JP4068262B2 - Fuel delivery pipe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a fuel delivery pipe for supplying fuel fed 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 of a communication pipe having a fuel passage and a socket (holder) portion for receiving a fuel indicator.
[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 injector spool) and the pulsating pressure caused by the reciprocating motion of the spool of the fuel pump and related There has been a problem that parts vibrate and generate strange noises.
[0003]
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 Examined 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 the noise of the injector wrap, and pulsates due to the flexibility of the diaphragm And 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.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a fuel delivery pipe structure capable of preventing the generation of abnormal noise by suppressing vibration caused by a reflected wave of fuel and pulsation pressure.
[0005]
[Means for Solving the Problems]
The aforementioned object of the present invention is achieved by adopting a structure that reduces or attenuates the reflected wave and pulsation pressure of the fuel in the fuel delivery pipe. The basis is that at least one outer wall surface of the communication pipe is constituted by a flexible damping surface. In addition, according to the present invention, a flexible end cap having an uneven portion protruding outward and / or inward is fixed to at least one end of the communication pipe so as to contact the damping surface, and at least Provided is a structure in which a portion connected to the damping surface has a thin shape . This is because when a hard cap (sealing member) is fixed to the end of the communication pipe as in the past, the damping surface is constrained and bending is restricted, and further, brazing and welding at the corner of the cap. This is because the stress concentrates and there is a risk of cracking.
[0006]
The end cap is realized by the following three patterns.
(A) A flexible end cap having a convex portion protruding outward is fixed to at least one end portion of the communication pipe. (B) A concave portion protruding inward is provided to at least one end portion of the communication pipe. (C) A flexible end cap having a concavo-convex portion protruding in an outward and inward waveform is fixed to at least one end portion of the communication pipe.
[Action]
By adopting such a structure, according to the fuel delivery pipe of the present invention, since the damping surface exhibits an impact energy absorption effect, abnormal noise due to vibration and pulsation caused by the reflected wave of the injector and the damping capacity of the communication pipe Can be prevented. Furthermore, in the present invention, by adopting a flexible end cap, the restraint at the end of the damping surface is relaxed, the impact energy absorption effect is enhanced, and the stress is dispersed to increase the durability. .
Theoretically, it is understood that the impact energy generated when the fuel injector is opened and closed is absorbed by the combined bending of the damping surface and the end cap.
[0008]
The end cap in the present invention is formed in a thin shape at least at a portion connected to the damping surface in order to cooperate with the damping surface . Further, it is desirable that the uneven portion of the end cap is made to have a radius of curvature of 3 mm or more from the viewpoint of elasticity and strength.
In the present invention, the shape of the communication pipe, the aspect ratio, the plate thickness of the damping surface and the end cap, etc. can be determined by experiments and analyzes so that vibration and pulsation are minimized, especially when the engine is idling. .
[0009]
Since the present invention basically relates to the structure of the communication pipe itself, 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.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show the overall shape of a preferred embodiment of a fuel delivery pipe (top feed type) 10 according to the present invention, and a communication pipe 11 made of a steel pipe having a square cross section extends along the crankshaft direction. The fuel introduction pipe 2 is fixed to the side portion of the communication pipe 11 via the 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 a problem.
[0011]
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 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 fuel inlet 13 of the socket 3 into each intake passage or each cylinder via a fuel injector (not shown).
[0012]
As shown in FIGS. 2A and 2B, according to the present invention, of the cross section of the communication tube 11, only the upper surface 11a is formed of a thin steel plate so that it acts as a flexible damping surface, and the other surface 11b is thick. Made of solid material.
Further, according to the present invention, end caps 15 and 16 are fixed to both ends of the communication pipe 11 by brazing or welding. The end caps 15 and 16 can be made from a thin metal, for example, a band plate material such as SPCC, SPHC, SUS, or the like, by plastic working such as drawing.
[0013]
FIG. 3 shows the shape of three patterns of end caps according to the present invention, FIG. 3A is an outwardly convex shape, FIG. 3B is an inwardly concave shape, and FIG. 3C is a waveform in which outward and inward are combined. It is made in an uneven shape. These end caps preferably have a structure that is thin overall and cooperates with the deflection of the damping surface, at least on the side connected to the damping surface 11a by brazing or welding. Moreover, as for the uneven | corrugated | grooved part of an edge part cap, it is desirable for the curvature radius to be 3 mm or more.
[0014]
4A to 4E show that the end cap according to the present invention can be applied even when the communicating pipe and its damping surface adopt various shapes. In FIG. 4A, only the side surface 21a of the communication tube 21 provides a damping surface, and the other surface 21b is made of a solid steel tube. The end cap 25 is fixed to one end or both ends of the communication pipe 21. In FIG. 4B, the entire surface 31 a of the communication pipe 31 provides an elliptical damping surface, and the end cap 35 is thin as a whole and is fixed to one end or both ends of the communication pipe 31.
[0015]
In FIG. 4C, the entire surface 41 a of the communication pipe 41 provides a receiver-shaped damping surface, and the end cap 45 is fixed to one or both ends of the communication pipe 41. In FIG. 4D, the entire surface 51 a of the communication pipe 51 provides an inverted eye mask-shaped damping surface, and the end cap 55 is fixed to one or both ends of the communication pipe 51. In FIG. 5E, the entire surface 61 a of the communication pipe 61 provides a sideways T-shaped damping surface, and the end cap 65 is fixed to one or both ends of the communication pipe 61.
[0016]
【The invention's effect】
As described above in detail, according to the present invention, the flexible damping surface and the end cap cooperate to absorb impact energy, resulting from the reflected wave of the injector and the damping capacity of the communication pipe. The generation of abnormal noise due to vibrations and pulsations can be prevented, and the technical effect is extremely remarkable.
[Brief description of the drawings]
FIG. 1 is a front view showing an entire fuel delivery pipe according to the present invention.
2 is a left side view of the fuel delivery pipe of FIG. 1 and a cross-sectional view taken along line BB. FIG.
FIG. 3 is a cross-sectional view showing three patterns of end caps.
FIG. 4 is a cross-sectional view of a socket portion showing a damping surface and an end cap in communication pipes of various shapes.
[Explanation of symbols]
2 Fuel introduction pipe 3 Socket 10 Fuel delivery pipes 11, 21, 31, 41, 51, 61 Communication pipes 11a, 21a, 31a Damping surface 13 Fuel inlets 15, 16, 17, 18 End caps 25, 35, 45 , 55, 65 End caps 41a, 51a, 61a Damping surface

Claims (2)

A metal 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, and a part of the fuel communication pipe projecting across the communication pipe. In a fuel delivery pipe for an internal combustion engine comprising a plurality of sockets that communicate with the passage and whose open ends receive the tip of the fuel injection nozzle,
A flexible end portion in which at least one outer wall surface of the communication pipe is configured by a flexible damping surface, and at least one end portion of the communication pipe has an uneven portion protruding outward and / or inward. A fuel delivery pipe, wherein a cap is fixed so as to be in contact with the damping surface, and at least a portion connected to the damping surface is formed in a thin shape .   The fuel delivery pipe according to claim 1, wherein the uneven portion of the end cap has a radius of curvature of 3 mm or more.

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