Measuring and testing – Instrument proving or calibrating – Volume of flow – speed of flow – volume rate of flow – or mass...
Reexamination Certificate
1998-06-12
2001-07-17
Noland, Thomas P. (Department: 2856)
Measuring and testing
Instrument proving or calibrating
Volume of flow, speed of flow, volume rate of flow, or mass...
C073S001740, C073S114220, C073S001720, C029S888400
Reexamination Certificate
active
06260404
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for manufacturing a cylinder interior fuel injection valve for directly injecting fuel into a combustion chamber of an internal combustion engine, and an apparatus for adjusting a fuel injection amount used therefor.
2. Description of the Related Art
FIG. 6
is a cross-sectional view showing a cylinder interior fuel injection valve.
In
FIG. 6
, a cylinder interior fuel injection valve
1
is composed of a housing body
2
and a valve assembly
3
fixed to one end of the housing body
2
by press-fitting or the like and covered by a sleeve
35
. A fuel supply pipe (not shown) is connected to the other end of the housing body
2
for supplying pressurized fuel from the fuel supply pipe through a filter
37
into the cylinder interior fuel injection valve
1
.
The housing body
2
is provided with a first housing
30
having a flange
30
a
for mounting the cylinder interior fuel injection valve
1
on a cylinder head (not shown) of an internal combustion engine, and a second housing
40
on which a solenoid assembly
50
is mounted. The solenoid assembly
50
is provided with a bobbin
52
around which a coil
51
is wound and a core
53
installed in an inner circumferential portion of the bobbin
52
. A winding of the coil
51
is connected to a terminal
56
. The core
53
is formed into a hollow cylindrical shape so that its interior serves as a fuel passage. A valve closing spring
55
is interposed and compressed between an adjuster
54
and a needle valve
12
in the hollow cylindrical portion. An armature
31
is mounted at the other end of the needle valve
12
so as to face to a tip end of the core
53
. Disposed in an intermediate portion of the needle valve
12
are a guide
12
a
for sliding and guiding the valve
12
along the inner circumferential surface of a valve body
9
and a needle flange
12
b
which is in contact with a spacer
32
disposed in the first housing
30
. The housing body
2
constitutes a housing of the cylinder interior fuel injection valve
1
in cooperation with the sleeve
35
.
The valve assembly
3
is provided with a stepped hollow cylindrical valve main body
9
having a small diameter portion
7
and a large diameter portion
8
, a valve seat
11
having a fuel injection port
10
and fixed to a tip end of a center hole within the valve main body
9
, a needle valve
12
serving as a valve body for being seated on or separated away from the seat
11
by the solenoid assembly
50
for opening and closing the fuel injection port
10
, and a swirl member
13
for guiding the needle valve
12
in an axial direction while imparting a swirl motion to the fuel to be introduced into the fuel injection port
10
of the seat
11
in a radially inward direction.
Here, the first housing
30
, the core
53
and the armature
31
are made of magnetic material, for example, electromagnetic stainless steel to form a magnetic circuit.
The tip end side of the thus constructed cylinder interior fuel injection valve
1
is inserted into a fuel injection insertion hole (not shown) provided in the cylinder head, a retainer jig (not shown) is applied to the flange
30
a
from the outside, and the retainer jig is securely fastened to the cylinder head by mounting bolts (not shown). A flat washer or a corrugated washer is interposed between the cylinder interior fuel injection valve
1
and the cylinder head and a seal between the cylinder interior fuel injection valve
1
and the cylinder head is maintained by a pressure of the retainer jig in the axial direction. Also, a mounting hole of the fuel supply pipe is fitted and fixed to an O-ring portion for sealing the upper portion of the cylinder interior fuel injection valve
1
.
Then, the electric application to the coil
51
is controlled so that the needle valve
12
is moved in the axial direction to open/close the fuel injection port
10
.
Then, when the fuel injection port
10
is open, the pressurized fuel fed from the fuel supply pipe is caused to pass through the fuel passage in the interior of the core
53
and is subjected to the swirl energy by the swirl member
13
to be atomized and injected from the fuel injection port
10
into the combustion chamber.
A method for manufacturing the conventional cylinder interior fuel injection valve
1
will now be described with reference to FIG.
7
.
In the method for manufacturing the conventional cylinder interior fuel injection valve
1
, it is necessary to adjust the fuel injection amount so that it falls within a range of a rated value. The fuel injection amount adjusting step is carried out before the fixture of the adjuster
54
to the core
53
. As shown in
FIG. 8
, under the condition that the fuel filter
37
is removed away, an adjusting pin
18
inserted from the fuel supply side is inserted or retracted so that the axial position of the adjuster
54
is adjusted to change the compression amount of the valve closing spring
55
to adjust the fuel injection amount.
Namely, the adjusting pin
18
inserted from the fuel supply side is moved in the axial direction to adjust the position of the adjuster
54
(step
100
), and at this time, the fuel injection amount is measured (step
101
). It is then judged whether or not the measured value of the fuel injection amount falls within the rated range (step
102
). If the measured value of the fuel injection amount falls within the rated range, the core
53
is press-fitted from the outside. The adjuster
54
is fixed to the core
53
(step
103
) to finish the fuel injection amount adjusting step. The process moves to the next step (step
104
). Also, if the measured value of the fuel injection amount does not fall within the rated range, the process is returned back to step
100
, and the position of the adjuster
54
is adjusted again so that the fuel injection amount falls within the rated range.
The following function in addition to the function of adjusting the fuel injection amount as described above is required for the spring force of the valve closing spring
55
in such a kind of the cylinder interior fuel injection valve
1
.
First, the cylinder interior fuel injection valve
1
faces to the combustion chamber of the internal combustion engine and the combustion gas pressure of the combustion chamber is applied to the needle valve
12
in the valve opening direction. It is necessary to set a lower limit to the spring force of the valve closing spring
55
so that the needle valve
12
is seated on the valve seat
11
to maintain the valve closed condition and the introduction of the combustion gas into the cylinder interior fuel injection valve
1
is prevented even if the combustion gas pressure is applied to the needle valve
12
in the non-application of the current to the coil
51
.
Secondly, the magnetic suction force of the solenoid assembly
50
has to be greater than the sum of the force in the valve closing direction by the spring force of the valve closing spring
55
and the force in the valve closing direction by the fuel pressure in order to open the needle valve
12
in the electric application to the coil
51
. The fuel pressure used in such a kind of a cylinder interior fuel injection valve
1
is high in comparison with the conventional fuel injection valve, and the force in the valve closing direction by the fuel pressure is also high. However, the excessively increasing the suction force of the solenoid assembly
50
for coping with this would raise the problems in size, heat generation and cost. Accordingly, an upper limit has to be set for the spring force of the valve closing spring
55
, and the needle valve
12
has to be opened to inject fuel upon the electric application to the coil
51
within the fuel pressure range which would be generated in the actual product.
However, in the adjusting step of the fuel injection amount in the manufacturing method of the conventional cylinder interior fuel injection valve
1
, the positional adjustment of the adjuster
54
is repeated
Aota Masayuki
Matsunaga Kazuo
Munezane Tsuyoshi
Sumida Mamoru
Mitsubishi Denki & Kabushiki Kaisha
Noland Thomas P.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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