1
FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
FUEL INJECTION APPARATUS
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND EXISTING
UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3, MARUNOUCHI 2-CHOME,
CHIYODA-KU, TOKYO 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND
THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
DESCRIPTION
Technical Field
5 [0001]
The present disclosure relates to a fuel injection apparatus.
Background Art
[0002]
10 In recent years, while the exhaust-gas regulation on an internal
combustion engine mounted in an automobile has been being tightened,
it has been required to micronize a fuel spray injected from a fuel
injection apparatus of an internal combustion engine; accordingly,
there have been made various studies related to a method in which
15 the micronization is performed by use of a swirling flow.
[0003]
A conventional fuel injection apparatus disclosed in Patent
Document 1 includes a valve body that can move in response to a control
signal from an internal combustion engine control module, a valve
20 seat in which the valve body seats itself or from which the valve
body separates, and a fuel-injection-apparatus nozzle provided at
a position that is in the immediate vicinity of the valve seat and
is at the downstream side of the valve seat in the flowing direction
of a fuel; in the fuel-injection-apparatus nozzle, there are provided
25 two or more groove-shaped flow paths that communicate with one another
3
at the central portion thereof and two or more vortex chambers that
communicate with the downstream side of the respective flow paths;
an injection hole for injecting a fuel is provided in each of the
vortex chamber.
5 [0004]
In the conventional fuel injection apparatus disclosed in Patent
Document 1, a fuel that has flowed from the valve seat into the central
portion of the fuel injection nozzle uniformly flows into the two
or more groove-shaped flow paths; after being rectified through the
10 flow path, the fuel flows into the vortex chamber; then, the fuel
flows into the injection hole while producing a swirling flow. The
swirling flow of the fuel that has flowed into the injection hole
is kept even inside the injection hole so as to form a thin liquid
film along the inner wall of the injection hole. The thin liquid film
15 formed along the inner wall of the injection hole is injected through
the injection hole into a combustion chamber of the internal
combustion engine in a hollow and conical manner so as to be
micronized; thus, micronization of the fuel is facilitated.
[Prior Art Reference]
20 [Patent Literature]
[0005]
[Patent Document 1] Japanese Patent Application Laid-Open No.
2002-98028
25 Disclosure of the Invention
4
Problems to be Solved by the Invention
[0006]
In recent years, there has increased the case where in a method
in which a fuel is injected inside an intake port of an internal
combustion engine, the fuel is injected in the intake 5 stroke of the
internal combustion engine in order to improve the gasoline mileage.
As is well known, an intake-stroke fuel injection is a method in which
a fuel is injected under the condition that the intake valve is opened,
in which a fuel spray is made to directly flow into the combustion
10 chamber of the internal combustion engine so that the vaporization
cooling effect inside the combustion chamber is raised and hence the
knock resistance is enhanced, and in which the compression ratio of
the internal combustion engine is increased so that the gasoline
mileage can be improved.
15 [0007]
In the foregoing conventional fuel injection apparatus
disclosed in Patent Document 1, the performance of micronizing a fuel
spray is excellent but the penetration force of the fuel spray is
small; thus, because, due to the effect of an intake air flow produced
20 in the intake port when a fuel is injected in the intake stroke of
the internal combustion engine, the fuel spray is made to flow to
the ceiling portion side of the intake port and hence part of the
fuel spray adheres to the inner wall surface of the ceiling portion
of the intake port, the inflow amount of the fuel spray into the
25 combustion chamber may be reduced. Accordingly, because the
5
vaporization cooling effect in the combustion chamber becomes
insufficient, the knock resistance cannot be raised and hence the
compression ratio of the internal combustion engine cannot be
increased; thus, there has been a problem that no sufficient effect
in gasoline-mileage improvement 5 can be obtained.
[0008]
Moreover, in the foregoing conventional fuel injection
apparatus, there has been a problem that even in the case of an
exhaust-stroke injection in which fuel injection is performed under
10 the condition that the intake valve is closed, for example, because
in the case where there is provided an effect of intake air pulsation
that occurs among the intake ports of a multi-cylinder internal
combustion engine or in the case where the injection amount is large
and the injection period is long, a necessary amount of fuel cannot
15 be injected in the exhaust stroke and hence the latter part of the
fuel injection operation transits to the intake stroke, the effect
of an intake air flow makes the fuel spray flow to the ceiling portion
of the intake port and become liable to adhere to the ceiling portion
of the intake port, and hence gasoline-mileage improvement is
20 hindered.
[0009]
The present disclosure has been implemented in order to solve
the problems in the foregoing conventional fuel injection apparatus;
the objective thereof is to provide a fuel injection apparatus that
25 makes it possible that adhesion of a fuel to the inner wall of an
6
intake port is reduced so that gasoline-mileage improvement is
facilitated.
Means for Solving the Problems
5 [0010]
In a fuel injection apparatus according to the present
disclosure, a valve body for opening or closing a valve seat is
provided and the valve body is operated in response to an operation
signal from a control apparatus, so that after passing through a gap
10 between the valve body and a seat portion of the valve seat, a fuel
is injected through two or more injection holes provided in an
injection hole plate attached to a valve seat opening portion at a
downstream side of the valve seat. The fuel injection apparatus is
characterized
15 in that an upstream-side endface of the injection hole plate
has two or more swirling chambers that are arranged radially outside
the valve seat opening portion and each provide swirling force to
a fuel, a fuel path for making a fuel flow from the valve seat opening
portion into a central portion thereof and for making the fuel flow
20 out thereof to each of the swirling chambers connected with respective
corresponding end portions thereof, and the injection holes each of
which opens in the corresponding swirling chamber and through which
a fuel is injected toward the outside,
in that in the case where the upstream-side endface of the
25 injection hole plate is viewed from the upstream side in a center-axis
7
direction of the valve seat opening portion, the two or more swirling
chambers and injection holes are arranged in point symmetry with
respect to the center of the fuel path, and the center axis of the
fuel path is offset from the center of the valve seat opening portion,
5 and
in that among the two or more injection holes, at least one
injection hole is provided in such a way as to be offset from the
center axis of the fuel path toward a side where the center of the
valve seat opening portion is positioned, and at least one injection
10 hole is provided in such a way as to be offset from the center axis
of the fuel path toward a side opposite to the side where the center
of the valve seat opening portion is positioned.
