JP2000283000A - Fuel delivery pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain vibration due to reflecting liquid or pulsating pressure of fuel to prevent abnormal sound from generating by providing a gas reservoir for air, fuel vapor, or the like for absorbing pulsative pressure in a communicating pipe. SOLUTION: In a communicating pipe 21, the section is formed into a L-shape (inverted L-shape), and the upper face 21a opposite to the fuel inflow port 13 of a socket 3 is formed flat. When a fuel delivery pipe 10 is fitted to an internal combustion engine, this flat face 21a is made to incline with respect to the horizontal face. Hereby, a gas reservoir 22 for air, fuel vapor, or the like is formed nearby the upper side end part of the flat face 21a. Because the socket 3 is positioned on the underside, a large quantity of gas is not sucked in. By the above-mentioned, because the gas reservoir 22 functions as a cushion tank, abnormal sound by vibration or pulsation due to reflecting liquid of an injector or damping capacity of the communicating pipe 21 can be prevented from generating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to supplying fuel supplied from a fuel pressurizing pump of an electronic fuel injection type automobile engine to each intake passage or each cylinder of the engine via a fuel injector (injection nozzle). In particular, the invention relates to a cross-sectional structure of a communication pipe having a fuel passage and a connection structure of a socket (holder) portion for receiving the fuel pipe and a fuel injector.

[0002]

2. Description of the Related Art Fuel delivery pipes are widely used in electronic fuel injection systems of gasoline engines. After fuel is supplied from a communication pipe having a fuel passage to a fuel injector through a plurality of cylindrical sockets, There are a type having a return passage for returning to the fuel tank side and a type having no return passage (returnless). Recently, the number of types without return passages has increased due to cost reduction. However, due to reflected waves and pulsating pressure caused by reciprocating motion of the fuel pump (plunger pump) and injector spool, fuel delivery pipes and related A problem has arisen in that parts vibrate and generate unpleasant noises.

Japanese Patent Application Laid-Open No. 11-2164, "Fuel Delivery", pays attention to this problem, and manufactures a delivery body by a sheet metal press in order to reduce the pulsation resonance speed of the fuel piping system to an idle speed or less. It is proposed to set the rigidity and the internal capacity of each of them in a certain range. However,
In many cases, the body of the fuel delivery pipe is made of a steel pipe having a circular or square cross section, and there are many problems in adopting the above method from the viewpoint of engine specifications, strength, and cost. Japanese Patent Publication No. 3-62904, "Fuel Rail for Internal Combustion Engine", uses a diaphragm to partition the inside of the communicating pipe into a socket side and a pipe wall side in order to prevent noise from the injector, and pulsates due to the flexibility of the diaphragm. And the residual reaction of indiecta. However, arranging a flexible diaphragm in the longitudinal direction of the communication pipe requires a sealing member, which complicates the structure, restricts the overall shape, and supports a wide variety of engine specifications. There is a drawback that you can not.

In Japanese Patent Application Laid-Open No. Hei 9-170516, "Delivery Pipe for Fuel Supply Apparatus" and Japanese Patent Application Laid-Open No. Hei 9-170517, air bubbles generated in a fuel pipe flow into an internal combustion engine to inject fuel. Reduce the amount,
Assuming that idling is unstable and restartability is reduced, a method has been proposed in which bubbles are gradually fed into the internal combustion engine while the bubbles do not grow significantly.

The present inventors have conducted experiments on the assumption that if bubbles actually grow large, the bubbles have the effect of absorbing and attenuating the pulsating pressure of the fuel. Since steam and the like are immediately sucked into the injector, it has been found that bubbles do not grow significantly with the conventional structure.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel delivery pipe structure capable of suppressing vibration caused by a reflected wave or pulsating pressure of fuel and preventing generation of abnormal noise. It is in.

[0007]

The above object of the present invention is attained by providing a gas reservoir such as air or fuel vapor for absorbing pulsating pressure of fuel in a communication pipe. It is desirable that this gas reservoir be formed at a position as far as possible from the fuel inlet of the socket, so that a large amount of gas is not simultaneously sucked into the socket. More specific structures are realized by several patterns. The present invention provides the following four patterns as examples of the cross-sectional structure of the communication pipe and the connection structure between the communication pipe and the socket.

