Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
1998-11-23
2001-03-13
Miller, Carl S. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
C123S456000
Reexamination Certificate
active
06199538
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel injection valve for the cylinder injection of fuel which injects fuel directly into the combustion chamber of an internal combustion engine.
2. Description of the Related Art
An example of a conventional (but not prior art) fuel injection valve
1
for the cylinder injection is shown in
FIGS. 2
to
4
.
FIG. 2
shows a cross-sectional view of a fuel injection valve
1
for the cylinder injection. In the figure, the tip of the fuel injection valve
1
for the cylinder injection is inserted into an injection valve socket
6
in a cylinder head
5
in an internal combustion engine. A flange portion
2
a
of a housing
2
is held by a generally plate-shaped fork
28
, and the fuel injection valve
1
for the cylinder injection is attached to the cylinder head
5
by securing the fork
28
to the cylinder head
5
by means of a bolt
29
. A seal is formed between the cylinder head
5
and the fuel injection valve
1
for the cylinder injection by means of a corrugated washer
160
.
The fuel injection valve
1
for the cylinder injection comprises the above housing
2
and a valve assembly
3
supported by one end of this housing
2
by a fastening means such as caulking.
The valve assembly
3
comprises: a stepped, hollow, cylindrical valve main body
9
which has a small-diameter cylinder portion
7
and a large-diameter cylinder portion
8
; a valve seat
11
which has a fuel injection hole
10
and is secured to the tip of the central hole within the valve main body
9
; a needle valve
12
which is a valve body which is moved in and out of contact with the valve seat
11
by means of a solenoid assembly
26
to close and open the fuel injection hole
10
; and a swirler body
13
which guides the needle valve in the axial direction and also imparts a swirling motion to the fuel as it is about to flow radially inward into the fuel injection hole
10
of the valve seat
11
.
The solenoid assembly
26
, which comprises a coil
27
, is disposed within the housing
2
. A core
33
which, together with an armature
30
and the housing
2
, defines a magnetic circuit is disposed within the solenoid assembly
26
. Within the core
33
, there are cylindrical bores
33
a
and
33
b
of different diameter. A spring
31
which pushes the needle valve
12
against the valve seat
11
and a hollow cylindrical rod
32
which adjusts the tension in the spring
31
are disposed in the cylindrical bore
33
a
, and a fuel filter
34
is disposed in the cylindrical bore
33
b.
In addition, a delivery pipe O-ring
35
is disposed around the outside of one end of the core
33
between backup rings
36
,
37
to prevent fuel which is supplied to the fuel injection valve
1
for the cylinder injection from the high-pressure fuel pump, which is not shown, via the inside of the delivery pipe
4
from leaking between the core
33
and the delivery pipe
4
.
A bush
38
, which has a thin cylindrical wall
38
a
, is disposed around the outside of the other end of the core
33
adjacent to the solenoid assembly
26
. An external O-ring
40
is disposed around the outside of this thin cylindrical wall
38
a
to form a seal between the housing
2
and the thin cylindrical wall
38
a
of the bush
38
, and an internal O-ring
41
is disposed around the inside of the thin cylindrical wall
38
a
to form a seal between the core
33
and the thin cylindrical wall
38
a
of the bush
38
, so that fuel is prevented from seeping into the coil
27
. Also, a spacer
39
is disposed on the opposite side of the external O-ring
40
and internal O-ring
41
from the coil
27
to position the external O-ring
40
and the internal O-ring
41
in the axial direction.
FIG. 3
is an enlarged sectional view showing the vicinity of the swirler body
13
, which constitutes part of the valve assembly
3
, and
FIG. 4
is a view of the swirler body
13
from the direction of an arrow X of FIG.
3
. In
FIGS. 3 and 4
, the swirler body
13
is a hollow, generally-cylindrical member which has a central bore
15
which surrounds and centrally supports the needle valve
12
which is a valve member, so that it can slide in the axial direction, and the swirler body
13
comprises: a first end surface
16
which comes into contact with the valve seat
11
when assembled in the valve assembly
3
; a second end surface
17
at the opposite end from the valve seat
11
; and an outer surface
19
between these two end surfaces which comes into contact with a curved inner surface
18
of the valve main body
9
.
The second end surface
17
of the swirler body
13
comes into contact with and is supported around its circumference by a shoulder portion
20
on the curved inner surface
18
of the valve main body
9
, and has passage grooves
21
formed therein which extend radially and allow fuel to flow from the inner portion to the radially outer portion of the second end surface
17
.
A plurality of flat surfaces which extend in the axial direction and are spaced evenly around the circumference are formed in the outer surface
19
of the swirler body
13
, and as a result, in the outer surface
19
there are formed: a plurality of curved outer surface portions which come into contact with the curved inner surface
18
of the valve main body
9
and regulate the position of the outer surface
19
with respect to the valve main body
9
; and channel portions
23
which are flat surfaces disposed between these curved outer surface portions and, together with the curved inner surface
18
, defines axial channels
22
for the fuel. These axial channels
22
are the spaces between the curved inner surface
18
of the valve main body
9
and the flat channel portions
23
, and so they have a substantially D-shaped cross-section (shaded portion in FIG.
4
).
In the first end surface
16
of the swirler body
13
which faces the valve seat
11
, there are disposed: an inner annular groove
24
of a prescribed width formed on the inside edge where the first end surface
16
meets the central bore
15
; and rotation grooves
25
which are connected at one end to the channel portions
23
of the outer surface
19
, extend generally radially inwards from there at a tangent to the inner annular groove
24
, and are connected at a tangent to the inner annular groove
24
at the other end.
In the fuel injection valve
1
for the cylinder injection constructed in this way, the fuel in the delivery pipe
4
passes through the fuel filter
34
, through the cylindrical bore in the rod
32
, through the cylindrical bore
33
a
in the core
33
, and through the cylindrical bore in the armature
30
, then passes through a two-sided cut portion
12
a
on the needle valve
12
, through an opening in a U-shaped stopper
42
, and around a four-sided cut portion
12
b
on the needle valve
12
, and is fed as far as the swirler body
13
.
When electricity is supplied to the coil
27
, magnetic flux is generated in the magnetic circuit formed by the armature
30
, the core
33
, and the housing
2
, and the armature
30
is attracted towards the core
33
. The needle valve
12
, which moves together with the armature
30
, is separated from the valve seat
11
, forming a gap, and fuel flows first via the passage grooves
21
in the second end surface
17
of the swirler body
13
through the axial channels
22
in the outer surface
19
, flows radially inwards into the rotation grooves
25
in the first end surface
16
, flows into the inner annular groove
24
of the first end surface
16
at a tangent thereto and forms a swirling current, then enters the injection hole
10
of the valve seat
11
and is sprayed from the outlet at the tip thereof.
In the fuel injection valve
1
for the cylinder injection constructed in this way, the fastening portion
33
d
in the flange portion
33
c
of the core
33
, where the core
33
is fastened to the housing
2
, is conventionally caulked to prevent the core
33
from being dislodged in the axial direction with respect to the housing
Aota Masayuki
Matsumoto Osamu
Munezane Tsuyoshi
Miller Carl S.
Mitsubishi Denki & Kabushiki Kaisha
Sughrue Mion Zinn Macpeak & Seas, PLLC
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