FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
FUEL INJECTION VALVE;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND EXISTING
UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3, MARUNOUCHI 2-CHOME,
CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE
MANNER IN WHICH IT IS TO BE PERFORMED
2
DESCRIPTION
Technical Field
[0001]
The present disclosure relates to a fuel injection valve.
Background Art
[0002]
In recent years, the exhaust-gas regulation on an automobile
internal combustion engine and the like has been tightened; with
regard to fuel spray to be injected from a fuel injection valve, it
has been required that in consideration of fuel adhesion to an
intake-pipe wall surface, fuel is sufficiently micronized or atomized
(hereinafter referred to as “micronized”) before fuel spray is
performed, while the spraying angle is suppressed from excessively
expanding. As one of the approaches for micronizing a fuel, there
exists a fuel micronization method utilizing a swirling flow of fuel;
there have been made various studies related to this fuel
micronization method.
[0003]
For example, Patent Document 1 discloses a fuel injection valve
in which there are provided a valve seat having an opening portion
through which fuel from the upstream side passes, a valve body, and
a plate that is provided at the downstream side of the valve seat
3
and forms a swirling flow; there has been proposed a plate shape for
a fuel injection valve in which at the upstream side of the plate,
a radial recess having a branch portion, an introduction portion,
a cylinder portion, and a swirling portion is formed, in which at
the downstream side of the cylinder portion, an injection hole is
formed, and in which the size of the flow path including the swirling
portion is regulated so that further micronization of fuel to be
sprayed is realized.
[0004]
Patent Document 1 describes that the terminal surface of the
swirling portion in the plate is slanted by an angle of θ from the
center axis of the introduction portion, that when the angle θ is
in a range from 0° to 45°, a fuel flow A that directly flows into
the cylinder portion from the introduction portion and a fuel flow
B that flows into the cylinder portion by way of the swirling portion
face each other, and that when letting W1 denote the width of the
introduction portion and letting W2 denote the width of the swirling
portion and the equation [0.3 ≤ W2/W1 ≤ 0.7] is established, the
respective strengths of the fuel flow A and the fuel flow B become
substantially equal to each other. It is argued that because as a
result, a swirling flow is homogenous and hence the thickness of a
fuel liquid film formed on the inner wall of the injection hole is
uniform, the degree of fuel micronization becomes excellent. In
contrast, in the method, disclosed in Patent Document 1, in which
a swirling flow makes fuel become a thin film and then the liquid
4
film is split so as to be micronized, although enhancement of the
swirling force of the fuel facilitates expansion of the liquid film
and hence the micronization is facilitated, the spraying angle of
the fuel is concurrently expanded.
[0005]
As an approach for realizing sufficient micronization of fuel
while suppressing fuel spray from expanding, Patent Document 2
proposes a method in which the position at which an injection hole
is disposed is adjusted and in which the injection hole is slanted.
It is argued that an fuel injection valve disclosed in the foregoing
patent document makes it possible that because the strength of the
swirling force of the fuel is adjusted through disposal of the
injection hole, the fuel spray is suppressed from expanding and
because the angle of the injection hole is concurrently adjusted,
the collision force of the fuel to the inner wall surface is increased,
so that the micronization performance is suppressed from
deteriorating or is enhanced.
[0006]
In addition, in Patent Document 2, it is argued that by adjusting
the injection-hole position, i.e., by adjusting the position of the
center axis of the introduction portion and the injection-hole offset
amount, the swirling force of fuel is adjusted so as to suppress the
fuel spray from expanding and so as to slant the injection hole in
a direction opposed to the direction of the fuel flow, so that part
of the fuel flow A collides with the inner wall surface of the injection
5
hole, so that the velocity component in the plane direction
perpendicular to the injection-hole axis is increased, and so that
the fuel that has passed through the injection hole becomes a thin
film immediately below the injection hole and hence the micronization
is facilitated. Moreover, it is described in Patent Document 2 that
as a range of the injection-hole slant direction where the effect
can be obtained, the range between 0 to 180, i.e., the range where
the injection hole is slanted in a direction opposed to the offset
direction of the injection-hole portion from the introduction portion
is regarded as the range where the micronization is facilitated.
[Prior Art Reference]
[Patent Document]
[0007]
[Patent Document 1] International Publication No.
WO2017/060945
[Patent Document 2] Japanese Patent Application Laid-Open No.
2017-210907
Disclosure of the Invention
Problems to be Solved by the Invention
[0008]
In each of Patent Documents 1 and 2, it is described that there
exist a flow A along which a fuel directly flows from an introduction
portion into an injection hole and a flow B through which the fuel
flows into the injection hole by way of a swirling chamber. In Patent
6
Document 1, it is described that the fuel flow A and the fuel flow
B are opposed to each other and the respective strengths of fuel flow
A and the fuel flow B are made to be substantially equal to each other,
so that the homogeneity of a liquid film in the injection hole is
raised and hence micronization of the fuel is improved; however, as
described above, there has been a problem that although enhancement
of swirling force facilitates expansion of the liquid film and hence
the micronization is facilitated, the spraying angle is concurrently
and largely expanded.
[0009]
In the approach described in Patent Document 2, a fuel is made
to become a thin film and is micronized by a swirling flow of the
fuel; in order to raise the micronization, it is important to increase
the peripheral velocity of both the fuel flows A and B in the injection
hole. In the approach, described in Patent Document 2, in which part
of the fuel flow A is made to positively collide with the inner wall
surface of the injection hole and the fuel flow B forms a swirling
flow in the injection hole, there has been a problem that because
the collision of part of the fuel flow A with the inner wall surface
causes the fuel to separate at a time when the fuel flow A rushes
into the injection hole, not only enhancing effect for the peripheral
speed of the fuel flow in the injection hole cannot be obtained but
also there is caused an interference element to the swirling flow
of the fuel flow B in the injection hole, resulting in deterioration
in the swirling force of the whole flow in the injection hole.
