JPH0979115A - Fuel injection valve of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid counterflow fuel from staying in an assist air supply system in a fuel injection valve to which assist air is supplied. SOLUTION: A part of suction air is introduced as assist air from the throttle valve upstream side to an assist air introducing part 6 formed around a fuel injection valve through an assist air supply passage 4. Here, the assist air introducing part 6 to which the assist air supply passage 4 faces is formed in a circular arc shape, and air nozzles 7a and 7b are opened in its both end parts. The flow of assist air introduced from the assist air supply passage 4 butts cutoff walls 5g and 5f on both ends of the assist air introducing part 6, and is made to blow out of the air nozzles 7a and 7b opening in a butting part, and the assist air is prevented from stagnating in the assist air introducing part 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve for an internal combustion engine, and more particularly, to a technique for preventing backflow of fuel to an assist air supply system in a fuel injection valve that aims to atomize fuel by assist air.

[0002]

2. Description of the Related Art Conventionally, a part of intake air is guided from the intake passage on the upstream side of a throttle valve as assist air to the vicinity of a nozzle hole of a fuel injection valve, and the assist air collides with the fuel spray injected from the fuel injection valve. It is known that the fuel is atomized by doing so to improve combustion, thereby improving fuel efficiency and exhaust gas properties (see Japanese Patent Laid-Open No. 10224/1993).

Conventionally, as such a fuel injection valve, there has been one having a structure as shown in FIG. Fuel injection valve 1 shown in FIG.
Is installed in the holder 2 and is attached to an intake port portion (not shown) with the vertical direction of the drawing as a substantially vertical direction. Incidentally, FIG.
The direction of penetrating the sheet of paper is the arrangement direction of the fuel injection valves 1. Fuel of a predetermined pressure supplied into the holder 2 via a fuel gallery not shown passes through the cylindrical filter 3 and is introduced into the fuel injection valve 1. Then, the valve body is lifted by the magnetic attraction force of the electromagnetic coil, so that the fuel is injected from the injection hole provided at the tip portion.

Further, as a structure for causing assist air to collide with the fuel spray injected from the injection hole, an assist air supply passage 4 whose one end is connected to an intake passage on the upstream side of the throttle valve connects the holder 2 to the holder 2. It penetrates and opens in the holder 2. An adapter 5 having an air nozzle is fitted into the tip of the fuel injection valve 1, and an annular space surrounded by the reduced diameter portion 5a of the adapter 5 and the inner circumference of the holder 2 is formed as an assist air introducing portion 6. As a result (see FIG. 7), the other end of the assist air supply passage 4 faces the inside of the assist air introducing portion 6.

As shown in FIG. 6, the adapter 5 has:
A hollow portion 5b into which the tip portion of the fuel injection valve 1 is inserted, and spray passages 5c, 5d through which the fuel spray from the fuel injection valve 1 passes are formed continuously with the hollow portion 5b. In the example shown in FIG. 6, the spray passages 5c and 5d are branched and extended in two directions in response to the fuel injection valve 1 injecting in two left and right directions.

Further, in the adapter 5, a pair of air nozzles 7a and 7b, one end of which faces the reduced diameter portion 5a and the other end of which faces the spray passages 5c and 5d, face each other around the axis of the injection valve. Formed, and the assist air supply path 4
The assist air introduced into the assist air introducing section 6 through the branching flow to the left and right in the assist air introducing section 6, and the spray passage 5c, the spray passage 5c, through the air nozzles 7a, 7b.
It jets out into 5d and collides with fuel spray.

[0007]

In the fuel injection valve having the above structure, when the engine is under a heavy load, the fuel flows back into the assist air introducing portion 6 through the air nozzles 7a and 7b, and the fuel is assisted. Air introduction part 6
Is accumulated in the space below the air nozzle opening on the side of the anti-assist air supply passage, and when the accumulated fuel becomes a low load, it is supplied into the intake passage to make the air-fuel ratio overrich, thereby improving startability, There was a risk of deteriorating the drivability and exhaust properties.

That is, since the air nozzle is not provided on the side opposite to the assist air supply path of the assist air introducing portion 6 and the assist air flows from both directions collide with each other, the assist air is accumulated. Stagnation occurs. For this reason, if the backflowed fuel enters the stagnation portion, it becomes difficult to discharge the fuel along with the flow of the assist air, and a large amount of fuel stays in the space portion below the air nozzle opening. It is a thing.

The present invention has been made in view of the above problems, and in a fuel injection valve provided with an assist air supply system, the backflow fuel is prevented from staying and the staying fuel is supplied to the engine. It is an object of the present invention to prevent the air-fuel ratio from becoming excessively rich due to such a situation.

[0010]

Therefore, a fuel injection valve for an internal combustion engine according to the invention of claim 1 is provided with an assist air supply passage for supplying assist air to the fuel injection valve, and the assist formed around the fuel injection valve. An assist air introducing portion into which assist air is introduced through the air supply passage; and an air nozzle having one end opened to the assist air introducing portion and the other end opening toward fuel spray from the fuel injection valve. In the assist air introduction part of the fuel injection valve of the configured internal combustion engine, a blocking wall for blocking the flow of the assist air introduced through the assist air supply passage is provided, and at least the blocking wall blocks the flow. The air nozzle is configured to be opened near the portion.

