JPH04279761A - Fuel injector for engine - Google Patents

Abstract

PURPOSE:To provide a fuel injector for an engine capable of improving the fuel atomization and reducing the fuel adhesion to the inner walls of intake channels. CONSTITUTION:Air injection nozzles 423 are provided on the intake channel 2 side of the fuel injection nozzle 414 of a fuel injection valve, and two air injection nozzles 423 are arranged so as to open facing to each other. Especially in a two-intake-valve type engine, air injection nozzles 423 facing to each other are arranged in a direction perpendicular to an arranged direction of intake valves 22.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a fuel injection device for an engine.

0002

2. Description of the Related Art Conventionally, a fuel injection device for an engine is generally known, which is configured to mix fuel and air on the upstream side of its injection port (for example, Japanese Patent Application Laid-open No. 59-123661 (see official bulletin). In other words, air is mixed before injecting fuel, and the mixed fuel is injected from the injection port.

0003

[Problems to be Solved by the Invention] In the above-mentioned conventional fuel injection device for an engine, the mixture of air and fuel from the injection port is injected with a circular cross-sectional shape. The injected fuel collides with and adheres to the inner wall surface, causing problems such as biased or uneven fuel supply to the intake valves.

[0004] In particular, in a two-valve intake engine in which two intake valves are provided for one combustion chamber, the intake passage is formed to branch into two corners corresponding to the two intake valves. Then, the injected fuel directly hits and adheres to the branch portion.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a fuel injection device for an engine that can improve fuel atomization and reduce the adhesion of fuel to the wall of the intake passage. It is an object.

[0006]

[Means for Solving the Problems] In order to achieve the above object, claim 1 provides a fuel injection device for an engine equipped with a fuel injection valve arranged facing an intake passage, in which a plurality of air introduction portions are arranged above the intake passage. The fuel injection valve is provided so as to open toward the intake passage side from the fuel injection port of the fuel injection valve, and at least two of the plurality of air introduction portions are arranged to face each other.

According to a second aspect of the present invention, in the first aspect, the intake passage downstream of the fuel injection valve is branched to correspond to the two intake valves, and the two opposing air introduction portions are connected to the intake valve. It was arranged so that it was arranged in a direction perpendicular to the arrangement direction of.

[0008] Furthermore, in a third aspect of the present invention, in the above-mentioned claim 2, two sets of two opposing air introduction portions are provided, one of which is perpendicular to the arrangement direction of the intake valves, and the other is perpendicular to the arrangement direction of the intake valves. It is configured so that they are arranged in each direction.

[0009]

[Operation] According to the first aspect, air is ejected from the air introduction part due to the negative pressure on the intake passage side, and this air is applied to the outer peripheral surface of the injected fuel having a circular cross-sectional shape and injected from the fuel injection port. As a result of the collision, the collided part is dented inward, and the other part is pushed out to the outer circumference by the air blown into the interior, resulting in an irregular cross-sectional shape of the injected fuel, and the difference between the injected fuel and the intake air from the intake passage. Fuel atomization is improved due to the increased contact area.

[0010] Also, according to the above claim 2, the above claim 1
In addition to this effect, the center of the injected fuel is depressed due to the collision of the air ejected from the opposing air introduction portions, and the injected fuel bulges out from the center to both sides. As a result, these both sides are divided into branch passages of the intake passage, and since the recessed center part hits the branch part of the branch passage, the injected fuel whose cross-sectional shape remains circular collides with this branch part. The adhesion of the injected fuel to the wall is reduced compared to the case.

According to claim 3, in addition to the effect of claim 2, air is ejected from both sides of the intake valve in the arrangement direction and collides with the injected fuel, so that excessive air is not generated in the arrangement direction. Haramidashi is regulated.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 2 and 3, 1 is a combustion chamber of an engine, 2 is an intake passage, 3 is an exhaust passage, and 4 is a fuel injection valve. The intake passage 2 has a downstream end branched into two sections, and each branch passage 21 communicates with the combustion chamber 1 via an intake valve 22, so that the intake passage 2 has a two-valve configuration. Further, the fuel injection valve 4 faces the intake passage 2 on the upstream side of the branch portion 23 and is arranged toward the intake valve 21.