Advantage of the Invention
15 [0011]
In a fuel injection apparatus according to the present
disclosure, a valve body for opening or closing a valve seat is
provided and the valve body is operated in response to an operation
signal from a control apparatus, so that after passing through a gap
20 between the valve body and a seat portion of the valve seat, a fuel
is injected through two or more injection holes provided in an
injection hole plate attached to a valve seat opening portion at a
downstream side of the valve seat; an upstream-side endface of the
injection hole plate has two or more swirling chambers that are
25 arranged radially outside the valve seat opening portion and each
8
provide swirling force to a fuel, a fuel path for making a fuel flow
from the valve seat opening portion into a central portion thereof
and for making the fuel flow out thereof to each of the swirling
chambers connected with respective corresponding end portions thereof,
and the injection holes each of which opens in 5 the corresponding
swirling chamber and through which a fuel is injected toward the
outside; in the case where the upstream-side endface of the injection
hole plate is viewed from the upstream side in a center-axis direction
of the valve seat opening portion, the two or more swirling chambers
10 and injection holes are arranged in point symmetry with respect to
the center of the fuel path, and the center axis of the fuel path
is offset from the center of the valve seat opening portion; among
the two or more injection holes, at least one injection hole is
provided in such a way as to be offset from the center axis of the
15 fuel path toward a side where the center of the valve seat opening
portion is positioned, and at least one injection hole is provided
in such a way as to be offset from the center axis of the fuel path
toward a side opposite to the side where the center of the valve seat
opening portion is positioned. Thus, there can be provided a fuel
20 injection apparatus that makes it possible that adhesion of a fuel
to the inner wall of an intake port is reduced so that gasoline-mileage
improvement is facilitated.
Brief Description of the Drawings
25 [0012]
9
FIG. 1 is a longitudinal cross-sectional view of a fuel injection
apparatus according to Embodiment 1;
FIG. 2 is a longitudinal cross-sectional view of part of the
fuel injection apparatus according to Embodiment 1;
FIG. 3 is a transverse cross-sectional view 5 of a cross section
along the line A  A in FIG. 2 when viewed from the direction indicated
by the arrows;
FIG. 4 is an explanatory view of an upstream-side endface of
an injection hole plate of the fuel injection apparatus according
10 to Embodiment 1;
FIG. 5 is an explanatory view of an upstream-side endface of
an injection hole plate of a fuel injection apparatus according to
Embodiment 2;
FIG. 6 is a longitudinal cross-sectional view of part of a fuel
15 injection apparatus according to Embodiment 3;
FIG. 7 is a transverse cross-sectional view of a cross section
along the line B  B in FIG. 6 when viewed from the direction indicated
by the arrows;
FIG. 8 is an explanatory view illustrating an upstream-side
20 endface of an injection hole plate of the fuel injection apparatus
according to Embodiment 3;
FIG. 9 is an explanatory view illustrating the case where a fuel
injection apparatus according to Embodiment 4 is provided in an intake
port of an internal combustion engine; and
25 FIG. 10 is an explanatory view of an upstream-side endface of
10
an injection hole plate in the fuel injection apparatus according
to Embodiment 4 when a cross section along the line C  C in FIG.
9 is viewed from the direction indicated by the arrows.
Best Mode for Carrying 5 Out the Invention
[0013]
Embodiment 1
FIG. 1 is a longitudinal cross-sectional view of a fuel injection
apparatus according to Embodiment 1; FIG. 2 is a longitudinal
10 cross-sectional view of part of the fuel injection apparatus according
to Embodiment 1; FIG. 3 is a transverse cross-sectional view of a
cross section along the line A  A in FIG. 2 when viewed from the
direction indicated by the arrows. In each of FIGS. 1, 2, and 3, a
fuel injection apparatus 1 includes a solenoid device 4 and a valve
15 device 9. The 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, a metal housing 5, as a yoke, disposed
at the outer circumference portion of the coil 7, a core 6, as a metal
20 fixed iron core, 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 in which the
coil 7, the frame member 71, the core 6, and the housing 5 are buried.
[0014]
25 The valve device 9 has a valve body 10, an armature 8 formed
11
of metal that is a magnetic material, a valve seat 12, a valve holder
11, and an injection hole plate 13. One axial-direction end portion
of the valve holder 11 is pressed onto 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 5 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. The armature 8 is pressed onto one
axial-direction end portion of the valve body 10 and then is fixed
10 on 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 15 is fixed on the other
15 axial-direction end portion of the valve body 10 through welding and
has two or more flat faces 15a formed through chamfering.
[0015]
The valve seat 12 is formed in the shape of a hollow cylinder
whose one axial-direction end portion is opened and whose the other
20 end portion is sealed by an end wall portion 121. 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 shiftably disposed
in the axial direction. In the inner surface of the end wall portion
121 in the valve seat 12, there is formed a ring-shaped seat portion
25 12a in which the ball 15 seats itself. In the central portion of the
12
end wall portion 121 in the valve seat 12, a valve seat opening portion
12b penetrating the end wall portion 121 is provided. When the ball
15 seats itself in the seat portion 12a of the valve seat 12, the
valve seat opening portion 12b is sealed; when the ball 15 departs
from the seat portion 12a, the valve seat opening 5 portion 12b is
released from the sealing and makes the inside and the outside of
the valve seat 12 communicate with each other.
