JP2009299630A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection valve capable of highly dispersing/highly atomizing spray. <P>SOLUTION: The fuel injection valve is provided with a valve body on which an injection hole 3 from which fuel is injected is formed. The injection hole 3 is formed with a projection part 6 provided on an inner wall 31 of the injection hole 3 by forming a plurality of small injection holes 5 with each section mutually overlapped. The small injection holes 5 are arranged at turn back positions LZP of zigzag line LZ. Consequently, spray from the injection hole 3 can be highly dispersed/highly atomized. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel injection valve used for fuel supply of an internal combustion engine.

  In order to improve engine combustion, in gasoline direct-injection engines, fuel spray injected into the engine cylinder is required to be highly dispersed / highly atomized, and fuel spray valves improve spray dispersion and atomization. Various attempts have been made. As such a fuel injection valve, a fuel injection valve in which the shape of an injection hole into which fuel is injected is improved is disclosed (see Patent Document 1).

This nozzle hole is formed by arranging a plurality of small nozzle holes in a straight line, and by providing protruding portions on the inner wall by forming respective parts of the plurality of small nozzle holes so as to overlap each other. For this reason, in the fuel flow in the vicinity of the nozzle hole and in the vicinity of the nozzle hole, minute vortices such as Karman vortices are generated by the protrusions, thereby promoting internal disturbance. By promoting this internal turbulence, the dispersion and atomization of the spray from the nozzle holes are being improved.
Japanese Utility Model Publication No. 62-64875

  In order to further improve the dispersion and atomization of the spray, it is necessary to further promote the internal disturbance of the fuel flow. For this purpose, the number of protrusions needs to be increased, so the number of small injection holes is increased. It is necessary to let However, in the above-described prior art, since the plurality of small nozzle holes are arranged on a straight line and the protrusions are provided, if the number of small nozzle holes is increased, the length of the nozzle holes in the longitudinal direction is increased. Problems arise. For this reason, when there is a restriction in the length in the longitudinal direction of the nozzle hole, the dispersion and atomization of the spray cannot be further improved.

  Further, since the plurality of small nozzle holes are arranged in a straight line and the protrusions are provided, the dimension between the protrusions adjacent to each other increases, and internal turbulence of the fuel flow due to the protrusions may be separated from each other. There is. For this reason, the spray from the nozzle hole becomes non-uniform, in which the region where the atomization is improved by the protrusion is divided by the region where the atomization is not improved because there is no protrusion. .

  For these reasons, in the prior art, it is difficult to further improve the dispersion and atomization of the spray.

  The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a fuel injection valve capable of highly dispersing / highly atomizing the spray.

  In order to achieve the above object, the present invention employs the following technical means.

  According to the first aspect of the present invention, it is provided with a valve body in which an injection hole into which fuel is injected is formed, and the injection hole is formed by overlapping each part of the plurality of small injection holes to form an inner wall of the injection hole. The small nozzle hole is arranged at the folding position of the zigzag line.

  According to this configuration, since the small nozzle holes are arranged at the zigzag line folding position, compared to the case where a plurality of small nozzle holes are arranged on a straight line, the unit nozzle length per unit length is longer The number of protrusions can be increased. For this reason, since internal disturbance by the protrusion part which arises in a fuel flow in a nozzle hole and the vicinity of a nozzle hole can be accelerated | stimulated, it becomes possible to make the spray from a nozzle hole highly disperse | distributed / highly atomized.

  According to invention of Claim 2, the small nozzle hole is arrange | positioned by the arrangement | positioning from which the dimension between mutually adjacent protrusion parts becomes less than the radius of the circle which is the same area as the hole area of a small nozzle hole, It is characterized by the above-mentioned. And

  According to this configuration, since the dimension between the protrusions adjacent to each other is smaller than the radius of the circle having the same area as the hole area of the small nozzle hole, the protrusion is generated in the fuel flow in and near the nozzle hole. It is possible to suppress internal disturbances from being separated from each other. For this reason, in spraying from a nozzle hole, it can suppress that the area | region where atomization is improving by the protrusion part is divided by the area | region where atomization is not improving because there is no protrusion part. Therefore, the spray from the nozzle holes can be more highly dispersed / highly atomized.

  According to a third aspect of the present invention, the injection hole is formed such that the peripheral length of the injection hole is gradually increased from the fuel inlet side toward the fuel outlet side.

