Technical Field
[0001] The present invention relates mainly to a fuel injection valve used in an engine
fuel supply system, and more particularly to an improvement in a port injection type fuel
injection valve, that is, a type that injects fuel into an intake port.
10
Background Art
[0002] Hitherto, as such a fuel injection valve, there has been known, as disclosed in
Patent Literature 1 below, a fuel injection valve that includes a valve seat member having
a conical valve seat and a valve hole passing through the central portion of the valve seat,
15 a valve body which interacts with the valve seat to open and close the valve hole, and a
nozzle plate which is joined to the outer end surface of the valve seat member where the
valve hole opens. An imaginary double concentric circle, one of which is large and the
other of which is small, is set around the axis line of the valve hole on the inner surface of
the nozzle plate, and a boundary surface is set, which includes the axis line of the valve
20 hole and divides the imaginary double concentric circle into one imaginary double
semicircle and the other imaginary double semicircle. A first fuel injection hole group
consisting of a plurality of fuel injection holes placed on one imaginary double semicircle
and a second fuel injection hole group consisting of a plurality of fuel injection holes placed
on the other imaginary double semicircle are drilled in the nozzle plate, and first and second
25 fuel spray foams are emitted from the first and the second fuel injection hole groups in
diagonally opposite directions to each other, sandwiching the boundary surface
therebetween.
Citation List
30 Patent Literature
2
[0003] Patent Literature 1: Japanese Patent Application Laid-Open No. 2008-169766
Summary of Invention
Technical Problem
5 [0004] In the fuel injection valve disclosed in Patent Literature described above, the first
and the second fuel spray foams individually have circular cross-sectional shapes, and the
fuel particles are distributed throughout.
[0005] However, in the fuel injection valve that injects fuel toward the downstream of
the intake port of an engine, when the target point of fuel injection is set to the valve parts
10 of a pair of intake valves due to the compactness of the engine, if the above-described
conventional fuel injection valve is adopted and the first and the second fuel foams emitted
from the first and the second fuel injection hole groups are directed toward the valve parts
of the pair of intake valves, then the first and the second fuel spray foams will come in
contact with the valve stems of the pair of intake valves, inconveniently causing many fuel
15 particles to adhere to the valve stems. Further, if the spread angle between the first and
the second fuel spray foams is increased to avoid the above-described adherence of fuel
particles, then the first and the second fuel spray foams will in turn inconveniently come in
greater contact with port wall surfaces. This phenomenon not only hinders the
improvement of fuel efficiency of the engine, but also leads to an increase in PN (particulate
20 number of emissions).
[0006] The present invention has been made in view of the circumstances described
above, and an object of the invention is to provide a fuel injection valve that enables first
and second fuel injection hole groups to efficiently emit first and second fuel spray foams
toward both valve parts while minimizing contact with the valve stems of both intake valves
25 when a fuel injection target point is the valve parts of a pair of intake valves.
Solution to Problem
[0007] In order to achieve the above-described object, a first aspect of the present
invention provides a fuel injection including: a valve seat member having a conical valve
30 seat and a valve hole passing through a central portion of the valve seat; a valve body which
3
interacts with the valve seat to open and close the valve hole; and a nozzle plate which is
joined to the outer end surface of the valve seat member where the valve hole opens,
characterized in that, on an inner surface of the nozzle plate that is adjacent to the valve
seat member, an imaginary single circle is set around an axis line of the valve hole, a
5 boundary surface is set, which includes the axis line of the valve hole and divides the
imaginary single circle into one imaginary semicircle and the other imaginary semicircle,
a first fuel injection hole group consisting of a plurality of fuel injection holes with inlets
thereof open on the one imaginary semicircle and a second fuel injection hole group
consisting of a plurality of fuel injection holes with inlets thereof open on the other
10 imaginary semicircle are provided in the nozzle plate, hole axis lines of the fuel injection
holes are inclined in a direction away from the axis line of the valve hole from an inlet side
thereof toward an outlet side thereof, and a first and a second fuel spray foams are emitted
from the first and the second fuel injection hole groups in diagonally opposite directions
from each other, sandwiching the boundary surface therebetween, wherein a taper angle is
15 given to each of the plurality of fuel injection holes such that an outlet diameter thereof is
larger than an inlet diameter thereof, different swing angles are given to the hole axis lines
of the plurality of fuel injection holes with respect to the boundary surface in a plan view
of the nozzle plate, and a concave groove that opens toward the boundary surface is formed
in each of the first and the second fuel spray foams.