7
[0010]
The present disclosure has been implemented in order to solve
the foregoing problems; the objective thereof is to provide a fuel
injection valve that enhances the fuel-spray micronization
performance and suppresses fuel spray from excessively expanding.
Means for Solving the Problems
[0011]
A fuel injection valve disclosed in the present disclosure
includes
a valve seat having a valve-seat opening portion for making
a fuel flow out,
a valve body for opening or closing the valve-seat opening
portion, and
an injection hole plate that is disposed at a downstream
side of a flow of the fuel in such a way as to face the valve-seat
opening portion and that has two or more injection hole portions for
injecting the fuel to the outside; injection of the fuel from the
injection hole portion is controlled by making the valve body travel
in an axial direction of the valve seat so as to open or close the
valve-seat opening portion, based on an operation signal from an
external control apparatus. The fuel injection valve is
characterized
in that the injection hole plate includes, in an endface thereof
at an upstream side of the fuel flow,
8
two or more swirling chambers arranged at a radially
outside of the valve-seat opening portion,
a central portion to be connected with the valve-seat
opening portion, and
two or more introduction portions that each guide the fuel
from the central portion to the respective swirling chambers,
in that the injection-hole portion has an injection-hole inlet
portion that opens in the swirling chamber, and an injection-hole
outlet portion that opens in a downstream-side endface, of the
injection hole plate, that faces the upstream-side endface thereof,
in that the introduction portion has a first side wall portion
and a second side wall portion that face each other across a center
axis of said introduction portion,
in that a center of the injection-hole inlet portion is provided
in such a way as to be offset from the center axis of the introduction
portion toward the first side wall portion and in such a way as to
coincide with a center of the swirling chamber,
in that the swirling chamber includes a curved-surface wall
portion having a curved wall surface,
in that the curved-surface wall portion is connected with the
first side wall portion through the intermediary of a first
straight-surface wall portion that extends linearly,
in that the injection-hole portion is disposed at a position
where the injection-hole inlet portion and a virtual extended line
obtained by extending the first side wall portion toward the
9
injection-hole portion intersect each other, and a center axis of
the injection-hole portion that connects the center of the
injection-hole inlet portion with a center of the injection-hole
outlet portion is slanted from a plate-thickness direction of the
injection hole plate, and
in that when there is imagined an orthogonal coordinate system
defined by a Y axis that is parallel to the center axis of the
introduction portion and whose positive direction heads for the
central portion from the swirling chamber and an X axis that is
perpendicular to the Y axis and along whose positive direction, the
center of the injection-hole inlet portion is offset from the center
axis of the introduction portion, a projected center axis, obtained
by projecting the center axis of the injection-hole portion on a
virtual plane perpendicular to the center axis of the valve seat,
exists at a position to which the positive-direction Y axis turns
by an angle 1 toward the positive-direction X axis with respect to
the origin of the orthogonal coordinate system, and the angle 1 has
a value satisfying an equation [0 ≤ 1  180].
Advantage of the Invention
[0012]
The present disclosure makes it possible to obtain a fuel
injection valve that raises the micronization performance for fuel
spray and suppresses the fuel spray from excessively expanding.
10
Brief Description of the Drawings
[0013]
FIG. 1 is a cross-sectional view of a fuel injection valve
according to each of Embodiments 1 through 5;
FIG. 2A is a partially enlarged cross-sectional view
illustrating part of the fuel injection valve in FIG. 1 in an enlarged
manner;
FIG. 2B is a conceptual view of an injection hole plate, when
viewed along the arrow Z in FIG. 2A;
FIG. 3 is an explanatory view illustrating, in an enlarged manner,
part of the injection hole plate of the fuel injection valve according
to Embodiment 1;
FIG. 4 is an explanatory view illustrating, in an enlarged manner,
part of an injection hole plate of an fuel injection valve according
to Comparative Example 1;
FIG. 5 is another explanatory view illustrating, in an enlarged
manner, part of the injection hole plate of the fuel injection valve
according to Embodiment 1;
FIG. 6 is another explanatory view illustrating, in an enlarged
manner, part of an injection hole plate of an fuel injection valve
according to Embodiment 2;
FIG. 7 is an explanatory view illustrating, in an enlarged manner,
part of an injection hole plate of an fuel injection valve according
to Comparative Example 2;
FIG. 8 is an explanatory view illustrating, in an enlarged manner,
11
part of an injection hole plate of an fuel injection valve according
to Embodiment 3;
FIG. 9 is an explanatory view illustrating, in an enlarged manner,
part of an injection hole plate of an fuel injection valve according
to Embodiment 4;
FIG. 10 is another explanatory view illustrating, in an enlarged
manner, part of the injection hole plate of the fuel injection valve
according to Embodiment 4;
FIG. 11 is an explanatory view illustrating, in an enlarged
manner, part of an injection hole plate of an fuel injection valve
according to Comparative Example 3; and
FIG. 12 is an explanatory view illustrating, in an enlarged
manner, part of an injection hole plate of an fuel injection valve
according to Embodiment 5.
Best Mode for Carrying Out the Invention
[0014]
Embodiment 1
Hereinafter, a fuel injection valve according to Embodiment 1
will be explained with reference to the drawings. FIG. 1 is a
cross-sectional view of a fuel injection valve according to each of
Embodiments 1 through 5; FIG. 2A is a partially enlarged
cross-sectional view illustrating part of the fuel injection valve
in FIG. 1 in an enlarged manner; FIG. 2B is a conceptual view of an
injection hole plate, when viewed along the arrow Z in FIG. 2A. FIG.
12
2B illustrates the concept of an injection hole plate of the fuel
injection valve according to each of Embodiments 1 through 5; the
detailed configuration of the injection hole plate according to each
of the embodiments will be described later.
