Fuel injection valve

Details Fuel injection valve Fuel injection valve

2000-08-31

2003-02-04

Morris, Lesley D. (Department: 3752)

Fluid sprinkling, spraying, and diffusing

Flow deflecting or rotation controlling means

Fluid rotation inducing means upstream of outlet

C239S585400

Reexamination Certificate

active

06513732

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention is suitable for a fuel injection valve, particularly a fuel injection valve for cylinder injection, and relates to a structure of the fuel injection valve for injecting fuel from a fuel injection hole be applying swirl energy to a fuel flow.
FIG. 8
is a sectional side view showing the entire configuration of a conventional fuel injection valve
71
for cylinder injection. The fuel injection valve
71
for cylinder injection comprises a housing body
72
and a valve unit
73
which is swaged in one end of this housing body
72
and is covered with a holder
105
. A fuel supply pipe
74
is connected to the other end of the housing body
72
and high-pressure fuel is supplied from this fuel supply pipe
74
into the fuel injection valve
71
for cylinder injection through a fuel filter
127
. Also, the top end of the fuel injection valve
71
for cylinder injection is inserted into an insertion hole
76
for injection valve of a cylinder head
75
of an internal combustion engine and is sealed and mounted by a wave washer
130
.
The valve unit
73
comprises a stepped hollow cylindrical-shaped valve body
79
having a small diameter cylindrical part
77
and a large diameter cylindrical part
78
, a valve seat
81
which is fixed in the top of a center hole within the valve body
79
and has a fuel injection hole
80
, a needle valve
82
which is a valve element for opening or closing the fuel injection hole
80
by making or breaking contact with the valve seat
81
using a solenoid unit
120
(described later), and a swirl body
83
which guides the needle valve
82
in the axial direction and applies swirl movements to fuel flowing into the fuel injection hole
80
of the valve seat
81
inwardly in the diameter direction. The valve body
79
of the valve unit
73
forms a housing of the fuel injection valve
71
for cylinder injection in cooperation with the housing body
72
.
The housing body
72
comprises a first housing
100
having a flange
100
a
for mounting the fuel injection valve
71
for cylinder injection in the cylinder head
75
, and has the solenoid unit
120
within the first housing
100
. The solenoid unit
120
comprises a bobbin
122
wound by a coil
121
and a core
123
installed in an inner circumferential portion of this bobbin
122
, and a winding of the coil
121
is connected to a connection terminal
126
. The core
123
is formed in a hollow cylindrical shape so that the inside of the core
123
is used as a fuel passage, and a spring
125
is suspended between a sleeve
124
and the needle valve
82
in the hollow portion of the core
123
.
A moving armature
101
is mounted in the other portion of the needle valve
82
in opposition to the top side of the core
123
, and also the intermediate portion of the needle valve
82
is provided with a guide
82
a
for sliding and guiding the needle valve
82
along an inner circumferential surface of the valve body
79
and a needle flange
82
b
in engagement with a spacer
102
installed in the first housing
100
.
FIG. 9
is an enlarged sectional side view showing the vicinity of the valve seat of the valve unit
73
and
FIG. 10
is a front view seen from the side of the valve seat
81
of the swirl body
83
. In the drawings, the swirl body
83
of the valve unit
73
is a member with a substantially hollow cylindrical shape having a center hole
85
for surrounding the needle valve
82
(valve element) in the center and slidably supporting it in the axial direction, and comprises a first end surface
86
in engagement with the valve seat
81
, a second end surface
87
opposite to the valve seat
81
, and a circumferential surface
89
having a portion in engagement with an inner circumferential surface
88
of the valve body
79
being a part of a hollow housing between these end surfaces when the swirl body
83
is assembled in the valve unit
73
.
The second end surface
87
of the swirl body
83
is supported in engagement with a shoulder part
90
of the inner circumferential surface
88
of the valvehody
79
in the periphery, and also it is configured so that a passage groove
91
extending in the diameter direction is formed and fuel can flow from the inner circumferential portion to the outer circumferential portion of the second end surface
87
.
The circumferential surface
89
of the swirl body
83
is provided with a plurality of outer circumferential surface parts
89
a
for defining a position to the valve body
79
in engagement with the inner circumferential surface
88
of the valve body
79
and a flow passage part
89
b
which is disposed between these outer circumferential surface parts
89
a
and forms an axial flow passage
92
of fuel along with the inner circumferential surface
88
.
The axial end surface facing the valve seat
81
of the swirl body
83
, namely the first end surface
86
is provided with an inner circumferential ring groove
94
with a predetermined width formed on an inner circumferential side adjacent to the center hole
85
of the first end surface
86
, and a swirl groove
95
which is connected to the flow passage part
89
b
of the circumferential surface
89
at one end and extends inwardly in the approximately diameter direction therefrom and is connected to the inner circumferential ring groove
94
in the tangential direction at the other end.
Next, an operation of the fuel injection valve for cylinder injection will be described. Referring first to
FIG. 8
, when energizing the coil
121
of the solenoid unit
120
through connection terminal
126
from the outside, a magnetic flux is generated in a magnetic passage formed by the moving armature
101
, the core
123
and the housing body
72
, and the moving armature
101
is attracted to the side of the core
123
against an elastic force of the spring
125
. Then, the needle valve
82
integral with the moving armature
101
moves to the right side (shown in
FIG. 8
) of a predetermined stroke until the needle flange
82
b
is brought into engagement with the spacer
102
. Incidentally, the needle valve
82
is guided and held in the inner circumferential surface of the valve body
79
by the guide
82
a.
Then, in
FIGS. 9 and 10
, when the top end of the needle valve
82
moves away from the valve sear
81
to form a gap, high—pressure fuel of introduced from the fuel supply pipe
74
first flows into the axial flow passage
92
of the circumferential surface from a passage between the valve body
79
and the needle valve
82
through the passage groove
91
of the second end surface
87
of the swirl body
83
. Next, the high-pressure fuel flows into the swirl groove
95
of the first end surface
86
of the swirl body
83
inwardly in the diameter direction and flows into the inner circumferential ring groove
94
of the first end surface
86
in the tangential direction and forms swirl flow in a swirl chamber W constituted by the inner circumferential ring groove
94
. Subsequently, the fuel flows into the injection hole
80
of the valve seat
81
and is sprayed from an outlet of the top of the injection hole
80
.
Since the conventional fuel injection valve is configured as described above, a non-contact portion remains between the outer circumferential surface of the swirl body and the inner circumferential surface of the valve element, with the result that there was a problem that another radiator is required in case where combustion heat is large and temperature in the top of the fuel injection valve tends to become high. Also, in case of a specification of the swirl groove with a large sectional area, there was a problem that the axial flow passage relatively becomes narrow, so that pressure loss occurs in the axial flow passage and a desired flow velocity cannot be obtained in the swirl groove.
SUMMARY OF THE INVENTION
The invention is implemented to solve such problems, and it is an object of the invention to provide a fuel injection valve capable of achieving weight reduction of a swirl body while speeding heat radiation from the

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