JP4130515B2 - 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, in the present invention, a cross-sectional shape perpendicular to the axial direction of the communication pipe on the damping surface is formed in a loose (corrugated) shape over the entire length in the longitudinal direction of the communication pipe . Further, the present invention provides a structure in which the entire wall surface of the communication pipe constitutes a damping surface and the cross-sectional shape perpendicular to the axial direction of the communication pipe is formed in a crown shape having a loose shape at the top .
[0006]
[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. Further, in the present invention, by adopting a loosely shaped cross section extending over the entire length in the longitudinal direction of the communication pipe for this damping surface, the amount of bending at the damping surface increases and the impact energy absorbing effect is enhanced.
Theoretically, it is understood that the impact energy generated when the fuel injector is opened and closed is absorbed by the bending of the damping surface due to the loose shape.
[0007]
In the present invention, the entire wall surface of the communication pipe may form a damping surface, and the cross-sectional shape perpendicular to the axial direction of the communication pipe may be formed into a crown shape having a loose shape at the top. In this case, the amount of deflection is remarkably increased and the damping effect is enhanced. In the present invention, the number of jagged peaks and valleys can be freely selected.
[0008]
Further, in the present invention, the shape of the communication pipe, the aspect ratio, the thickness of the damping surface and the loose portion can be determined by experiments and analyzes so that vibration and pulsation are minimized, especially at the time of engine 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
FIG. 1 is a partial exploded view of the overall shape of a preferred embodiment of a fuel delivery pipe (top feed type) 10 according to the present invention. The fuel introduction pipe 2 is fixed to the side portion of the communication pipe 11 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 FIG. 1, 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 side surface and the bottom surface 11b are thick and solid. It is made of various materials. The cross-sectional shape perpendicular to the axial direction of the communication pipe on the damping surface is formed in a jagged (corrugated) shape over the entire length in the longitudinal direction of the communication pipe.
[0013]
Further, an end cap 15 made of a solid flat plate is fixed to one end of the communication pipe 11 by brazing or welding, and a dome-shaped end cap 16 made of a thin plate is brazed to the other end. It is fixed by welding. This is because when a hard cap (sealing member) is fixed to both ends of the communication pipe as in the past, the damping surface is restrained and the bending is restricted, and further, stress is applied to the brazed or welded portion of the cap corner. This is because there is a risk of cracking due to concentration. Of course, dome-shaped end caps 16 may be fixed to both ends.
[0014]
The end cap 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. The end cap can be formed not only in a convex shape but also in a concave or concave corrugated shape, and its curvature radius is preferably 3 mm or more from the viewpoint of elasticity and strength.
[0015]
FIG. 2 shows a method for processing a loose end according to the present invention. FIG. 2A shows an example in which the end of the waveform 11a of the communication tube 11 is cut as it is and is fixed to the side surface 11b. In this example, the end of 21a is stretched and inserted so as to be parallel to side surface 21b. The example of FIG. 2B has the advantage that brazing due to stress concentration and cracking of the welded portion can be prevented.
[0016]
3A and 3B show an embodiment in which all the wall surfaces 31a and 41a of the communication pipes 31 and 41 constitute a damping surface, and these communication pipes are made into a crown shape having a loose shape (waveform) on the upper surface. Yes. Compared to the communication pipe 31 of FIG. 3A, the example of the communication pipe 41 of FIG. 3B has a large curvature and is easily bent. As described above, the curvature radius is preferably 3 mm or more from the viewpoint of elasticity and strength.
[0017]
【The invention's effect】
As described above in detail, according to the present invention, the loose shape of the flexible damping surface acts to absorb impact energy, and is caused by vibration and pulsation caused by the reflected wave of the injector and the damping capacity of the communication pipe. The generation of abnormal noise can be prevented, and the technical effect is extremely remarkable.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an entire fuel delivery pipe according to the present invention.
FIG. 2 is a cross-sectional view of a socket portion representing a loose end processing.
FIG. 3 is a cross-sectional view of a socket portion showing an example of a crown-shaped loose shape.
[Explanation of symbols]
2 Fuel introduction pipe 3 Socket 10 Fuel delivery pipes 11, 21, 31, 41 Communication pipes 11a, 21a, 31a, 41a Damping surface 13 Fuel inlets 15, 16 End caps

Claims (1)

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,
At least one outer wall surface of the communication pipe is formed of a flexible damping surface, and a cross-sectional shape perpendicular to the axial direction of the communication pipe of the damping surface is formed in a loose shape over the entire length of the communication pipe ,
A fuel delivery pipe characterized in that the entire wall surface of the communication pipe forms a damping surface, and a cross-sectional shape perpendicular to the axial direction of the communication pipe is formed in a crown shape having a loose shape at the top .

Images