[0015]
In each of FIGS. 1, 2A, and 2B, a fuel injection valve 1 is
provided with
a valve seat 12 having a valve-seat opening portion 12d
for making a fuel flow out,
a valve body 10 for opening or closing the valve-seat
opening portion 12d, and
an injection hole plate 13 that is disposed at the
downstream side of a fuel flow in such a way as to face the valve-seat
opening portion 12d and that has two or more injection-hole portions
14 for injecting the fuel to the outside; injection of the fuel from
the injection hole portion 14 is controlled by making the valve body
travel 10 in the axial direction of the valve seat 12, based on an
operation signal from an external control apparatus (unillustrated),
so that the valve-seat opening portion 12d is opened or closed.
[0016]
A solenoid device 4 includes
a resin-made frame member 71 provided with respective
flange portions at both axial-direction end portions thereof,
a coil 7 wound around the outer circumference portion of
the frame member 71,
13
a metal housing 5, as a yoke, disposed at the outer
circumference portion of the coil 7,
a metal core 6 that is inserted between the inner
circumferential surface of the frame member 71 and the inner
circumferential surface of the housing 5, and
a resin-made insulating covering 41 in which the coil 7,
the frame member 71, the core 6, and the housing 5 are buried.
[0017]
The valve device 9 has the valve body 10, an armature 8 formed
of metal that is a magnetic material, the valve seat 12, a valve holder
11, and the injection hole plate 13. One axial-direction end portion
of the valve holder 11 is press-fitted into the outer circumference
portion of one axial-direction end portion of the core 6 and then
is fixed on the core 6 through welding. In its inner circumferential
surface at the one axial-direction end portion side, the valve holder
11 has a ring-shaped guide portion 11a protruding from the inner
circumferential surface.
[0018]
One axial-direction end portion of the valve body 10 is
press-fitted into the hollow portion of the armature 8; then, the
armature 8 is fixed integrally with the valve body 10 through welding.
The armature 8 is slidably supported in the axial direction by the
guide portion 11a of the valve holder 11; as described later, when
attracted by the core 6, the armature 8 slides in the axial direction
and an endface 8a thereof abuts on one endface of the core 6. A ball
14
15 is fixed on the other axial-direction end portion of the valve
body 10 through welding and has two or more, for example, six flat
faces 15a formed through chamfering.
[0019]
The valve seat 12 is formed in the shape of a hollow cylinder
whose one axial-direction end portion is opened; a valve-seat opening
portion 12d is provided in an end wall portion at the other
axial-direction end portion thereof. In the valve seat 12, the
foregoing ball 15, fixed on the other axial-direction end portion
of the valve body 10 through welding, is disposed. The ball 15 moves
as the valve body 10 moves in the axial direction. In the inner surface
of the end wall portion in the valve seat 12, there is formed a
ring-shaped valve-seat sheet portion 12a whose surface is inclined
toward the axial direction. When the ball 15 seats itself in the
valve-seat sheet portion 12a of the valve seat 12, the valve-seat
opening portion 12d is sealed; when the ball 15 departs from the
valve-seat sheet portion 12a, the valve-seat opening portion 12d is
released from the sealing and makes the inside and the outside of
the valve seat 12 communicate with each other. The valve body 10 is
constantly urged toward the valve seat 12 by a compression spring
16.
[0020]
The injection hole plate 13 formed in the shape of a plate has
two or more injection-hole portions 14, is disposed in such a way
as to face the valve seat 12 at the downstream side of the fuel flow,
15
and is fixed to the downstream-side endface of the valve seat 12
through a welding portion 50. The respective peripheral portions of
the valve seat 12 and the injection hole plate 13 are fixed on the
inner circumference portion of the other axial-direction end portion
of the valve holder 11 in such a way as to abut thereon. In the surface
thereof facing the valve seat 12, i.e., in the endface thereof at
the upstream side of the fuel flow, the injection hole plate 13 has
a central portion 13a, two or more introduction portions 13b connected
with the central portion 13a, and two or more swirling chambers 13c
that are provided in such a way as to correspond to the two or more
introduction portions 13b and are connected with the corresponding
introduction portions 13b. The central portion 13a, the introduction
portion 13b, and the swirling chamber 13c are formed in the
upstream-side endface of the injection hole plate 13.
[0021]
As illustrated in FIG. 2B, in the endface thereof at the upstream
side of the fuel flow, the injection hole plate 13 has the central
portion 13a, four introduction portions 13b connected with the central
portion 13a, and four swirling chambers 13c that are provided in such
a way as to correspond to these introduction portions 13b and are
connected with the corresponding introduction portions 13b. The
central portion 13a is provided at a position facing the valve-seat
opening portion 12d so that the fuel flowing out through the valve-seat
opening portion 12d flows to the central portion 13a. Each of the
introduction portions 13b is formed in such a way as to introduce
16
the fuel that has flowed to the central portion 13a to the
corresponding swirling chamber 13c. The injection-hole portions 14
are provided in the respective swirling chambers 13c. The central
portion 13a, the introduction portion 13b, and the swirling chamber
13c are formed in such a way that the respective bottom surfaces
thereof are continuously connected with one another in such a way
as to be substantially coplanar. The center of the central portion
13a coincides with the center axis F of the fuel injection valve 1.
In addition, in FIG. 2B, four pieces each of the introduction portions
13b, the swirling chambers 13c, and the injection-hole portions 14
are provided; however, the number of each thereof is not limited to
four.
[0022]
Next, the operation of the fuel injection valve 1 will be
explained. When an operation signal is transmitted from an
internal-combustion-engine control apparatus to a driving circuit
for the fuel injection valve 1, the coil 7 of the fuel injection valve
1 is energized; magnetic flux is produced in the magnetic circuit
including the armature 8, the core 6, the housing 5, and the valve
holder 11; the armature 8 is attracted by the core 6 so as to move
toward the core 6 in such a way as to resist the urging force of the
compression spring 16; the ball 15 of the valve body 10 integrated
with the armature 8 departs from the valve-seat sheet portion 12a
of the valve seat 12; a gap is formed between the ball 15 and the
valve-seat sheet portion 12a.
