to the open surface of a rigid channel member 46.
Provides an absolute surface.

FIG. 5 shows that the fuel supply pipes 52 and 53 are not the end faces in the longitudinal direction of the main body portion 51 but the absorbing faces 5.
This is an example in which the pulsation of fuel flowing in and out of the pipes 52 and 53 collides directly with the absorber surfaces 54 and 55, so that the pulsation of the fuel flowing in and out of the pipes 52 and 53 is directly opposed to the pulsation absorbing container 51. There is an advantage that the amount of deflection is increased and the pulsation absorbing effect is enhanced. In addition, pipe 5
2 and 53 may be provided on the same side surface facing the absorber surface.

FIGS. 6A and 6B show an example in which the entire body 61a of the pulsation absorbing container 61 and the connecting pipes 61b and 61c are integrally formed of synthetic rubber. Acts as an absorber surface for
If the fuel pressure rises due to fuel pressure fluctuations, the elliptical shape will be deformed to become circular, and if the fuel pressure falls, it will be deformed to further flatten, thereby changing the internal volume and absorbing pulsation Can be. In this example, FIG.
As shown in B, even if the thickness of the cross section is selected to be about 1 to 5 mm, a sufficient pulsation absorbing effect can be obtained.

FIGS. 7A and 7B show examples in which the pulsation absorbing containers 71 and 81 are formed of a synthetic resin. The pulsation absorbing container 71 of FIG. 7A
Is made of N6G (nylon 66 + glass fiber) as a material, and a somewhat thick channel-shaped member 71b and a thin-walled arc-shaped cover 71a are integrally formed by bonding or welding. In this example, the arc-shaped cover 71a acts as an absorptive surface and absorbs pulsation in conjunction with the change in internal volume.
Similarly, the pulsation absorption container 81 of FIG.
(Nylon 66 + glass fiber) is used, and the thick channel member 81b and the thin planar member 81a are integrally formed by bonding or welding. In this example, the flat member 81a
Acts as an absorptive surface and absorbs pulsation in conjunction with changes in internal volume.

[0016]

As described above in detail, according to the present invention, the pulsation absorbing container is provided with the function of communication between the reflected wave of the injector, the fuel pressure fluctuation from the high pressure supply pump synchronized with the high pressure fuel pumping to the pump suction port, and the communication. It is possible to prevent the generation of abnormal noise due to vibration or pulsation caused by the damping ability of the pipe and to absorb the vibration transmitted to the vehicle body, and the technical effect is extremely remarkable.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an entire pulsation absorbing system according to the present invention.

FIG. 2 is a perspective view illustrating an entire pulsation absorbing system according to another embodiment.

FIG. 3 is an external perspective view and a central partial cross-sectional view of a pulsation absorbing container.

FIG. 4 is a cross-sectional view illustrating a cross-sectional shape of a central portion of the pulsation absorbing container.

FIG. 5 is a cross-sectional view illustrating a positional relationship between a pulsation absorbing container and a connection pipe.

FIG. 6 is a perspective view showing a pulsation absorbing container made of synthetic rubber.

FIG. 7 is a cross-sectional view illustrating a central cross-sectional shape of a pulsation absorption container made of a synthetic resin.

FIG. 8 is a schematic perspective view showing a fuel piping system in a conventional automobile.

[Explanation of symbols]

10a, 10b Engine 12 Fuel Tank 13 Fuel Pipe 14 Clip 15 Fuel Delivery Pipe 20, 30 Pulsation Absorbing System 21 Pulsation Absorbing Container 21a Absorbing Surface 22-25 Piping Parts 26, 40 Fuel Piping System 28 High Pressure Supply Pump 51, 61, 71 , 81 Pulsation absorption container 47, 54, 55, 61a, 71a, 81a Absorb surface

Claims (2)

[Claims] 1. A fuel delivery pipe for supplying fuel to each intake passage or each cylinder of an electronic fuel injection type automobile engine via a fuel injector, a fuel tank, and a fuel delivery pipe from the fuel delivery pipe to the fuel tank. A pulsation absorbing container made of metal, synthetic rubber, or synthetic resin is inserted in the middle of the fuel piping. Has an outer wall portion including at least one flexible absorbing surface, so that the pulsating pressure and shock wave of the fuel in the fuel pipe are reduced by the deflection of the absorbing surface of the pulsation absorbing container and the change in the internal volume. A pulsation absorbing system for a fuel piping system, comprising: 2. The pulsation absorbing system according to claim 1, wherein a fuel pipe is fixed at a position facing an absorptive surface of the pulsation absorbing container.