According to this structure, the assist air introduced into the assist air introducing portion through the assist air supply passage flows through the assist air introducing portion and is ejected from the air nozzle. The blocking wall blocks the flow of assist air, and since the air nozzle opens in the vicinity of the blocking wall, the assist air is introduced at the assist air introduction section from the assist air supply path to the air nozzle. The space where the air stagnates can be eliminated. Therefore, even if the fuel enters the assist air introducing portion due to the reverse flow, it is possible to prevent the fuel from being pushed out by the flow of the assist air and staying in the assist air introducing portion.

In the second aspect of the present invention, the two air nozzles are provided in the assist air introducing portion so as to face each other around the axis of the fuel injection valve, and the assist is provided at positions substantially equidistant from the openings of the air nozzles. An air supply path is connected and a blocking wall is provided near each of the openings of the air nozzle. According to this structure, the assist air introduced into the assist air introducing portion through the assist air supply passage is divided into the right and left and strikes the flow blocking wall, but is ejected through the air nozzle opening near the blocking wall. Therefore, in the assist air introduction portion, there is no space where the assist air stagnates and the backflow fuel is retained.

According to a third aspect of the present invention, in the assist air introducing portion, a blocking wall which allows only a flow of the assist air in one direction around the fuel injection valve is provided at a portion to which the assist air supply passage is connected. A flow of the assist air that is formed and introduced through the assist air supply passage and makes a round around the fuel injection valve is blocked by the blocking wall, and the flow is blocked by at least the blocking wall. An air nozzle is opened in the vicinity.

According to this structure, the flow direction of the assist air introduced into the assist air introducing portion through the assist air supply passage is regulated by the blocking wall, and it flows in only one direction to make a round, and the blocking wall. However, since the air nozzle opens at the portion where the flow is blocked by the blocking wall, the flow of the assist air can be generated over the entire circumference of the fuel injection valve without causing the stagnation of the assist air. .

According to a fourth aspect of the present invention, in the configuration according to the third aspect, the air nozzle is also opened at a position facing the air nozzle opened in the vicinity where the flow is blocked by the blocking wall. According to this structure, since the air nozzle that is opened in the portion facing the blocking wall also faces the flow of the assist air, the assist of the two air nozzles does not occur without causing the stagnation of the assist air. In a fuel injection valve that ejects air to perform two-way injection, for example, atomization can be achieved in each spray direction.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. A first example of the embodiment is shown in FIGS. 1 and 2. still,
The same elements as those in FIGS. 5 to 7 are designated by the same reference numerals and the description thereof will be omitted. The adapter 5 shown in FIG. 1 and FIG. 2 has a recessed portion 5e formed over a substantially half circumference thereof, and the recessed portion 5e and the inner periphery of the holder 2 form an arc-shaped assist air introducing portion 6. To be formed.

The assist air supply passage 4 is connected to a substantially central portion of the assist air introducing portion 6 in the circumferential direction, and the adapters 5 at both ends of the assist air introducing portion 6 in the circumferential direction are provided. Air nozzles 7a and 7b are opened in the recessed portion 5e. In the above-described configuration, the assist air introduced from the assist air supply passage 4 into the assist air introducing portion 6 flows left and right separately, but the rising surfaces 5f and 5g in the circumferential direction of the recess 5e serve as blocking walls to prevent the flow. It is blocked and does not go around to the anti-assist air supply passage 4 side, and is jetted without stagnating through the air nozzles 7a, 7b opening near the blocking walls 5f, 5g.

Therefore, in the above-mentioned structure, the space where the assist air stagnates does not occur in the assist air introducing portion 6, and even if the fuel flows backward in the assist air introducing portion 6, it does not stay and the assist air flows. It can be sequentially loaded and supplied to the engine. Therefore, even if a reverse flow occurs, a large amount of fuel does not stay, so it is possible to avoid over-riching of the air-fuel ratio due to the supply of stagnant fuel, thereby avoiding deterioration of startability, drivability, and exhaust properties. it can.

Further, in the configuration shown in FIGS. 1 and 2, even if the flow of the assist air is stopped by stopping the engine or shutting off the assist air, the assist air introducing portion 6 is positioned below the openings of the air nozzles 7a, 7b. Since the volume of the space to be used can be almost eliminated, it is possible to avoid the fuel from staying in the assist air introducing portion 6. In addition, in the configuration shown in FIGS. 1 and 2, a space on the side of the anti-assist air supply passage 4 is left, and a blocking wall having a predetermined thickness is provided in the vicinity of the air nozzles 7a and 7b to provide a space on the side of the anti-assist air supply passage 4. It may be configured to prevent the assist air from wrapping around.

