TECHNICAL FIELD
[0001]
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 to a spraying flow rate adjusting method, and particularly relates to a fuel injection valve that can promote atomization in spraying characteristics.
BACKGROUND ART
[0002]
In recent years, as exhaust emission regulations for internal combustion engines in automobiles, etc., are augmented, there is demand for atomization of fuel sprays that are sprayed from fuel injection valves.
[0003]
In Patent Literature 1, for example, a conventional fuel injection valve has been disclosed that includes: a valve casing that is formed so as to be symmetrical relative to a longitudinal axis, in which a central opening is disposed downstream from a valve seat face, at least two tangential conduits extend radially outward from the central opening, each of the tangential conduits opens tangentially onto a respective swirling chamber, and fuel metering openings respectively lead outside from central portions of the swirling chambers! and a valve closing member that operates together with the valve seat face that is disposed inside the valve casing.
[0004]
In the conventional fuel injection valve according to Patent Literature 1, the flow of fuel is smoothed and accelerated by the tangential conduits, and that fuel flows into the swirling chambers, forms a swirling flow in the swirling chambers, and is then sprayed out of the nozzle apertures while swirling through the nozzle apertures. The fuel that is sprayed out of the nozzle apertures is spread into hollow cone shapes in a thin liquid film state by edge portions of the opening portions of the nozzle apertures, facilitating atomization of the fuel.

CITATION LIST PATENT LITERATURE
[0005]
Patent Literature V Japanese Patent Laid-Open No. HEI 1-271656 (Gazette)
SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
[0006]
However, because the conventional fuel injection valve according to Patent Literature 1 attempts to atomize the fuel using the swirling flow of the fuel, it has been necessary to design not only the dimensions of the nozzle apertures, but also the dimensions, number, and arrangement, i.e., groove shape, of the swirling chambers depending on the flow rate and angle of spread of the spray mist that is aimed for. Thus, one problem has been that the groove shape must be modified for each and every different specification of spraying flow rate, making manufacturing cost reductions unachievable.
[0007]
In contrast to that, the spraying flow rate could conceivably be modified without modifying the groove shape, by changing the aperture diameters of the nozzle apertures and the number of nozzle apertures. However, if the aperture diameters of the nozzle apertures are changed, not only the spraying flow rate, but also the angle of spread of the spray mist changes. One problem has been that if the angle of spread of the spray mist is large, controllability of the engine deteriorates due to fuel adhering to wall surfaces of the air intake port, and if the angle of spread of the spray mist is small, the liquid fuel film that is sprayed becomes thicker, making atomization poor.
[0008]
If, on the other hand, the number of nozzle apertures is changed by predisposing a plurality of swirling chambers and forming nozzle apertures on the number of swirling chambers that corresponds to the required spraying flow rate, then the spraying flow rate can be changed without changing the angle of spread of the spray mist. However, because there

are swirling chambers on which nozzle apertures are not formed, that is, swirling chambers that are not used for spraying, fuel enters the swirling chambers which are not used for spraying. The total volume of these swirling chambers that are not used for spraying constitutes a dead volume of fuel. One problem has been that if the dead volume of fuel becomes large, insufficiently smoothed and accelerated fuel is sprayed immediately after the commencement of spraying, making atomization of the fuel spray poor in the early stages of spraying.
[0009]
The present invention aims to solve the above problems and an object of the present invention is to provide a fuel injection valve and a spraying flow rate adjusting method that enables manufacturing cost reductions by standardizing groove shapes for different spraying flow rate specifications, and that also suppresses formation of fuel dead volume to facilitate fuel spray atomization from early stages of spraying.
MEANS FOR SOLVING THE PROBLEM
[0010]
A fuel injection valve according to the present invention includes: a valve seat including: a truncated conical seat surface in which a diameter reduces toward a downstream end; and a cylindrical valve seat opening portion that is formed downstream from the seat surface so as to be coaxial to the seat surface, the valve seat having an axial center of the seat surface and the opening portion as a central axis! a valve member that stops outflow of fuel from the opening portion by sitting on the seat surface, and that allows outflow of fuel from the opening portion by separating from the seat surface! and a nozzle aperture plate that is disposed downstream from the valve seat such that a flat upper surface thereof faces upstream, a plurality of swirling chambers being formed on the upper surface, the swirling chambers each including: a swirling portion that applies a swirling force to the fuel; and a fuel introducing portion that introduces the fuel to the swirling portion, the plurality of swirling chambers include: a first swirling chamber in which the swirling portion communicates with the valve seat opening portion by means of the fuel introducing portion; and a second swirling chamber in which the swirling portion does not communicate with the valve seat opening portion, and a nozzle aperture for

