FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
ELECTROMAGNETIC 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 5 PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

DESCRIPTION
Technical Field
[0001]
The present application relates to an electromagnetic
fuel injection valve.

Background Art
[0002]
An electromagnetic fuel injection valve disclosed in,
for example, Patent Literature 1 is known as a fuel injection
device of an internal combustion engine or the like. The
electromagnetic fuel injection valve disclosed in Patent
Literature 1 is such that a magnetic attraction force acts in
a core direction on a movable element owing to a coil being
energized, and a valve body joined to the movable element
operates so as to slide inside a holder, after which the movable
element comes into contact with the core, which is a fixed core,
and an opened valve state occurs. Also, as shown in Fig. 5
of the same literature, the movable element has a tapered face
that becomes smaller in diameter heading downstream in a fuel
injection direction from an end portion. Furthermore, as
shown in Fig. 3 of the same literature, the core has a flat
face that opposes the movable element, and a structure is such
that the end portion of the movable element collides with the
flat face of the core when opening the valve.
Citation List
Patent Literature
[0003]
Patent Literature 1: JP-T-8-506877 (Fig. 1, Fig. 5, Fig.
3) (the term JP-T as used herein means a published Japanese
translation 5 of a PCT application)
Summary of Invention
Technical Problem
[0004]
The electromagnetic fuel injection valve disclosed in
Patent Literature 1 is such that a movable element receiving
a magnetic attraction force in a core direction owing to a coil
being energized slides inside a holder, and collides with the
core at a predetermined speed. When this collision takes place,
the movable element receives a repulsive force in a
perpendicular direction from a flat face of the core, and
bouncing of a valve body including the movable element starts.
The flat face of the core is normally designed in such a way
as to be perpendicular with respect to an axis of the fuel
injection valve. Due to manufacturing variation, however,
products wherein the flat face of the core has an inclination
of in the region of several degrees with respect to the
perpendicular exist. Because of this, products wherein the
repulsion of the movable element is in the direction of
inclination of the flat face of the core, the movable element
bounces while wobbling in a radial direction inside a holder,
and containment of the bouncing is slow, have been manufactured.
Further, due to containment of the bouncing being slow, there
is a problem in that linearity of a low injection amount region
among injection amount characteristics worsens.
[0005]
The present application discloses technology for
resolving the heretofore described kind of problem, and has
an object of providing an electromagnetic fuel injection valve
such that containment of bouncing of a valve body after a valve
opening collision is improved, and behavior of the valve body
is stabilized.
Solution to Problem
[0006]
An electromagnetic fuel injection valve disclosed in the
present application includes a valve body including a valve
portion and a movable element, a holder that houses the valve
body in an interior, and in which an inner peripheral face
having a gap with the movable element is configured, a core
that is provided on an upstream side of the valve body in a
fuel injection direction, and which comes into contact with
the movable element in an opened valve state, a coil that
encloses an outer side of the core, a valve seat that comes
into contact with the valve portion in a closed valve state,
and a spring that presses the valve body to a valve closing
side, wherein a tapered face that becomes smaller in diameter
heading downstream in the fuel injection direction from an
outer peripheral side end portion is formed in an upstream side
end face of the movable element in the fuel injection direction,
a tapered face that becomes smaller in diameter heading to the
upstream side in the fuel injection 5 direction from an outer
peripheral side end portion is formed in a downstream side end
face of the core in the fuel injection direction, and when a
diameter of the outer peripheral side end portion of the movable
element is D1, a diameter of the outer peripheral side end
portion of the core is D2, an outer diameter of the movable
element is D3, and an inner diameter of the holder opposing
the outer diameter of the movable element is D4, there is a
relationship such that |D1 – D2| < D4 – D3.
Advantageous Effects of Invention
[0007]
According to the electromagnetic fuel injection valve
disclosed in the present application, containment of bouncing
of a valve body after a valve opening collision is improved,
and behavior of the valve body can be stabilized.

Brief Description of Drawings
[0008]
Fig.1 is an overall sectional view of an electromagnetic
fuel injection valve according to a first embodiment.
Fig.2 is a main portion enlarged illustration of the
electromagnetic fuel injection valve according to the first
embodiment.
Fig.3 is a main portion enlarged view of a closed state
of the electromagnetic fuel injection valve according to the
first embodiment.
Fig.4 is a main portion 5 enlarged view of the
electromagnetic fuel injection valve according to the first
embodiment when a valve opening collision occurs.
