BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel injection valve that is used to supply fuel to an internal combustion engine of an automobile, etc., and particularly relates to a fuel injection valve that aims to achieve both atomization promotion in spraying characteristics and narrower angle and increased penetration in spray shape.
2. Description of the Related Art
In gasoline internal combustion engines in automobiles in recent years, one fuel injection valve has been mounted per cylinder in order to improve controllability of fuel supply to cylinders. Furthermore, in order to achieve both improvements in output and improvements in fuel economy, two air intake ports are disposed per cylinder in most cases. Thus, in fuel injection valves in such cases, fuel is sprayed toward the respective air intake ports bidirectionally, and suppression of adhesion of fuel spray onto inner wall surfaces of the air intake ports is also required.
At the same time, atomization of fuel spray is also required for improvement in fuel economy and reduction of exhaust gases. Wide-angle spraying (i.e., low-penetration spraying) is effective as an atomizing means. However, since narrow-angle spraying (i.e., high-penetration spraying) is required in order to suppress fuel spray adhesion onto the air intake ports, it is difficult to achieve both atomization and narrow-angle, high-penetration spraying by manipulation of the spraying angle alone.
In answer to that, in conventional fuel injection valves, cluster sprays have been formed in which wide-angle, low-penetration spraying and narrow-angle, high-penetration spraying are mixed by changing a ratio of spraying aperture length L to spraying aperture diameter D (spraying aperture L/D) for each spraying aperture. Furthermore, suppression of spray adhesion onto the air intake port inner wall surfaces on an outer circumferential side of

the cylinder has been attempted using drag effects of a narrow-angle, high-penetration spray (in which particle size is poor) that is aimed at sides of air intake valves near a cylinder center by surrounding the narrow-angle, high-penetration sprays to suppress scattering of wide-angle, low-penetration sprays (in which particle size is improved) that are aimed at the outer circumferential side of the cylinder (see Patent Literature 1 through 3, for example).
[0005]
In other conventional fuel injection valves, a plurality of spraying apertures are divided into two spraying aperture groups that have as a boundary a plane that includes a valve aperture shaft axis of a valve seat member, and are disposed in a fuel diffusion chamber downstream from the valve seat member. Spacing between the two spraying aperture groups is made greater than a distance between the spraying apertures within each of the spraying aperture groups. In addition, diameters of the spraying apertures at central portions in each of the spraying aperture groups are made greater than diameters of the spraying apertures on two sides thereof. Furthermore, total area of the spraying apertures at the central portion is made smaller than total area of the spraying apertures on the two sides.
[0006]
Using a configuration of this kind, suppression of spray adhesion in a vertical direction on the air intake port inner wall surfaces on the outer circumferential side of the cylinder is attempted by achieving spraying in which outlines in the vertical direction are sharp and penetration is high (see Patent Literature 4, for example).
CITATION LIST
PATENT LITERATURE
[0007] [Patent Literature 1]
Japanese Patent Laid-Open No. 2005-23875 (Gazette) [Patent Literature 2]
Japanese Patent Laid-Open No. 2005-207291 (Gazette) [Patent Literature 3]
Japanese Patent Laid-Open No. 2009-79598 (Gazette)

[Patent Literature 4]
Japanese Patent No. 4138778 (Gazette)
[0008]
However, in the conventional fuel injection valves that are disclosed in Patent Literature 1 through 3, scattering of the wide-angle, low-penetration sprays is suppressed by the drag effects of the narrow-angle, high-penetration spray, but it has not been possible to suppress scattering of the wide-angle, low-penetration spray sufficiently by that alone. Even if a certain amount of suppressing effect is hypothetically obtainable, this effect is limited to being obtained at a downstream end of the spray where spray breakup has advanced, spray particle size is small, and spray velocity is low, and drag effects cannot be expected at an upstream end of the spray where spray breakup is partially complete, spray particle size is large, and spray velocity is high.
[0009]
At the same time, in internal combustion engines in automobiles in recent years, passage area of air intake ports has been minimized in order to raise intake air flow velocity and enhance intake air tumble flow inside the cylinder, and the area of fuel spraying passages that lead from the leading end of the fuel injection valve to the air intake port has also been minimized, reducing clearance between the spray and inner wall surfaces of the spraying passage at the upstream end of the spray.
[0010]
Consequently, suppression of adhesion of the fuel spray onto the spraying passage inner wall surfaces is difficult using the conventional fuel injection valves that are disclosed in Patent Literature 1 through 3. Moreover, since the spraying passage inner wall surfaces are separated from the cylinder, and wall surface temperatures are low, one problem has been that once fuel spray adheres there, it is difficult to vaporize, making controllability of fuel supply into the cylinder poor.
[0011]
In most cases, air intake ports are curved in the vertical direction (vertically) in order to enhance the intake air tumble flow, and in that case, it is difficult to ensure clearance between the straight spray and the curved air intake port inner wall surfaces in the vertical direction inside the air intake port.

