Fluid handling – Diverse fluid containing pressure systems – Fluid separating traps or vents
Reexamination Certificate
2001-06-19
2003-05-06
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Diverse fluid containing pressure systems
Fluid separating traps or vents
C137S043000
Reexamination Certificate
active
06557578
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to a fuel vapor treating apparatus that prevents fuel vapors in a vehicular fuel tank from being discharged to the atmosphere and, more particularly, to a fuel vapor treating apparatus that prevents fuel from being transferred to a canister via a vent line when a fuel tank is filled with fuel and that stops fuel from flowing out when a vehicle inclines or rolls over.
2. Description of Related Art
A vehicular fuel tank is provided with a liquid level sensing valve that closes a vent line when the fuel tank is filled with fuel, a fuel-cut valve that closes an evaporate line to prevent fuel from flowing out of the evaporate line when the vehicle inclines or rolls over, and so on.
Each of these valves is composed of a float that moves vertically in accordance with a liquid level of fuel.
Hereinafter, a known fuel vapor controlling apparatus according to one example of the related art will be described with reference to FIG.
3
.
A fuel tank
1
is fitted with a valve casing
4
in which a liquid level sensing valve
2
is integrated with a fuel-cut valve
3
.
The valve casing
4
is composed of a lower valve casing
4
A and an upper valve casing
4
B that is provided above the lower valve casing
4
A. A liquid level sensing float
5
and a fuel-cut float
6
are provided in the lower valve casing
4
A.
A valve portion
7
is provided on an upper face of the liquid level sensing float
5
. A valve portion
8
is provided also in an upper portion of the fuel-cut float
6
. Valve ports
9
,
10
are provided between the lower valve casing
4
A and the upper valve casing
4
B. The valve port
9
is opened and closed by the valve portion
7
, whereas the valve port
10
is opened and closed by the valve portion
8
. The upper valve casing
4
B is provided with a vent passage portion
11
that is connected to the valve port
9
via a space portion
12
. The space portion
12
is connected to the valve port
10
via a passage
13
.
Hereinafter, operation of the known fuel vapor controlling apparatus according to the related art shown in
FIG. 3
will be described.
If the pressure of fuel vapors in the fuel tank
1
becomes high during supply of fuel, the fuel vapors pass through the valve port
9
provided in the valve casing
4
and are discharged into a canister (not shown), an intake pipe (not shown) and so on as indicated by an arrow P shown in FIG.
3
.
If the liquid level of fuel in the fuel tank
1
becomes high, the liquid level sensing float
5
rises and the valve body
7
closes the valve port
9
. Thus, fuel is prevented from being fed directly to the canister and so on.
If the pressure of fuel vapors in the fuel tank
1
remains high during normal operation, the liquid level sensing float
5
is stuck to the valve port
9
and the vent passage portion
11
remains closed. Therefore, the pressure in the fuel tank
1
needs to be reduced.
Thus, the liquid level sensing float
5
is designed to fall because of its own weight.
In the case where the vehicle has greatly inclined or rolled over, there is an apprehension that a large amount of fuel in the fuel tank
1
may flow out toward the canister via the valve port
10
and the passage
13
. However, if the vehicle has greatly inclined or rolled over, the fuel-cut float
6
rises and the valve body
8
closes the valve port
10
to prevent fuel from flowing out.
As shown in
FIG. 3
, while the liquid level sensing float
5
and the fuel-cut float
6
are provided in the same valve casing
4
, they are provided in separate valve casings.
A fuel vapor treating apparatus according to a second example of the related art of the invention will be described with reference to FIG.
4
.
A fuel tank
21
is fitted with a liquid level sensing valve
22
and a fuel-cut valve
23
separately. A vent passage portion
25
is provided in a valve casing
24
for the liquid level sensing valve
22
, and a passage
27
is provided in a valve casing
26
for the fuel-cut valve
23
. A space portion
28
is provided in the valve casing
24
for the liquid level sensing valve
22
, and a connecting port
29
is provided in the space portion
28
. The connecting port
29
is connected to the passage
27
by a hose
30
.
Also in the related art shown in
FIG. 4
, the same operation as in the construction shown in
FIG. 3
is performed. Namely, if the liquid level of fuel in the fuel tank
21
becomes high, the liquid level sensing valve
22
closes the vent passage portion
25
. Thus, fuel is prevented from being fed directly to the canister and so on.
If the pressure of fuel vapors in the fuel tank
21
remains high during normal operation, the float of the liquid level sensing valve
22
is stuck to the valve port and the vent passage portion
25
remains closed. Therefore, the pressure in the fuel tank
21
needs to be reduced. Thus, using the valve port of the fuel-cut valve
23
, the float is designed to fall because of its own weight.
In the case where the vehicle has greatly inclined or rolled over, there is a possibility that a large amount of fuel in the fuel tank
21
may flow out toward the canister via the valve port of the fuel-cut valve
23
and the passage
27
. However, if the vehicle has greatly inclined or rolled over, the float of the fuel-cut valve
23
rises to close the valve port and thus prevent fuel from flowing out.
However, the fuel vapor treating apparatuses of the above described related art contain the following problems.
First, since the space portions
12
,
28
are directly connected to the vent passage portions
11
,
25
respectively, fuel that has leaked from the valve port
9
due to vibration of the vehicle or the like may be transferred toward the canister and adversely affect the canister.
Further, since the valve port
9
is directly exposed to fuel in the fuel tank, fuel may leak from the valve port
9
.
Further, in the construction in which the connecting port
29
of the liquid level sensing valve
22
is connected to the passage
27
of the fuel-cut valve
23
by the hose
30
(See, e.g., FIG.
4
), assembly of parts cannot be performed by single simple step. Therefore, this operation is time-consuming and laborious and requires preparing a large number of different types of parts. This leads to an increase in number of parts.
Japanese Patent Application No. 11-369719 discloses a fuel vapor treating apparatus that improves the disadvantages of the fuel vapor treating apparatuses of the above related art, including, e.g., reducing an amount of fuel leakage, simplifying the mounting of pipe lines, and reducing the number of parts.
Hereinafter, the fuel vapor treating apparatus disclosed in Japanese Patent Application No. 11-369719 includes the following three features.
First, a partition for stopping the flow of fuel is provided between a space portion of a liquid level sensing valve and a vent passage portion so as to reduce the amount of fuel leakage. Next, a tubular cover covers the liquid level sensing valve so as to prevent a valve port of the liquid level sensing valve from being exposed directly to fuel. Further, a connecting port of the liquid level sensing valve is connected to a passage of a fuel-cut valve by a connector that allows assembly by single simple step, or by a nipple used to make fingertip connection possible, in an attempt to reduce the number of parts and for ease of assembly.
FIGS. 5 and 6
illustrate a third example of the related art. A partition for stopping flow of fuel is provided between a space portion of a liquid level sensing valve and a vent passage portion.
A valve casing of a liquid level sensing valve
41
is composed of a lower valve casing
42
and an upper valve casing
43
that is provided above the lower valve casing
42
.
A float
44
is provided in the lower valve casing
42
, and a valve portion
45
is provided on an upper face of the float. A valve port
46
is provided between the lower valve casing
42
and the upper valve casing
43
and is opened and closed by the valve portion
45
. A
Masuda Hidemi
Shimamura Hiroshi
Sugimura Norikazu
Sugiura Koji
Kyosan Denki Co. Ltd.
Michalsky Gerald A.
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