  According to this configuration, since the peripheral length of the nozzle hole is gradually increased from the fuel inlet side toward the fuel outlet side, the fuel flow in which the internal disturbance is generated by the protruding portion After erupting from, it expands away from the nozzle hole. For this reason, as the distance from the nozzle hole increases, the contact area between the fuel and the air in the fuel flow increases, and the shear force that the fuel in the fuel flow receives from the air increases. Therefore, in the fuel flow after being ejected from the nozzle hole, internal turbulence due to the protrusion is further promoted, and the effect of high dispersion / high atomization by the protrusion can be further enhanced in the spray from the nozzle hole.

  According to the invention of claim 4, the small nozzle holes have the same shape and the same size. For this reason, it becomes easy to take the structure which satisfies the arrangement | positioning relationship of the small nozzle hole mentioned above in a nozzle hole, and it becomes easier to make the spray from a nozzle hole highly dispersed / highly atomized.

  According to invention of Claim 5, a small nozzle hole is circular, It is characterized by the above-mentioned.

  According to this configuration, since the small injection hole is a circular shape that is easy to process, the above-described effects can be achieved while suppressing the processing cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the mutually same or equivalent part in a figure.

  A fuel injection valve 1 shown in FIGS. 1 and 2 is attached to a cylinder head 11, and is formed by an inner peripheral surface of a cylinder block 10, an inner peripheral surface of the cylinder head 11, and an upper end surface of a piston 12. 14, the fuel is injected while the central axis SA of the spray S is inclined with respect to the longitudinal axis VA of the fuel injection valve 1. As a result, the spray S is prevented from directly adhering to the inner peripheral surface of the spark plug 13 and the cylinder block 10 and becoming liquid.

  In order to inject the fuel as described above, the injection hole 3 through which the fuel is injected is formed in the valve body 2 on the distal end side of the fuel injection valve 1 in the shape shown in FIGS. The valve body 2 is formed in a bottomed cylindrical shape as shown in FIG. 3, has a conical inner surface 21 whose diameter is reduced in the fuel flow direction (downward in FIG. 3), and the needle 4 can be seated. A valve seat 22 is formed on the inner surface 21. An injection hole 3 for injecting fuel is formed in the valve body 2 on the downstream side of the fuel flow with respect to the valve seat 22 (downward in FIG. 3).

  The needle 4 that opens and closes the nozzle hole 3 is configured to move in the vertical direction in FIG. When the needle 4 moves upward and separates from the valve seat 22, the high-pressure fuel passes through the gap between the inner surface 21 of the valve body 2 and the needle 4, toward the outlet 33 from the inlet 32 of the nozzle hole 3. 3 is sprayed as spray S. When the needle 4 moves downward and seats on the valve seat 22, fuel injection from the injection hole 3 is blocked.

  In FIG. 4, the slit-like nozzle hole 3 whose longitudinal direction is the longitudinal direction is formed at a position shifted from the center of the valve body 2 to the left side in FIG. The high-pressure fuel has a fan-shaped shape extending in the direction shown in FIG. 3 from the slit-shaped nozzle hole 3, and in the direction shown in FIG. 5, as a flat spray S inclined with respect to the axis VA of the fuel injection valve 1. Be injected.

  As shown in FIG. 6, the injection hole 3 is formed by providing protrusions 6 on the inner wall 31 of the injection hole 3 by forming each part of the plurality of small injection holes 5 so as to overlap each other. In the example shown in FIG. 6, seven small injection holes 5 having the same radius R (FIG. 7) are overlapped with each other in the overlapping region A <b> 1, and thereby 12 holes are formed on the inner wall 31 of the injection hole 3. The projections 6 are provided to form the nozzle holes 3. The small nozzle holes 5 are arranged at the folding position LZP of the zigzag line LZ, and the center 51 of the small nozzle holes 5 is located at the folding position LZP. Since the small injection holes 5 are arranged at the folding position LZP of the zigzag line LZ, it can be said that the injection holes 3 are formed in a slit shape having a length L0 in the longitudinal direction.

  Further, in FIG. 7, the small injection holes 5 are formed between all adjacent protrusions 6 including the dimension L1 between the protrusions 61 and 62 adjacent to each other and the dimension L2 between the protrusions 62 and 63 adjacent to each other. Are arranged in such an arrangement that the dimension is less than the radius R of the small nozzle hole 5.