17
[0023]
When a gap is formed between the ball 15 and the valve-seat sheet
portion 12a, the fuel passes through a gap between the valve-seat
sheet portion 12a and the valve body 10 from a flat face 15a of the
boll 15, flows to the central portion 13a of the injection hole plate
13 through the valve-seat opening portion 12d, and then flows into
the swirling chamber 13c connected with the corresponding one of the
introduction portions 13b that radially extend from the central
portion 13a, by way of that corresponding introduction portion 13b.
The fuel that has flowed into the swirling chamber 13c swirls along
a curved-surface wall portion 13c1 of the swirling chamber 13c, flows
into an injection-hole inlet portion 141 of the injection-hole portion
14, and then is injected into an intake port of the internal combustion
engine through an injection-hole outlet portion 142.
[0024]
Next, when an operation stop signal is transmitted from the
control apparatus of the internal combustion engine to the driving
circuit of the fuel injection apparatus 1, the energization of the
coil 7 is stopped and the magnetic flux in the magnetic circuit
decreases, so that the elastic force of the compression spring 16
pressing the valve body 10 in a valve-closing direction makes the
valve body 10 moves toward the valve seat 12 and then the ball 15
of the valve body 10 seats itself in the valve-seat sheet portion
12a. As a result, the gap between the ball 15 of the valve body 10
and the valve-seat sheet portion 12a is closed and hence fuel injection
18
through the injection-hole portion 14 ends.
[0025]
As described above, in order to realize micronization of the
fuel by causing a swirling flow of the fuel in the swirling chamber
13c, the central portion 13a communicating with the valve-seat opening
portion 12d, the introduction portions 13b having a flat cross section,
and the swirling chambers 13c including the injection-hole portion
14 are arranged in the injection hole plate 13 in such a way as to
communicate with one another. The fuel that has flowed into the
swirling chamber 13c further flows into the injection hole portion
14 while producing a swirling flow; the swirling flow is kept also
in the injection hole portion 14 and hence a thin liquid film is formed
along the inner wall of the injection hole portion 14; the thin liquid
film is injected in a hollow and conical manner, through the
injection-hole outlet portion 142 of the injection hole portion 14;
as a result, the micronization of the fuel is facilitated.
[0026]
Next, the configuration of the injection hole plate in the fuel
injection valve according to Embodiment 1 will be explained. FIG.
3 is an explanatory view illustrating, in an enlarged manner, part
of the injection hole plate of the fuel injection valve according
to Embodiment 1; FIG. 3 illustrates each one of the two or more
introduction portions 13b and swirling chambers 13c, the
injection-hole portion 14, and part of the central portion 13a. In
FIG. 3, as described above, the swirling chamber 13c is provided at
19
the radially outside of the valve-seat opening portion 12d and is
configured in such a way as to have the curved-surface wall portion
13c1 forming part of a virtual arc and in such a way as to make the
fuel introduced by the introduction portion 13b swirl in the swirling
chamber 13c.
[0027]
The injection-hole portion 14 provided in the swirling chamber
13c has the injection-hole inlet portion 141 that opens inside the
swirling chamber 13c and the injection-hole outlet portion 142 that
opens in the surface, at the downstream side of the fuel flow, of
the injection hole plate 13. The center O of the injection-hole inlet
portion 141 is provided at a position that is offset from the center
axis M of the introduction portion 13b toward the first side wall
portion 13b1 of the introduction portion 13b and in such a way as
to coincide with the center of the swirling chamber 13c. The second
side wall portion 13b2 of the introduction portion 13b faces the first
side wall portion 13b1 across the center axis M.
[0028]
The first side wall portion 13b1 toward which the center O of
the injection-hole inlet portion 141 is offset is connected with the
curved-surface wall portion 13c1 of the swirling chamber 13c by way
of a first straight-surface wall portion L. The angle between the
first straight-surface wall portion L and the center axis M of the
introduction portion 13b is 2.
[0029]
20
The injection-hole portion 14 is disposed in such a way that
the injection-hole inlet portion 141 and a virtual extended line 13b1v,
obtained by extending the first side wall portion 13b1 of the
introduction portion 13b toward the injection-hole portion 14,
intersect each other and in such a way that a center axis N
(unillustrated) that connects the center O of the injection-hole inlet
portion 141 with the center of the injection-hole outlet portion 142
is slanted by an injection-hole angle  from the plate-thickness
direction of the injection hole plate 13. The injection-hole angle
 is an angle between the Z axis of after-mentioned virtual orthogonal
coordinates, i.e., the axis extending perpendicularly to the plane
of the paper of FIG. 3 and the center axis N that connects the center
O of the injection-hole inlet portion 141 with the center of the
injection-hole outlet portion 142.
[0030]
When there is imagined an orthogonal coordinate system defined
by a Y axis that is parallel to the center axis M of the introduction
portion 13b and whose positive direction heads for the central portion
13a from the swirling chamber 13c and an X axis that is perpendicular
to the Y axis and whose positive direction is the one along which
the center of the injection-hole inlet portion 141 is offset from
the center axis M of the introduction portion 13b, a projected axis
N1 of the center axis M of the introduction portion 13b, projected
on a virtual plane perpendicular to the center axis F of the valve
seat 12, exists at a position to which the positive-direction Y axis
21
turns by an angle 1 toward the positive-direction X axis with respect
to the origin of the orthogonal coordinate system; the angle 1 has
a value satisfying the equation [0° ≤ θ1  180°]. In addition, each
of the two or more swirling chambers 13c and introduction portions
13b formed in the injection hole plate 13 has the foregoing
configuration illustrated in FIG. 3.