(A) The upper surface of the communication pipe is flattened, and when mounted on the internal combustion engine, the flat surface is inclined with respect to the horizontal plane, and a gas reservoir is formed near the end of the flat surface, so that the socket is flat. (B) The cross section of the communication tube is L-shaped or T-shaped, the uppermost portion is formed in a convex shape, the socket is arranged on the lower side, and gas is supplied to the convex portion. (C) The cross section of the communication pipe is formed in a T-shape. When the communication pipe is attached to the internal combustion engine, the communication pipe is inclined, and a gas body is formed at the upper end of the T-shaped horizontal element and / or the vertical element. A reservoir is formed so that the socket is located on the lower side. (D) A partition plate is arranged near the gas reservoir in the communication pipe, and relatively small holes are provided in this partition plate to allow passage of fuel and gas. Enable

[0009]

According to the fuel delivery pipe of the present invention, by employing such a structure, the gas reservoir formed on the fuel level acts as a cushion tank, and the reflected wave of the injector and the communication pipe of the communication pipe are formed. It is possible to prevent generation of abnormal noise due to vibration or pulsation due to damping ability.
As a theoretical basis, it is understood that the shock wave generated when the fuel injector is opened and closed is relaxed due to the change in the volume of the cushion tank, and absorbs the fuel pressure fluctuation.

In the present invention, the thickness of each side of the communication pipe, the ratio of length to width, the range of the gap between the socket and the surface facing the fuel inlet, and the like are values at which vibration and pulsation are minimized especially when the engine is idling. Can be determined by experiment or analysis so that

Since the present invention basically relates to the cross-sectional structure of the communication pipe and the connection structure of the communication pipe and the socket, it is possible to maintain compatibility with the conventional fuel delivery pipe by maintaining the mounting dimensions of the bracket. Can be maintained. Other features and advantages of the present invention will become apparent from the following description with reference to embodiments of the accompanying drawings.

[0012]

FIG. 1 shows the entire basic shape of a fuel delivery pipe (top feed type) 10 according to the present invention. A communication pipe 11 formed of a steel pipe having a square cross section is formed along a crank axis direction. And extend the communication pipe 1
A fuel introduction pipe 2 is fixed to a side portion of the fuel cell 1 via a connector 5 by brazing or welding. A return pipe for returning to the fuel tank can be provided at the end of the communication pipe. However, a return pipe is not provided in a returnless type fuel delivery pipe in which pulsation pressure of fuel is a problem.

On the bottom of the communication pipe 11, three sockets 3 for receiving the tip of the injection nozzle are attached at a predetermined angle in the case of a three-cylinder engine. Two thick and rigid brackets 4 for attaching the fuel delivery pipe to the engine main body are further laterally bridged over the communication pipe 11. 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).

2A to 2E show various embodiments of the fuel delivery pipe 10 according to the present invention in the form of a cross section of a socket portion. In FIG. 2A, the communication pipe 21 has an L-shaped (inverted L-shaped) cross section, and the upper surface 21 a of the socket 3 facing the fuel inlet 13 is formed flat. When the fuel delivery pipe 10 is attached to the internal combustion engine, the flat surface 21a is inclined with respect to the horizontal plane, and a gas reservoir 22 such as air or fuel vapor is formed near the upper end of the flat surface 21a. It has become. Since the socket 3 is located on the lower side, a large amount of gas is not sucked from the fuel inlet 13.

In FIG. 2B, the communication pipe 31 has an L-shaped cross section (inverted L-shape), and the fuel inlet 13 of the socket 3 is formed.
A convex portion 31a is formed at an upper portion away from the main body. The fuel delivery pipe 10 is substantially horizontal even when attached to the internal combustion engine, and the upper part of the projection 31 a provides a gas reservoir 32. Since the socket 3 is located on the lower side, a large amount of gas is not sucked from the fuel inlet 13.

In FIG. 2C, the communication pipe 41 has a rectangular cross section, and the upper surface 41a of the socket 3 facing the fuel inlet 13 is formed flat. When the fuel delivery pipe 10 is attached to the internal combustion engine, the flat surface 41a is inclined with respect to the horizontal plane, and the upper end of the flat surface 41a provides the gas reservoir 42. Since the socket 3 is located on the lower side, a large amount of gas is not sucked from the fuel inlet 13.

In FIG. 2D, the communication pipe 51 has a T-shaped (inverted T-shaped) cross section, and the fuel inlet 1 of the socket 3 is formed.
A convex portion 51a is formed at an upper portion away from the projection 3. The fuel delivery pipe 10 is substantially horizontal even when attached to the internal combustion engine, and the upper part of the projection 51 a provides a gas reservoir 32. Since the socket 3 is located on the lower side, a large amount of gas is not sucked from the fuel inlet 13.