In addition, if fuel is injected during an intake stroke for the purpose of improving fuel economy, then the spray adheres easily to a ceiling inner wall surface of the air intake port because the fuel spray is blown off course by the intake air flow.
[0012]
Because of that, another problem has been that if fuel is injected during the intake stroke using the conventional fuel injection valves that are disclosed in Patent Literature 1 through 3, the wide-angle, low-penetration spray that is aimed at the outer circumferential side of the cylinder is easily blown off course by the intake air flow, and the spray adheres easily to the ceiling inner wall surface of the air intake port.
[0013]
In contrast to that, in the conventional fuel injection valve that is disclosed in Patent Literature 4, the fuel spray is not blown off course by the intake air flow even if fuel is injected during an intake stroke because the vertical spray is a high-penetration spray. Suppression of fuel spray adhesion onto the ceiling and bottom surface of the air intake port inner wall surfaces is possible because the low-penetration spray that is positioned between vertical walls of high-penetration spray is not blown off course by the intake air flow either.
[0014]
However, although the spray of fuel that is sprayed from the spraying apertures at the central portion diffuses in a direction of spraying under the influence of radial flow components inside the fuel diffusion chamber, one problem has been that fuel adhesion onto the air intake port inner wails in the direction of spraying cannot be suppressed because spray diffusion in the direction of spraying cannot be suppressed by the narrow-angle, high-penetration spray on the two sides.
[0015]
Because total cross-sectional area of the central spraying apertures that are aimed at atomization is less than that of the spraying apertures on the two sides, another problem has been that there are more particles that have a large particle size than particles that have a small particle size, making overall particle size of the spray poor.
SUMMARY OF THE INVENTION

[0016]
The present invention aims to solve the above problems and an object of the present invention is to provide a fuel injection valve that can achieve both atomization of a fuel spray and suppression of fuel adhesion onto air intake port inner wall surfaces by achieving both promotion of atomization of fuel that is sprayed and narrower angle and increased penetration in spray shape.
[0017]
In order to achieve the above object, according to one aspect of the present invention, there is provided a fuel injection valve including: a valve seat including: a seat surface that is inclined such that a diameter is gradually reduced downstream; and a valve seat opening that is disposed downstream from the seat surface; a valve body that is placed in contact with the seat surface to stop outflow of fuel from the valve seat opening, and that is separated from the seat surface to allow outflow of fuel from the valve seat opening; and a spraying aperture plate that is fixed to a downstream end surface of the valve seat, and that includes a plurality of spraying apertures that spray to an external portion fuel that flows out of the valve seat opening, wherein: the spraying aperture plate is disposed such that an imaginary circular conical surface that is a downstream extension of the seat surface and an upstream end surface of the spraying aperture plate intersect to form an imaginary circle; the spraying apertures are disposed nearer to a valve seat central axis than the valve seat opening, which constitutes a smallest inside diameter of the valve seat, and form two spraying aperture groups so as to form a bidirectional cluster spray; outlet centers of the spraying apertures are disposed at positions that are further away from the valve seat central axis than inlet centers of the spraying apertures when the spraying apertures are projected vertically onto a plane that is perpendicular to the valve seat central axis; spraying aperture central axes from the inlet centers to the outlet centers are inclined toward a central axis of the cluster spray relative to radial straight lines from the valve seat central axis to the inlet centers; when an angle of the inclination is an inward angle jS, an inward angle jS1 of central spraying apertures that are spraying apertures that are disposed at a central portion of each of the spraying aperture groups is smaller than an inward angle /32 of end portion spraying apertures that are spraying apertures that are disposed on two end portions of each of the spraying aperture groups; and a diameter of the central spraying apertures is larger than a diameter of at least spraying

apertures that are disposed near a ceiling inner wall surface of an air intake port among the end portion spraying apertures.
According to another aspect of the present invention, there is provided a fuel injection valve including: a valve seat including: a seat surface that is inclined such that a diameter is gradually reduced downstream; and a valve seat opening that is disposed downstream from the seat surface; a valve body that is placed in contact with the seat surface to stop outflow of fuel from the valve seat opening, and that is separated from the seat surface to allow outflow of fuel from the valve seat opening; and a spraying aperture plate that is fixed to a downstream end surface of the valve seat, and that includes a plurality of spraying apertures that spray to an external portion fuel that flows out of the valve seat opening, wherein: the spraying aperture plate is disposed such that an imaginary circular conical surface that is a downstream extension of the seat surface and an upstream end surface of the spraying aperture plate intersect to form an imaginary circle; the spraying apertures are disposed nearer to a valve seat central axis than the valve seat opening, which constitutes a smallest inside diameter of the valve seat, and form two spraying aperture groups so as to form a bidirectional cluster spray; outlet centers of the spraying apertures are disposed at positions that are further away from the valve seat central axis than inlet centers of the spraying apertures when the spraying apertures are projected vertically onto a plane that is perpendicular to the valve seat central axis; spraying aperture central axes from the inlet centers to the outlet centers are inclined toward a central axis of the cluster spray relative to radial straight lines from the valve seat central axis to the inlet centers; when an angle of the inclination is an inward angle jS, an inward angle /J1 of central spraying apertures that are spraying apertures that are disposed at a central portion of each of the spraying aperture groups is smaller than an inward angle jS2 of end portion spraying apertures that are spraying apertures that are disposed on two end portions of each of the spraying aperture groups; the central spraying apertures include: a spraying aperture main body; and an enlarged diameter portion that is formed so as to overlap partially with an outlet of the spraying aperture main body; a diameter of the enlarged diameter portion is larger than a diameter of the spraying aperture main body; and a center of the enlarged diameter portion is disposed at a position that is further away from the valve seat central axis than an outlet center of the spraying aperture main body,
[0018]