spraying the fuel is formed on the swirling portion of the first swirling chamber.
EFFECTS OF THE INVENTION
[0011]
In the present invention, the plurality of swirling chambers include^ a first swirling chamber in which the swirling portion communicates with the valve seat opening portion by means of the fuel introducing portion; and a second swirling chamber in which the swirling portion does not communicate with the valve seat opening portion, and a nozzle aperture is formed on the swirling portion of the first swirling chamber. Because the number of first swirling chambers, i.e., the number of nozzle apertures, can thereby be adjusted by changing the aperture diameter of the valve seat opening portion, for example, the groove shape can be standardized for specifications that have different spraying flow rates, enabling manufacturing costs to be reduced.
Furthermore, because the swirling portion of the second swirling chamber, which does not contribute to the spraying, does not communicate with the valve seat opening portion, fuel will not enter the second swirling chamber. Thus, because the dead volume of fuel is reduced, sufficiently smoothed and accelerated fuel is sprayed immediately after commencement of spraying, facilitating fuel spray atomization in the early stages of spraying.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012]
Figure 1 is a longitudinal cross section that explains a configuration of a fuel injection valve according to Embodiment 1 of the present invention!
Figure 2 is a diagram that shows a vicinity of a valve seat of the fuel injection valve according to Embodiment 1 of the present invention;
Figure 3 is a diagram that explains fuel flow in a swirling chamber of the fuel injection valve according to Embodiment 1 of the present invention!
Figure 4 is a cross section that shows a configuration that increases a spraying flow rate of the fuel injection valve according to Embodiment 1 of the present invention;

Figure 5 is a diagram that shows a vicinity of a valve seat of a fuel injection valve according to Embodiment 2 of the present invention!
Figure 6 is a diagram that shows a vicinity of a valve seat of a fuel injection valve according to Embodiment 3 of the present invention!
Figure 7 is a diagram that shows a vicinity of a valve seat of a fuel injection valve according to Embodiment 4 of the present invention!
Figure 8 is a diagram that shows a vicinity of a valve seat of a fuel injection valve according to Embodiment 5 of the present invention!
Figure 9 is a diagram that shows a vicinity of a valve seat of a fuel injection valve according to Embodiment 6 of the present invention!
Figure 10 is a diagram that shows a vicinity of a valve seat of a fuel injection valve according to Embodiment 7 of the present invention!
Figure 11 is a diagram that shows a vicinity of a valve seat when a spraying flow rate is low in a fuel injection valve according to Embodiment 8 of the present invention! and
Figure 12 is a diagram that shows a vicinity of a valve seat when the spraying flow rate is high in the fuel injection valve according to Embodiment 8 of the present invention.
DESCRIPTION OF EMBODIMENTS
[0013] Embodiment 1
Figure 1 is a longitudinal cross section that explains a configuration of a fuel injection valve according to Embodiment 1 of the present invention, and Figure 2 is a diagram that shows a vicinity of a valve seat of the fuel injection valve according to Embodiment 1 of the present invention, Figure 2(a) being a longitudinal cross section thereof, and Figure 2(b) being a cross section that is taken along A - A in Figure 2(a) so as to be viewed in the direction of the arrows. Figure 3 is a diagram that explains fuel flow in a swirling chamber of the fuel injection valve according to Embodiment 1 of the present invention, and Figure 4 is a cross section that shows a configuration that increases a spraying flow rate of the fuel injection valve according to Embodiment 1 of the present invention. Moreover, Figure 4 is a cross section in a position that corresponds to Figure 2(b). Furthermore, a "longitudinal cross section" is a view that shows a cross section in a plane that includes a central axis A0 of the fuel injection valve.