In FIG. 2E, the communication pipe 61 has a T-shaped (inverted T-shaped) cross section, and the fuel inlet 1 of the socket 3 is formed.
A convex portion 61a is formed directly above and away from 3. The fuel delivery pipe 10 is substantially horizontal even when attached to the internal combustion engine, and the upper part of the projection 61 a provides a gas reservoir 62. In this example, socket 3
Gas reservoir 6 immediately above the reflected wave that flows backward from
In order to reach 2, it is considered that the pulsation can be efficiently absorbed. Since the socket 3 is located on the lower side, a large amount of gas is not sucked from the fuel inlet 13.

FIG. 3 shows a fuel delivery pipe according to another embodiment of the present invention. The cross section of the communication pipe 71 is formed in a T-shape (inverted T-shape) similar to FIG. 1D. When the delivery pipe is attached to the internal combustion engine, it is greatly inclined, and has two T-shaped ends 71a, 7a.
Gas reservoirs 72 and 73 are formed in 1b. This example has an advantage that a large amount of gas can be stored. Since the socket 3 is located on the lower side, a large amount of gas is not sucked from the fuel inlet 13.

FIG. 4 shows a fuel delivery pipe according to still another embodiment of the present invention.
A protrusion 81a is formed at an upper portion away from the fuel inlet 13 of the fuel cell. The fuel delivery pipe 10 keeps a substantially horizontal state even when attached to the internal combustion engine.
The upper part of 1a provides a gas reservoir 82. further,
In the embodiment of FIG. 4, a partition plate 85 is disposed near the gas reservoir 82 in the communication pipe 81, and a relatively small through hole 85 a is provided on a side surface of the partition plate 85 so that fuel and gas can pass through. I have to. Providing the partition plate 85 has an effect of preventing a large gas body from being simultaneously sent to the fuel inlet 13 of the socket.

[0021]

As described above in detail, according to the present invention, the gas reservoir formed on the fuel level acts as a cushion tank, and is caused by the reflected wave of the injector and the damping ability of the communication pipe. It is possible to prevent generation of abnormal noise due to vibration or pulsation, 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.

FIG. 2 is a cross-sectional view illustrating an example of a socket portion of the delivery pipe of FIG.

FIG. 3 is a sectional view of a socket portion according to another embodiment.

FIG. 4 is a sectional view of a socket portion according to another embodiment.

[Explanation of symbols]

2 Fuel introduction pipe 3 Socket 10 Fuel delivery pipe 11, 21, 31, 41, 51, 61, 71, 81 Communication pipe 13 Fuel inlet 21a, 41a Flat surface 22, 32, 42, 52, 62, 72, 73 , 82 Gas reservoir 51a, 61a, 71a, 71b, 81a Convex portion 85 Partition plate 85a Through hole

Claims (5)

[Claims] 1. A communication pipe made of metal having a fuel passage extending in a straight line therein, a fuel introduction pipe fixed to an end or a side of the communication pipe, and a projection intersecting the communication pipe. A fuel delivery pipe for an internal combustion engine, the fuel delivery pipe having a plurality of sockets partially communicating with the fuel passage and having an open end receiving a tip of a fuel injection nozzle, for absorbing pulsating pressure of fuel in the communication pipe. A fuel delivery pipe provided with a gas reservoir for air or fuel vapor. 2. An upper surface of the communication pipe is flattened, and when attached to an internal combustion engine, the flat surface is inclined with respect to a horizontal plane and the gas reservoir is formed near an end of the flat surface,
2. The fuel delivery pipe according to claim 1, wherein said socket is located on a lower side facing said flat surface. 3. The communication pipe according to claim 1, wherein a cross section of the communication pipe is L-shaped or T-shaped, an uppermost portion is formed in a convex shape, and the socket is disposed on a lower side, and the gas reservoir is formed in the convex portion. Item 1
Fuel delivery pipe as described. 4. The communication pipe has a T-shaped cross section, the communication pipe is inclined when attached to an internal combustion engine, and the gas reservoir is formed at an upper end of a T-shaped horizontal element and / or a vertical element. 2. The fuel delivery pipe according to claim 1, wherein the socket is located on a lower side. 5. The partition according to claim 1, wherein a partition plate is disposed in the communication pipe near a gas reservoir, and a relatively small through hole is provided in the partition plate so that fuel and gas can pass therethrough. The fuel delivery pipe described in 1.