20 [0008] Further, in addition to the first aspect, a second aspect of the present invention is
characterized in that each of the fuel injection hole groups has at least a central fuel injection
hole positioned at the center of the group, a pair of first outer fuel injection holes positioned
on both sides of the central fuel injection hole, and a pair of second outer fuel injection
holes positioned on both sides of the first outer fuel injection holes, and in a plan view of
25 the nozzle plate, a central hole axis line, which is a hole axis line of the central fuel injection
hole, intersects with the axis line of the valve hole, while first outer hole axis lines, which
are the hole axis lines of the first outer fuel injection holes, and second outer hole axis lines,
which are the hole axis lines of the second outer fuel injection holes, are sequentially spaced
apart from the axis line of the valve hole so as to intersect with the boundary surface, and
30 when swing angles formed by the central hole axis line, the first outer hole axis lines, and
4
the second outer hole axis lines with respect to the boundary surface are denoted by α, β,
and γ, α > β > γ is set.
[0009] Further, in addition to the first and the second aspects, a third aspect of the present
invention is characterized in that each fuel injection hole of the first and the second fuel
5 injection hole groups is formed such that an extended line of a generatrix of a conical
surface forming the valve seat passes through an inlet of the fuel injection hole and
intersects with an inner peripheral surface thereof.
Effect of the Invention
[0010] According to the first aspect of the present invention, it is possible to generate a
10 concave groove, which opens toward the boundary surface, in each of the first and the
second fuel spray foams emitted from the first and the second fuel injection hole groups in
diagonally opposite directions from each other, sandwiching the boundary surface
therebetween. Thus, when the first and the second fuel spray foams described above are
directed toward the valve parts of a pair of intake valves, the concave grooves of the first
15 and the second fuel spray foams receive the valve stems of both intake valves. This makes
it possible to minimize the contact of the first and the second fuel spray foams to both valve
stems, thus contributing to improvement of fuel efficiency of an engine and also a reduction
in PN.
[0011] According to the second aspect of the present invention, in each fuel injection
20 hole group, the central hole axis line intersects with the axis line of the valve hole, while
the first outer hole axis lines and the second outer hole axis lines are sequentially spaced
apart from the axis line of the valve hole to intersect with the boundary surface in the plan
view of the nozzle plate, and when the swing angles formed by the central hole axis line,
the first outer hole axis lines, and the second outer hole axis lines with respect to the
25 boundary surface are denoted by α, β, and γ, α > β > γ is set. This makes it possible to
accurately form, in the first and the second fuel spray foams, the concave grooves that open
toward the boundary surface. Therefore, when the first and the second fuel spray foams
are directed toward the valve parts of the pair of intake valves, the concave grooves of the
first and the second fuel spray foams accurately receive the valve stems of both intake
30 valves, so that the contact of the first and the second fuel spray foams to the valve stems
5
can be effectively avoided, thus permitting further contribution to the improvement of
engine fuel efficiency and a reduction in PN. In addition, interference between fuels
injected from adjacent fuel injection holes in each fuel injection hole group can be
prevented, and also a sufficient spread angle between the hole axis lines of the second outer
5 fuel injection holes of both fuel injection hole groups can be secured so as to prevent
interference between fuels injected from both second outer fuel injection holes, thus
suppressing the occurrence of fuel wetting on the outer surface of the nozzle plate, making
it possible to contribute to prevention of deposits from building up.
[0012] According to the third aspect of the present invention, each fuel injection hole of
10 the first and the second fuel injection hole groups is formed such that an extended line of a
generatrix of a conical surface forming the valve seat passes through the inlet of the fuel
injection hole and intersects with the inner peripheral surface thereof. Therefore, fuel that
passes through the valve hole flows into the inlet of each fuel injection hole and violently
collides with the inner peripheral surface of the injection hole, thus accelerating atomization,
15 before being injected through the outlet thereof. This enables each fuel injection hole to
emit fuel spray foam with well atomized fuel, making it possible to further contribute to
improvement of engine fuel efficiency and a reduction in PN.
Brief Description of Drawings
20 [0013] FIG. 1 is a sectional view of a major section of an engine provided with a fuel
injection valve according to the present invention, the fuel injection valve emitting fuel
spray foams.