[0016]
The upstream-side endface of the injection hole plate 13 formed
10 in the shape of a plate is fixed on the downstream side of the valve
seat 12 through welding. A welding portion 50 indicates the place
of the welding. 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
15 11 in such a way as to abut thereon.
[0017]
As illustrated in FIG. 3, the injection hole plate 13 is provided
with a first swirling chamber 18a, a second swirling chamber 18b,
a fuel path 17 connected with the first swirling chamber 18a and the
20 second swirling chamber 18b, and a first injection hole 14a and a
second injection hole 14b that penetrate the injection hole plate
13 in the board-thickness direction thereof. The first swirling
chamber 18a, the second swirling chamber 18b, and the fuel path 17
are formed by recessing the upstream-side endface of the injection
25 hole plate 13 and are configured in such a way that the respective
13
bottom surfaces thereof are continuously connected with one another
in such a way as to be substantially coplanar. The details of the
configuration of the injection hole plate 13 will be described later.
[0018]
The first injection hole 14a is formed in the 5 central portion
of the first swirling chamber 18a; the second injection hole 14b is
formed in the central portion of the second swirling chamber 18b.
The center 13c of the injection hole plate 13 and center 12c of the
valve seat opening portion 12b in the valve seat 12 are positioned
10 on the center axis X of the fuel injection apparatus 1. One end portion
of a compression spring 16 inserted into the core 6 is fixed on the
core 6, and the other end portion thereof abuts on the one
axial-direction end portion of the valve body 10; the compression
spring 16 constantly presses the valve body 10 toward the valve seat
15 12.
[0019]
Next, the operation of the fuel injection apparatus according
to Embodiment 1 will be explained. When an operation signal is
transmitted from a control apparatus (unillustrated) of an internal
20 combustion engine to a driving circuit (unillustrated) of the fuel
injection apparatus 1, the coil 7 in the fuel injection apparatus
1 is energized and magnetic flux is generated in a magnetic circuit
including the armature 8, the core 6, the housing 5, and the valve
holder 11, so that the armature 8 is attracted by the core 6 and moves
25 thereto, while resisting pressing force exerted by the compression
14
spring 16. Because the armature 8 is attracted by the core 6 and moves
thereto, the ball 15 of the valve body 10 fixed on the armature 8
departs from the seat portion 12a of the valve seat 12 and hence the
valve seat opening portion 12b is released from the sealing by the
5 ball 15.
[0020]
When the valve seat opening portion 12b is released from the
sealing by the ball 15, a high-pressure fuel filled into the valve
holder 11 flows into the central portion of the fuel path 17 in the
10 injection hole plate 13, by way of a gap between the flat face 15a
of the ball 15 of the valve body 10 and the inner circumferential
surface of the valve seat 12, a gap between the seat portion 12a of
the valve seat 12 and the outer circumferential surface of the ball
15, and the valve seat opening portion 12b. The fuel that has flowed
15 into the central portion of the fuel path 17 ramifies at the central
portion of the fuel path 17 and flows into the first swirling chamber
18a and the second swirling chamber 18b and then is injected from
the first swirling chamber 18a into an intake port of the internal
combustion engine, by way of the first injection hole 14a;
20 concurrently, the fuel is injected from the second swirling chamber
18b into the intake port of the internal combustion engine, by way
of the second injection hole 14b.
[0021]
Next, when a stop signal for stopping fuel-injection operation
25 is transmitted from the control apparatus of the internal combustion
15
engine to the driving circuit of the fuel injection apparatus 1, the
energization of the coil 7 is cut off and the magnetic flux in the
magnetic circuit including the armature 8, the core 6, the housing
5, and the valve holder 11 decreases, so that the pressing force of
the compression spring 16 makes the armature 8 slide 5 on the surface
of the guide portion 11a of the valve holder 11 and move toward the
valve seat 12. Accordingly, the ball 15 of the valve body 10 seats
itself in the seat portion 12a of the valve seat 12 so as to seal
the valve seat opening portion 12b. As a result, injection of the
10 fuel through the first injection hole 14a and the second injection
hole 14b is stopped.
[0022]
The configuration of the injection hole plate 13 will be
explained further in detail, here. FIG. 4 is an explanatory view of
15 the upstream-side endface of the injection hole plate of a fuel
injection apparatus according to Embodiment 1. As illustrated in FIG.
4, in the upstream-side endface of the injection hole plate 13, the
first swirling chamber 18a and the second swirling chamber 18b that
exert swirling force on the fuel are formed at the radially outside
20 of the valve seat opening portion 12b.
[0023]
Then, the first injection hole 14a is provided in the central
portion of the first swirling chamber 18a, and the second injection
hole 14b is provided in the central portion of the second swirling
25 chamber 18b. The fuel path 17 having a central portion facing the
16
valve seat opening portion 12b is provided on the upstream-side
endface of the injection hole plate 13. The fuel that has flowed out
of the valve seat opening portion 12b flows into the fuel path through
the central portion of the fuel path 17 and then ramifies into the
first swirling chamber 18a and the second swirling 5 chamber 18b that
adjoin the respective end portions of the fuel path 17.
[0024]
The center 12c of the valve seat opening portion 12b and the
center 13c of the injection hole plate 13 are arranged in such a way
10 as to coincide with each other when the upstream-side endface of the
injection hole plate 13 is viewed from the upstream side on the center
axis X that passes through the center of the valve seat opening portion
12b. Then, the first swirling chamber 18a and the second swirling
chamber 18b are arranged in point symmetry with respect to the center
15 17c of the fuel path 17. The first injection hole 14a and the second
injection hole 14b are formed in point symmetry with respect to the
center 17c of the fuel path 17.