[0014]
In Figures 1 and 2, a fuel injection valve 100 includes: a valve apparatus; a solenoid apparatus that generates an electromagnetic force that opens the valve apparatus! and a spring 8 that generates a spring force that closes the valve apparatus.
[0015]
The solenoid apparatus includes: a core 1 that is produced using a magnetic metal material so as to have a cylindrical shape, and that constitutes a fixed core portion of a magnetic circuit; a coil 2 that is disposed so as to be wound onto a bobbin 3 that is made of an insulating resin so as to surround a first end portion of the core V, a yoke 4 that is produced using a magnetic metal material, and that constitutes a yoke portion of the magnetic circuit; and an armature 7 that constitutes a movable core portion of the magnetic circuit. The core 1, the coil 2, and the yoke 4 are configured so as to be integrated by a housing 5 that is made of an electrically insulating resin. In addition, a terminal 6 that supplies electric power to the coil 2 is formed integrally on the housing 5.
[0016]
The spring 8 is disposed in an internal portion of the core 1, and is fixed to the internal portion of the core 1 such that a rod 9 can adjust the spring force from the spring 8.
[0017]
The valve apparatus includes a valve main body 10, a valve body 11, and a valve seat 12. The valve main body 10 is produced using a magnetic metal material so as to have a cylindrical shape, and is mounted to the core 1 by being welded to an outer circumferential portion at a first end of the core 1 in a press-fitted state. The valve body 11 is welded to the armature 7 in a press-fitted state inside the armature 7, and is mounted so as to protrude toward a first end portion from the armature 7. The armature 7 is disposed inside the valve main body 10 so as to face a first end surface of the core 1 so as to be movable in a direction that is parallel to the central axis A0 of the fuel injection valve 100. A ball 15 that functions as a valve member is fixed to a first end of the valve body 11, and is disposed inside a first end of the valve main body 10. The valve seat 12 is fixed to a first end portion of the valve main body 10. A flat nozzle aperture plate 13 is fixed

to a first end surface of the valve seat 12 by weld portions 16 such that a flat upper surface thereof faces toward the valve seat 12.
[0018]
A guiding portion 10a is formed by expanding a vicinity of a second end portion of an inner circumferential surface of the valve main body 10. The armature 7 is disposed inside the valve main body 10 so as to be slidable on an inner circumferential surface of the guiding portion 10a. A second end of the valve body 11 contacts the spring 8, and bears the spring force from the spring 8. The valve seat 12 includes^ a truncated cone-shaped seat surface 12a that has a tapered shape in a vicinity of a first end; a cylindrical valve seat opening portion 12b that is formed in a vicinity of the first end of the seat surface 12a; and a cylindrical sliding surface 12c that is formed in a vicinity of a second end of the seat surface 12a. Moreover, central axes of the seat surface 12a, the valve seat opening portion 12b, and the sliding surface 12c are aligned with the central axis A0. Beveled portions 15a are formed on an outer circumferential surface of the ball 15 such that an outer circumferential portion of the ball 15 is formed so as to have an approximately pentagonal shape. The ball 15 is able to sit on and separate from the seat surface 12a by moving in a direction that is parallel to the central axis A0 such that corner portions of the pentagonal shape of the ball 15 are guided by the sliding surface 12c.
[0019]
A first swirling chamber 17a and a second swirling chamber 17b are formed on the nozzle aperture plate 13 by indenting an upper surface thereof. The first swirling chamber 17a and the second swirling chamber 17b are each constituted by: a swirling portion 18 that is formed so as to have a cylindrical shape, and that applies a swirling force to the fuel; and a fuel introducing portion 19 that is formed in a rectilinear shape so as to have a predetermined width, that is connected tangentially to the swirling portion 18, and that introduces the fuel to the swirling portion 18. Here, the first swirling chamber 17a and the second swirling chamber 17b are disposed on opposite sides of the central axis A0 such that the fuel introducing portions 19 are oriented toward the central axis A0 and longitudinal directions of the fuel introducing portions 19 align in a radial direction that is centered on the central axis A0. The fuel introducing portion 19 of the first swirling chamber 17a enters into the valve seat