Fig.5 is a main portion enlarged view of the
electromagnetic fuel injection valve according to the first
embodiment when a valve opening collision occurs.
Fig.6 is a main portion enlarged view of the
electromagnetic fuel injection valve according to the first
embodiment when a valve opening collision occurs.
Fig.7A is a main portion enlarged illustration of the
electromagnetic fuel injection valve according to the first
embodiment.
Fig.7B is a main portion enlarged illustration of the
electromagnetic fuel injection valve according to the first
embodiment.
Fig.8 is a main portion enlarged illustration
illustrating a form of a movable element of an electromagnetic
fuel injection valve according to a second embodiment.
Fig.9 is a main portion enlarged view of a state partway
through an opening of the electromagnetic fuel injection valve
according to the second embodiment.
Fig.10 is a main portion enlarged illustration of the
electromagnetic fuel injection valve according to the second
embodiment.
Description of Embodiments
[0009]
Hereafter, preferred embodiments of an electromagnetic
fuel injection valve according to the present application will
be described using the drawings. Identical reference signs
in the drawings indicate identical or corresponding portions.
[0010]
First Embodiment
Fig. 1 is an overall sectional view of an electromagnetic
fuel injection valve according to a first embodiment. An
electromagnetic fuel injection valve 1 is such that a lower
portion is attached facing an inside of an internal combustion
engine intake pipe, a fuel supply pipe is connected to an upper
portion, and fuel to which fuel pressure is applied is supplied.
In Fig. 1, the intake pipe and the fuel supply pipe are omitted
from the drawing.
The electromagnetic fuel injection valve 1 includes a
valve portion 2 downstream in a fuel injection direction
(hereafter referred to simply as downstream) and a movable
element 3 upstream in the fuel injection direction (hereafter
referred to simply as upstream), and includes a pipe 4 between the valve portion 2 and the movable element 3,joined to both.
The valve portion 2, the movable element 3, and the pipe 4
configure a valve body 5, and are housed in an interior of a
holder 6.
[0011]
The electromagnetic fuel 5 injection valve 1 further
includes a core 7, which is a fixed core opposing the movable
element 3, a coil 8 that encloses an outer side of the core
7, a spring 9 that is provided in an interior of the core 7
and presses the valve body 5 to the downstream side, a rod 10
that forms a base of the spring 9 and is fixed to the core 7,
a terminal 11 for energizing the coil 8 from an exterior, a
valve seat 12 on which the valve portion 2 sits and which seals
off fuel, and a plate 13 that is joined to a downstream side
of the valve seat 12 and has an orifice.
[0012]
Fig. 2 is a main portion enlarged illustration of the
electromagnetic fuel injection valve 1, wherein a tapered face
that becomes smaller in diameter heading downstream from an
outer peripheral side end portion is formed in an upstream side
end face of the movable element 3, and a tapered face that
becomes smaller in diameter heading upstream from an outer
peripheral side end portion is formed in a downstream side end
face of the core 7. Angles of inclination of the tapered faces
are each 10° with respect to a horizontal plane in the
embodiment.
[0013]
Herein, a diameter of an upstream side end portion of
the movable element 3 is D1, a diameter of a downstream side
end portion of the core 7 is D2, an outer diameter of the movable
element 3 is D3, and an inner diameter 5 of the holder 6 opposing
the outer diameter of the movable element 3 is D4. The movable
element 3 is housed having a gap with an inner periphery of
the holder 6. As shown in Fig. 2, a one side gap A is (D4 –
D3)/2. Also, a one side gap B between the upstream side end
10 portion of the movable element 3 and the downstream side end
portion of the core 7 is |D1 – D2|/2.
[0014]
In a state wherein there is no energization of the coil
8, the valve body 5 is pressed in the downstream direction by
a load applied by fuel pressure and a load applied by the spring
9, and the valve portion 2 comes into contact with a seating
face of the valve seat 12, thereby sealing off the fuel, as
shown in Fig. 2. The valve portion 2 is also housed having
a gap with an inner periphery of the valve seat 12, and owing
to these gaps existing, the valve body 5 is in a state of being
able to perform a sliding operation in the interior of the
holder 6.
