Fluid handling – Line condition change responsive valves – Bi-directional flow valves
Reexamination Certificate
1999-04-16
2001-03-06
Hepperle, Stephen M. (Department: 3753)
Fluid handling
Line condition change responsive valves
Bi-directional flow valves
C137S493500, C137S493900, C137S630220
Reexamination Certificate
active
06196258
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pressure control valve. Further, the present invention relates an evaporation fuel discharge control device which, when fuel is supplied to a fuel tank of a car, is used to control the discharge of evaporation fuel from the fuel tank.
The present application is based on Japanese Patent Applications No. Hei. 10-106055 and 11-59674 which are incorporated herein by reference.
2. Description of the Related Art
Generally, in a car, evaporation fuel from a fuel tank is temporarily stored in a canister through an evapo-pipe, and it is introduced into an engine suitably. There is disposed a pressure control valve in the evapo-pipe.
And, conventionally, as a pressure control valve which is used in such pipe, for example, there is known a pressure control valve which is disclosed in Japanese Utility Model Publication No. Hei. 1-83976.
FIG. 17
shows the pressure control valve that is disclosed in the above-cited publication. That is, the pressure control valve comprises a cap
202
which includes a first port
201
in communication with a fuel tank, and a body
204
including a second port
203
in communication with a canister.
The body
204
includes a partition wall
205
in the interior portion thereof; and, in particular, between the upper surface of the partition wall
205
and the inner surface of the cap
202
, there is interposed a first valve
206
, and, inside the first valve
206
, in particular, between the upper surface of the partition wall
205
and a valve body
207
, there is interposed a second valve
208
.
And, in the portion of the partition wall
205
that is situated on the inner side of the second valve
208
, there is formed a fluid passage
209
.
However, in the above-structured conventional pressure control valve, since the fluid passage
209
is formed only in the portion of the partition wall
205
that is situated on the inner side of the second valve
208
, when the pressure within the fuel tank increases suddenly, it is difficult to introduce the evaporation fuel within the fuel tank through the first and second ports
201
and
203
to the canister side quickly.
Further, as an evaporation fuel discharge control device which, when fuel is supplied to a fuel tank of a car, is used to control the discharge of evaporation fuel from the fuel tank, for example, there is known a device which is disclosed in Japanese Patent Publication No. Hei. 8-189423.
Now,
FIG. 18
shows the evaporation fuel discharge control device disclosed in the above-cited patent publication. In this evaporation fuel discharge control device, a tank main body
302
of a fuel tank
301
is connected to a canister
303
through an evaporation fuel passage
304
.
Within the tank main body
302
, there is disclosed a float valve
306
which is used to close an entrance portion
305
of the evaporation fuel passage
304
when fuel within the tank main body
302
exceeds a given liquid level.
And, in the evaporation fuel passage
304
, there is disposed a switch valve assembly
307
.
The switch valve assembly
307
has a diaphragm valve which divides a positive pressure chamber
307
a
and a back pressure chamber
307
b
, while the evaporation fuel passage
304
includes the positive pressure chamber
307
a.
And, when the pressure on the positive pressure chamber
307
a
side is higher by a predetermined value or more than the pressure on the back pressure chamber
307
b
side, the evaporation fuel passage
304
is opened.
On the back pressure chamber
307
b
side of the switch valve assembly
307
, there is opened a pressure introduction passage
309
which is connected to an entrance portion
308
a
of a fuel supply pipe
308
.
And, the portion of the evaporation fuel passage
304
on the upstream side of the switch valve assembly
307
is connected to the pressure introduction passage
309
by a communicating passage
310
.
In the communicating passage
310
, there is disposed a check valve
311
which is structured such that it can be opened when the pressure on the upstream side of the switch valve assembly
307
is higher by a given value or more than the pressure on the pressure introduction passage
309
side.
In the evaporation fuel discharge control device of this type, if a cap (not shown) of the fuel supply pipe is removed when starting fuel supply, then the pressure on the back pressure chamber
307
b
side of the switch valve assembly
307
is reduced down by the predetermined value or more than the pressure on the positive pressure chamber
307
a
side of the switch valve assembly
307
through the pressure introduction passage
309
to thereby open the switch valve assembly
307
, so that the evaporation fuel from the tank main body
302
is fed through the evaporation fuel passage
304
and is stored to the canister
303
.
And, if the internal pressure of the tank main body
302
is increased due to start of the fuel supply and the upstream side pressure of the switch valve assembly
307
is thereby increased by the given value or more than the pressure on the pressure introduction passage
309
of the check valve
311
, then the check valve
311
, which is disposed in the communicating passage
310
, is caused to open. As a result of this, a part of the evaporation fuel within the tank main body
302
is introduced through the pressure introduction passage
309
into the entrance portion
308
a
of the fuel supply pipe
308
and is then returned back into the tank main body
302
together with fuel which is supplied from a fuel supply gun
312
.
And, if the tank main body
302
is filled with fuel, then the entrance portion
305
of the evaporation fuel passage
304
is closed by the float valve
306
, with the result that the pressure on the upstream side of the switch valve assembly
307
with the communication thereof with respect to the interior portion of the tank main body
302
cut off is caused to decrease quickly to thereby close the switch valve assembly
307
and check valve
311
.
And, if the cap (not shown) is mounted on the fuel supply pipe
308
after completion of the fuel supply, then the pressure of the entrance portion
308
a
of the fuel supply pipe
308
increases together with and equally to the pressure of the interior portion of the tank main body
302
, so that the pressure on the back pressure chamber
307
b
side of the switch valve assembly
307
is caused to increase through the pressure introduction passage
309
and the pressure of the check valve
311
on the pressure introduction passage
309
side thereof is also caused to increase.
However, in the above-mentioned conventional evaporation fuel discharge control device, because, if the interior portion of the tank main body
302
is filled with the fuel, then not only the entrance portion
305
of the evaporation fuel passage
304
is closed by the float valve
306
but also the switch valve assembly
307
and check valve
311
are closed, the pressure on the upstream side of the switch valve assembly
307
remains as pressure equivalent to the atmospheric pressure, which causes the float valve
306
to stick to the entrance portion
305
of the evaporation fuel passage
304
.
Therefore, conventionally, in order to prevent the float valve
306
from sticking to the entrance portion
305
of the evaporation fuel passage
304
, for example, the float valve
306
is divided in two upper and lower stages. However, in this case, there arise other problems: that is, the float valve
306
is complicated in structure, the manufacturing cost thereof is increased, and the response property thereof is lowered.
SUMMARY OF THE INVENTION
The present invention aims at the above-mentioned problems found in the conventional pressure control valve. Accordingly, it is an object of the invention to provide a pressure control valve which, when the pressure on the first port side increases suddenly, can flow a large quantity of fluid to the second port side.
It is another object of the invention to provide an evaporation fue
Araki Shinji
Kanazawa Hideaki
Kimura Satoshi
Calsonic Corporation
Hepperle Stephen M.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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