[0025]
Moreover, a center axis 40 of the fuel path 17 is provided in
20 such a way as to be offset by a predetermined amount from the center
12c of the valve seat opening portion 12b and the center 13c of the
injection hole plate 13. As a result, the first injection hole 14a
provided in the first swirling chamber 18a is offset by a predetermined
amount from the center axis 40 of the fuel path 17 toward a side where
25 the center 12c of the valve seat opening portion 12b is positioned,
17
and the second injection hole 14b provided in the second swirling
chamber 18b is offset by a predetermined amount from the center axis
40 of the fuel path 17 toward the side opposite to the side where
the center 12c of the valve seat opening portion 12b is positioned.
5 [0026]
The fuel that has flowed through the valve seat opening portion
12b of the valve seat 12 onto the upstream-side endface of the
injection hole plate 13 flows into the central portion of the fuel
path 17 radially with respect to the center 12c of the valve seat
10 opening portion 12b; however, because the first injection hole 14a
provided in the first swirling chamber 18a is offset from the center
axis 40 of the fuel path 17 toward the side where the center 12c of
the valve seat opening portion 12b is positioned, a main flow 30a
of the fuel that flows through the fuel path 17 into the first injection
15 hole 14a provided in the first swirling chamber 18a flows toward a
side wall 17w, of the fuel path 17, that is at a side opposite to
the side where the first injection hole 14a is positioned, with respect
to the center 17c of the fuel path 17. Accordingly, the fuel hardly
enters the first injection hole 14a in a direct manner; a strong first
20 swirling flow 30a1 of the fuel occurs in the first swirling chamber
18a; a fuel spray that has small penetration force and is sufficiently
micronized is formed; then, the fuel spray is injected through the
first injection hole 14a into the intake port of the internal
combustion engine.
25 [0027]
18
In contrast, because the second injection hole 14b provided in
the second swirling chamber 18b is offset from the center axis 40
of the fuel path 17 toward a side opposite to the side where the center
12c of the valve seat opening portion 12b is positioned, a main flow
30b of the fuel that flows through the fuel path 5 17 into the second
injection hole 14b provided in the second swirling chamber 18b flows
toward the second injection hole 14b; thus, the fuel readily flows
into the second injection hole 14b in a direct manner. Accordingly,
because a second swirling flow 30b1 that is weaker than the foregoing
10 first swirling flow 30a1 occurs in the second swirling chamber 18b,
a fuel spray having large penetration force is formed and then is
injected through the second injection hole 14b into the intake port
of the internal combustion engine.
[0028]
15 As described above, the fuel that has flowed through the valve
seat opening portion into the swirling chamber flows into the
injection hole while producing a swirling flow, and the swirling flow
is kept even inside the injection hole; thus, a thin liquid film is
formed along the inner wall of the injection hole and then is injected
20 through the injection hole in a hollow and conical manner, so that
micronization of the fuel is facilitated.
[0029]
In the fuel injection apparatus according to Embodiment 1,
because in a single injection hole plate, two directions, i.e., the
25 direction toward the injection hole and the direction departing from
19
the injection hole can be set for the main flow of the fuel that flows
from the valve seat opening portion into the injection hole provided
in the swirling chamber, through the fuel path, it is made possible
to produce two kinds of swirling flows, i.e., a weak swirling flow
and a strong swirling flow, in the swirling chamber; 5 therefore, two
kinds of fuel sprays, i.e., a fuel spray having a large penetration
force and a fuel spray that has a small penetration force and is
sufficiently micronized can be formed. Accordingly, even in the case
where when an intake-air flow exists in the intake port, fuel injection
10 is performed, a fuel spray is hardly blown by the intake-air flow;
therefore, it is made possible to reduce fuel sprays that adhere to
the wall of the intake port. Accordingly, the direct entry rate of
a fuel spray for the combustion chamber can be raised; the vaporization
cooling effect in the combustion chamber is enhanced; the knock
15 resistance is raised and hence the compression ratio can be increased;
as a result, the gasoline mileage can be improved.
[0030]
In contrast, in the case of the conventional fuel injection
apparatus disclosed in Patent Document 1, because the respective
20 centers of the two or more fuel paths that are provided in the
upstream-side endface of the injection hole plate and radially spread
coincide with the center of the valve seat opening portion, the
direction of each of the main flows of the fuels that flow through
the valve seat opening portion into the respective fuel paths and
25 head for the respective injection holes becomes substantially
20
parallel to the center axis of the corresponding fuel path; thus,
because swirling flows of the fuel that have substantially the same
strength are produced in the respective swirling chambers, fuel sprays
having substantially the same penetration force are injected through
the respective injection holes. Therefore, the foregoing 5 effect of
the fuel injection apparatus according to Embodiment 1 of the present
disclosure cannot be obtained.
[0031]
Moreover, in the case where in a fuel injection apparatus based
10 on a fuel micronization method in which an ordinary swirling flow
of a fuel is utilized, fuel sprays having different penetration forces
are formed with a single injection hole plate, it is required to form
differently shaped injection holes, differently shaped swirling
chambers, differently shaped fuel paths, and the like that correspond
15 to the respective fuel sprays having different penetration forces;
thus, the flow-path structure for the fuel becomes complex and hence
the workability is deteriorated. In contrast, in the fuel injection
apparatus according to Embodiment 1 of the present disclosure, the
respective shapes of the injection holes that correspond to different
20 penetration forces are one and the same, which is applied to the
swirling chambers and the fuel paths, and hence it is only necessary
that the center axis of the fuel path is offset with respect to the
center of the valve seat opening portion; therefore, the flow-path
structure for the fuel can be simplified and hence the workability
25 can be improved.