[0031]
The fuel injection valve 1 according to Embodiment 1 has the
injection hole plate 13 configured in such a manner as described above;
therefore, when rushes into the injection-hole portion 14, the fuel
flow A, which directly flows into the injection-hole portion 14 from
the introduction portion 13b, is suppressed from being separated from
the inner wall surface of the injection-hole portion 14, and the fuel
is injected to the outside through the injection-hole outlet portion
142, while swirling along the inner wall surface of the injection-hole
portion 14 in the injection-hole portion 14; thus, the peripheral
velocity of the fuel flow A increases inside the injection-hole
portion 14. Moreover, an interference component that is produced
when the fuel flow A collides with the inner wall surface of the
injection-hole portion 14 and that interferes with the fuel flow B
is also suppressed and hence the pressure loss in the whole fuel flow
in the injection-hole portion 14 is suppressed; thus, there is
demonstrated an effect that the micronization of the fuel is
facilitated.
[0032]
22
Moreover, because the inflow direction of the fuel flow B into
the injection-hole portion 14 can be adjusted by adjusting the angle
2 between the first straight-surface wall portion L and the center
axis M, the balance between the respective strengths of the fuel flow
B and the fuel flow A can be adjusted; thus, there is demonstrated
an effect that the uniformity of the thickness of the fuel liquid
film to be formed on the inner wall surface of the injection-hole
portion 14 is raised and hence the micronization of the fuel can be
facilitated.
[0033]
FIG. 4 is an explanatory view illustrating, in an enlarged manner,
part of an injection hole plate of an fuel injection valve according
to Comparative Example 1; FIG. 4 is a drawing for comparing the fuel
injection valve according to Comparative Example 1 with the fuel
injection valve according to Embodiment 1. In Embodiment 1, as
described above, the angle 1 has a value satisfying the equation [0
≤ 1  180]; however, in Comparative Example 1 illustrated in FIG.
4, the angle 1 has a value satisfying the equation [1  180]. The
other configurations are the same as those in Embodiment 1.
[0034]
In the case of the fuel injection valve, provided with the
injection hole plate 13, according to Comparative Example 1
illustrated in FIG. 4, the fuel flow A directly flows into the
injection-hole portion 14 from the introduction portion 13b, collides
with the inner wall surface of the injection-hole portion 14, and
23
then ramifies into a flow AL and a flow AR. The direction in which
the flow AL that has separated from the flow A flows is opposite to
the direction in which the fuel flow B from the introduction portion
13b flows into the injection-hole portion 14 after swirling clockwise
in the drawing in the swirling chamber 13c. In contrast, the direction
in which the flow AR that has separated from the flow A flows is the
same as the direction in which the fuel flow B from the introduction
portion 13b flows into the injection-hole portion 14. Accordingly,
the flow AL interferes more with the flow B than the flow AR does.
[0035]
As described above, in the fuel injection valve according to
Comparative Example 1 illustrated in FIG. 4, when rushes into the
injection-hole portion 14, the fuel flow A separates from the inner
wall surface of the injection-hole portion 14, collides with the inner
wall surface of the injection-hole portion 14, and then ramifies into
the flow AL and the flow AR; because the direction in which the
separated flow AL flows is the one that impedes the swirling flow
of the flow B, the pressure loss in the whole fuel flow increases.
[0036]
In the foregoing fuel injection valve 1 provided with the
injection hole plate 13 according to Embodiment 1 illustrated in FIG.
3, the angle 1 has a value satisfying the equation [0 ≤ 1  180];
therefore, unlike the fuel injection valve provided with the injection
hole plate 13 according to Comparative Example 1 illustrated in FIG.
4, the fuel flow A does not ramify into the flow AL and the flow AR.
24
Thus, because no flow separated from the fuel flow A does not interfere
with the fuel flow B, the pressure loss in the whole fuel flow does
not increase.
[0037]
Next, the injection hole plate 13 of the fuel injection valve
according to Embodiment 1 will further be explained. FIG. 5 is another
explanatory view illustrating, in an enlarged manner, part of the
injection hole plate of the fuel injection valve according to
Embodiment 1. As illustrated in FIG. 5, the injection hole plate 13
is configured in such a way that in order to reduce the amount of
fuel spray that adheres to the intake pipe of the internal combustion
engine, there is decreased the spraying angle after the fuel is
injected through the injection-hole outlet portion 142 of the
injection-hole portion 14.
[0038]
In FIG. 5, letting Q denote a virtual orthogonal line that
intersects, at the center O of the injection-hole inlet portion 141,
a virtual straight line OK connecting an intersection point K of the
respective center axes M of the two or more introduction portions
13b with the center O of the injection-hole inlet portion 141, the
angle  between the Y axis of the orthogonal coordinate system and
the virtual orthogonal line Q and the angle 1 have respective values
satisfying the equation [1  ].
[0039]
In the injection hole plate 13 configured in such a manner as
25
described above, the fuel spray to be injected through the
injection-hole portion 14 provided in each of the two or more swirling
chambers 13c is injected toward the inner-diameter side, i.e., in
a direction heading for the center axis F of the valve seat 12, so
that there is demonstrated an effect that the spraying angle is
decreased. First and foremost among others, it has been confirmed
through an experimental evaluation that the foregoing angle , which
is an injection-hole angle, has a value satisfying the equation [
≤ 15], the effect of decreasing the spraying angle is further raised;
thus, it is desirable that the angle 1 and the angle  have respective
values satisfying the equations [1  ] and [ ≤ 15].
[0040]
Embodiment 2
Next, a fuel injection valve according to Embodiment 2 will be
explained. FIG. 6 is an explanatory view illustrating, in an enlarged
manner, part of an injection hole plate of the fuel injection valve
according to Embodiment 2. As illustrated in FIG. 6, the
injection-hole inlet portion 141 that is disposed at a position where
it intersects a virtual extended line 13b1v, obtained by extending
the first side wall portion 13b1 of the introduction portion 13b toward
the injection-hole portion 14, is virtually divided by the intersected
virtual extended line 13b1v into a first part S1 existing at the
introduction portion side and a second part S2 existing at the side
toward which the center O of the injection-hole inlet portion 141
is offset from the center axis M of the introduction portion 13b.