A fuel injection valve according to the present invention can achieve both atomization of a fuel spray and suppression of fuel adhesion onto air intake port inner wall surfaces by achieving both promotion of atomization of fuel that is sprayed and narrower angle and increased penetration in spray shape.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019]
Figure 1 is a cross section parallel to a shaft axis of a fuel injection valve according to Embodiment 1 of the present invention;
Figure 2 is a diagram that combines an enlargement of a valve seat, a spraying aperture plate, and a ball from Figure 1 and a plan that shows a central portion of the spraying aperture plate;
Figure 3 is a cross section that is taken along line III - III in Figure 2;
Figure 4 is a cross section that is taken along line IV - IV in Figure 2;
Figure 5 is a diagram that combines an enlargement of a valve seat, a spraying aperture plate, and a ball from Figure 1 and a plan that shows states of spray from respective spraying apertures;
Figure 6 is a graph that shows time variation in spray particle size during fuel injection by the fuel injection valve in Figure 1;
Figure 7 is a cross section that shows a state in which a fuel injection valve according to Embodiment 2 of the present invention is mounted onto an air intake port;
Figure 8 is a view of a spraying aperture plate from Figure 7 in a direction of arrow VIII from downstream from the fuel injection valve;
Figure 9 is a diagram that combines a partial cross section of a fuel injection valve according to Embodiment 3 of the present invention, and a plan that shows a central portion of a spraying aperture plate;
Figure 10 is a cross section that is taken along line X - X in Figure 9;
Figure 11 is a cross section that is taken along line XI - XI in Figure 9;
Figure 12 is a cross section that shows a state in which a fuel injection valve according to Embodiment 4 of the present invention is mounted onto an air intake port;
Figure 13 is a view of a spraying aperture plate from Figure 7 in a direction of arrow XIII from downstream from the fuel injection valve;

Figure 14 is a cross section that shows a central spraying aperture of a fuel injection valve according to Embodiment 5 of the present invention enlarged;
Figure 15 is a diagram that combines a partial cross section of a fuel injection valve according to Embodiment 6 of the present invention, a plan that shows a central portion of a spraying aperture plate and states of spray from respective spraying apertures;
Figure 16 is a diagram that combines a partial cross section of a fuel injection valve according to Embodiment 7 of the present invention and a plan that shows a central portion of a spraying aperture plate;
Figure 17 is a cross section that is taken along line XVII - XVII in Figure 16; and
Figure 18 is a cross section that is taken along line XVIII - XVIII in Figure 16.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020]
Preferred embodiments of the present invention will now be explained with reference to the drawings.
Embodiment 1
Figure 1 is a cross section parallel to a shaft axis of a fuel injection valve according to Embodiment 1 of the present invention, fuel flowing downward from an upper end of the fuel injection valve in Figure 1. In the figure, a cylindrical fixed core 2 is fixed to an upper end portion of a magnetic pipe 1. The magnetic pipe 1 and the fixed core 2 are disposed coaxially. The magnetic pipe 1 is press-fitted onto a downstream end portion of the fixed core 2 and is welded.
[0021]
A valve seat 3 and a spraying aperture plate 4 are fixed to a lower end portion inside the magnetic pipe 1. A plurality of spraying apertures 5 that spray fuel are disposed on the spraying aperture plate 4. The spraying apertures 5 pass through the spraying aperture plate 4 in a plate thickness direction.
[0022]

The spraying aperture plate 4 is fixed to a downstream end surface of the valve seat 3 by a first weld portion 4a, is inserted into the magnetic pipe 1 in that state, and is then fixed to the magnetic pipe 1 by a second weld portion 4b.
[0023]
Inserted inside the magnetic pipe 1 are: a ball 6 that constitutes a valve body; a needle pipe 7 that is fixed by welding onto the ball 6; and an armature (a movable core) 8 that is fixed onto an upstream end portion (an end portion at an opposite end from the ball 6) of the needle pipe 7. The armature 8 is press-fitted into the upstream end portion of the needle pipe 7 and is welded.
[0024]
The armature 8 is slidable in an axial direction inside the magnetic pipe
1. A guiding portion 1a that guides the sliding movement of the armature 8 is
disposed on an inner circumferential surface of the magnetic pipe 1. The
needle pipe 7 and the armature 8 move together in the axial direction when the
armature 8 slides. The ball 6 is thereby placed in contact with and separated
from the valve seat 3. An upper end surface of the armature 8 is also placed in
contact with and separated from a lower end surface of the fixed core 2.
Chamfered portions 6a are disposed on an outer circumference of the ball 6.
[0025]
A compression spring 9 that presses the needle pipe 7 in a direction that pushes the ball 6 against the valve seat 3 is inserted inside the fixed core 2. An adjuster 10 that adjusts the load of the compression spring 9 is also fixed inside the fixed core 2. In addition, a filter 11 is inserted into an upper end portion of the fixed core 2, which constitutes a fuel inlet portion.
[0026]
An electromagnetic coil 12 is fixed onto an outer circumference of a downstream end portion (an end portion near the armature 8) of the fixed core
2. The electromagnetic coil 12 has: a resin bobbin 13; and a coil main body
14 that is wound onto an outer circumference thereof. A metal sheet (a
magnetic circuit component member) 15 that constitutes a yoke portion of a
magnetic circuit is fixed by welding between the magnetic pipe 1 and the fixed
core 2.
[0027]
The magnetic pipe 1, the fixed core 2, the electromagnetic coil 12, and the metal sheet 15 are molded integrally into a resin housing 16. A connector