21
[0032]
Embodiment 2
Next, a fuel injection apparatus according to Embodiment 2 of
the present disclosure will be explained. The fuel injection
apparatus according to Embodiment 1 is provided 5 with two injection
holes in the upstream-side endface of the injection hole plate;
however, the fuel injection apparatus according to Embodiment 2 is
provided with four injection holes in the upstream-side endface of
the injection hole plate. FIG. 5 is an explanatory view of the
10 upstream-side endface of the injection hole plate of the fuel
injection apparatus according to Embodiment 2.
[0033]
In FIG. 5, on the upstream-side endface of the injection hole
plate 13, there are provided a first fuel path 17 and a second fuel
15 path 171 in such a way as to intersect each other at a common center
17c and to be perpendicular to each other. The first swirling chamber
18a is connected with one end portion of the first fuel path 17, and
the second swirling chamber 18b is connected with the other end portion
of the first fuel path 17. A third swirling chamber 18c is connected
20 with one end portion of the second fuel path 171, and a fourth swirling
chamber 18d is connected with the other end portion of the second
fuel path 171. Each of the first swirling chamber 18a, the second
swirling chamber 18b, the third swirling chamber 18c, and the fourth
swirling chamber 18d is formed at the radially outside of the valve
25 seat opening portion 12b.
22
[0034]
The first fuel path 17, the second fuel path 171, the first
swirling chamber 18a, the second swirling chamber 18b, the third
swirling chamber 18c, and the fourth swirling chamber 18d are formed
by recessing the upstream-side endface of the foregoing 5 injection
hole plate 13 and 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.
[0035]
10 The first injection hole 14a penetrating the injection hole
plate 13 in the board-thickness direction opens in the central portion
of the first swirling chamber 18a; the second injection hole 14b
penetrating the injection hole plate 13 in the board-thickness
direction opens in the central portion of the second swirling chamber
15 18b; a third injection hole 14c penetrating the injection hole plate
13 in the board-thickness direction opens in the central portion of
the third swirling chamber 18c; a fourth injection hole 14d
penetrating the injection hole plate 13 in the board-thickness
direction opens in the central portion of the fourth swirling chamber
20 18d.
[0036]
The center 12c of the valve seat opening portion 12b and the
center 13c of the injection hole plate 13 coincide with each other
when the upstream-side endface of the injection hole plate 13 is viewed
25 from the upstream side on the center axis X that passes through the
23
center 12c of the valve seat opening portion 12b. Then, the first
swirling chamber 18a and the second swirling chamber 18b are arranged
in point symmetry with respect to the common center 17c of the first
fuel path 17 and the second fuel path 171; the first injection hole
14a and the second injection hole 14b are arranged 5 in point symmetry
with respect to the common center 17c of the first fuel path 17 and
the second fuel path 171; the third swirling chamber 18c and the fourth
swirling chamber 18d are arranged in point symmetry with respect to
the common center 17c of the first fuel path 17 and the second fuel
10 path 171; the third injection hole 14c and the fourth injection hole
14d are arranged in point symmetry with respect to the common center
17c of the first fuel path 17 and the second fuel path 171.
[0037]
Moreover, each of the center axis 40 of the first fuel path 17
15 and the center axis 401 of the second fuel path 171 is provided in
such a way as to be offset by a predetermined amount from the center
12c of the valve seat opening portion 12b. The first injection hole
14a provided in the first swirling chamber 18a and the third injection
hole 14c provided in the third swirling chamber 18c are provided in
20 such a way as to be offset by a predetermined amount toward the center
12c of the valve seat opening portion 12b from the center axis 40
of the first fuel path 17 and the center axis 401 of the second fuel
path 171, respectively; the second injection hole 14b provided in
the second swirling chamber 18b and the fourth injection hole 14d
25 provided in the fourth swirling chamber 18d are provided in such a
24
way as to be offset by a predetermined amount toward the side opposite
to the side where the center 12c of the valve seat opening portion
12b is positioned, from the center axis 40 of the first fuel path
17 and the center axis 401 of the second fuel path 171, respectively.
5 [0038]
The fuel that has flowed through the valve seat opening portion
12b onto the upstream-side endface of the injection hole plate 13
flows into the respective central portions of the first fuel path
17 and the second fuel path 171 radially with respect to the center
10 12c of the valve seat opening portion 12b; however, because the first
injection hole 14a provided in the first swirling chamber 18a is offset
from the center axis 40 of the first fuel path 17 toward the center
12c of the valve seat opening portion 12b, a main flow 30a of the
fuel that flows through the first fuel path 17 into the first injection
15 hole 14a provided in the first swirling chamber 18a flows toward a
side wall 17w, of the first fuel path 17, that is at a side opposite
to the side where the first injection hole 14a is positioned, with
respect to the center axis 40 of the first fuel path 17. Accordingly,
the fuel hardly enters the first injection hole 14a in a direct manner;
20 a strong first swirling flow 30a1 of the fuel occurs in the first
swirling chamber 18a; a fuel spray that has small penetration force
and is sufficiently micronized is formed; then, the fuel spray is
injected through the first injection hole 14a into the intake port
of the internal combustion engine.