[0015]
In the actual electromagnetic fuel injection valve 1,
however, the valve body 5 is subjected to an offset load by
the spring 9, and the movable element 3 comes into contact with
a right side of the inner periphery of the holder 6, as shown
in Fig. 3, and is in a state of being eccentric by A = (D4 –
D3)/2 to the right. At this time, the one side gap B between
the upstream side end portion of the movable 5 element 3 and the
downstream side end portion of the core 7 is formed to be shorter
than A, because of which a right side end portion 3R of the
movable element 3 is farther to the right than a right side
end portion 7R of the core 7, and a left side end portion 3L
of the movable element 3 is farther to the right than a left
side end portion 7L of the core 7.
[0016]
When the coil 8 is energized via the terminal 11 in
accordance with a command from an unshown control instrument
in this state, a magnetic attraction force acts in the direction
of the core 7 on the movable element 3, and when an
electromagnetic force exceeds the load applied by the spring
9 and the fuel pressure, the valve body 5 is displaced toward
upstream, a gap is formed between the valve portion 2 and the
valve seat 12, and fuel injection is started. A radial
direction magnetic attraction force acting between an outer
periphery of the movable element 3 and the inner periphery of
the holder 6 is at a maximum on the right side, where the gap
is small, because of which the valve body 5 is displaced in
an axial direction while maintaining the state of inclining
to the right. Heretofore, the right and the right side, or
the left and the left side, mean the right and the right side
or the left and the left side in Fig. 3, and in the following
description too, the right and the right side, or the left and
the left side, mean the right and the 5 right side or the left
and the left side in the relevant drawing.
[0017]
Subsequently, when the movable element 3 comes into
contact with the core 7, as shown in Fig. 4, the electromagnetic
fuel injection valve 1 attains an opened state. When the right
side tapered face of the movable element 3 collides with the
right side end portion 7R of the core 7, the movable element
3 receives a rightward reactive force F from the core 7 and
reacts, and bouncing is started. The valve body 5 is in a state
of being eccentric to the right side before the valve opening
collision, the state of being reliably pressed to the right
side is maintained by the valve body 5 receiving a rightward
reactive force when the collision occurs, there is no radial
direction looseness during the bouncing, and behavior of the
valve body 5 stabilizes, because of which bouncing containment
improves.
[0018]
Fig. 5 is a drawing illustrating a case in which the left
side tapered face of the core 7 and the left side end portion
3L of the movable element 3 collide. When the left side tapered
face of the core 7 collides with the left side end portion 3L
of the movable element 3, the movable element 3 receives the
rightward reactive force F from the core 7 and reacts, and
bouncing is started. In this state too, the valve body 5 is
in a state of being eccentric to the 5 right side before the valve
opening collision, the state of being reliably pressed to the
right side is maintained by the valve body 5 receiving the
rightward reactive force F when the collision occurs, there
is no radial direction looseness during the bouncing, and
behavior of the valve body 5 stabilizes, because of which
bouncing containment improves. In Fig. 5, C1 indicates a
central line of an end face of the core 7, and C2 indicates
a central line of an end face of the movable element 3.
[0019]
In Fig. 6, the right side tapered face of the movable
element 3 collides with the right side end portion 7R of the
core 7, the movable element 3 receives the rightward reactive
force F from the core 7 and reacts, and bouncing is started.
[0020]
In this way, the right side end portion 3R and the left
side end portion 3L of the movable element 3 are positioned
on the right side of the right side end portion 7R and the left
side end portion 7L respectively of the core 7 in a state wherein
the movable element 3 is eccentric to the right side inside
the holder 6, because of which the movable element 3 receives
a rightward reactive force, even when a direction of
inclination of the end face of the core 7 differs and a collision
position varies. Consequently, the state of being reliably
pressed to the right side is maintained, there is no radial
direction looseness during the bouncing, 5 and behavior of the
valve body 5 stabilizes, because of which bouncing containment
improves.
[0021]
As shown in Fig. 7A, the valve body 5 may be fabricated
by inserting the pipe 4 into the movable element 3, and
subsequently welding around a whole periphery of a boundary
portion of the two using, for example, irradiation with a laser
beam L. The boundary portion of the movable element 3 and the
pipe 4 irradiated with the laser beam L is melted once, forming
a joint portion, and subsequently solidified, whereby joining
is completed. As the melted portion contracts when solidified,
deflection occurs in the movable element 3, originating in the
joint portion, and the movable element 3 reaches a state of,
for example, being deflected to the left, as shown in Fig. 7B.