portion 16a is disposed on the resin housing 16. Terminals 17 that are electrically connected to the coil main body 14 are led out into the connector portion 16a.
[0028]
Figure 2 is a diagram that combines an enlargement of the valve seat 3, the spraying aperture plate 4, and the bail 6 from Figure 1 and a plan (a view of a portion that is exposed to the fuel flow channel from a side near the ball 6 in the direction of arrow li) that shows a central portion of the spraying aperture plate 4, Figure 3 is a cross section that is taken along line III - III in Figure 2, and Figure 4 is a cross section that is taken along line IV - IV in Figure 2.
[0029]
A seat surface 3a on which the ball 6 is separably placed in contact is disposed inside the valve seat 3. The seat surface 3a is inclined such that a diameter thereof is gradually reduced downstream. A circular valve seat opening 3b that faces the spraying aperture plate 4 is also disposed centrally on the downstream end portion of the valve seat 3 at a downstream end of the seat surface 3a.
[0030]
The ball 6 is placed in contact with the seat surface 3a to stop outflow of fuel from the valve seat opening 3b, and is separated from the seat surface 3a to allow outflow of fuel from the valve seat opening 3b. The spraying aperture plate 4 is disposed such that an imaginary circular conical surface 18a that is a downstream extension of the seat surface 3a and an upstream end surface of the spraying aperture plate 4 intersect to form an imaginary circle 18b.
[0031]
When the spraying aperture plate 4 is viewed along a valve seat central axis 3c, the respective spraying apertures 5 are disposed on a single circle (a circle of spraying aperture disposal) 18c that is centered around a valve seat central axis that is formed nearer to the valve seat central axis 3c than the valve seat opening 3b, which constitutes a smallest inside diameter portion of the valve seat 3.
[0032]
The spraying apertures 5 form two spraying aperture groups 5a so as to form a bidirectional cluster spray 21 (Figure 5). In the plan of the spraying aperture plate 4 in Figure 2, a first spraying aperture group 5a is constituted by

the four spraying apertures 5 on the right, and a second spraying aperture group 5a is constituted by the four spraying apertures 5 on the left.
[0033]
Each of the spraying aperture groups 5a is constituted by: a plurality of (two in Figure 2) central spraying apertures 5-1 that are disposed centrally in the circumferential direction of the circle 18c in each of the spraying aperture groups 5a; and plurality of (two in Figure 2) end portion spraying apertures 5-2 that are disposed at two end portions in the circumferential direction of the circle 18c.
[0034]
When the respective spraying apertures 5 are projected vertically onto a plane that is perpendicular to the valve seat central axis 3c, outlet centers 5c of the spraying apertures 5 are disposed at positions that are further away from the valve seat central axis 3c than inlet centers 5b of the spraying apertures 5. In other words, the spraying apertures 5 are inclined so as to be positioned further outward in a radial direction of the spraying aperture plate 4 progressively downstream.
[0035]
When the respective spraying apertures 5 are projected vertically onto a plane that is perpendicular to the valve seat central axis 3c, spraying aperture central axes 5d from the inlet centers 5b of the spraying apertures 5 toward the outlet centers 5c of the spraying apertures 5 are inclined by an inward angle /3 toward a central axis 21a of the cluster spray 21 relative to radial straight lines 19 that are directed from the valve seat central axis 3c toward the inlet centers 5b. In addition, in each of the spraying aperture groups 5a, an inward angle j81 of the central spraying apertures 5-1 is less than an inward angle /32 of the end portion spraying apertures 5-2.
[0036]
Furthermore, a diameter of the central spraying apertures 5-1 is larger than a diameter of the end portion spraying apertures 5-2. In other words, the diameter of the end portion spraying apertures 5-2 is smaller than the diameter of the central spraying apertures 5-1. In this example, the diameters of the central spraying apertures 5-1 are larger than the diameters of all of the end portion spraying apertures 5-2. Moreover, Figure 3 shows a cross section that is taken along the spraying aperture central axis 5d of the central spraying

apertures 5-1, and Figure 4 shows a cross section that is taken along the spraying aperture central axis 5d of the end portion spraying apertures 5-2.
[0037]
A salient portion 4c that is curved to protrude downstream parallel (or approximately parallel) to a tip end portion of the ball 6 is disposed centrally on the spraying aperture plate 4. A flat spraying aperture plate flat portion 4d is disposed around the salient portion 4c. The spraying apertures 5 are disposed on the spraying aperture plate flat portion 4d.
[0038]
Next, operation of the fuel injection valve will be explained. When an actuating signal is sent from an engine controlling apparatus to a fuel injection valve driving circuit, an electric current is made to flow to the electromagnetic coil 12 through the terminals 17 such that magnetic flux arises in a magnetic circuit that is constituted by the armature 8, the fixed core 2, the metal sheet 15, and the magnetic pipe 1.
[0039]
Thus, the armature 8 is attracted toward the fixed core 2, making the armature 8, the needle pipe 7, and the ball 6, which constitute an integrated construction, move upward in Figure 2. Then, when the ball 6 separates from the valve seat 3 to form a gap between the ball 6 and the valve seat 3, fuel passes through the gaps between the chamfered portions 6a of the ball 6 and the valve seat 3, and is sprayed from the spraying apertures 5 into an engine air intake port.
[0040]
Next, when an operation stopping signal is sent from the engine controlling apparatus to the fuel injection valve driving circuit, the passage of electric current to the electromagnetic coil 12 is stopped, magnetic flux in the magnetic circuit is reduced, and the armature 8, the needle pipe 7, and the ball 6 move downward in Figure 2 due to the spring force from the compression spring 9. Thus, the gap between the ball 6 and the valve seat 3 is closed, completing fuel injection.
[0041]
When fuel flow that moves toward inlets of the respective spraying apertures 5 is projected vertically onto a plane that is perpendicular to the valve seat central axis 3c, a main flow of the fuel flow that moves directly from the seat surface 3a toward the inlet centers 5b of the spraying apertures 5 forms a