As shown in FIG. 1, the fuel injection valve 4 includes an injection valve body 41 and a head portion 411 of the injection valve body 41.
The sleeve 42 attached to the injection valve main body 41
and a holder 43 that holds the sleeve 42 inside. The injection valve main body 41 has a plunger 412 that is held movably forward and backward, and a solenoid 413 that controls the amount of movement of the plunger 412.As shown in FIG. The annular fuel injection port 414 is opened, and fuel is injected through the fuel injection port 414 . This injection port 4
14 and the plunger head 415 are formed so that the injected fuel spreads out from between them in a conical shape with a circular cross section.

The sleeve 42 has a circular cross-sectional shape;
As shown in FIGS. 1 and 4, a guide hole 421 is formed inside the injection valve body 421 so as to widen toward the tip, and the upper end opening communicates with the fuel injection port 414.
is connected to. This sleeve 42 has four air jet ports 423a and 423b formed in its peripheral wall portion 422 so as to communicate with an air supply passage 431 (shown only in FIG. 1) formed in the holder 43 and open into the guide hole 421. It is formed through. These air outlets 423a, 423b
As shown in FIGS. 4 and 5, two pairs face each other, one pair is arranged in the arrangement direction of the branch passages 21 (see FIG. 2) corresponding to the arrangement direction of the intake valves 22, and the other The pairs are arranged in a direction perpendicular to the arrangement direction thereof, and the air is ejected diagonally downward. In other words, the air jet ports 423a and 423b are formed so that air is jetted obliquely in the fuel injection direction from the outer peripheral side in the radial direction toward the inner peripheral side with respect to the outer peripheral surface of the injected fuel from the fuel injection port 414. has been done. The air outlet 423a
, 423b, the air supply passage 431, and the like constitute an air introduction section.

In the above configuration, when the plunger 412 of the fuel injection valve main body 41 is operated to open the valve by the solenoid 413, fuel flows from the fuel injection port 414 into a cross-sectional shape as shown by the dashed line in FIGS. 4 and 6. will be ejected in a conical pattern in a circular pattern. At the same time as this fuel injection, air is sucked into the negative pressure on the side of the intake passage 2 and is ejected from the air jet ports 423a, 423b, and as the ejected air collides with the injected fuel, the air is mixed with the injected fuel. The pattern changes into a distorted shape as shown by the solid line in FIG. That is, when the air ejected from the air jet ports 423a and 423b hits the outer peripheral surface of the injected fuel, the part of the injected fuel that it hit is dented inward, and the part other than the dented part becomes the inner part of the injected fuel. The air blown into the periphery causes it to bulge out to the outer periphery. In other words, the injected fuel after colliding with the ejected air has a cross-sectional shape that is concave in the direction of arrangement of the branch passages 21 and in the direction perpendicular thereto, as shown by the dashed line in FIG. 7, and this pattern is maintained. As it advances towards the intake valve 22 side, it is greatly expanded and sucked into the combustion chamber 1.

Therefore, the amount of injected fuel adhering to the inner wall of the intake passage 2 due to its collision is reduced compared to the conventional device. That is, in the conventional device, in order to mix the fuel with air before injecting the fuel and inject the air-mixed fuel from the fuel injection port, the injected fuel flows into the two branch passages 21 as shown by the two-dot chain line in FIG. In contrast, in this embodiment, the air ejected from the air outlet 423b directly collides with the portion of the inner wall near the branch 23 that is different from the shape of the inner wall because the air is injected in a circular pattern. 2
Since the injected fuel is recessed in accordance with the shape near the branch portion 23, the amount of collision near the branch portion 23 is reduced. In addition, since the air ejected from the air jet port 413a prevents excessive protrusion in the direction in which the branch passages 21 are arranged, the injected fuel does not spread excessively in the direction in which the two branch passages 21 are arranged. It will be distributed to 21 people.

