Fluid sprinkling – spraying – and diffusing – Rigid fluid confining distributor – Orifice in separable disc or plate
Reexamination Certificate
2001-11-30
2004-08-03
Nguyen, Dinh Q. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Rigid fluid confining distributor
Orifice in separable disc or plate
C239S533120, C239S533140, C239S552000, C239S585100, C239S900000
Reexamination Certificate
active
06769638
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a fuel injection valve, more particularly to a fuel injection valve used for an internal combustion engine.
2. Description of the Related Art
Fuel injection valves accelerating atomization of fuel used so far include, for instance, the one disclosed in Japanese Published Unexamined Patent No. 2000-104647.
FIG. 13
is a cross-sectional elevation of a fuel injection valve disclosed in that publication,
FIG. 14
an enlarged view of the lower end of the fuel injection valve of
FIG. 13
, and
FIG. 15
a view of the bottom of the fuel injection valve of
FIG. 14
seen from the direction shown by arrow E in the Figure.
The illustrated fuel injection valve
1
includes an electromagnetic coil
3
, a fixed iron core
4
and metal plates
5
defining a magnetic current path, all disposed in a resin housing
2
. The electromagnetic coil assembly
3
consists of a resin bobbin
3
a
, a coil
3
b
being wound around the outer periphery of the bobbin
3
a
, and a terminal
6
formed for connecting to an external source of electric power. The resin housing
2
is molded around the electromagnetic coil assembly
3
.
An adjuster
8
for adjusting the loads on a compression spring
7
is secured to the inside of the fixed iron core
4
. Each of the two metal plates
5
forming a magnetic current path is fixed at one end to the fixed iron core
4
by welding and is welded at the other end to an electromagnetic pipe
9
forming a magnetic current path. A non-magnetic pipe
11
is situated in the space between the fixed iron core
4
and the magnetic pipe
9
and secured thereto in a way enabling a movable iron core
10
situated within the magnetic pipe
9
to move up and down.
A needle pipe
12
is welded and secured to one end of the movable iron core
10
. The movable iron core
10
is abutting at the other end (or the end of the needle pipe
12
whereto the movable iron core
10
is secured) against a compression spring
7
, and a valve head
101
is fixed as a valve to the other end of the needle pipe
12
. The valve head
101
is guided to a valve seat
102
situated within the magnetic pipe
9
and is situated in a seating section
102
a
of the valve seat
102
in a way enabling its settling in and lifting off the seating section
102
a
. The outer periphery of the section of the valve head
101
guided by the valve seat
102
is processed into a polygonal shape, thus giving space between a guiding section
102
b
of the valve seat
102
and the valve head
101
for fuel to flow through. An orifice plate
104
having a plurality of fuel injection orifices
103
is situated at the lower end of the valve seat
102
, as well illustrated in
FIGS. 14 and 15
. Each of the injection orifices
103
is formed to be oblique from axis C of the fuel injection valve at a given angle.
In such conventional fuel injection valves like this, the valve head
101
is moved up and down by an electromagnetic driving means provided by the electromagnetic coil
3
, the movable iron core
10
and other members locating upwards to open and close the valve through the settling in and lifting off the valve seat
102
of the valve head
101
. Fuel flows through the space between the valve head
101
and the valve seat
102
into a fuel cavity
105
situated beneath the lower end of the valve head
101
and above the orifice plate
104
, and then injected out of the injection orifices
103
formed in the orifice plate
104
.
The fuel injection valve
1
as shown in
FIGS. 13-15
wherein the direction of fuel injection is defined by the angle of inclination of the injection orifices
103
formed in the plate
104
is imperfect in that it is difficult to achieve a satisfactorily large spray angle for the injected fuel because the fuel flowing through the fuel cavity
105
onto the orifice plate
104
generally gathers in the central section from the outer periphery. For achieving a large spray angle (say, 15° or more) by using a double-spray type valve it is necessary to form the injection orifices
103
having a large angle of inclination, and it is difficult to form such largely inclined orifices with small diameters, meaning that it is difficult to achieve a satisfactory atomization of fuel for which orifices must have small diameters. If largely inclined orifices with small diameters are successfully formed, the processing of such orifices in the orifice plate will involve a considerable cost. In case of an orifice plate in which more than six injection orifices are to be formed for the acceleration of atomization, it is particularly difficult to form these orifices because their diameters must be reduced further.
Although it is possible to govern the direction of fuel injection and to induce larger spray cone angles by increasing L/&phgr;d, or the ratio of depth L of the injection orifices
103
to be formed in the orifice plate
104
to diameter &phgr;d, or the diameter of the injection orifice, this could result in an impaired atomization. Further, it is difficult to perform the work to form the injection orifices
103
with larger L/&phgr;d values in the orifice plate
104
, and the work to form the injection orifices
103
having larger angles of inclination as well involves a significant manufacturing cost increase because it is difficult to form such injection orifices in the orifice plate
104
.
Although a fuel injection valve having an orifice plate with a fuel cavity formed wherein has been proposed as described in the Japanese Published Unexamined Patent Application Hei 10-122096, it is difficult to manufacture such an orifice plate, and thus involving a significant manufacturing cost increase.
In fuel injection valves injecting spray flows from a plurality of injection orifices to a plurality of directions, injection orifices are disposed along the circumferences of a plurality of concentric circles as described in Japanese Published Unexamined Patent Application Hei 11-72067. However, such fuel injection valves are imperfect in that they fail to produce spray flows consisting of fuel droplets of uniform size because of an inconsistency in the particle size composition of the fuel flows from the injection orifices disposed along the circumferences between inner and outer circles.
SUMMARY OF THE INVENTION
The present invention provides a low-priced and efficient fuel injection valve enabling the production of atomized uniform spray flows at a large spray angle (say, 15° and more) as well as the acceleration of atomization of injected fuel and including an orifice plate in which injection orifices are easily formed.
According to one form of the present invention, a fuel injection valve includes an orifice plate having a plurality of (more than six) injection orifices formed therein, a valve seat with a valve seating formed in the upstream section of said injection orifices, a single cylindrical fuel flow path formed in said valve seat, a fuel cavity formed in the space between said fuel flow path and said orifice plate having a plurality of said injection orifices and situated directly above a plurality of said injection orifices, and a valve member supported by said valve seat in a way enabling reciprocations and having an abutting section that can be settled in and lifted off a valve seating formed in said valve seat, and produces a plurality of spray flows consisting of a plurality of fuel flows injected out of injection orifices disposed in said orifice plate, wherein a plurality of injection orifices formed in said orifice plate are disposed only along ØP, or the diameter of a single pitch circle with its center coinciding with the axis of the fuel flow path, and the diameter of the fuel flow path (&phgr;D
1
), the diameter of each of the injection orifices (&phgr;d), &phgr;P and the depth in the axial direction of the fuel cavity (t) are made have the relationships &phgr;D
1
+&phgr;d<&phgr;P and t<&phgr;d.
In a preferred embodiment, of a plurality of said injection orifices formed in said orifice plate, ea
Munezane Tsuyoshi
Sumida Mamoru
Mitsubishi Denki & Kabushiki Kaisha
Nguyen Dinh Q.
Sughrue & Mion, PLLC
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