flow 20a that moves toward the valve seat central axis 3c, as shown in the plan in Figure 2. The spraying apertures 5, are each inclined away from the valve seat central axis 3c progressively downstream. Because of that, the fuel flow is peeled off at the inlets of the spraying apertures 5, the fuel collides into inner walls of the spraying apertures 5 on sides near the valve seat central axis 3c, and then flows 20d are formed in which liquid films of fuel are spread thinly over the inner walls of the spraying apertures 5.
[0042]
Because the central spraying apertures 5-1 in particular, in which the inward angle jQ1 is smaller, are oriented so as to face the main flow 20a of the fuel almost directly in the abovementioned plane, the fuel collides with the inner walls as shown in Figure 3, and then the flows 20d in which the liquid films of fuel are spread thinly over the inner walls are further intensified. Because the diameters of the central spraying apertures 5-1 are also large, the liquid films can be spread more thinly on the inner walls.
[0043]
Consequently, the fuel that is sprayed from the central spraying apertures 5-1 is efficiently formed into films, enabling atomization to be promoted. The spray shape is made into a wide-angle, low-penetration spray by reducing the spraying aperture L/D (spraying apertures L/D < 1, for example) so as to be diffused in a direction (a side surface direction) that is perpendicular to the direction of spraying.
[0044]
Because the end portion spraying apertures 5-2, on the other hand, in which the inward angle 02 is larger, do not face the main flow 20a of the fuel directly in the abovementioned plane, liquid film formation on the inner walls is weakened, as shown in Figure 4. Because the diameters of the end portion spraying apertures 5-2 are smaller, by increasing the spraying aperture L/D (spraying apertures L/D > 1, for example), fuel fills the spraying apertures 5-2 as it flows and is sprayed as a full spray from the outlets, making a narrow-angle, high-penetration spray shape.
[0045]
Figure 5 is a diagram that combines an enlargement of the valve seat 3, the spraying aperture plate 4, and the ball 6 from Figure 1 and a plan (a view from a side near the ball 6 in the direction of arrow V) that shows states of spray from respective spraying apertures 5.

[0046]
As shown in Figure 5, narrow-angle, high-penetration sprays 21c from the end portion spraying apertures 5-2 form a wall where the sprays that are sprayed from the respective spraying apertures 5 interfere with each other, suppressing excessive diffusion of the wide-angle, low-penetration sprays (the atomized sprays) 21b from the central spraying apertures 5-1 in the side surface direction. At the same time, because the wide-angle, low-penetration sprays 21b from the central spraying apertures 5-1 do not diffuse excessively in the direction of spraying (a front surface direction), they become narrow-angle sprays in both the side surface direction and the front surface direction, enabling adhesion of the fuel sprays onto the air intake port inner wall surfaces to be suppressed.
[0047]
In Embodiment 1, because a total sum of the flow channel area of the central spraying apertures 5-1 is made greater than a total sum of the flow channel area of the end portion spraying apertures 5-2, there is a greater amount of wide-angle, low-penetration spray 21b that has a high degree of atomization than narrow-angle, high-penetration spray 21c that has a low degree of atomization, enabling overall average particle size of the sprays to be reduced.
[0048]
In addition, at the commencement of spraying, because fuel inside a space (a dead volume) that is surrounded by the inner walls of the valve seat 3 downstream from the seat surface 3a, the upstream end surface of the spraying aperture plate 4, and the tip end portion of the ball 6 is discharged from the spraying apertures 5, spraying velocity is reduced compared to during steady spraying after completion of the valve opening operation of the ball 6, and because of that, there is a tendency for spray particle size to be larger in the initial spray at the commencement of spraying than during steady spraying.
[0049]
In answer to that, in Embodiment 1, dead volume is reduced by disposing the spraying aperture plate 4 such that an imaginary circular conical surface 18a that is a downstream extension of the seat surface 3a and an upstream end surface of the spraying aperture plate 4 intersect to form an imaginary circle 18b. Because of that, the amount of spraying of initial spray

that has a larger particle size is reduced, enabling the overall spray particle size of initial spray and steady spray combined to be reduced, as shown in Figure 6.
[0050]
Because the dead volume is reduced, the amount of fuel evaporation inside the dead volume under high temperature and negative pressure during cessation of spraying is also reduced, enabling changes in the amount of spraying (the amount of static flow and the amount of dynamic flow) that accompany changes in temperature and ambient pressure to be reduced.
[0051]
In addition, as shown in the plan in Figure 2, a flow 20b of fuel that passes beyond the spraying apertures 5 is included in the fuel flow downstream from the seat surface 3a, in addition to the main flow 20a of fuel that flows directly from the seat surface 3a into the inlets of the spraying apertures 5. The flow 20b collides at a central portion of the spraying aperture plate 4 with the fuel that has flowed from the opposite side, forming a back flow 20c toward the spraying apertures 5.
[0052]
In Embodiment 1, because a salient portion 4c that is curved to protrude downstream parallel to a tip end portion of the ball 6 is disposed centrally on the spraying aperture plate 4, as shown in Figure 3, the back flow 20c is a flow along the salient portion 4c, making it less likely to flow into the spraying apertures 5 that are disposed on the spraying aperture plate flat portion 4d outside the salient portion 4c.
[0053]
The main flow 20a of fuel, on the other hand, slides in under the back flow 20c, and becomes more likely to collide with upstream ends of the inner walls of the spraying apertures 5. Thus, effective lengths of the inner walls of the spraying apertures 5 that are necessary to spread the liquid films out can be increased, enabling the fuel to be formed into films efficiently, thereby enabling atomization to be promoted.
[0054]
As shown in the cross section in Figure 2, a distance between the seat surface 3a and the upstream end surface of the spraying aperture plate 4 in a vicinity of the valve seat central axis 3c can also be shortened while avoiding interference between the tip end portion of the ball 6 and the spraying aperture