25 [0039]
25
Similarly, because the third injection hole 14c provided in the
third swirling chamber 18c is offset from the center axis 401 of the
second fuel path 171 toward the center 12c of the valve seat opening
portion 12b, a main flow 30c of the fuel that flows through the second
fuel path 171 into the third injection hole 14c provided 5 in the third
swirling chamber 18c flows toward a side wall 171w, of the second
fuel path 171, that is at a side opposite to the side where the third
injection hole 14c is positioned, with respect to the center axis
401 of the second fuel path 171. Accordingly, the fuel hardly enters
10 the third injection hole 14c in a direct manner; a strong third
swirling flow 30c1 of the fuel occurs in the third swirling chamber
18c; a fuel spray that has small penetration force and is sufficiently
micronized is formed; then, the fuel spray is injected through the
third injection hole 14c into the intake port of the internal
15 combustion engine.
[0040]
In contrast, because the second injection hole 14b provided in
the second swirling chamber 18b is offset from the center axis 40
of the first fuel path 17 toward a side opposite to the side where
20 the center 12c of the valve seat opening portion 12b is positioned,
a main flow 30b of the fuel that flows through the first fuel path
17 into the second injection hole 14b provided in the second swirling
chamber 18b flows toward the second injection hole 14b; thus, the
fuel readily flows into the second injection hole 14b in a direct
25 manner. Accordingly, because a second swirling flow 30b1 that is
26
weaker than the foregoing first swirling flow 30a1 occurs in the second
swirling chamber 18b, a fuel spray having large penetration force
is formed and then is injected through the second injection hole 14b
into the intake port of the internal combustion engine.
5 [0041]
Similarly, because the fourth injection hole 14d provided in
the fourth swirling chamber 18d is offset from the center axis 401
of the second fuel path 171 toward a side opposite to the side where
the center 12c of the valve seat opening portion 12b is positioned,
10 a main flow 30d of the fuel that flows through the second fuel path
171 into the fourth injection hole 14d provided in the fourth swirling
chamber 18d flows toward the fourth injection hole 14d; thus, the
fuel readily flows into the fourth injection hole 14d in a direct
manner. Accordingly, because a fourth swirling flow 30d1 that is
15 weaker than the foregoing third swirling flow 30c1 occurs in the fourth
swirling chamber 18d, a fuel spray having large penetration force
is formed and then is injected through the fourth injection hole 14d
into the intake port of the internal combustion engine.
[0042]
20 As described above, in the fuel injection apparatus according
to Embodiment 2, four injection holes are provided, so that it is
made possible that in a single injection hole plate, there are formed
two kinds of fuel sprays having different penetration forces, i.e.,
a fuel spray having large penetration force and a fuel spray that
25 has small penetration force and is sufficiently micronized; as a
27
result, an effect the same as that of the fuel injection apparatus
according to Embodiment 1 can be obtained.
[0043]
Moreover, the first injection hole 14a and the third injection
hole 14c that each form a fuel spray having small 5 penetration force
and being sufficiently micronized are arranged close to each other
and collectively, and the second injection hole 14b and the fourth
injection hole 14d that each form a fuel spray having large penetration
force are arranged close to each other and collectively; in addition,
10 the pair of the first injection hole 14a and the third injection hole
14c are arranged in line symmetry with the pair of the second injection
hole 14b and the fourth injection hole 14d, with respect to the common
center 17c of the first fuel path 17 and the second fuel path 171,
and are arranged separately therefrom. As a result, because fuel
15 sprays injected through the respective injection holes hardly
interfere with one another, micronization can be suppressed from being
deteriorated.
[0044]
In addition, with regard to the fuel injection apparatus
20 according to Embodiment 2, the case where the number of the injection
holes is four has been described; however, the number of the injection
holes may further be increased. Because an effect the same as the
foregoing one can be obtained by forming two or more fuel sprays having
different penetration forces, the injection amount can be increased
25 through multi-injection holes; thus, even the case where the required
28
flow rate of the fuel injection apparatus is large can be dealt with.
[0045]
Embodiment 3
Next, a fuel injection apparatus according to Embodiment 3 of
the present disclosure will be explained. In 5 the foregoing fuel
injection apparatus according to Embodiment 1, the center of the fuel
path is provided in such a way as not to coincide with the center
of the injection hole plate and to be offset from the center of the
injection hole plate; however, in the fuel injection apparatus
10 according to Embodiment 3, the center of the injection hole plate
and the center of the fuel path coincide with each other and are offset
from the center of the valve seat opening portion when the
upstream-side endface of the injection hole plate is viewed from the
upstream side of the center axis that passes through the center of
15 the valve seat opening portion. The other configurations are the same
as those of the fuel injection apparatus according to Embodiment 1.
[0046]
FIG. 6 is a longitudinal cross-sectional view of part of the
fuel injection apparatus according to Embodiment 3; FIG. 7 is a
20 transverse cross-sectional view of a cross section along the line
B  B in FIG. 6 when viewed from the direction indicated by the arrows;
FIG. 8 is an explanatory view of the upstream-side endface of the
injection hole plate of the fuel injection apparatus according to
Embodiment 3. In FIGS. 6, 7, and 8, the center 17c of the fuel path
25 17 coincide with the center 13c of the injection hole plate 13; the
29
first injection hole 14a, the second injection hole 14b, the first
swirling chamber 18a, the second swirling chamber 18b, and the fuel
path 17 that are provided in the injection hole plate 13 are arranged
in point symmetry with respect to the center 13c of the injection
hole plate and the center 17c of the fuel path. The 5 injection hole
plate 13 is formed in the shape of a flat disk and in such a way that
the outer diameter thereof is smaller than that of the valve seat
12.
[0047]
10 In the Embodiment 1, the injection hole plate 13 is formed in
the shape of a plate; however, in Embodiment 3, the injection hole
plate 13 is formed in the shape of a flat disk, so that there is
demonstrated a merit that production or machining of the injection
hole plate 13 is facilitated. Moreover, in Embodiment 3, the
15 injection hole plate 13 is formed in such a way that the diameter
thereof is smaller than that of the valve seat 12. Accordingly, even
when the valve seat 12 and the injection hole plate 13 are not fixed
to be strictly concentric with each other, the outer edge portion
of the injection hole plate 13 does not abut on the inner wall of
20 the valve holder 11; thus, assembly of the valve seat 12 and the valve
holder 11 can be facilitated.
