JPH0932704A - Fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection device which can form an air flow having a speed component to one direction. SOLUTION: The device is provided with a fuel injection valve 12 provided with a cylindrical nozzle part 14 provided with a spout hole 26 and a valve main body 16 and a cylindrical adapter 18 surrounding the circumference of the nozzle part 14 and for forming a ring shape clearance 36 between the outer periphery of the nozzle part 14 and the adapter. An air introducing port 38 opened in the inner wall of this adapter 18 and for introducing the air while pointing a certain angle for the radius direction of the nozzle part 14 is provided and the said air introducing port 38 is opened in the more valve main body side than the spout hole 26 of the nozzle part 14.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fuel injection device for injecting fuel.

[0002]

2. Description of the Related Art In order to improve combustion, it is known to collide a swirling air flow with fuel injected from a fuel injection valve to atomize the fuel. For example, JP-A-63
No. 223362 and Japanese Patent Laid-Open No. 2-55869 disclose a fuel injection valve having a cylindrical nozzle portion having an injection hole and a valve body, and a space surrounding the nozzle portion and surrounding the nozzle portion. Is provided with a cylindrical adapter and an air inlet opening in the inner wall of the adapter to introduce air in the radial direction of the nozzle portion, and the air inlet is closer to the valve body than the nozzle hole of the nozzle portion. An open fuel injector is disclosed. Further, the fuel injection device includes a linear air passage communicating with the air gap and injecting air into the circular space. In such a fuel injection device, a swirling flow is formed in the circular space by injecting air from the air passage into the circular space in the tangential direction thereof.

[0003]

However, in the above fuel injection device, since the air passage is short, the flow of air cannot be rectified in the air passage, and there are velocity components in multiple directions. Since it is injected into the circular space as it is, it is not possible to form a swirling flow sufficient for atomization.

Therefore, an object of the present invention is to provide a fuel injection device capable of forming an air flow having a velocity component in one direction.

[0005]

In order to solve the above problems, according to the present invention, a fuel injection valve having a cylindrical nozzle portion having an injection hole and a valve body, and the periphery of the nozzle portion are provided. A cylindrical adapter that surrounds the nozzle portion and forms an annular gap between the nozzle portion and the outer periphery of the nozzle portion; Provided is a fuel injection device having an introduction port, the air introduction port opening on the valve body side from the injection hole of the nozzle portion. In the present invention, by introducing the air from the air inlet opening on the inner wall of the adapter to the annular gap at a constant angle with respect to the radial direction of the nozzle portion, a circumferential velocity component is given to the air. Air for atomizing the fuel swirls in the annular gap.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings. 1 is an overall external view of a fuel injection device showing an embodiment of the present invention, FIG. 2 is a sectional view taken along line AA of FIG.
FIG. 3 shows a longitudinal sectional view at a position deviated from FIG. 2 by 90 °. In these figures, 10 is a fuel injection device, 1
Reference numeral 2 denotes a fuel injection valve having a nozzle portion 14 and a valve body 16, and 18 denotes an adapter fitted to the side surface of the nozzle portion 14.

As shown in FIG. 2, which is a sectional view taken along the line AA of FIG. 1, the nozzle portion 14 in this embodiment has a nozzle body 20 having a circular cross section and a nozzle plate 22 attached to the tip portion of the nozzle body 20. It consists of and. A cavity having a nozzle port 24 filled with fuel injected from the fuel injection valve 12 is formed in the center of the nozzle body 20, and a plurality of cavities communicating with the nozzle port 24 are formed in the center of the nozzle plate 22. Of the fuel injection valve 12
It is provided obliquely to the axis line of. Nozzle body 20
Has a large diameter portion 28 and a small diameter portion 30.

As shown in FIG. 3, which is a longitudinal sectional view at a position deviated from the position shown in FIG. 2 by 90 °, the adapter 18 has a concave portion 32 which is fitted to the side surface of the large diameter portion 28 of the nozzle body 20.
It has two fuel passages 34 that extend from the bottom surface of the recess 32 and allow the fuel injected from the two pairs of injection holes 26 to pass therethrough. When the nozzle body 20 is arranged at a predetermined position in the recess 32, the outer peripheral surface of the small diameter portion 30 and the inner peripheral surface of the recess 32 form an annular space 36 (see FIG. 4). The width d of the annular gap 36 is selected to be narrower than the diameter of the air inlet 38. Further, as shown in FIG. 2 and FIG. 4 of the BB cross section, the adapter 18 has two air introduction ports 38 that are opened in the inner wall so as to face each other and introduce air in a substantially tangential direction of the annular space 36. Prepare These air introduction ports 38 open on the valve body 16 side from the injection holes 26 of the nozzle portion 14 and communicate with the annular space 36. These air inlets 38 are provided symmetrically with respect to the center point of the nozzle body 20. Here, the valve body side is the right side as viewed in FIG. 2, and the adapter side is the left side. Further, these air introduction ports 38 are connected to an air pump.