opening portion 12b when viewed from a direction of the central axis AO. A nozzle aperture 14 is formed on the nozzle aperture plate 13 inside the swirling portion 18 of the first swirling chamber 17a so as to pass through in a plate thickness direction. The fuel introducing portion 19 of the second swirling chamber 17b is positioned outside the valve seat opening portion 12b when viewed from the direction of the central axis AO. A nozzle aperture 14 is not formed on the swirling portion 18 of the second swirling chamber 17b.
[0020]
In this manner, the groove shape that is formed on the upper surface of the nozzle aperture plate 13 is a shape in which the first swirling chamber 17a and the second swirling chamber 17b are disposed on opposite sides of the central axis AO such that longitudinal directions of the fuel introducing portions 19 align in a radial direction that is centered on the central axis AO and distances from the central axis AO to the fuel introducing portion 19 are different. Furthermore, when viewed from the direction of the central axis AO, the swirling portions 18 of the first swirling chamber 17a and the second swirling chamber 17b are positioned outside the valve seat opening portion 12b such that fuel is introduced only through the fuel introducing portions 19.
[0021]
Next, operation of the fuel injection valve 100 that is configured in this manner will be explained.
[0022]
In an initial state, there is no passage of electric current to the coil 2, the valve body 11 is pressed toward the valve seat 12 by the spring force from the spring 8, and the ball 15 is placed in contact with the seat surface 12a of the valve seat 12, forming a valve closed state. The armature 7 is spaced apart from the core 1. Fuel is supplied to the fuel injection valve 100 from a vicinity of a second end of the central axis AO.
[0023]
When an actuating signal is sent to a driving circuit of the fuel injection valve 100 by an engine controlling apparatus, current is passed through the coil 2 of the fuel injection valve 100 from outside by means of the terminals 6. Magnetic flux is thereby generated in a magnetic circuit that is constituted by the armature 7, the core 1, the yoke 4, and the valve

main body 10. Thus, magnetic attraction that attracts the armature 7 toward the core 1 is generated. The armature 7 thereby slides on the inner circumferential surface of the guiding portion 10a, and moves toward the core 1 in opposition to the spring force from the spring 8 to contact the first end surface of the core 1. The ball 15, which is linked to the armature 7 by means of the valve body 11, enters a valve open state by separating from the seat surface 12a of the valve seat 12.
[0024]
Thus, fuel that has been supplied to the fuel injection valve 100 flows toward the ball 15 through the internal portion of the core 1. The fuel then passes between the beveled portions 15a of the ball 15 and the sliding surface 12c, passes between the ball 15 and the seat surface 12a, and flows into the valve seat opening portion 12b. As indicated by arrows in Figure 3, the fuel that has flowed into the valve seat opening portion 12b passes through the fuel introducing portion 19 that enters into the valve seat opening portion 12b, and flows into the swirling portion 18 of the first swirling chamber 17a tangentially. The fuel thereby passes along the inner circumferential wall surface of the swirling portion 18 of the first swirling chamber 17a and swirls. In this manner, a swirling force is applied to the fuel in the swirling portion 18 of the first swirling chamber 17a. The fuel to which a swirling force has been applied is then sprayed into an air intake passage of an engine while swirling so as to pass along an inner circumferential wall surface of the nozzle aperture 14. Here, the fuel that is sprayed out of the nozzle aperture 14 is spread into a hollow cone shape in a thin liquid film state by an edge portion of the opening portion of the nozzle aperture 14, facilitating atomization of the fuel.
[0025]
Next, when an operation stopping signal is sent to the driving circuit of the fuel injection valve 100 by the engine controlling apparatus, the passage of electric current through the coil 2 is stopped. Thus, the magnetic attraction that attracts the armature 7 toward the core 1 disappears. The armature 7 then slides on the inner circumferential surface of the guiding portion 10a, and moves toward the valve seat 12 due to the spring force from the spring 8. The ball 15 then enters a valve closed state by contacting the seat surface 12a in a pressed state due to the spring force from the spring 8, and spraying of the fuel is stopped.

[0026]
In Embodiment 1, a first swirling chamber 17a and a second swirling chamber 17b are formed on a nozzle aperture plate 13, and only the fuel introducing portion 19 of the first swirling chamber 17a on which the nozzle aperture 14 is formed enters into the valve seat opening portion 12b. Thus, as shown in Figure 4, the fuel introducing portion 19 of the second swirling chamber 17b can be made to enter into the valve seat opening portion 12b by increasing the aperture diameter of the valve seat opening portion 12b. The second swirling chamber 17b thereby changes into a first swirling chamber 17a. In addition, the number of first swirling chambers 17a that communicate with the valve seat opening portion 12b, in other words, the number of nozzle apertures 14, can be changed by additionally milling nozzle apertures 14 in the swirling portion 18 of the modified second swirling chamber 17b. Moreover, each of the swirling portions 18 is positioned outside the valve seat opening portion 12b.
[0027]
If the second swirling chamber 17b that is not used in spraying enters into the valve seat opening portion 12b, then fuel flows in as far as the second swirling chamber 17b that is not used in spraying. Thus, the total volume of the second swirling chamber 17b that is not used in spraying becomes a dead volume of fuel. According to Embodiment 1, because the second swirling chamber 17b that is not used in spraying does not enter into the valve seat opening portion 12b, the dead volume of fuel can be reduced. Because the dead volume of fuel is reduced thereby, smoothed and accelerated fuel is sprayed even immediately after the commencement of spraying. Thus, fuel injection that has improved atomization can be achieved from the early stages of spraying.
[0028]
Now, in Embodiment 1, a case is shown in which the number of swirling chambers is two, i.e., the first swirling chamber 17a and the second swirling chamber 17b, but the number of swirling chambers can be set according to circumstances to meet a required fuel injection rate. Thus, various fuel injection rates can be accommodated simply by assuming the largest required fuel injection rate when designing the groove shape, and changing the aperture diameter of the valve seat opening portion 12b and additionally milling nozzle apertures 14 using the single designed groove