plate 4 when the valve is closed, enabling the imaginary circle 18b to be enlarged.
[0055]
Thus, the inlet centers 5b of the spraying apertures 5 that are disposed on the spraying aperture plate flat portion 4d outside the salient portion 4c can be disposed inside the imaginary circle 18b, enabling the flow that promotes spreading out of liquid films over the inner walls of the spraying apertures 5 to be strengthened. Consequently, the fuel can be formed into films efficiently, enabling atomization to be promoted.
[0056]
In addition, because the above-mentioned dead volume can be further reduced while avoiding interference between the tip end portion of the ball 6 and the spraying aperture plate 4 when the valve is closed, the amount of spraying of initial spray that has a larger particle size is further reduced, enabling the overall spray particle size of initial spray and steady spray combined to be further reduced.
[0057] Embodiment 2
Next, Figure 7 is a cross section that shows a state in which a fuel injection valve according to Embodiment 2 of the present invention is mounted onto an air intake port 22, and Figure 8 is a view of a spraying aperture plate 4 from Figure 7 in a direction of arrow VIII from downstream from the fuel injection valve.
[0058]
If fuel is injected during an intake stroke, one problem has been that spray adheres easily to a ceiling inner wall surface 22a of an air intake port 22 and a fuel spraying passage 22c because the fuel spray is blown off course by intake air flow.
[0059]
In answer to that, in Embodiment 2, among end portion spraying apertures 5-2, diameters of spraying apertures 5 that are disposed near the ceiling inner wall surface 22a are reduced, and diameters of spraying apertures 5 that are disposed near a bottom portion inner wall surface 22b of the air intake port 22 are increased. In other words, the diameters of the end portion spraying apertures 5-2 that are disposed near the bottom portion inner wall

surface 22b are larger than the diameters of the end portion spraying apertures 5-2 that are disposed near the ceiling inner wall surface 22a.
[0060]
In this example, the diameters of the end portion spraying apertures 5-2 that are disposed near the bottom portion inner wall surface 22b are equal or approximately equal to the diameters of the central spraying apertures 5-1. The rest of the configuration is similar or identical to that of Embodiment 1.
[0061]
Thus, even if fuel is injected during the intake stroke, the central portion of the spray and the spray in the direction of the bottom portion inner wall surface 22b can be set to a wide-angle, low-penetration atomized spray while suppressing spray adhesion onto the ceiling inner wall surface 22a and the fuel spraying passage 22c, enabling the atomization of the entire spray to be promoted. Here, because the spray in the direction of the bottom portion inner wall surface 22b is a low-penetration atomized spray, spray adhesion onto the bottom portion inner wall surface 22b due to fuel spray being blown off course by the intake air flow during intake stroke injection is suppressed.
[0062]
Consequently, the atomized spray can be directly injected into the cylinder, enabling a spray that is suitable for intake stroke spraying for the purpose of improving fuel economy.
[0063] Embodiment 3
Next, Figure 9 is a diagram that combines a partial cross section of a fuel injection valve according to Embodiment 3 of the present invention and a plan (a view of a portion that is exposed to a fuel flow channel from a side near a ball 6 in the direction of arrow IX) that shows a central portion of a spraying aperture plate 4, Figure 10 is a cross section that is taken along line X - X in Figure 9, and Figure 11 is a cross section that is taken along line XI - XI in Figure 9.
[0064]
In Embodiment 3, central spraying apertures 5-1 are each constituted by: a spraying aperture main body 5e that is similar or identical to the central spraying apertures 5-1 according to Embodiment 1; and an enlarged diameter portion (a large diameter portion) 5h that is formed so as to overlap partially

with an outlet portion of the spraying aperture main body 5e. The spraying aperture main bodies 5e and the enlarged diameter portions 5h have one-to-one correspondence.
[0065]
Each of the enlarged diameter portions 5h is a cylinder that is centered around an axis that is perpendicular to a spraying aperture plate 4 (parallel to a valve seat central axis 3c). Centers 5i of the enlarged diameter portions 5h are disposed at positions that are further away from the valve seat central axis 3c than outlet centers 5c of the spraying aperture main bodies 5e. Configurations other than the central spraying apertures 5-1 are similar or identical to those of Embodiments 1 or 2.
[0066]
In a fuel injection valve of this kind, because the liquid films are spread even more thinly over the inner walls of the enlarged diameter portions 5h, as shown in Figure 10, by fuel flowing from the spraying aperture main bodies 5e into the enlarged diameter portions 5h, spray adhesion onto the air intake port inner wall surfaces can be suppressed in a similar or identical manner to that of Embodiment 1 while further promoting atomization.
[0067] Embodiment 4
Next, Figure 12 is a cross section that shows a state in which a fuel injection valve according to Embodiment 4 of the present invention is mounted onto an air intake port 22, and Figure 13 is a view of a spraying aperture plate 4 from Figure 7 in a direction of arrow XIII from downstream from the fuel injection valve.
[0068]
In Embodiment 4, among end portion spraying apertures 5-2, enlarged diameter portions 5h are disposed on outlets of spraying apertures 5 that are disposed near a bottom portion inner wall surface 22b of an air intake port 22. The rest of the configuration is similar or identical to that of Embodiment 3.
[0069]
In a fuel injection valve of this kind, because the enlarged diameter portions 5h are disposed on the end portion spraying apertures 5-2 that are disposed near the bottom portion inner wall surface 22b, a spray is enabled that