FIG. 2 is a longitudinal sectional view taken along line 2-2 in FIG. 1.
FIG. 3 is an enlarged longitudinal sectional view of the fuel injection valve in
25 FIG. 1.
FIG. 4 is an enlarged view of section 4 in FIG. 3.
FIG. 5 is a sectional view taken along line 5-5 in FIG. 4.
FIG. 6 is an enlarged plan view observed from the inner surface side of a nozzle
plate.
30
6
Description of Reference Numerals
[0014] I…..fuel injection valve
B…..boundary surface
C…..imaginary circle
5 Ca…..one imaginary semicircle
Cb…..the other imaginary semicircle
d…..fuel injection hole inlet diameter
D…..fuel injection hole outlet diameter
Fa…..first fuel spray foam
10 Fb…..second fuel spray foam
θ …..fuel injection hole taper angle
Y…..axis line of valve hole 7
α…..swing angle of central hole axis line
β…..swing angle of first outer hole axis line
15 γ…..swing angle of second outer hole axis line
2…..valve housing
3…..valve seat member
7…..valve hole
8…..valve seat
20 10….nozzle plate
13….valve body
14….spherical valve part
50A…first fuel injection hole group
50B…second fuel injection hole group
25 51….fuel injection hole (central fuel injection hole)
52….fuel injection hole (first outer fuel injection hole)
53….fuel flow passage (second outer fuel injection hole)
51a…central hole axis line
52a…first outer hole axis line
30 53a…second outer hole axis line
7
57a…concave groove of first fuel spray foam
57b…concave groove of second fuel spray foam
Description of Embodiments
5 [0015] An embodiment of the present invention will be described below with reference
to the accompanying drawings. In an electromagnetic fuel injection valve I according to
the present invention, the fuel injection side will be referred to as the front, and the fuel
inlet side will be referred to as the rear.
[0016] First, in FIG. 1, an intake port 42 and a pair of intake valve holes 54a and 54b,
10 which are formed at the downstream end of the intake port 42 and which open to a
combustion chamber, are formed in a cylinder head 40 of an engine E. A pair of intake
valves 55 and 56 which open and close the intake valve holes 54a and 54b are slidably
supported by the cylinder head 40. These intake valves 55 and 56 are composed of
umbrella-shaped valve parts 55a and 56a and rod-shaped valve stems 55b and 56b,
15 respectively. Further, the electromagnetic fuel injection valve I is attached to a mounting
hole 41 of the cylinder head 40 via a seal-cushion ring 43. At that time, the fuel injection
valve I is placed such that a boundary surface B, which includes an axis line Y thereof and
which will be described later, passes through the midpoint between the pair of intake valves
55 and 56. Further, the fuel injection valve I is adapted to emit first and second fuel spray
20 foams Fa and Fb toward the pair of valve parts 55a and 56a, sandwiching the boundary
surface B therebetween.
[0017] As illustrated in FIG. 3 and FIG. 4, a valve housing 2 of the fuel injection valve
I is composed of a cylindrical valve seat member 3, a magnetic cylindrical body 4 which is
fitted to and welded liquid-tightly to the outer peripheral surface of the rear end portion of
25 the valve seat member 3, a non-magnetic cylindrical body 6 which is abutted against and
welded liquid-tightly to the rear end of the magnetic cylindrical body 4, a hollow cylindrical
fixed core 5 having a small-diameter front end portion 5a fitted to and welded liquid-tightly
to the inner peripheral surface of the non-magnetic cylindrical body 6, and a fuel inlet pipe
26 which is fitted to and welded liquid-tightly to the outer periphery of the rear end portion
30 of the fixed core 5.
8
[0018] The valve seat member 3 has a valve seat 8 formed with a conical surface having
a central angle , a valve hole 7 penetrating the central portion of the valve seat 8, a valve
guide hole 9 communicating with the large-diameter part of the valve seat 8, and a tapered
hole 16 communicating with the rear end of the valve guide hole 9.
5 [0019] At the front end of the non-magnetic cylindrical body 6, a portion is left that does
not fit with the fixed core 5, a hollow cylindrical movable core 12 facing the front end
surface of the fixed core 5 is fitted from the above-mentioned portion to the magnetic
cylindrical body 4, and a valve body 13 is connected to the movable core 12.