[0048]
Moreover, in Embodiment 3, the center 13c of the injection hole
plate 13 and the center 17c of the fuel path 17 are arranged in such
25 a way as to be offset by a predetermined amount in a direction
30
perpendicular to the center axis 40 of the fuel path 17, from the
center 12c of the valve seat opening portion 12b provided on the center
axis X of the valve seat 12.
[0049]
Accordingly, the fuel that has flowed through 5 the valve seat
opening portion 12b of the valve seat 12 onto the upstream-side endface
of the injection hole plate 13 flows into the central portion of the
fuel path 17 radially with respect to the center 12c of the valve
seat opening portion 12b; however, because the first injection hole
10 14a provided in the first swirling chamber 18a is offset from the
center axis 40 of the fuel path 17 toward the side where the center
12c of the valve seat opening portion 12b is positioned, a main flow
30a of the fuel that flows through the fuel path 17 into the first
injection hole 14a provided in the first swirling chamber 18a flows
15 toward a side wall 17w, of the fuel path 17, that is at a side opposite
to the side where the first injection hole 14a is positioned, with
respect to the center axis 40 of the fuel path 17. Accordingly, the
fuel hardly enters the first injection hole 14a in a direct manner;
a strong first swirling flow 30a1 of the fuel occurs in the first
20 swirling chamber 18a; a fuel spray that has small penetration force
and is sufficiently micronized is formed; then, the fuel spray is
injected through the first injection hole 14a into the intake port
of the internal combustion engine.
[0050]
25 In contrast, because the second injection hole 14b provided in
31
the second swirling chamber 18b is offset from the center axis 40
of the fuel path 17 toward a side opposite to the side where the center
12c of the valve seat opening portion 12b is positioned, a main flow
30b of the fuel that flows through the fuel path 17 into the second
injection hole 14b provided in the second swirling 5 chamber 18b flows
toward the second injection hole 14b; thus, the fuel readily flows
into the second injection hole 14b in a direct manner. Accordingly,
because a second swirling flow 30b1 that is weaker than the foregoing
first swirling flow 30a1 occurs in the second swirling chamber 18b,
10 a fuel spray having large penetration force is formed and then is
injected through the second injection hole 14b into the intake port
of the internal combustion engine.
[0051]
As described above, in the fuel injection apparatus according
15 to Embodiment 3, as the main flow of the fuel that flows through the
valve seat opening portion 12b into the first injection hole 14a and
the second injection hole 14b, two main flows, i.e., the main flow
30b having a direction toward the injection hole and the main flow
30b having a direction departing from the injection hole can be set,
20 as is the case with Embodiment 1; thus, it is made possible that there
are formed two kinds of fuel sprays, i.e., a fuel spray having large
penetration force and a fuel spray that has small penetration force
and is sufficiently micronized; as a result, an effect the same as
that of the fuel injection apparatus according to Embodiment 1 can
25 be obtained.
32
[0052]
Furthermore, in the fuel injection apparatus according to
Embodiment 3, the center of the valve seat 12 and the center of the
injection hole plate 13 are offset from each other and are mutually
fixed, without changing the shape of the flow path 5 including the fuel
path 17, the first swirling chamber 18a, and the second swirling
chamber 18b that are formed in the upstream-side endface of the
injection hole plate 13, so that the directions of the respective
flows of the fuel that heads for the first injection hole 14a and
10 the second injection hole 14b from the valve seat opening portion
12b can be adjusted by only adjusting the offset amount of the center
axis 40 of the fuel path 17 from the center 12c of the valve seat
opening portion; therefore, it is made possible to adjust the
penetration force of the fuel spray to the optimum strength
15 corresponding to each of various internal combustion engines.
Accordingly, in comparison with the case where in a
micronization-method fuel injection apparatus utilizing an ordinary
swirling flow, the penetration force of a fuel spray is adjusted by
changing the respective flow-path shapes of the injection hole, the
20 swirling chamber, the fuel path, and the like that are formed in the
upstream-side endface of the injection hole plate and provide a
swirling flow to the fuel, the designing man-hour required for the
adjustment can be reduced; furthermore, because the expenses, such
as the ones for changing the die of the injection hole plate, is not
25 necessary, the costs can be reduced.
33
[0053]
Embodiment 4
Next, a fuel injection apparatus according to Embodiment 4 of
the present disclosure will be explained. FIG. 9 is an explanatory
view illustrating the case where a fuel injection apparatus 5 according
to Embodiment 4 is provided in an intake port of an internal combustion
engine; FIG. 10 is an explanatory view of an upstream-side endface
of an injection hole plate in the fuel injection apparatus according
to Embodiment 4 when a cross section along the line C  C in FIG.
10 9 is viewed from the direction indicated by the arrows. In FIG. 9,
the fuel injection apparatus 1 disclosed in any one of foregoing
Embodiments 1 through 3 is mounted in a ceiling portion 70b of an
intake port 70 communicating with a combustion chamber 60 of an
internal combustion engine; a fuel is injected from the fuel injection
15 apparatus 1 onto an intake valve 80 of the internal combustion engine.