shape. Because a common groove shape can thereby be achieved for specifications that have different required fuel injection rates, manufacturing costs can be reduced.
[0029]
There is also a risk that the strength of the nozzle aperture plate 13 may degrade and the nozzle aperture plate 13 may deform due to long-term use of the fuel injection valve 100. If the nozzle aperture plate 13 deforms, gaps may arise between the nozzle aperture plate 13 and the valve seat 12, and fuel may flow into the second swirling chamber 17b through the gaps. In Embodiment 1, because a nozzle aperture 14 is not formed on the second swirling chamber 17b, fuel that has flowed into the second swirling chamber 17b through such gaps will not flow out externally. Because the outflow of fuel is thereby stopped even if the nozzle aperture plate 13 deforms, the spraying flow rate will not change, enabling stabilization of the spraying flow rate to be achieved.
[0030] Embodiment 2
Figure 5 is a diagram that shows a vicinity of a valve seat of a fuel injection valve according to Embodiment 2 of the present invention, Figure 5(a) being a longitudinal cross section thereof, and Figure 5(b) being a cross section that is taken along B - B in Figure 5(a) so as to be viewed in the direction of the arrows.
[0031]
In Figure 5, a first swirling chamber 17a and a second swirling chamber 17b are disposed on opposite sides of a central axis A0 such that fuel introducing portions 19 are oriented toward the central axis AO and longitudinal directions of the fuel introducing portions 19 align in a radial direction that is centered on the central axis AO. The fuel introducing portion 19 of the first swirling chamber 17a enters into the valve seat opening portion 12b when viewed from a direction of the central axis AO. The fuel introducing portion 19 of the second swirling chamber 17b is positioned outside the valve seat opening portion 12b when viewed from the direction of the central axis AO. Nozzle apertures 14 are formed on the swirling portions 18 of the first swirling chamber 17a and the second swirling chamber 17b.

Moreover, a remainder of the configuration is configured in a similar or identical manner to that of Embodiment 1 above.
[0032]
The groove shape that is formed on the upper surface of the nozzle aperture plate 13 in Embodiment 2 includes a first swirling chamber 17a and a second swirling chamber 17b that each have a swirling portion 18 and a fuel introducing portion 19. The first swirling chamber 17a and the second swirling chamber 17b are disposed on opposite sides of the central axis A0 such that longitudinal directions of the fuel introducing portions 19 align in a radial direction that is centered on the central axis AO and distances from the central axis AO to the fuel introducing portion 19 are different. Nozzle apertures 14 are formed on the swirling portions 18 of both the first swirling chamber 17a and the second swirling chamber 17b. Only the fuel introducing portion 19 of the first swirling chamber 17a enters into the valve seat opening portion 12b. Thus, fuel does not flow into the second swirling chamber 17b that is not used in spraying. In addition, the number of first swirling chambers 17a that communicate with the valve seat opening portion 12b, in other words, the number of nozzle apertures 14, can be changed by increasing the aperture diameter of the valve seat opening portion 12b to make the fuel introducing portion 19 of the first swirling chamber 17a and the second swirling chamber 17b enter into the valve seat opening portion 12b.
Consequently, similar or identical effects to those in Embodiment 1 above can also be achieved in Embodiment 2.
[0033]
According to Embodiment 2, nozzle apertures 14 are formed on the swirling portions 18 of the first swirling chamber 17a and the second swirling chamber 17b in advance. Thus, when changing the spraying flow rate, the number of first swirling chambers 17a that communicate with the valve seat opening portion 12b, in other words, the number of nozzle apertures 14, can be changed simply by increasing the aperture diameter of the valve seat opening portion 12b to make the fuel introducing portion 19 of the first swirling chamber 17a and the second swirling chamber 17b enter into the valve seat opening portion 12b. In other words, additional milling of nozzle apertures 14 is no longer required. Thus, not only a common groove shape, but also a common nozzle aperture plate 13, becomes possible