is suitable for intake stroke spraying for the purpose of improving fuel economy, in a similar or identical manner to that of Embodiment 2.
[0070] Embodiment 5
Next, Figure 14 is a cross section that shows a central spraying aperture 5-1 of a fuel injection valve according to Embodiment 5 of the present invention enlarged. In Embodiment 5, cylinder portions 5j that constitute smallest cross-sectional areas between the inlets and outlets of the spraying aperture main bodies 5e are disposed in flow channels of central spraying apertures 5-1. The rest of the configuration is similar or identical to that of Embodiment 3.
[0071]
In a fuel injection valve of this kind, because the fuel flow rate in the central spraying apertures 5-1 is determined by the cross-sectional area of the cylinder portion 5j, irregularities in flow rate due to irregularities in position between the spraying aperture main bodies 5e and the enlarged diameter portions 5h can be suppressed.
[0072]
Moreover, cylinder portions 5j may be disposed on the spraying aperture main bodies 5e of the end portion spraying apertures 5-2 near the bottom portion inner wall surface 22b of Embodiment 4. In other words, Embodiments 4 and 5 may be combined.
In Embodiments 3 through 5, the diameters of the central spraying apertures 5-1 do not necessarily have to be made greater than the diameters of the end portion spraying apertures 5-2.
[0073] Embodiment 6
Next, Figure 15 is a diagram that combines a partial cross section of a fuel injection valve according to Embodiment 6 of the present invention, a plan (a view of a portion that is exposed to a fuel flow channel from a side near a ball 6 in the direction of arrow XV) that shows a central portion of a spraying aperture plate 4 and states of spray from respective spraying apertures 5.
[0074]

In Embodiment 6, spacing y3 between two spraying aperture groups 5a is less than distances y1 and y2 between spraying apertures within each of the spraying aperture groups 5a. The rest of the configuration is similar or identical to that of Embodiments 1,2,3, 4, or 5.
[0075]
In a fuel injection valve of this kind, because the spacing y3 between the spraying aperture groups 5a is less than the distances y1 and y2 between the spraying apertures within each of the spraying aperture groups 5a, the distances y1 and y2 between the spraying apertures can be increased, enabling interference between the liquid films that are sprayed from the respective spraying apertures 5 to be suppressed at a stage of the liquid films after spraying before the sprays break up.
[0076]
Because angles j82 that are formed between the directions of the spraying aperture central axes 5d of the end portion spraying apertures 5-2 and the main flow 20a of fuel are also further increased in a plane that is perpendicular to the valve seat central axis 3c, liquid film formation inside the spraying apertures 5 is further weakened, enabling the narrow-angle, high-penetration spray to be further strengthened.
[0077] Embodiment 7
Next, Figure 16 is a diagram that combines a partial cross section of a fuel injection valve according to Embodiment 7 of the present invention and a plan (a view of a portion that is exposed to a fuel flow channel from a side near a ball 6 in the direction of arrow XVI) that shows a central portion of a spraying aperture plate, Figure 17 is a cross section that is taken along line XVII - XVII in Figure 16, and Figure 18 is a cross section that is taken along line XVIII - XVIII in Figure 16.
[0078]
In Embodiment 1, the salient portion 4c is disposed centrally on the spraying aperture plate 4, but in Embodiment 7, a center of a spraying aperture plate 4 is flat. In Embodiment 7, a ball flat portion (a valve body flat portion) 6b that is parallel (or approximately parallel) to the spraying aperture plate 4 is disposed on a tip end portion of a ball 6.
[0079]

The ball flat portion 6b faces an upstream end surface of the spraying aperture plate 4 centrally. When projected vertically onto a plane that is perpendicular to the valve seat central axis 3c, the ball flat portion 6b is disposed radially further inward than inlets of all spraying apertures 5. The rest of the configuration is similar or identical to that of Embodiments 1, 2, 3, 4, 5, or 6.
[0080]
In the plan in Figure 16, the flow channel cross-sectional area of the flow 20b of fuel that passes between the spraying apertures 5 and moves toward the center of the spraying aperture plate 4 reduces rapidly when the portion that faces the ball flat portion 6b is transited. Because of that, pressure loss is increased, and the velocity of the flow 20b decreases in the portion that faces the ball flat portion 6b.
[0081]
Because the velocity of back flow 20c also decreases therewith, back flow 20c is less likely to flow into the spraying apertures 5. Because of that, the main flow 20a of the fuel overcomes the back flow 20c at the inlets of the spraying apertures 5, and is able to collide with upstream ends of the inner walls of the spraying apertures 5, as shown in Figure 17.
[0082]
Thus, effective lengths of the inner walls of the spraying apertures 5 that are necessary to spread the liquid films out can be increased, enabling the fuel to be formed into films efficiently, thereby enabling atomization to be further promoted.
[0083]
As shown in the cross section in Figure 16, a distance between the seat surface 3a and the upstream end surface of the spraying aperture plate 4 in a direction of the valve seat central axis 3c can also be shortened while avoiding interference between the tip end portion of the ball 6 and the spraying aperture plate 4 when the valve is closed. The imaginary circle 18b can thereby be enlarged, enabling the inlet centers 5b of the spraying apertures 5 to be disposed inside the imaginary circle 18b. Consequently, the flow that promotes spreading out of liquid films over the inner walls of the spraying apertures 5 can be strengthened, thereby enabling the fuel to be formed into films efficiently, and enabling atomization to be promoted.
[0084]