  In FIG. 8, the nozzle hole 3 has the nozzle hole circumference C1, C2 gradually from the nozzle hole circumference C1 to the nozzle hole circumference C2 from the fuel inlet 32 side toward the fuel outlet 33 side. It is formed in a taper shape so as to be longer. The seven small nozzle holes 5 have the same shape and the same size, and specifically, the same radius circle (the same radius R on the outlet 33 side) on both the inlet 32 side and the outlet 33 side. And the same tapered shape from the inlet 32 side to the outlet 33 side. The dimensions of the small nozzle holes 5 are, for example, that the diameter of each small nozzle hole 5 on the inlet 32 side is 0.2 mm, the diameter of each small nozzle hole 5 on the outlet 33 side is 0.3 mm, and between the inlet 32 and the outlet 33. The dimension is set to 0.8 mm. In the example shown in FIG. 8, the twelve protrusions 6 are continuously formed between the inlet 32 and the outlet 33, respectively. The nozzle hole 3 has the shape described above and is formed by laser machining, electric discharge machining, or the like.

  Hereinafter, high dispersion / high atomization of the spray S from the nozzle hole 3 will be described.

  In FIG. 8, in the fuel flow S <b> 1 in the nozzle hole 3 and in the vicinity of the nozzle hole 3, a minute vortex S <b> 2 due to Karman vortex or the like is caused to enter the fuel flow S <b> 1 by the protrusion 6 formed continuously between the inlet 32 and the outlet 33. 32 and the outlet 33 are continuously generated, and the internal disturbance is promoted.

  In the nozzle hole 3, since the small nozzle holes 5 are arranged at the folding position LZP of the zigzag line LZ, compared with the nozzle holes 30 shown in FIG. 9 in which a plurality of small nozzle holes 5 are arranged on a straight line, The number of protrusions 6 per unit length can be increased in the longitudinal direction of the nozzle hole 3. Specifically, in the example shown in FIG. 9, the injection hole 30 is formed by arranging the same small injection holes 5 as the injection holes 3 on a straight line and overlapping each part of the small injection holes 5 with each other. It is formed. The length of the injection hole 30 in the longitudinal direction is the same L0 as that of the injection hole 3. For this reason, in the nozzle hole 30 in which the small nozzle holes 5 are arranged on a straight line, the number of the small nozzle holes 5 is five, whereas the small nozzle holes 5 are arranged at the folding position LZP of the zigzag line LZ. In the nozzle hole 3, the number of small nozzle holes 5 is increased to seven. Therefore, in the nozzle hole 30, the number of protrusions 60 is eight, whereas in the nozzle hole 3, the number of protrusions 6 is increased to twelve.

  Thus, in the nozzle hole 3, the number of protrusions 6 per unit length can be increased in the longitudinal direction of the nozzle hole 3 as compared with the nozzle hole 30, so that the fuel is generated in the nozzle hole 3 and in the vicinity of the nozzle hole 3. The minute vortex S2 caused by the protrusion 6 generated in the flow S1 can be increased, and the internal turbulence generated in the fuel flow S1 in the vicinity of the injection hole 3 and in the vicinity of the injection hole 3 can be further promoted. For this reason, the spray S from the nozzle hole 3 can be highly dispersed / highly atomized.

  Further, in the nozzle hole 3, as shown in FIG. 7, all the adjacent protrusions including the dimension L <b> 1 between the adjacent protrusions 61 and 62 and the dimension L <b> 2 between the adjacent protrusions 62 and 63. The dimension between 6 is less than the radius R of the small nozzle hole 5. For this reason, as shown in FIG. 10, the protrusion part area | region A2 in which the protrusion part 6 continues with the space | interval less than the radius R is formed along the length of the center side of the nozzle hole 3, and the protrusion part 6 is formed. The protrusion area A2 is not divided by the no protrusion area A3.