3 and 4 show a second example of the embodiment. In the fuel injection valve shown in FIGS. 3 and 4, the assist air supply passage 4 extends in the arrangement direction of the fuel injection valve 1 and faces the holder 2. An annular assist air introducing portion 6 is formed by the reduced diameter portion 5a of the adapter 5 and the inner circumference of the holder 2, and a blocking wall 8 for partially blocking the annular space is provided at a portion facing the assist air supply passage 4. It is formed integrally with the adapter 5.

The flow of the assist air introduced into the assist air introducing portion 6 by the assist air supply passage 4 is regulated by the blocking wall 8 in the counterclockwise direction in FIG. By making a round around the circumference of the injection valve 1, it hits the opposite surface of the blocking wall 8. An air nozzle 7 is provided on the anti-assist air supply path 4 side of the blocking wall 8.
Since a is opened, the assist air that hits the blocking wall 8 is ejected through the air nozzle 7a without stagnation.

Also in this structure, since the stagnation of the assist air does not occur in the assist air introducing portion 6, even if the fuel flows backward and enters the assist air introducing portion 6, the assist air is not accumulated and the assist air flows successively. Will be discharged. Further, by providing the air nozzle 7b also at a position facing the air nozzle 7a, assist air can be jetted in each spray direction in the fuel injection valve 1 that performs two-way injection. Further, since the flow of the assist air is generated over the entire circumference of the fuel injection valve 1 without stagnation, for example, four air nozzles may be provided to eject the assist air from four directions.

The air nozzle 7b is not provided in the vicinity of the blocking wall, but since the assist air flows toward the blocking wall 8, that is, the air nozzle 7a, the fuel that has entered from the air nozzle 7b does not stay.

[0024]

As described above, according to the fuel injection valve of the internal combustion engine according to the invention of claim 1, the assist air abutting against the blocking wall provided in the assist air introducing portion is located near the blocking wall. Since the air is ejected through the provided air nozzle, the assist air does not stagnant in the assist air introduction portion, and therefore, the backflow fuel can be prevented from staying.

According to the second aspect of the present invention, in the configuration in which the assist air supplied from the assist air supply passage is supplied in two directions to distribute the assist air to the two air nozzles, the assist air is introduced in the assist air introducing portion. There is an effect that it is possible to eliminate the generation of a space where the backflow fuel stagnates and accumulates. According to the third aspect of the present invention, it is possible to eliminate the generation of a space where the assist air stagnates and the backflow fuel stays while generating a flow of the assist air over substantially the entire circumference of the fuel injection valve. effective.

According to the invention described in claim 4, in the fuel injection valve for ejecting the assist air from each of the two air nozzles without causing the stagnation of the assist air, for example, in the two-direction injection, in each spray direction. There is an effect that atomization can be achieved.

[Brief description of drawings]

FIG. 1 is a front partial cross-sectional view showing a first example of an embodiment of the invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a front partial cross-sectional view showing a second example of the embodiment of the invention.

4 is a sectional view taken along the line IV-IV in FIG.

FIG. 5 is a front partial cross-sectional view showing a conventional fuel injection valve.

FIG. 6 is a sectional view taken along the line VI-VI of FIG. 5;

FIG. 7 is a sectional view taken along the line VII-VII of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel injection valve 2 Holder 4 Assist air supply path 5 Adapter 6 Assist air introduction part 7a, 7b Air nozzle 5f, 5g, 8 Blocking wall

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuyoshi Mori 1370 Onna, Atsugi City, Kanagawa Prefecture Unisia Jecs Co., Ltd.

Claims (4)

[Claims] 1. An assist air supply passage for supplying assist air to a fuel injection valve, an assist air introduction portion formed around the fuel injection valve for introducing assist air through the assist air supply passage, and the assist air introduction portion. In the assist air introduction section of the fuel injection valve of the internal combustion engine, which is configured to include an air nozzle having one end opened to the air introduction section and the other end opened toward fuel spray from the fuel injection valve, A fuel injection for an internal combustion engine, characterized in that a blocking wall for blocking the flow of the assist air introduced through the supply passage is provided, and the air nozzle is opened at least in the vicinity of a portion where the flow is blocked by the blocking wall. valve. 2. In the assist air introducing portion, two air nozzles are provided so as to face each other around the axis of the fuel injection valve, and the assist air supply path is connected to the air nozzles at positions substantially equidistant from the respective openings. 2. The fuel injection valve for an internal combustion engine according to claim 1, further comprising a blocking wall provided near each opening of the air nozzle. 3. A block wall for allowing only a flow of the assist air in one direction around the fuel injection valve is formed in a portion of the assist air introducing portion to which the assist air supply passage is connected. A flow of the assist air introduced around the fuel injection valve around the fuel injection valve is blocked by the blocking wall, and the air nozzle is opened at least in the vicinity of the flow blocked by the blocking wall. The fuel injection valve for an internal combustion engine according to claim 1, wherein 4. The fuel injection valve for an internal combustion engine according to claim 3, wherein the air nozzle is also opened at a position opposite to the air nozzle opened near where the flow is blocked by the blocking wall.