As described above, in this embodiment, the amount of injected fuel adhering to the wall surface of the intake passage 2 of a two-valve engine can be reduced compared to the case of the conventional device, thereby improving fuel consumption efficiency. be able to.

Furthermore, since the injection pattern of the injected fuel is deformed into an irregular shape by the ejected air, the contact area with the intake air from the intake passage 2 can be made larger than in the case of a conventional circular pattern. This makes it possible to promote and improve atomization of the injected fuel, thereby improving acceleration response.

Furthermore, since the individual droplets of the injected fuel are broken up into smaller particles by the collision energy of the ejected air, the degree of mixing of the air and the fuel can be further improved.Other aspects of the above embodiments are described below. show.

[0020]B. In the above embodiment, the present invention is applied to the intake passage of a two-valve type engine, but the present invention is not limited thereto, and may be applied to a one-valve type engine. Even in this case, it is possible to improve the atomization of the injected fuel, and it is possible to improve the acceleration response.

B. In the above embodiment, two pairs of air ejection ports are formed, but the invention is not limited to this, and for example, only one pair may be used. In this case, the pair of air jet ports 423c are
They may be arranged so as to face each other in a direction perpendicular to the arrangement direction of the branch passages 21, as shown in FIG. As a result, the pattern of the injected fuel can be formed into a gourd shape as shown by the dashed line in FIG. 8, and the amount of fuel attached to the wall can be reduced, and it can be efficiently distributed to the two branch passages 21.

C. In the embodiment described above, the pattern of the injected fuel may be changed by changing the cross-sectional area of the air jet port in the direction in which the branch passages are arranged and in the direction orthogonal thereto. Thereby, the pattern of the injected fuel can be changed depending on the cross-sectional shape of the intake passage.

[0023]

As explained above, according to the fuel injection device for an engine according to claim 1 of the present invention, it is possible to improve the atomization of the injected fuel, thereby improving the idling stability by improving the combustibility. It is possible to improve the acceleration response of the engine.

According to claim 2, in addition to the effects of claim 1, particularly in a two-valve intake type engine,
The amount of injected fuel adhering to the inner wall surface of the intake passage can be reduced.

Furthermore, according to claim 3, in addition to the effects of claim 2, the injected fuel can be efficiently distributed between the two intake ports.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing an embodiment of the present invention.

FIG. 2 is an explanatory plan view of an intake passage of the engine provided with the fuel injection valve in the above embodiment.

FIG. 3 is an explanatory longitudinal cross-sectional view of the intake passage of the engine provided with the fuel injection valve in the above embodiment.

FIG. 4 is a partially enlarged explanatory diagram of the fuel injection valve in FIG. 1;

FIG. 5 is a sectional view taken along line AA in FIG. 4;

FIG. 6 is an explanatory diagram of the cross-sectional shape of the injected fuel.

FIG. 7 is an explanatory cross-sectional view taken along line BB in FIG. 3;

FIG. 8 is an explanatory diagram of another embodiment of the air jet port.

[Explanation of symbols]

2 Intake passage 4 Fuel injection valve 21 Branch passage 22 Intake valve 23 Branch 414 Fuel injection port 423 Air outlet 431 Air supply passage

Claims (3)

[Claims] 1. A fuel injection device for an engine including a fuel injection valve disposed facing an intake passage, wherein a plurality of air introduction portions are opened toward the intake passage side from a fuel injection port of the fuel injection valve. 1. A fuel injection device for an engine, wherein at least two of the plurality of air introduction portions are arranged to face each other. Claim 2: An intake passage on the downstream side of the fuel injection valve is branched to correspond to two intake valves, and two valves are arranged facing each other.
2. The fuel injection device for an engine according to claim 1, wherein the two air introduction portions are arranged in a direction perpendicular to the arrangement direction of the intake valves. 3. Two sets of two opposing air introduction portions are provided, one of which is arranged in the direction in which the intake valves are arranged, and the other in a direction perpendicular to the direction in which the intake valves are arranged. The fuel injection device for an engine according to claim 2.