  On the other hand, in the nozzle hole 30, as shown in FIG. 11, the dimension L10 between the protrusions 601 and 602 adjacent to each other is less than the radius R of the small nozzle hole 5, whereas the protrusions 602 adjacent to each other. , 603 is longer than the radius R of the small nozzle hole 5. If the small nozzle holes 5 are arranged close to each other, the dimension L20 can be shortened, but the dimension L10 is increased. Furthermore, when the small nozzle holes 5 are brought close to each other, the protruding portion 60 becomes gentle, and there is a problem that the minute vortex S2 caused by the protruding portion 6 is hardly generated. Thus, in the nozzle hole 30, the dimensions between all the adjacent protrusions 60 cannot be arranged to be less than the radius R of the small nozzle hole 5. For this reason, in the nozzle hole 30, as shown in FIG. 9, the protrusions 60 are separated from each other by the protrusion-free area A <b> 30 without the protrusion 6. For this reason, the spray from the nozzle hole 30 is non-uniform, in which the region where the atomization is improved by the protrusion 60 is divided by the region where the atomization is not improved because there is no protrusion 60. turn into.

  On the other hand, in the nozzle hole 3, as shown in FIG. 10, since the protrusion area A <b> 2 is not divided by the protrusion-free area A <b> 3, the atomization by the protrusion 6 occurs in the spray S from the nozzle hole 3. It can suppress that the area | region which has improved is divided | segmented by the area | region where atomization has not improved since there is no protrusion part 6. FIG. Therefore, the spray S from the nozzle hole 3 can be more highly dispersed / atomized.

  Further, in the nozzle hole 3, the nozzle hole circumference C1, C2 of the nozzle hole 3 is gradually increased from the nozzle hole circumference C1 to the nozzle hole circumference C2 from the fuel inlet 32 side toward the fuel outlet 33 side. Therefore, the fuel flow S <b> 1 in which the internal turbulence is generated by the projecting portion 6 expands as the distance from the injection hole 3 increases after the injection from the injection hole 3. For this reason, as the distance from the nozzle hole 3 increases, the contact area between the fuel and the air in the fuel flow S1 increases, and the shear force that the fuel in the fuel flow S1 receives from the air increases. Therefore, in the fuel flow S <b> 1 after being ejected from the nozzle hole 3, the internal turbulence due to the protrusion 6 is further promoted, and the effect of high dispersion / high atomization by the protrusion 6 is further enhanced in the spray S from the nozzle hole 3. It becomes possible.

  Further, in the nozzle hole 3, since the small nozzle hole 5 is arranged at the folding position LZP of the zigzag line LZ, the spray S from the nozzle hole 3 is jetted in a slit shape having a longitudinal direction and a lateral direction. . For this reason, in the fuel flow S1 in which the internal disturbance is generated by the protrusion 6, the contact area with the air in the longitudinal direction of the nozzle hole 3 increases, and the shear force that the fuel of the fuel flow S1 receives from the air increases. Therefore, in the fuel flow S <b> 1 after being ejected from the nozzle hole 3, the internal turbulence due to the protrusion 6 is further promoted, and the effect of high dispersion / high atomization by the protrusion 6 is further enhanced in the spray S from the nozzle hole 3. It becomes possible.

  Further, in the nozzle hole 3, the fuel flow S1 is disturbed by the edge portion of the nozzle hole circumferential length C2, but as is apparent from the comparison between FIG. 6 and FIG. The hole circumferential length C2 is longer than the nozzle hole circumferential length C20 of the nozzle hole 30. For this reason, as compared with the edge portion of the nozzle hole circumferential length C20, the disturbance generated in the fuel flow S1 by the edge portion of the nozzle hole circumferential length C2 is further promoted. Therefore, in the spray S from the nozzle hole 3, it is possible to further enhance the effect of dispersion / atomization by the edge portion of the nozzle hole circumferential length C2.

  Furthermore, in the nozzle hole 3, since the seven small nozzle holes 5 have the same shape and the same size, it is easy to adopt a configuration that satisfies the arrangement relationship of the small nozzle holes 5 described above. Specifically, the small injection holes 5 are arranged at the turn-back position LZP of the zigzag line LZ, and further, the dimensions between all the adjacent protrusions 6 are less than the radius R of the small injection holes 5. This can be easily realized. For this reason, it becomes easier to make the spray S from the nozzle hole 3 highly dispersed / highly atomized.

  Furthermore, in the injection hole 3, since the small injection hole 5 is a round shape which is easy to process, the above-mentioned effect can be acquired at a reduced processing cost.