[0022]
When the valve body 5 in a state wherein the movable
element 3 is deflected to the left is used in this way, the
collision position of the valve body 5 when the valve opening
collision occurs is the right side end portion 7R of the core
7, and the right side end portion 7R of the core 7 collides
14
with the tapered face of the movable element 3, in the same
way as in the case shown in Fig. 6, because of which the movable
element 3 receives a rightward reactive force, the state of
being reliably pressed to the right side is maintained, there
is no radial direction looseness 5 during the bouncing, and
behavior of the valve body 5 stabilizes, because of which
bouncing containment improves.
[0023]
Second Embodiment
Next, an electromagnetic fuel injection valve according
to a second embodiment will be described. Fig. 8 is a drawing
illustrating a form of a movable element of the electromagnetic
fuel injection valve according to the second embodiment. As
the second embodiment is the same as the first embodiment with
the exception of the movable element, only the movable element
is shown in Fig. 8.
The electromagnetic fuel injection valve according to
the second embodiment is such that a tapered face that becomes
smaller in diameter heading downstream from an outer peripheral
side end portion is formed in an upstream side end face of the
movable element 3, in the same way as in the first embodiment,
and a stepped portion 30 shown in Fig. 8 is formed on an inner
diameter side of the tapered face. When a diameter of a
downstream side end portion of the core 7 is D2, an outer
diameter of the movable element 3 is D3, and an inner diameter
of the holder 6 opposing the outer diameter of the movable
element 3 is D4, a diameter D5 of the stepped portion 30 is
configured in such a way that D5 ˂ D2 – (D4 – D3). Because
of this, even though the movable element 3 has eccentricity
of (D4 – D3)/2, which is one-side clearance, 5 the stepped portion
is farther to the left side than the right side end portion
7R of the core 7, and the tapered face of the movable element
3 collides with the right side end portion 7R of the core 7.
As shown in Fig. 8, a flat face 31 of the same height as the
10 right side end portion 3R or the left side end portion 3L of
the movable element 3 is formed on an inner peripheral side
of the movable element 3, connected to the stepped portion 30,
and an inner diameter D6 of the flat face 31 is connected to
a curved portion or a chamfered portion (hereafter called a
curved portion) 32 connected to an inner peripheral face of
the movable element 3.
[0024]
When the stepped portion 30 is formed on the inner
diameter side of the tapered face of the movable element 3 in
this way, and the diameter of the stepped portion 30 is D5,
the diameter of the downstream side end portion of the core
7 is D2, the outer diameter of the movable element 3 is D3,
and the inner diameter of the holder 6 opposing the outer
diameter of the movable element 3 is D4, a configuration is
such that a relationship is D5 ˂ D2 – (D4 – D3). Because of
this, in a state partway through a valve opening shown in Fig.
9, a fluid loss due to a sudden reduction of a flow passage
area when passing over the stepped portion 30 occurs in a fuel
flow G that is pushed aside by movement of the movable element
3 and discharged from an outer peripheral 5 side of the movable
element 3 to an inner peripheral side, this forms resistance
to the movement of the valve body 5, and a buffering action,
which causes the valve body 5 to decelerate when the gap between
the movable element 3 and the core 7 immediately before the
10 valve opening is small, comes into effect. Owing to the valve
opening buffering action, there is an advantage in that an
amount of axial direction bouncing of the valve body 5 is
reduced. That is, bouncing containment is increased by
wobbling of the valve body 5 in the radial direction being
prevented in the first embodiment, but in the second embodiment,
the amount of bouncing is reduced by reducing the axial
direction speed of the valve body 5, whereby containment is
further increased.
[0025]
In the second embodiment, the flat face 31 of the same
height as the right side end portion 3R or the left side end
portion 3L of the movable element 3 is formed connected to the
stepped portion 30, and the inner diameter D6 of the flat face
31 is connected to the curved portion 32 formed on the inner
peripheral face of the movable element 3. Not only does a fluid
loss due to a sudden contraction of the flow passage when
passing over the stepped portion 30 occur in the fuel flow G
that is pushed aside by movement of the movable element 3 and
discharged from the outer peripheral side of the movable
element 3 to the inner peripheral side 5 partway through a valve
opening, but also fluid loss due to a sudden widening of the
flow passage occurs in the curved portion 32 when the fuel flows
out from the flat face 31 to the inner side of the movable element
3, because of which resistance works against the movement of
10 the valve body 5, and a buffering action, which causes the valve
body 5 to decelerate when the gap between the movable element
3 and the core 7 immediately before the valve opening is small,
comes into effect.
