Fluid sprinkling – spraying – and diffusing – Fluid pressure responsive discharge modifier* or flow... – Fuel injector or burner
Reexamination Certificate
2003-02-10
2003-12-30
Evans, Robin O. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Fluid pressure responsive discharge modifier* or flow...
Fuel injector or burner
C239S533200, C239S533140, C239S552000, C239S554000, C239S555000, C239S585100
Reexamination Certificate
active
06669116
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an injector to be used for fuel injection in an engine. More specifically, the present invention relates to an orifice plate disposed at the tip of the injector and used for setting characteristics of fuel injection.
2. Description of Related Art
An electromagnetic injector conventionally used for fuel injection in an engine is typically provided with a seat part at the tip of a nozzle body to cover a valve body formed at the tip of a needle valve from the tip. This seat part is provided with a fuel passage hole, to the tip of which a thin orifice plate having a plurality of orifices (small pores) is attached. Fuel having passed through the fuel passage hole is injected at a predetermined injection angle through those orifices.
Regarding the injector (fuel injection valve) including the above kind of orifice plate, the applicant of the present application has proposed a technique capable of prompting fuel atomization in Japanese patent unexamined publication No. 10-18943.
As shown in
FIG. 15
, the injector disclosed in the above publication includes a valve body
70
a
having a conical shape at the tip of a needle valve
70
. At the tip of a nozzle body
71
, a fuel passage hole
72
is formed. Around the fuel passage hole
72
, there is formed a seat part
71
a
on which the valve body
70
a
is seated for a valve closed time. Two orifice plates
73
and
74
are fixedly superposed one on top of the other at the tip of the nozzle body
71
to cover the fuel passage hole
72
from the front side (the lower side in FIG.
15
). These orifice plates
73
and
74
are provided with a plurality of orifices
73
a
and
74
a
, respectively, punched in positions within the fuel passage hole
72
. These orifices
73
a
and
74
a
, as shown in
FIG. 16
, are formed each having a central axis C
1
, C
2
, C
3
, or C
4
at an angle with a central axis O of the fuel passage hole
72
so that each distance between the axes C
1
and C
2
and between the axes C
3
and C
4
is widened downward. Thus, the orifices
73
a
and
74
a
are formed inclining to be oblique to each surface of the orifice plates
73
and
74
. These orifices
73
a
and
74
a
are arranged in corresponding positions in the two orifice plates
73
and
74
respectively and have an equal inner diameter. The orifices
73
a
and
74
a
being inclined as above have stepped parts
75
on a superposed surface, namely, a joint portion between the orifices
73
a
and
74
a
. By this stepped part
75
, the fuel flow passage provided by the orifices
73
a
and
74
a
is narrowed at the joint portion between the orifices
73
a
and
74
a
in a fuel injecting direction. Fuel to be sprayed will therefore impinge upon the stepped parts
75
, so that the flow of fuel becomes turbulent. This turbulent fuel is utilized to prompt atomization of the fuel to be injected.
However, the orifice plates
73
and
74
of the conventional injector disclosed in the above publication need manufacturing to have the inclined orifices
73
a
and
74
a
, which would make it difficult to machine the plates
73
and
74
with accuracy. This conventional technique, in addition, requires forming of a plurality of orifices
73
a
or
74
a
inclined in different directions in each single orifice plate
73
and
74
, as shown in FIG.
17
. This would increase the number of machining steps due to punching of the orifices
73
a
and
74
a
, leading to a problem of productivity.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above circumstances and has an object to overcome the above problems and to provide an orifice plate which can facilitate machining for providing an inclination to fuel to be injected through an orifice.
Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the purpose of the invention, there is provided an orifice plate which is mounted at a tip of an injector to cover a fuel passage hole formed at the tip, the orifice plate including: a plate body constructed in layers; and an orifice for allowing fuel having passed through the fuel passage hole to be injected; wherein the orifice is constructed of a plurality of holes each formed in each layer of the plate body so that each hole is perpendicular to a surface of the plate body, the holes being disposed in communication with each other and with displacements from each other along a line obliquely intersecting the plate body.
According to another aspect of the invention, there is provided an injector provided with the orifice plate described above, wherein the injector includes a plate holder provided with an injection hole, and the orifice plate is fixedly pressed against the tip of the injector by means of the plate holder and the orifice is positioned within the injection hole.
REFERENCES:
patent: 4923169 (1990-05-01), Grieb et al.
patent: 4934653 (1990-06-01), Grieb et al.
patent: 5899390 (1999-05-01), Arndt et al.
patent: 5924634 (1999-07-01), Arndt et al.
patent: 6168099 (2001-01-01), Hopf et al.
patent: 6357677 (2002-03-01), Ren et al.
patent: 2002/0092930 (2002-07-01), Itatsu
patent: 10-18943 (1998-01-01), None
Aisan Kogyo Kabushiki Kaisha
Evans Robin O.
Oliff & Berridg,e PLC
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