[0020] The valve body 13 is composed of a spherical valve part 14 capable of sliding in
10 the valve guide hole 9 so as to open and close the valve hole 7 by interacting with the valve
seat 8, and a valve stem 15 with the front end portion thereof connected by welding to the
spherical valve part 14, and the rear end portion of the valve stem 15 is press-fitted into the
inner peripheral surface of the movable core 12 and connected by welding. Thus, the
valve body 13 can move up and down integrally with the movable core 12 in the valve
15 housing.
[0021] The valve stem 15 is formed of a pipe material with a mortise 15a, and the inside
thereof communicates with the hollow portion of the movable core 12, and the inside and
outside of the valve stem 15 communicate with each other via the mortise 15a.
[0022] A retainer 20 formed of a pipe material with a mortise is press-fitted and fixed at
20 the middle of the hollow portion of the fixed core 5, and the front end portion thereof serves
as a first spring seat 21. Meanwhile, the rear end portion of the valve stem 15 ends
halfway in the hollow portion of the movable core 12, and the rear end portion thereof
forms a second spring seat 22, and a valve spring 23 is provided in a contracted state
between the first and the second spring seats 21 and 22. The set load of the valve spring
25 23 urges the movable core 12 in a direction away from the fixed core 5, i.e., in a direction
in which the valve body 13 is closed. The set load of the valve spring 23 is adjusted by
the depth to which the retainer 20 is pressed into the fixed core 5.
[0023] A ring-shaped stopper member 35 which is made of a non-magnetic material and
which protrudes slightly from the rear end surface of the movable core 12 is embedded in
30 the inner peripheral surface of the movable core 12. The stopper member 35 comes in
9
contact with the fixed core 5 when the fixed core 5 attracts the movable core 12, thereby
maintaining a certain gap between the two cores 5 and 12.
[0024] A coil assembly 28 is fitted around the outer periphery of the valve housing 2 in
correspondence with the two cores 5 and 12. This coil assembly 28 extends from the rear
5 end of the magnetic cylindrical body 4 to the fixed core 5 and is composed of a bobbin 29
which is made of a synthetic resin and which is fitted around the outer peripheral surface
thereof and a coil 30 that is wound therearound. The rear end portion of the bobbin 29
has a terminal support arm 29a which is integrally formed therewith and which supports
the proximal end portion of a power supply terminal 33 protruding to one side thereof, and
10 an end of the coil 30 is connected to the power supply terminal 33. A yoke 31 is disposed
on the outer periphery of the coil assembly 28. Thus, the fixed core 5, the movable core
12, the valve spring 23 and the coil assembly 28 constitute an electromagnetic actuation
device 11 that opens the valve body 13 when the coil 30 of the coil assembly 28 is energized.
[0025] A coating layer 27 made of a synthetic resin is injection-molded to cover the outer
15 peripheral surfaces of the magnetic cylindrical body 4 and the fuel inlet pipe 26 and to
embed the coil assembly 28. At this time, a coupler 34 that houses and holds the power
supply terminal 33 and protrudes to one side of the coil assembly 28 is molded integrally
with the coating layer 27.
[0026] A fuel filter 36 is installed to the inlet of the fuel inlet pipe 26. Further, a fuel
20 supply cap 46 is fitted, via a sealing member 47, to the outer periphery of the upper end
portion of the fuel inlet pipe 26. The fuel supply cap 46 is one of a plurality of fuel supply
caps formed by being branched off from a fuel rail 45 connected to a discharge port of a
fuel pump (not illustrated).
[0027] As illustrated in FIG. 4 and FIG. 5, the valve guide hole 9 provided in the valve
25 seat member 3 is formed to have a regular polygonal cross section (a regular hexagonal
shape in the illustrated example) and to extend rearward from the large-diameter portion of
the conical valve seat 8 along an axis line Y of the valve hole 7 (which is also the axis line
of the fuel injection valve I). More specifically, the valve guide hole 9 in the illustrated
example is formed by alternately arranging six flat surface portions 9a of the same width
30 and six inner corner portions 9b so as to surround the axis line Y of the valve hole 7 (i.e.,
10
the axis line of the valve hole 7), and the six flat surface portions 9a serve as guide portions
for guiding the lifting and lowering, i.e., the opening and closing operation, of the spherical
valve part 14. In addition, a plurality of fuel flow passages 37 connected to the valve seat
8 are defined between the six inner corner portions 9b and the spherical valve part 14.