for specifications that have different required fuel injection rates, enabling manufacturing costs to be reduced.
[0034] Embodiment 3
Figure 6 is a diagram that shows a vicinity of a valve seat of a fuel injection valve according to Embodiment 3 of the present invention, Figure 6(a) being a longitudinal cross section thereof, and Figure 6(b) being a cross section that is taken along C - C in Figure 6(a) so as to be viewed in the direction of the arrows.
[0035]
In Figure 6, two first swirling chambers 17a and two second swirling chambers 17b are disposed at a uniform angular pitch around a central axis AO such that fuel introducing portions 19 are oriented toward the central axis AO and longitudinal directions of the fuel introducing portions 19 align in a radial direction that is centered on the central axis AO. A distance between the pair of first swirling chambers 17a that are disposed so as to face each other on opposite sides of the central axis AO and the central axis AO is LI. A distance between the pair of second swirling chambers 17b that are disposed so as to face each other on opposite sides of the central axis AO and the central axis AO is L2. Here, a relationship among the distances LI and L2and a radius Rl of the valve seat opening portion 12b is LI < Rl < L2. In other words, the fuel introducing portions 19 of the pair of first swirling chambers 17a enter into the valve seat opening portion 12b when viewed from a direction of the central axis AO. The fuel introducing portions 19 of the pair of second swirling chambers 17b are positioned outside the valve seat opening portion 12b when viewed from the direction of the central axis AO. Nozzle apertures 14 are only formed on the swirling portions 18 of the pair of first swirling chambers 17a.
Moreover, a remainder of the configuration is configured in a similar or identical manner to that of Embodiment 1 above.
[0036]
The groove shape that is formed on the upper surface of the nozzle aperture plate 13 in Embodiment 3 includes two first swirling chambers 17a and two second swirling chambers 17b that each include a swirling portion 18 and a fuel introducing portion 19. The first swirling chambers 17a and the second swirling chambers 17b are arranged at a uniform angular pitch

around the central axis AO such that longitudinal directions of the fuel introducing portions 19 align in a radial direction that is centered on the central axis AO. The distance between the pair of first swirling chambers 17a that face each other on opposite sides of the central axis AO and the central axis AO is LI, and the distance between the pair of second swirling chambers 17b that face each other on opposite sides of the central axis AO and the central axis AO is L2, which is greater than LI. Only the fuel introducing portions 19 of the pair of first swirling chambers 17a enter into the valve seat opening portion 12b. In addition, nozzle apertures 14 are only formed on the swirling portions 18 of the pair of first swirling chambers 17a. Thus, fuel does not flow into the second swirling chambers 17b that are not used in spraying. In addition, the number of first swirling chambers 17a that communicate with the valve seat opening portion 12b, in other words, the number of nozzle apertures 14, can be changed by increasing the aperture diameter of the valve seat opening portion 12b to make the fuel introducing portions 19 of the two second swirling chambers 17b enter into the valve seat opening portion 12b, and additionally milling nozzle apertures 14.
Consequently, similar or identical effects to those in Embodiment 1 above can also be achieved in Embodiment 3.
[0037]
Now, in Embodiment 3 above, the distances between all four of the first swirling chambers 17a and second swirling chambers 17b and the central axis AO may be made different than each other. In that case, the number of nozzle apertures 14 can be changed to one, two, three, or four using a single groove shape, simply by changing the aperture diameter of the valve seat opening portion 12b, and additionally milling the nozzle apertures 14. Four specifications that have different spraying flow rates can thereby be accommodated using a single groove shape. In addition, the nozzle apertures 14 may be formed on the four first swirling chambers 17a and second swirling chambers 17b in advance. Four specifications that have different spraying flow rates can thereby be accommodated using a single nozzle aperture plate 13.
[0038] Embodiment 4