An average particle diameter SMD (μm) of the spray S injected from the nozzle hole 3 of the fuel injection valve 1 is shown in FIG. 12, and a photograph of the spray S taken is shown in FIG. 12 and 13, n-heptane (C ₇ H ₁₆ ) is used as the fuel. In FIG. 12, the average particle diameter is calculated as the average particle diameter SMD of Sauter by laser diffraction at a position 50 mm immediately below the nozzle hole 3. Measured. The average particle diameter SMD of Sauter is an average particle diameter obtained by assuming that the sum of the surface area of the oil droplet and the volume of the oil droplet is equal, and is the average particle size most reasonably associated with evaporation and combustion. In FIG. 12, the horizontal axis represents the fuel pressure P (MPa), and the vertical axis represents the average particle diameter SMD.

  FIG. 13 shows a photograph of the spray S injected from the injection hole 3 of the fuel injection valve 1 with the fuel pressure P being 20 MPa and the pulse width being 1 millisecond in the direction shown in FIG. In this case, the spray S is irradiated with laser light, and the scattered light from the spray S is photographed as the spray S. In the photograph, the spray S is represented in white with black as a background, but in order to make it easier to see FIG. 13, in FIG. 13, the black spray S is shown with white as the background, with black and white reversed. The spray S, which has been highly atomized with the average particle size SMD shown in FIG. 12, is strengthened and is highly dispersed as indicated by an arrow S3 in FIG.

(Modification)
Although the injection hole 3 shown in FIG. 8 is formed so that the small injection holes 5 overlap each other between the fuel inlet 32 and the outlet 33, the present invention is not limited to this. As shown in FIG. 14, it is also possible to form the injection holes 3A so that the small injection holes 5A overlap each other between the fuel outlet 33A and the dimension T2 and the small injection holes 5A do not overlap each other at the fuel inlet 32A. It is. In the nozzle hole 3, the protrusion 6 is continuously formed between the inlet 32 and the outlet 33, whereas in the nozzle hole 3A, the protrusion 6A is continuous only between the outlet 33A and the dimension T2. Is formed. Even with the nozzle hole 3A, the same effect as described above can be obtained.

  In order to secure the internal disturbance generated in the fuel flow S1 by the protrusion 6A at a predetermined level, the dimension T2 where the protrusion 6A is formed is 2/3 or more of the dimension T1 between the inlet 32 and the outlet 33. Is desirable.

  In the nozzle hole 3 shown in FIG. 8 described above, the nozzle hole circumference C1, C2 of the nozzle hole 3 extends from the nozzle hole circumference C1 toward the fuel outlet 33 side from the fuel inlet 32 side. Although it was formed in a tapered shape so as to gradually become longer in C2, it is not limited to this. As shown in FIG. 15, the injection hole 3B composed of the small injection holes 5B is formed in a straight shape so that the injection hole circumferential lengths C11 and C21 of the injection hole 3B are equal between the fuel inlet 32B and the outlet 33B. It is also possible. With the nozzle hole 3B, the same effect as described above can be obtained except for the effect of forming the nozzle hole 3 in a tapered shape.

  In the above example, the small nozzle holes 5, 5A, 5B are circular. However, the small nozzle holes 5C can be an elliptical small nozzle hole 5C shown in FIG. It is also possible to make a regular hexagonal small nozzle hole 5E shown in FIG.

  In FIG. 16, the injection holes 3C are formed by overlapping each part of the seven small injection holes 5C with each other, thereby forming the protrusions 6C on the inner wall of the injection holes 3C, and the small injection holes 5C are formed in a zigzag manner. Place at the line wrap position. Further, the small injection holes 5C are arranged in such an arrangement that the dimension between the adjacent protrusions 6C is less than the radius of a circle having the same area as the elliptical hole area of the small injection holes 5C.

  In FIG. 17, the injection holes 3D are formed by overlapping each part of the seven small injection holes 5D with each other to form the protrusions 6D on the inner wall of the injection holes 3D, and the small injection holes 5D are formed in a zigzag manner. Place at the line wrap position. Further, the small injection holes 5D are arranged in such an arrangement that the dimension between the adjacent protrusions 6D is less than the radius of a circle having the same area as the square hole area of the small injection holes 5D.