5 [0028] Thus, the hollow portions of the fuel inlet pipe 26, the fixed core 5, the valve
stem 15, and the valve housing 2, the mortise 15a of the valve stem 15, and the plurality of
the fuel flow passages 37 around the spherical valve part 14 constitute the sequence of a
fuel flow passage 39 extending from the inlet of the fuel inlet pipe 26 to the valve seat 8.
[0029] The nozzle plate 10 made of a steel plate is welded liquid-tightly to the front end
10 surface, i.e., the outer end surface, of the valve seat member 3 where the outlet of the valve
hole 7 opens.
[0030] As illustrated in FIG. 6, an imaginary single circle C centered on the axis line Y
of the valve hole 7 is set in the circular area surrounded by the outlet of the valve hole 7 on
the inner surface of the nozzle plate 10 that faces the outer end surface of the valve seat
15 member 3. Further, a boundary surface B is set which bisects the imaginary single circle
C into one imaginary semicircle Ca and the other imaginary semicircle Cb, and a first fuel
injection hole group 50A consisting of a plurality of fuel injection holes 51, 52 and 53
having the inlets thereof open on one imaginary semicircle Ca, and a second fuel injection
hole group 50B consisting of a plurality of fuel injection holes 51, 52 and 53 having the
20 inlets thereof open on the other imaginary semicircle Cb are drilled in the nozzle plate 10.
[0031] The first and the second fuel injection hole groups 50A and 50B each has at least
the central fuel injection hole 51 positioned at the center of the group, a pair of first outer
fuel injection holes 52 positioned on both sides of the central fuel injection hole 51, and a
pair of second outer fuel injection holes 53 positioned on both sides of the first outer fuel
25 injection holes 52.
[0032] The detail view in FIG. 4 illustrates the central fuel injection hole 51 of the first
fuel injection hole group 50A, which represents all of the fuel injection holes of the first
and the second fuel injection hole groups 50A and 50B. As is clear from this, hole axis
lines 51a, 52a and 53a of all of the fuel injection holes 51, 52 and 53 incline away from the
30 axis line Y of the valve hole 7 as spaced apart from the inlet side toward the outlet side, and
11
all of the fuel injection holes 51, 52 and 53 are given a taper angle θ such that outlet
diameters D thereof are larger than inlet diameters d thereof.
[0033] Referring back to FIG. 6, the first and the second fuel injection hole groups 50A
and 50B have symmetrical configurations, so that only the first fuel injection hole group
5 50A will be described, and a description of the second fuel injection hole group 50B will
be omitted.
[0034] First, in the first fuel injection hole group 50A, the hole axis line of the central
fuel injection hole 51 will be referred to as the central hole axis line 51a, the hole axis line
of the first outer fuel injection hole 52 will be referred to as the first outer hole axis line 52a,
10 and the hole axis line of the second outer fuel injection hole 53 will be referred to as the
second outer hole axis line 53a.
[0035] In a plan view observed from the inner surface side of the nozzle plate 10, the
central hole axis line 51a is orthogonal to the axis line Y of the valve hole 7, while the first
outer hole axis line 52a is spaced apart from the axis line Y of the valve hole 7 and intersects
15 with the boundary surface B, and the second outer hole axis line 53a is further spaced apart
from the axis line Y of the valve hole 7 and intersects with the boundary surface B. Further,
when the swing angles of the central hole axis line 51a, the first outer hole axis line 52a,
and the second outer hole axis line 53a with respect to the boundary surface B are denoted
by α, β, and γ, respectively, α > β > γ is set. All the fuel injection holes 51, 52, and 53 are
20 drilled in the nozzle plate 10 such that these conditions are satisfied.
[0036] The operation of the present embodiment will now be described.
[0037] When the coil 30 is in a power-off state, the movable core 12 and the valve body
13 are pressed forward by a set load of the valve spring 23, causing the spherical valve part
14 to seat on the valve seat 8. Therefore, the fuel pumped from a fuel pump (not
25 illustrated) through a fuel line to the fuel inlet pipe 26 fills the sequence of the fuel flow
passage 39 and stands by therein.