26
In this situation, letting S1a and S2a denote the area of the first
part S1 and the area of the second part S2, respectively, the area
S1a and the area S2a have respective values satisfying the equation
[S1a  S2a]. The other configurations are the same as those in
Embodiment 1.
[0041]
When the injection hole plate 13 is configured in such a manner
as described above, a fuel-flow component that directly heads for
the injection-hole outlet portion 142 without traveling along the
inner wall surface of the injection-hole portion 14 is suppressed
and hence the peripheral velocity of the fuel flow A increased; thus,
the fuel flow A is injected through the injection-hole outlet portion
142 after the swirling force of the whole fuel has sufficiently been
raised. As a result, there is demonstrated an effect that the
micronization of the fuel is further facilitated.
[0042]
FIG. 7 is an explanatory view illustrating, in an enlarged manner,
part of an injection hole plate of an fuel injection valve according
to Comparative Example 2; FIG. 7 is a drawing for comparing the fuel
injection valve according to Comparative Example 2 with the fuel
injection valve according to Embodiment 2. In Embodiment 2, the
injection-hole portion 14 is disposed in such a way that the area
S1a and the area S2a have respective values satisfying the equation
[S1a  S2a]; however, in Comparative Example 2, as illustrated in FIG.
7, the injection-hole portion 14 is disposed in such a way that the
27
offset amount of the center O of the injection-hole inlet portion
141 from the center axis M of the introduction portion 13b is smaller
than the offset amount of the center O in Embodiment 2 in FIG. 6 and
in such a way that the area S1a and the area S2a satisfy the equation
[S1a  S2a]. In the case of Comparative Example 2, most of the fuel
flow A directly heads for the injection-hole outlet portion 142 from
the introduction portion 13b and hence is injected when the peripheral
velocity thereof is insufficient; thus, the micronization of the fuel
is not facilitated.
[0043]
Embodiment 3
Next, a fuel injection valve according to Embodiment 3 will be
explained. FIG. 8 is an explanatory view illustrating, in an enlarged
manner, part of an injection hole plate of the fuel injection valve
according to Embodiment 3. In Embodiment 3, the connection portion
between the first straight-surface wall portion and the
curved-surface wall portion of the swirling chamber is formed of a
curved surface. That is to say, as illustrated in FIG. 8, the
connection portion h between the first straight-surface wall portion
L and the curved-surface wall portion 13c1 of the swirling chamber
13c is formed of a smooth curved surface Rh. The other basic
configurations are the same as those in Embodiment 1.
[0044]
Because the connection portion h is formed of the curved surface
Rh, the volume of the swirling chamber 13c can be reduced and hence
28
the micronization of fuel spray to be injected through the
injection-hole outlet portion 142 of the injection-hole portion 14
is facilitated; therefore, a change in the flow rate due to a change
in the temperature or the atmosphere is suppressed.
[0045]
In addition, because before the fuel flow B that flows into the
swirling chamber 13c reaches the first straight-surface wall portion
L, the direction thereof smoothly turns toward the injection-hole
inlet portion 141 due to the curved surface Rh, the pressure loss
in the fuel flow B is decreased and hence the micronization of the
fuel is facilitated. Moreover, because the connection portion
between the first straight-surface wall portion L and the
curved-surface wall portion 13c1 of the swirling chamber 13c is formed
of the curved surface Rh, the workability of the injection hole plate
13 is raised; additionally, when the swirling chamber 13c and the
like are formed through press working in the injection hole plate
13, the durability of the die can be raised.
[0046]
In the case where the flow path portions such as the swirling
chamber 13c and the like are formed through press working in the
injection hole plate 13, it is desirable that in consideration of
the workability of the die, the radius R of the curved surface Rh
is set to the same as or larger than 0.1 [mm]. In addition, in
Embodiment 3, because the connection portion between the first
straight-surface wall portion L and the first side wall portion 13b1
29
of the introduction portion 13b is also formed of a smooth curved
surface Rg, the workabilities of the foregoing flow path portions
are raised; additionally, when the flow path portions are formed
through press working, the durability of the die can be enhanced.
[0047]
Embodiment 4
Next, a fuel injection valve according to Embodiment 4 will be
explained. FIG. 9 is an explanatory view illustrating, in an enlarged
manner, part of an injection hole plate of the fuel injection valve
according to Embodiment 4. In Embodiment 4, a second
straight-surface wall portion is provided between the curved-surface
wall portion of the swirling chamber and the first straight-surface
wall portion of the introduction portion, and the connection portion
between the first straight-surface wall portion and the second
straight-surface wall portion is formed of a curved surface. That
is to say, as illustrated in FIG. 9, a second straight-surface wall
portion T circumscribed around the curved-surface wall portion 13c1
exists between the curved-surface wall portion 13c1 of the swirling
chamber 13c and the first straight-surface wall portion L, and the
connection portion between the second straight-surface wall portion
T and the first straight-surface wall portion L is formed of a smooth
curved surface Rj. The other basic configurations are the same as
those in Embodiment 1.
[0048]
Because a connection portion j between the second
30
straight-surface wall portion T and the first straight-surface wall
portion L is formed of the smooth curved surface Rj, the length of
the first straight-surface wall portion L can be adjusted without
being limited by the inner diameter of the swirling chamber 13c; thus,
the flow-path length of the fuel flow B and the direction in which
the fuel flows into the injection-hole portion 14 can be adjusted.
Accordingly, the balance between the respective strengths of the fuel
flow B and the fuel flow A can be adjusted, and hence the uniformity
of the thickness of the fuel liquid film to be formed on the inner
wall surface of the injection-hole portion 14 can be raised; thus,
there is demonstrated an effect that the micronization of the fuel
can further be improved. In addition, because the connection portion
j between the first straight-surface wall portion L and the second
straight-surface wall portion T is formed of the smooth curved surface
Rj, the workabilities of the flow path portions such as the swirling
chamber 13c and the like of the injection hole plate 13 are raised;
additionally, when the flow path portions are formed through press
working, the durability of the die can be enhanced.