Figure 7 is a diagram that shows a vicinity of a valve seat of a fuel injection valve according to Embodiment 4 of the present invention, Figure 7(a) being a longitudinal cross section thereof, and Figure 7(b) being a cross section that is taken along D - D in Figure 7(a) so as to be viewed in the direction of the arrows.
[0039]
In Figure 7, a first swirling chamber 20 is constituted by: a pair of swirling portions 18; and a fuel introducing portion 21 that is formed in a rectilinear shape so as to have a predetermined width, that passes through a central axis A0 and is connected tangentially to each of the swirling portions 18, and that introduces fuel to each of the swirling portions 18. The first swirling chamber 20 is disposed such that centers of the pair of swirling portions 18 are point-symmetrical so as to have the central axis A0 as a center of symmetry. Two second swirling chambers 17b are disposed on opposite sides of the central axis A0 such that fuel introducing portions
19 are oriented toward the central axis A0 and longitudinal directions of the
fuel introducing portions 19 align in a radial direction that is centered on
the central axis A0, and such that distances from the central axis A0 to the
fuel introducing portions are equal. Longitudinal directions of the fuel
introducing portions 19 of the second swirling chambers 17b are
perpendicular to the longitudinal direction of the fuel introducing portion 21
of the first swirling chamber 20. Distances between the second swirling
chambers 17b and the central axis A0 are L2, which is greater than a radius
Rl of the valve seat opening portion 12b. In other words, the fuel
introducing portions 19 of the second swirling chambers 17b do not enter
into the valve seat opening portion 12b when viewed from a direction of the
central axis A0. Nozzle apertures 14 are only formed on the swirling
portions 18 of the first swirling chamber 20.
Moreover, a remainder of the configuration is configured in a similar or identical manner to that of Embodiment 1 above.
[0040]
The groove shape that is formed on the upper surface of the nozzle aperture plate 13 in Embodiment 4 includes a single first swirling chamber
20 in which two swirling portions 18 are connected to each other by a fuel
introducing portion 21; and two second swirling chambers 17b that include
a swirling portion 18 and a fuel introducing portion 19. The first swirling

chamber 20 is disposed such that the two swirling portions 18 are point"symmetrical so as to have the central axis AO as a center of symmetry. The two second swirling chambers 17b are disposed on opposite sides of the central axis AO such that longitudinal directions of the fuel introducing portions 19 align in a radial direction that is centered on the central axis AO and such that longitudinal directions of the fuel introducing portions 19 are perpendicular to the longitudinal direction of the fuel introducing portion 21. In addition, distances between the two second swirling chambers 17b and the central axis AO are L2, which is greater than a radius Rl of the valve seat opening portion 12b. Nozzle apertures 14 are only formed on the swirling portions 18 of the first swirling chamber 20. Thus, fuel does not flow into the second swirling chambers 17b that are not used in spraying. In addition, the number of first swirling chambers 20 and first swirling chambers 17a that communicate with the valve seat opening portion 12b, in other words, the number of nozzle apertures 14, can be changed by increasing the aperture diameter of the valve seat opening portion 12b to make the fuel introducing portions 19 of the two second swirling chambers 17b enter into the valve seat opening portion 12b, and additionally milling nozzle apertures 14.
Consequently, similar or identical effects to those in Embodiment 1 above can also be achieved in Embodiment 4.
[0041]
Now, in Embodiment 4 above, the distances between the two second swirling chambers 17b and the central axis AO may be made different than each other. In that case, the number of nozzle apertures 14 can be changed to two, three, or four using a single groove shape, simply by changing the aperture diameter of the valve seat opening portion 12b, and additionally milling the nozzle apertures 14. Three specifications that have different spraying flow rates can thereby be accommodated using a single groove shape. In addition, the nozzle apertures 14 may be formed on the first swirling chamber 20 and the second swirling chambers 17b in advance. Three specifications that have different spraying flow rates can thereby be accommodated using a single nozzle aperture plate 13.
[0042]
Moreover, in Embodiment 4 above, the centers of the swirling portions 18 of the first swirling chamber 20 are disposed so as to be