[0038] When the coil 30 is switched to a power-on state, the magnetic flux generated by
the coil 30 passes through the fixed core 5, a yoke 31, the magnetic cylindrical body 4, and
the movable core 12 in sequence, and the magnetic force causes the movable core 12
30 together with the valve body 13 to be attracted to the fixed core 5 against the set load of the
12
valve spring 23, causing in turn the spherical valve part 14 of the valve body 13 to leave
the valve seat 8, opening the valve hole 7. Thus, in the fuel flow passage 39, the fuel
flows down through the plurality of fuel flow passages 37 around the spherical valve part
14, passes through the valve seat 8 and the valve hole 7, and is injected from the fuel
5 injection holes 51, 52 and 53 of the first and the second fuel injection hole groups 50A and
50B of the nozzle plate 10 toward the valve parts 55a and 56a of the pair of intake valves
55 and 56.
[0039] The first and the second fuel injection hole groups 50A and 50B each consists of
the plurality of fuel injection holes 51, 52 and 53 having the inlets thereof open on one
10 imaginary semicircle Ca and the other imaginary semicircle Cb set on the inner surface of
the nozzle plate 10. In addition, in each of the fuel injection hole groups 50A and 50B, all
the fuel injection holes 51, 52 and 53 are provided with the taper angle θ such that the outlet
diameters D thereof are larger than the inlet diameters d thereof, and the hole axis lines 51a,
52a and 53a of all the fuel injection holes 51, 52 and 53 are inclined so as to be spaced apart
15 from the axis line Y of the valve hole 7 toward the outlet side from the inlet side. Thus,
as illustrated in FIG. 1, the first fuel injection hole group 50A and the second fuel injection
hole group 50B can inject fuel in two directions diagonally opposite to each other,
sandwiching the boundary surface B therebetween, i.e., toward the valve parts 55a and 56a
of the pair of intake valves 55 and 56 so as to form the first and the second fuel spray foams
20 Fa and Fb.
[0040] At that time, especially each of the fuel injection holes 51, 52 and 53 of the first
and the second fuel injection hole groups 50A and 50B is formed such that an extended line
8a of the generatrix of the conical surface forming the valve seat 8 passes through the inlets
of the fuel injection holes 51, 52 and 53 and intersects with the inner peripheral surface
25 thereof. Therefore, when the fuel passes through the valve hole 7 and flows into the inlet
of each of the fuel injection holes 51, 52 and 53, the fuel violently collides with the inner
peripheral surface of each of the injection holes 51, 52 and 53, thus accelerating atomization
of the fuel before the fuel is injected through the outlets of the injection holes 51, 52 and
53. Consequently, the first and the second fuel spray foams Fa and Fb of well atomized
30 fuel can be emitted through the fuel injection holes 51, 52 and 53 of the first and the second
13
fuel injection hole groups 50A and 50B as illustrated in FIG. 1, making it possible to
contribute to improvement of engine fuel efficiency and a reduction in PN.
[0041] Furthermore, in each of the first and the second fuel injection hole groups 50A
and 50B, in the plan view of the nozzle plate 10, the central hole axis line 51a intersects
5 with the axis line Y of the valve hole 7, while the first outer hole axis line 52a and the
second outer hole axis line 53a are sequentially spaced apart from the axis line Y of the
valve hole 7 and intersect with the boundary surface B. When the swing angles of the
central hole axis line 51a, the first outer hole axis line 52a, and the second outer hole axis
line 53a with respect to the boundary surface B are denoted by α, β, and γ, respectively, α
10 > β > γ is set. This causes the first and the second fuel spray foams Fa and Fb to have Vshaped or U-shaped cross-sections with the concave grooves 57a and 57b, which open
toward the boundary surface B, as illustrated in FIG. 2. Therefore, the first and the second
fuel spray foams Fa and Fb directed toward the valve parts 55a and 56a of the pair of intake
valves 55 and 56 receive the valve stems 55b and 56b of both intake valves 55 and 56 into
15 the concave grooves 57a and 57b, thereby minimizing the contact of the first and the second
fuel spray foams Fa and Fb to both valve stems 55b and 56b. This minimize adhesion of
fuel to both valve stems 55b and 56b, making it possible to further contribute to
improvement of engine fuel efficiency and a reduction in PN.