By providing the air inlet 38 as described above, most of the velocity component of the introduced air is directed in the circumferential direction of the annular gap 36, so that the air swirls well in the annular gap 36. In this way, by utilizing the annular gap 36 between the adapter 18 and the nozzle portion 14, the air introduction port 38 for introducing air into the annular gap 36 is provided closer to the valve main body side than the injection hole 26, and the air is formed in the annular gap 36. By swirling, it is possible to secure a long air flow path. Therefore, the velocity components of the air, which were traveling in multiple directions when being introduced from the air introduction port 38, traveled in one direction, that is, the tangential direction while swirling in the annular gap 36, and the air flow was rectified.

As shown in FIG. 6, the nozzle plate 22 has an arc-shaped side surface 4 conforming to the shape of the tip of the nozzle body 20.
It has 0. The side surface connecting the arc side surfaces 40 is
It is formed as straight side surfaces 42 parallel to each other, which are concave portions with respect to the circular cross-sectional shape. Further, in the recess 32, two protrusions 44 are formed as engagement walls that engage with the respective straight side surfaces 42 of the nozzle plate 22. The diameter of the arc side surface 40 of the nozzle plate 22 is
An air passage 48 having the same diameter as the small diameter portion 30 of 0 and communicating with the annular inner surface 46 of the recess 32 is formed as shown in FIG. The height H of the straight inner surface 50 of the protrusion 44 is formed to be larger than the thickness t of the nozzle plate 22, and a space 52 on the nozzle plate 22 communicating with the air passage 48 is formed. It communicates with the atomization space 54 formed in 34. The size of the space 52 is set so that the discharged air is larger than the velocity of the air flow swirling in the annular gap 36.

The air swirling along the annular gap 36 passes through the air passage 48 and is discharged from the space 52 to the atomization space 54. The air discharged from the space 52 is a rectified air flow having a tangential velocity component as described above, and therefore an air flow having a velocity component deviating from the tangential direction of the atomization space 54 is small. Become. Therefore, a sufficient swirl flow is formed in the atomization space 54, and the fuel injected into the atomization space 54 can be atomized well.

The air introduced into the annular space 36 also has a function of cooling the nozzle body 20. Fuel injection device 10
Is generally located near the engine, so that the temperature becomes extremely high, and a phenomenon occurs in which the fuel vaporizes inside the nozzle body 20. By introducing air around the nozzle body 20 to cool it, vaporization of fuel can be prevented,
It is possible to accurately control the fuel injection amount.

In the above-mentioned embodiment, the air inlet 38 is oriented substantially in the tangential direction of the annular space 36, but this does not limit the present invention and the air inlet 38 is not limited thereto.
However, even if it does not necessarily face the tangential direction, if it is directed at a certain angle with respect to the radial direction of the nozzle portion 14 on a plane including the axis, the velocity component heading in the circumferential direction of the annular gap 36 is relatively large. Becomes larger and thus the air is
Make a sufficient turn within 6. Further, as described above, the air inlet 3
If 8 is oriented at a constant angle with respect to the radial direction of the nozzle portion 14, the plane including the axis of the air inlet 38 need not be perpendicular to the axis of the nozzle portion 14 as in this embodiment. . Further, in the above-described embodiment, the air inlet 38 has two ports.
Although one or two or more may be provided, if two or more are provided, each air inlet may be provided in the nozzle portion as long as it is directed so that the airflows introduced from the respective air inlets do not collide. It may be directed at different angles with respect to the radial direction of 14.

In the present invention, it is not necessary to reduce the diameter of the air passage or lengthen the length of the air passage as in the conventional case in order to rectify the air for atomizing and to have a velocity component in one direction. Therefore, by reducing the diameter of the air passage, it is easy to block the air passage due to foreign matter or freezing mixed in the air, and by increasing the length of the air passage, the fuel injection device is not upsized.

[0015]

As described above, according to the fuel injection device of the present invention, since the air is swirled by using the annular gap between the adapter and the nozzle portion, the flow passage of the air can be secured sufficiently long, so that the flow can be improved. Can be rectified to obtain an air flow having a velocity component in one direction, so that the air can be collided with the fuel to sufficiently atomize the fuel, and good combustion can be realized.

[Brief description of drawings]

FIG. 1 is an overall outline view showing a fuel injection device.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view showing a tip portion of the fuel injection device at a position shifted by 90 ° from FIG.

FIG. 4 is a sectional view taken along line BB of FIG. 2;

FIG. 5 is a sectional view taken along line CC of FIG. 2;

FIG. 6 is a perspective view of a nozzle portion including a nozzle plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Fuel-injection apparatus 12 ... Fuel-injection valve 14 ... Nozzle part 16 ... Valve main body 18 ... Adapter 26 ... Injection hole 36 ... Annular gap 38 ... Air inlet

Claims (1)

[Claims] 1. A fuel injection valve having a cylindrical nozzle portion having an injection hole and a valve body, and a cylindrical shape which surrounds the periphery of the nozzle portion and forms an annular space between the outer periphery of the nozzle portion. And an air inlet opening into the inner wall of the adapter for introducing air at a certain angle with respect to the radial direction of the nozzle portion, the air inlet opening from the nozzle hole of the nozzle portion. Fuel injection device that opens on the valve body side.