[0054]
In the case of intake-stroke injection in which a fuel is
injected during an intake stroke of an internal combustion engine,
an intake air flow 90 occurs, inside the intake port 70, from the
20 upstream side to the downstream side in the flow direction of the
fuel; however, because the penetration force of a fuel spray in the
foregoing conventional fuel injection apparatus is small, the fuel
spray is blown by the intake air flow 90 to the ceiling portion 70b
of the intake port 70 and adheres to the inner wall surface of the
25 ceiling portion 70b and hence the amount of the fuel entering the
34
combustion chamber is small; accordingly, because the vaporization
cooling effect in the combustion chamber 60 becomes insufficient,
the knock resistance is not raised and hence the compression ratio
cannot be increased, no sufficient effect in gasoline-mileage
improvement 5 can be obtained.
[0055]
As illustrated in FIG. 10, in the fuel injection apparatus
according to Embodiment 4, the first injection hole 14a, which is
offset from the center axis 40 of the fuel path 17 to the side where
10 the center 12c of the valve seat opening portion 12b is positioned,
is disposed in such a way as to be on a side Y1 that is closer to
the bottom portion 70a of the intake port than the center 17c of the
fuel path 17 is; the second injection hole 14b, which is offset from
the center axis 40 of the fuel path 17 to a side opposite to the side
15 where the center 12c of the valve seat opening portion 12b is
positioned, is disposed in such a way as to be on a side Y2 that is
closer to the ceiling portion 70b of the intake port than the center
17c of the fuel path 17 is. Accordingly, a first fuel spray F1, which
has small penetration force and is sufficiently micronized, is
20 injected through the first injection hole 14a toward the bottom
portion 70a of the intake port 70; a second fuel spray F2, which has
large penetration force, is injected through the second injection
hole 14b toward the ceiling portion 70b of the intake port 70.
[0056]
25 Embodiment 4 makes it possible that second fuel spray F2 having
35
large penetration force suppress the first fuel spray F1, which has
small penetration force and is sufficiently micronized, from being
blown by the intake air flow 90, produced during intake-stroke
injection, onto the ceiling portion 70b of the intake port 70 so as
to adhere to the wall 5 surface thereof.
[0057]
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
10 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
infinite number of unexemplified variant examples are conceivable
15 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.
20
Industrial Applicability
[0058]
A fuel injection apparatus 1 according to the present disclosure
can be applied to the field of an internal combustion engine or to
25 the automobile industry.
36
Description of Reference Numerals
[0059]
1: fuel injection apparatus
5 4: solenoid device
5: housing
6: core
7: coil
8: armature
10 9: valve device
10: valve body
11: valve holder
12: valve seat
12b: valve seat opening portion
15 13: injection hole plate
14a: first injection hole
14b: second injection hole
14c: third injection hole
14d: fourth injection hole
20 15: ball
16: compression spring
17: fuel path
17: first fuel path
171: second fuel path
25 18a: first swirling chamber
37
18b: second swirling chamber
18c: third swirling chamber
18d: fourth swirling chamber
50: welding portion
60: 5 combustion chamber
70: intake port
80: intake valve
90: intake air flow
F1: first fuel spray
10 F2: second fuel spray
38
We Claim :
1. A fuel injection apparatus
wherein a valve body for opening or closing a valve seat is
provided and the valve body is operated in response to an operation
signal from a control apparatus, so that after passing 5 through a gap
between the valve body and a seat portion of the valve seat, a fuel
is injected through two or more injection holes provided in an
injection hole plate attached to a valve seat opening portion at a
downstream side of the valve seat,
10 wherein an upstream-side endface of the injection hole plate
has
two or more swirling chambers that are arranged radially
outside the valve seat opening portion and each provide swirling force
to a fuel,
15 a fuel path for making a fuel flow from the valve seat
opening portion into a central portion thereof and for making the
fuel flow out thereof to each of the swirling chambers connected with
respective corresponding end portions thereof, and
the injection holes each of which opens in the
20 corresponding swirling chamber and through which a fuel is injected
toward the outside,
wherein in the case where the upstream-side endface of the
injection hole plate is viewed from the upstream side in a center-axis
direction of the valve seat opening portion, the two or more swirling
25 chambers and injection holes are arranged in point symmetry with
39
respect to the center of the fuel path, and the center axis of the
fuel path is offset from the center of the valve seat opening portion,
and
wherein among the two or more injection holes, at least one
injection hole is provided in such a way as to 5 be offset from the
center axis of the fuel path toward a side where the center of the
valve seat opening portion is positioned, and at least one injection
hole is provided in such a way as to be offset from the center axis
of the fuel path toward a side opposite to the side where the center
10 of the valve seat opening portion is positioned.
2. The fuel injection apparatus according to claim 1, wherein among
the two or more injection holes, at least two injection holes that
are offset from the center axis of the fuel path toward a side where
15 the center of the valve seat opening portion is positioned are
collectively arranged close to each other, and at least two injection
holes that are offset from the center axis of the fuel path toward
a side opposite to the side where the center of the valve seat opening
portion is positioned are collectively arranged close to each other.
20
3. The fuel injection apparatus according to any one of claims 1 and
2,
wherein in the case where the upstream-side endface of the
injection hole plate is viewed from the upstream side in the
25 center-axis direction of the valve seat opening portion, the
40
respective centers of the injection hole plate and the fuel path
coincide with each other, and
wherein the center of the injection hole plate is offset from
the center of the valve seat opening portion.
5
4. The fuel injection apparatus according to any one of claims 1
through 3, being disposed at a ceiling side of an intake port
communicating with a combustion chamber of an internal combustion
engine,
10 wherein among the two or more injection holes, the injection
hole that is offset from the center axis of the fuel path toward a
side where the center of the valve seat opening portion is positioned
is disposed in the injection hole plate at a bottom side of the intake
port, and
15 wherein the injection hole that is offset from the center axis
of the fuel path toward a side opposite to the side where the center
of the valve seat opening portion is positioned is disposed in the
injection hole plate at a ceiling side of the intake port.