[0042] In addition, all the fuel injection holes 51, 52 and 53 of the first and the second
20 fuel injection hole groups 50A and 50B are placed on the imaginary single circle C set on
the inner surface of the nozzle plate 10, thus making it possible to secure sufficient mutual
distances among the fuel injection holes 51, 52 and 53 to avoid mutual interference of fuels
injected from the adjacent fuel injection holes 51, 52 and 53. In addition, a sufficient
spread angle  between the second outer hole axis lines 53a of both fuel injection hole
25 groups 50A and 50B is secured, so that mutual interference between the fuels injected from
both second outer fuel injection holes 53 can be effectively prevented. Thus, the
occurrence of fuel wetting on the outer surface of the nozzle plate 10 due to mutual
interference between injected fuels can be suppressed, thereby preventing the accumulation
of deposits.
30 [0043] The present invention is not limited to the embodiment described above, and a
14
variety of design changes can be made within a scope that does not deviate from the gist of
the present invention.
15
WE CLAIM:
1. A fuel injection valve comprising: a valve seat member (3) having a conical valve
seat (8) and a valve hole (7) passing through a central portion of the valve seat (8); a valve
5 body (13) which interacts with the valve seat (8) to open and close the valve hole (7); and
a nozzle plate (10) which is joined to an outer end surface of the valve seat member (3)
where the valve hole (7) opens, characterized in that, on an inner surface of the nozzle plate
(10) that is adjacent to the valve seat member (3), an imaginary single circle (C) is set
around an axis line (Y) of the valve hole (7), a boundary surface (B) is set, which includes
10 the axis line (Y) of the valve hole (7) and divides the imaginary single circle (C) into one
imaginary semicircle (Ca) and the other imaginary semicircle (Cb), a first fuel injection
hole group (50A) composed of a plurality of fuel injection holes (51, 52 and 53) with inlets
thereof open on the one imaginary semicircle (Ca) and a second fuel injection hole group
(50B) composed of a plurality of fuel injection holes (51, 52 and 53) with inlets thereof
15 open on the other imaginary semicircle (Cb) are provided in the nozzle plate (10), hole axis
lines (51a, 52a and 53a) that connect inlet centers and outlet centers of the plurality of fuel
injection holes (51, 52 and 53) are inclined in a direction away from the axis line (Y) of the
valve hole (7) from an inlet side thereof toward an outlet side thereof, a taper angle (θ) is
given to each of the plurality of fuel injection holes (51, 52 and 53) such that an outlet
20 diameter (D) thereof is larger than an inlet diameter (d) thereof, and a first and a second
fuel spray foams (Fa and Fb) are emitted from the first and the second fuel injection hole
groups (50A and 50B) in diagonally opposite directions from each other, sandwiching the
boundary surface (B) therebetween,
wherein a taper angle (θ) is given to each of the plurality of fuel injection holes
25 (51, 52 and 53) such that an outlet diameter (D) thereof is larger than an inlet diameter (d)
thereof,
different swing angles (α, β, and γ) are given to the hole axis lines (51a, 52a and
53a) of the plurality of fuel injection holes (51, 52 and 53), which are projected in a plan
view of the nozzle plate (10), with respect to the boundary surface (B),
30 each of the fuel injection hole groups (50A and 50B) has at least a central fuel
16
injection hole (51) positioned at a center of the group, a pair of first outer fuel injection
holes (52) positioned on both sides of the central fuel injection hole (51), and a pair of
second outer fuel injection holes (53) positioned on both sides of the first outer fuel
injection holes (52),
5 in a plan view of the nozzle plate (10), a central hole axis line (51a), which is a
hole axis line of the central fuel injection hole (51), intersects with the axis line (Y) of the
valve hole (7),
while first outer hole axis lines (52a), which are the hole axis lines of the first
outer fuel injection holes (52), and second outer hole axis lines (53a), which are the hole
10 axis lines of the second outer fuel injection holes (53), are sequentially spaced apart from
the axis line (Y) of the valve hole (7) so as to intersect with the boundary surface (B),
in a case where swing angles formed by the central hole axis line (51a), the first
outer hole axis lines (52a), and the second outer hole axis lines (53a) with respect to the
boundary surface (B) are denoted by α, β, and γ, α > β > γ is applied, and
15 concave grooves (57a and 57b) that open toward the boundary surface (B) are
formed in the first and the second fuel spray foams (Fa and Fb).
2. The fuel injection valve according to claim 1, wherein each of the fuel injection
holes (51, 52 and 53) of the first and the second fuel injection hole groups (50A and 50B)
20 is formed such that an extended line (8a) of a generatrix of a conical surface forming the
valve seat (8) passes through an inlet of each of the fuel injection holes (51, 52 and 53)
and intersects with an inner peripheral surface thereof.