[0026]
With regard to a flow passage area when the fuel flows
out to the inner side of the movable element 3, as shown in
Fig. 10, the flat face 31 is of the same height as an end portion
of the movable element 3, because of which a gap height H between
the movable element 3 of the curved portion 32 and the core
7 is extremely small, and as the flat face 31 is connected to
the inner peripheral side of the curved portion 32, a diameter
of the curved portion 32 is also comparatively small, because
of which a flow passage area of the curved portion 32 is
extremely small, and the curved portion 32 has a shape such
that fluid loss due to a sudden widening of the flow passage
is extremely large.
Furthermore, in the first embodiment, the upstream side
end face of the movable element 3 is a tapered face, because
of which the gap with the core 7 is large on the inner peripheral
side, but in the second embodiment, 5 the flat face 31 is formed
on the inner peripheral side, whereby the gap with the core
7 is comparatively small on the inner peripheral side, and an
increase in the magnetic attraction force acting on the movable
element 3 is achieved.
[0027]
Although the present application is described in terms
of various exemplifying embodiments and implementations, the
various features, aspects, and functions described in one or
a multiple of the embodiments are not limited in their
applicability to a particular embodiment, but instead can be
applied, alone or in various combinations, to other
embodiments.
It is therefore understood that numerous modifications
that have not been exemplified can be devised without departing
from the scope of the present application. For example, at
least one constituent component may be modified, added, or
eliminated, and furthermore, at least one constituent
component may be extracted and combined with the constituent
components of another embodiment.
Reference Signs List
[0028]
1 electromagnetic fuel injection valve, 2 valve portion, 3
movable element, 3L left side end portion, 3R right side end
portion, 4 pipe, 5 valve body, 6 holder, 5 7 core, 7R right side
end portion, 7L left side end portion, 8 coil, 9 spring, 10
rod, 11 terminal, 12 valve seat, 13 plate, 30 stepped portion,
flat face, 32 curved portion, C1, C2 central line, F reactive
force, G fuel flow, L laser beam.

We Claim:
[Claim 1]
An electromagnetic fuel injection valve, comprising:
a valve body including a valve portion and a movable
element;
a holder that houses the valve body in an interior, and
in which an inner peripheral face having a gap with the movable
element is configured;
a core that is provided on an upstream side of the valve
body in a fuel injection direction, and which comes into contact
with the movable element in an opened valve state;
a coil that encloses an outer side of the core;
a valve seat that comes into contact with the valve
portion in a closed valve state; and
a spring that presses the valve body to a valve closing
side, wherein
a tapered face that becomes smaller in diameter heading
downstream in the fuel injection direction from an outer
peripheral side end portion is formed in an upstream side end
face of the movable element in the fuel injection direction,
a tapered face that becomes smaller in diameter heading to the
upstream side in the fuel injection direction from an outer
peripheral side end portion is formed in a downstream side end
face of the core in the fuel injection direction,
and when a diameter of the outer peripheral side end
portion of the movable element is D1, a diameter of the outer
peripheral side end portion of the core is D2, an outer diameter
of the movable element is D3, and an inner diameter of the holder
opposing the outer diameter of the movable element is D4, there
is a relationship such that 5 |D1 – D2| < D4 – D3.
[Claim 2]
The electromagnetic fuel injection valve according to
claim 1, wherein the valve body is configured by a multiple
of members being welded.
[Claim 3]
The electromagnetic fuel injection valve according to
claim 1 or 2, wherein a stepped portion is formed on an inner
side of the tapered face formed in the movable element, and
when a diameter of the stepped portion is D5, there is a
relationship of D5< D2 – (D4 - D3) between D2, D3, and D4.
[Claim 4]
The electromagnetic fuel injection valve according to
claim 1 or 2, wherein a flat face of the same height as the
outer peripheral side end portion is formed on an inner side
of the tapered face formed in the movable element, and the flat
face is formed in such a way as to be connected to a curved
portion or a chamfered portion formed in an inner periphery
of the movable element.
[Claim 5]
The electromagnetic fuel injection valve according to
claim 1 or 2, wherein a stepped portion is formed on an inner
side of the tapered face formed in the movable element, there
is a relationship of D5< D2 – (D4 - D3) between D2, D3, and
D4 when a diameter of the stepped portion is D5,
a flat face of the same height 5 as the outer peripheral
side end portion is formed on an inner side of the tapered face
formed in the movable element, and the flat face is formed in
such a way as to be connected to a curved portion or a chamfered
portion formed in an inner periphery of the movable element.