point"symmetrical so as to have the central axis AO as a center of symmetry, but it is not absolutely necessary for the centers of the swirling portions 18 to be point-symmetrical so as to have the central axis AO as a center of symmetry, provided that they are disposed so as to be spaced apart on opposite sides of the central axis AO.
[0043] Embodiment 5
Figure 8 is a diagram that shows a vicinity of a valve seat of a fuel injection valve according to Embodiment 5 of the present invention, Figure 8(a) being a longitudinal cross section thereof, and Figure 8(b) being a cross section that is taken along E - E in Figure 8(a) so as to be viewed in the direction of the arrows.
[0044]
In Figure 8, an aperture diameter of a valve seat opening portion 12b is large, and fuel introducing portions 19 of a first swirling chamber 17a and a second swirling chamber 17b each enter into the valve seat opening portion 12b. An intermediate plate 30 is disposed between a valve seat 12 and a nozzle aperture plate 13. The valve seat 12, the intermediate plate 30, and the nozzle aperture plate 13 are fixed and integrated by weld portions 16. A cylindrical intermediate opening portion 30a that is smaller in diameter than the valve seat opening portion 12b is formed on the intermediate plate 30 so as to be coaxial to the valve seat opening portion 12b. Only the fuel introducing portion 19 of the first swirling chamber 17a is positioned inside the intermediate opening portion 30a when viewed from the direction of the central axis A0. A nozzle aperture 14 is formed only on the swirling portion 18 of the first swirling chamber 17a.
Moreover, a remainder of the configuration is configured in a similar or identical manner to that of Embodiment 1 above.
[0045]
The groove shape that is formed on the upper surface of the nozzle aperture plate 13 in Embodiment 5 includes a first swirling chamber 17a and a second swirling chamber 17b that each have a swirling portion 18 and a fuel introducing portion 19. The first swirling chamber 17a and the second swirling chamber 17b are disposed so as to face each other on opposite sides of the central axis A0 such that longitudinal directions of the fuel introducing portions 19 align in a radial direction that is centered on

the central axis AO and distances to the central axis AO are different. The aperture diameter of the valve seat opening portion 12b is large, and the fuel introducing portions 19 of both the first swirling chamber 17a and the second swirling chamber 17b enter into the valve seat opening portion 12b. The intermediate plate 30 is disposed between the valve seat 12 and the nozzle aperture plate 13, and only the fuel introducing portion 19 of the first swirling chamber 17a is positioned inside the intermediate opening portion 30a that is formed on the intermediate plate 30. A nozzle aperture 14 is formed only on the swirling portion 18 of the first swirling chamber 17a.
[0046]
Thus, fuel does not flow into the second swirling chamber 17b that is not used in spraying. In addition, the number of first swirling chambers 17a that communicate with the valve seat opening portion 12b, in other words, the number of nozzle apertures 14, can be changed by removing the intermediate plate 30 to make the fuel introducing portion 19 of the second swirling chamber 17b enter into the valve seat opening portion 12b, and additionally milling a nozzle aperture 14.
Consequently, similar or identical effects to those in Embodiment 1 above can also be achieved in Embodiment 5.
According to Embodiment 5, because the number of nozzle apertures 14 can be changed simply by removing the intermediate plate 30, and additionally milling a nozzle aperture 14, it is not necessary to change the valve seat 12, enabling reductions in cost to be achieved.
[0047]
Now, in Embodiment 5 above, nozzle apertures 14 may be formed on the first swirling chamber 17a and the second swirling chamber 17b in advance. Two specifications that have different spraying flow rates can thereby be accommodated using a single nozzle aperture plate 13.
[0048] Embodiment 6
Figure 9 is a diagram that shows a vicinity of a valve seat of a fuel injection valve according to Embodiment 6 of the present invention, Figure 9(a) being a longitudinal cross section thereof, and Figure 9(b) being a cross section that is taken along F - F in Figure 9(a) so as to be viewed in the direction of the arrows.
[0049]

In Figure 9, an aperture diameter of a valve seat opening portion 12b is large, and fuel introducing portions 19 of first swirling chambers 17a and second swirling chambers 17b each enter into the valve seat opening portion 12b. An intermediate plate 30 is disposed between a valve seat 12 and a nozzle aperture plate 13. The valve seat 12, the intermediate plate 30, and the nozzle aperture plate 13 are fixed and integrated by weld portions 16. An intermediate opening portion 30a is formed on the intermediate plate 30 so as to be coaxial to the valve seat opening portion 12b. Only the fuel introducing portions 19 of the first swirling chambers 17a are positioned inside the intermediate opening portion 30a when viewed from the direction of the central axis A0. Nozzle apertures 14 are formed only on the swirling portions 18 of the first swirling chambers 17a.
Here, a radius Rl of the valve seat opening portion 12b, a radius R2 of the intermediate opening portion 30a, a distance LI between the first swirling chambers 17a that communicates with the intermediate opening portion 30a and the central axis A0, and a distance L2 between the second swirling chambers 17b, which do not communicate with the intermediate opening portion 30a, and the central axis A0, are in a relationship LI < R2< L2