[0049]
In addition, in Embodiment 4, because the connection portion
between the first straight-surface wall portion L and the first side
wall portion 13b1 of the introduction portion 13b is also formed of
the smooth curved surface Rg, the workabilities of the foregoing flow
path portions are raised; additionally, when the flow path portions
are formed through press working, the durability of the die can be
31
enhanced.
[0050]
FIG. 10 is another explanatory view illustrating, in an enlarged
manner, part of the injection hole plate of the fuel injection valve
according to Embodiment 4. In Embodiment 4, in addition to the
foregoing configuration, the injection hole plate is configured in
such a way that the curved-surface wall portion of the swirling chamber
is part of a virtual arc and in such a way that a minimum gap portion
between the center of the injection-hole inlet portion and the
connection portion between the first straight-surface wall portion
and the first side wall portion exists within the area of the virtual
arc.
[0051]
As described above, because the injection hole plate is
configured in such a way that a minimum gap portion E between the
center O of the injection-hole inlet portion and the curved surface
Rg, which is the connection portion between the first straight-surface
wall portion L and the first side wall portion 13b1, exists within
the area of a virtual arc 13c1v, an after-mentioned separate flow
As that is separated from the fuel flow A and heads for the swirling
chamber 13c can effectively be suppressed and hence the pressure loss
caused by collision between the separate flow As and the flow B is
reduced; thus, the micronization of fuel spray is facilitated.
Moreover, because the fuel flow B is suppressed from having a
superfluous flow-path length, there is demonstrated that the
32
foregoing pressure loss can be reduced and the volume of the swirling
chamber 13c can be suppressed; thus, micronization of the fuel spray
is facilitated and hence a change in the flow rate due to a change
in the temperature or the atmosphere can be suppressed.
[0052]
As illustrated in FIG. 10, the injection hole plate 13 according
to Embodiment 4 is configured in such a way that the straight-line
distance between the center O of the injection-hole inlet portion
141 and a maximum distance point P, at which the distance from the
center O of the injection-hole inlet portion 141 becomes maximum in
a section that extends from the curved-surface wall portion 13c1 to
the first side wall portion 13b1 by way of the second straight-surface
wall portion T and the first straight-surface wall portion L, is twice
as large as the radius of the virtual arc 13c1v or smaller. Such a
configuration enhances the effect of reducing the pressure loss in
the fuel flow B by suppressing the flow-path length, and suppression
of the volume of the swirling chamber facilitates the micronization
of the fuel spray; therefore, a change in the flow rate due to a change
in the temperature or the atmosphere is suppressed.
[0053]
FIG. 11 is an explanatory view illustrating, in an enlarged
manner, part of an injection hole plate of an fuel injection valve
according to Comparative Example 3; FIG. 7 is a drawing for comparing
the fuel injection valve according to Comparative Example 3 with the
fuel injection valve according to Embodiment 4. As illustrated in
33
FIG. 11, in Comparative Example 3, the distance between the center
O of the injection-hole inlet portion 141 and the minimum gap portion
E between the curved surface Rg and the first straight-surface wall
portion L is set to larger than the radius of the virtual arc 13c1v;
thus, the minimum gap portion E exists outside the virtual arc 13c1v.
In this comparison example, the separate flow As that is separated
from the fuel flow A and heads for the swirling chamber 13c cannot
be suppressed; therefore, the pressure loss caused by collision
between the separate flow As and the flow B increases, and hence the
micronization of fuel spray is impeded. Moreover, because the fuel
flow B has a superfluous flow-path length and the volume of the
swirling chamber 13c increases, the micronization of fuel spray is
impeded and hence a change in the flow rate due to a change in the
temperature or the atmosphere increases.
[0054]
Embodiment 5
Next, a fuel injection valve according to Embodiment 5 will be
explained. FIG. 12 is an explanatory view illustrating, in an
enlarged manner, part of an injection hole plate of the fuel injection
valve according to Embodiment 5. In Embodiment 5, as illustrated in
FIG. 12, when 2 denotes the angle between the first straight-surface
wall portion L and the center axis M of the introduction portion 13b
and when the direction that turns from the positive-direction Y axis
toward the positive-direction X axis of the virtual orthogonal
coordinate system, with respect to the origin of the orthogonal
34
coordinate system, is defined as a positive-angle direction, the
angles 1 and 2 have respective values satisfying the equation
[|1-2| ≤ 60]. The other basic configurations are the same as those
in Embodiment 1.
[0055]
In the approach of micronizing fuel spray by means of a fuel
swirling flow, uniforming the thickness of a fuel liquid film, formed
on the inner wall surface of the injection-hole portion 14, results
in improvement of the micronization of the fuel. In the fuel injection
valve according to Embodiment 5, the foregoing configuration
strengthens a flow component obtained when the fuel flow A and the
fuel flow B face each other inside the injection-hole portion 14 and
can make the respective strengths of the fuel flow A and the fuel
flow B substantially equal to each other; thus, the homogeneity of
the liquid film on the inner wall of the injection-hole portion 14
is raised and hence there is demonstrated an effect that the
micronization of the fuel is improved.
[0056]
Although the present application is described above in terms
of various exemplary embodiments and implementations, it should be
understood that the various features, aspects and functions described
in one or more of the individual embodiments are not limited in their
applicability to the particular embodiment with which they are
described, but instead can be applied, alone or in various
combinations to one or more of the embodiments. Therefore, an
35
infinite number of unexemplified variant examples are conceivable
within the range of the technology disclosed in the present
application. For example, there are included the case where at least
one constituent element is modified, added, or omitted and the case
where at least one constituent element is extracted and then combined
with constituent elements of other embodiments.