  In FIG. 18, the injection holes 3E are formed by overlapping each part of the seven small injection holes 5E with each other, so that the protrusions 6E are provided on the inner wall of the injection holes 3E, and the small injection holes 5E are zigzag-shaped. Place at the line wrap position. Further, the small injection holes 5E are arranged in such an arrangement that the dimension between the adjacent protrusions 6E is less than the radius of a circle having the same area as the regular hexagonal hole area of the small injection holes 5E.

  In the nozzle holes 3C, 3D, 3E, the same effects as described above can be obtained.

  The small nozzle hole is not limited to the above-described shape, and the same effect as described above can be obtained even if the small nozzle hole is a quadrangle other than a square or other polygons.

  In the above example, the hole areas of the small nozzle holes 5 are the same, the hole areas of the small nozzle holes 5A are the same, the hole areas of the small nozzle holes 5B are the same, and the small nozzle holes Although the hole areas of 5C are the same, the hole areas of the small injection holes 5D are the same, and the hole areas of the small injection holes 5E are the same, this is not restrictive. The injection hole is formed by overlapping each part of a plurality of small injection holes having different hole areas to form a protrusion on the inner wall of the injection hole, and the small injection hole is formed at the zigzag line folding position. It is also possible to arrange. In this case, the small nozzle holes are further arranged in such an arrangement that the dimension between adjacent protrusions is less than the radius of a circle having the same area as the average value of the hole areas of the different small nozzle holes. As a result, the same effect as described above can be obtained.

  Further, the number of small nozzle holes is not limited to seven, and other numbers can be used.

It is sectional drawing which shows the attachment position of the fuel injection valve by one Embodiment of this invention, and the spray to a combustion chamber. It is an expanded sectional view of the II section in FIG. It is sectional drawing of the III-III line | wire in FIG. It is IV arrow line view in FIG. It is sectional drawing of the VV line | wire in FIG. It is an enlarged view of the VI section in FIG. It is an enlarged view of the VII part in FIG. It is a perspective view of the nozzle hole shown in FIG. It is an enlarged view which shows the comparative example of FIG. It is explanatory drawing of the effect of a nozzle hole shown in FIG. It is an enlarged view of the XI part in FIG. It is a graph which shows the relationship between the average particle diameter of the spray from a nozzle hole shown in FIG. 6, and fuel pressure. It is the photograph which image | photographed the spray from the nozzle hole shown in FIG. It is a perspective view of the nozzle hole which shows the 1st modification of FIG. It is a perspective view of the nozzle hole which shows the 2nd modification of FIG. It is an enlarged view of the nozzle hole which shows the 1st modification of FIG. It is an enlarged view of the nozzle hole which shows the 2nd modification of FIG. It is an enlarged view of the nozzle hole which shows the 3rd modification of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection valve, 2 valve body, 21 inner surface, 22 valve seat 3,3A, 3B, 3C, 3D, 3E, 30 injection hole, 31,301 inner wall 32,32A, 32B inlet, 33,33A, 33B outlet, 4 Needle 5, 5A, 5B, 5C, 5D, 5E Small injection hole, 51 center 6, 6A-6E, 60, 61-63, 601-603 Projection 10 Cylinder block, 11 Cylinder head, 12 Piston, 13 Spark plug 14 Combustion chamber, S spray, SA center axis, S1 fuel flow, S2 vortex S3 roll up, VA axis, A1 overlap area, A2 protrusion area A3, A30 No protrusion area, C1, C11, C2, C20, C21 injection hole Circumference L0, L1, L2, L10, L20, T1, T2 dimensions, LZ zigzag line LZP Folding position, R radius

Claims (5)

Comprising a valve body formed with a nozzle hole through which fuel is injected;
The nozzle hole is formed by providing a protruding portion on the inner wall of the nozzle hole by forming each of a plurality of small nozzle holes overlapping each other.
The fuel injection valve, wherein the small injection hole is disposed at a zigzag line folding position.   2. The small nozzle hole is arranged in an arrangement in which a dimension between adjacent projecting portions is less than a radius of a circle having the same area as the hole area of the small nozzle hole. The fuel injection valve as described.   The injection hole is formed so that the peripheral length of the injection hole is gradually increased from the fuel inlet side toward the fuel outlet side. The fuel injection valve as described.   The fuel injection valve according to any one of claims 1 to 3, wherein the small injection holes have the same shape and the same size.   The fuel injection valve according to any one of claims 1 to 4, wherein the small injection hole is circular.

Images