In addition, the above-mentioned dead volume can be further reduced while avoiding interference between the tip end portion of the ball 6 and the spraying aperture plate 4 when the valve is closed. The amount of spraying of initial spray that has a larger particle size is thereby further reduced, enabling the overall spray particle size of initial spray and steady spray combined to be further reduced.

WE CLAIM:
1. A fuel injection valve comprising:
a valve seat (3) including:
a seat surface (3a) that is inclined such that a diameter is gradually reduced downstream; and
a valve seat opening (3b) that is disposed downstream from the seat surface (3a);
a valve body (6) that is placed in contact with the seat surface (3a) to stop outflow of fuel from the valve seat opening (3b), and that is separated from the seat surface (3a) to allow outflow of fuel from the valve seat opening (3b); and
a spraying aperture plate (4) that is fixed to a downstream end surface of the valve seat (3), and that includes a plurality of spraying apertures (5) that spray to an external portion fuel that flows out of the valve seat opening (3b),
wherein:
the spraying aperture plate (4) is disposed such that an imaginary circular conical surface (18a) that is a downstream extension of the seat surface (3a) and an upstream end surface of the spraying aperture plate (4) intersect to form an imaginary circle (18b);
the spraying apertures (5) are disposed nearer to a valve seat central axis (3c) than the valve seat opening (3b), which constitutes a smallest inside diameter of the valve seat (3), and form two spraying aperture groups (5a) so as to form a bidirectional cluster spray (21);
outlet centers (5c) of the spraying apertures (5) are disposed at positions that are further away from the valve seat central axis (3c) than inlet centers (5b) of the spraying apertures (5) when the spraying apertures (5) are projected vertically onto a plane that is perpendicular to the valve seat central axis (3c);
spraying aperture central axes (5d) from the inlet centers (5b) to the outlet centers (5c) are inclined toward a central axis (21a) of the cluster spray (21) relative to radial straight lines (19) from the valve seat central axis (3c) to the inlet centers (5b);
when an angle of the inclination is an inward angle β, an inward angle β1 of central spraying apertures (5-1) that are spraying apertures (5) that are disposed at a central portion of each of the spraying aperture groups (5a) is smaller than an inward angle β2 of end portion spraying apertures (5-2) that are spraying apertures (5) that are disposed on two end portions of each of the spraying aperture groups (5a);
the central spraying apertures (5-1) include: a spraying aperture main body (5e); and

an enlarged diameter portion (5h) that is formed so as to overlap partially with an outlet of the spraying aperture main body (5e);
a diameter of the enlarged diameter portion (5h) is larger than a diameter of the spraying aperture main body (5e); and
a center (5i) of the enlarged diameter portion (5h) is disposed at a position that is further away from the valve seat central axis (3c) than an outlet center (5c) of the spraying aperture main body (5e).
2.. The fuel injection valve according to Claim 1, wherein the enlarged diameter portion
(5h) is also disposed on outlets of spraying apertures (5) that are disposed near a bottom portion inner wall surface (22b) of an air intake port (22) among the end portion spraying apertures (5-2).
3. The fuel injection valve according to either of Claims 1 or 2, wherein cylinder portions (5j) that have a smallest cross-sectional area between inlets and outlets of the spraying aperture main body (5e) are disposed in flow channels of the spraying apertures (5) on which the enlarged diameter portions (5h) are disposed.
4. The fuel injection valve according to any one of Claims 1 to 3, wherein a spacing between the two spraying aperture groups (5a) is less than distances between the spraying apertures (5) within the spraying aperture groups (5a).
5. The fuel injection valve according to any one of Claims 1 to 4, wherein a total sum of flow channel area of the central spraying apertures (5-1) is greater than a total sum of flow channel area of the end portion spraying apertures (5-2).
6. The fuel injection valve according to any one of Claims 1 to 5, wherein:
a salient portion (4c) that protrudes downstream is disposed on the spraying aperture plate (4) in order to avoid interference with a tip end portion of the valve body (6) during valve closing;
a flat spraying aperture plate flat portion (4d) is disposed around the salient portion (4c) of the spraying aperture plate (4); and
the spraying apertures (5) are disposed on the spraying aperture plate flat portion (4d).

7. The fuel injection valve according to any one of Claims 1 to 5, wherein:
a valve body flat portion (6b) that is parallel or approximately parallel to the
spraying aperture plate (4) is disposed on a tip end portion of the valve body (6) in order to
avoid interference with the spraying aperture plate (4) during valve closing; and
the valve body flat portion (6b) is disposed radially further inward than inlets of the
spraying apertures (5) when projected vertically onto the plane.