Industrial Applicability
[0057]
The present disclosure can be applied to the field of a fuel
injection valve or to the field of an automobile having an internal
combustion engine.
Description of Reference Numerals
[0058]
1: fuel injection valve
4: solenoid device
41: insulating covering
5: housing
6: core
7: coil
71: frame member
8: armature
8a: endface
9: valve device
36
10: valve body
11: valve holder
11a: guide portion
12: valve seat
12a: valve-seat sheet portion
12b: valve-seat opening portion
13: injection hole plate
13a: central portion
13b: introduction portion
13b1: first side wall portion
13b2: second side wall portion
13c: swirling chamber
13c1: curved-surface wall portion
14: injection-hole portion
141: injection-hole inlet portion
142: injection-hole outlet portion
15: ball
15a: flat face
16: compression spring
50: welding portion
A, B: fuel flow
L: first straight-surface wall portion
T: second straight-surface wall portion

WE CLAIM:
1. A fuel injection valve comprising:
a valve seat having a valve-seat opening portion for making a
fuel flow out;
a valve body for opening or closing the valve-seat opening
portion; and
an injection hole plate that is disposed at a downstream side
of a flow of the fuel in such a way as to face the valve-seat opening
portion and that has two or more injection hole portions for injecting
the fuel to the outside,
wherein injection of the fuel from the injection hole portion
is controlled by making the valve body travel in an axial direction
of the valve seat so as to open or close the valve-seat opening portion,
based on an operation signal from an external control apparatus,
wherein the injection hole plate includes, in an endface thereof
at an upstream side of the fuel flow,
two or more swirling chambers arranged at a radially
outside of the valve-seat opening portion,
a central portion to be connected with the valve-seat
opening portion, and
two or more introduction portions that each guide the fuel
from the central portion to the respective swirling chambers,
wherein the injection-hole portion has
an injection-hole inlet portion that opens in the swirling
chamber, and
38
an injection-hole outlet portion that opens in a
downstream-side endface, of the injection hole plate, that faces the
upstream-side endface thereof,
wherein the introduction portion has a first side wall portion
and a second side wall portion that face each other across a center
axis of said introduction portion,
wherein a center of the injection-hole inlet portion is provided
in such a way as to be offset from the center axis of the introduction
portion toward the first side wall portion and in such a way as to
coincide with a center of the swirling chamber,
wherein the swirling chamber has a curved-surface wall portion
formed of part of a virtual arc,
wherein the curved-surface wall portion is connected with the
first side wall portion through the intermediary of a first
straight-surface wall portion that extends linearly,
wherein the injection-hole portion is disposed at a position
where the injection-hole inlet portion and a virtual extended line
obtained by extending the first side wall portion toward the
injection-hole portion intersect each other, and a center axis of
the injection-hole portion that connects the center of the
injection-hole inlet portion with a center of the injection-hole
outlet portion is slanted from a plate-thickness direction of the
injection hole plate, and
wherein when there is imagined an orthogonal coordinate system
defined by a Y axis that is parallel to the center axis of the
39
introduction portion and whose positive direction heads for the
central portion from the swirling chamber and an X axis that is
perpendicular to the Y axis and along whose positive direction, the
center of the injection-hole inlet portion is offset from the center
axis of the introduction portion, a projected center axis, obtained
by projecting the center axis of the injection-hole portion on a
virtual plane perpendicular to the center axis of the valve seat,
exists at a position to which the positive-direction Y axis turns
by an angle 1 toward the positive-direction X axis with respect to
the origin of the orthogonal coordinate system, and the angle 1 has
a value satisfying an equation [0 ≤ 1  180].
2. The fuel injection valve according to claim 1, wherein letting
Q denote a virtual orthogonal line that intersects, at the center
of the injection-hole inlet portion, a virtual straight line
connecting an intersection point of the respective center axes of
the two or more introduction portions with the center of the
injection-hole inlet portion, an angle  between the Y axis and the
virtual orthogonal line and the angle 1 have respective values
satisfying the equation [1  ].
3. The fuel injection valve according to any one of claims 1 and 2,
wherein the injection-hole inlet portion is virtually divided
by the intersected virtual extended line into a first part existing
at the introduction portion side and a second part existing at the
40
offset side, and
wherein letting S1a and S2a denote an area of the first part
and an area of the second part, respectively, the area S1a and the
area S2a have respective values satisfying the equation [S1a  S2a].
4. The fuel injection valve according to any one of claims 1 through
3, wherein a connection portion between the first straight-surface
wall portion and the curved-surface wall portion is formed of a curved
surface.
5. The fuel injection valve according to any one of claims 1 through
4,
wherein a second straight-surface wall portion is provided
between the curved-surface wall portion and the first
straight-surface wall portion, and
wherein a connection portion between the first straight-surface
wall portion and the second straight-surface wall portion is formed
of a curved surface.
6. The fuel injection valve according to claim 5, wherein a
straight-line distance between the center of the injection-hole inlet
portion and a maximum distance point, at which the distance from the
center of the injection-hole inlet portion becomes maximum in a
section that extends from the curved-surface wall portion to the first
side wall portion by way of the second straight-surface wall portion
41
and the first straight-surface wall portion, is twice as large as
a radius of the virtual arc or smaller.
7. The fuel injection valve according to any one of claims 1 through
6, wherein a minimum gap portion between the center of the
injection-hole inlet portion and a connection portion between the
first straight-surface wall portion and the first side wall portion
exists within an area of the virtual arc.
8. The fuel injection valve according to any one of claims 1 through
7, wherein when 2 denotes an angle between the first straight-surface
wall portion and the center axis of the introduction portion and when
a direction that turns from the positive-direction Y axis toward the
positive-direction X axis, with respect to an origin of the orthogonal
coordinate system, is defined as a positive-angle direction, the
angles 1 and 2 have respective values satisfying the equation
[|1-2| ≤ 60].