JP3312318B2 - Fuel cut-off device for fuel tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention, in the fuel tank mounted on a vehicle such as an automobile, which is used attached to the tank body, the evaporated fuel gas generated in the tank body, The fuel is discharged from the tank body to the canister to prevent an abnormal rise in gas pressure (tank pressure) inside the tank body, but the fuel liquid that fluctuates due to vehicle shaking, etc., is prevented from flowing out to the outside. The present invention relates to improvement of a shutoff device.

[0002]

2. Description of the Related Art As a fuel cut-off device for an automobile or the like, the one shown in FIG. 4 (Japanese Utility Model Laid-Open No. 62-75278) is already known. In this case, the tank body a
The casing b provided in an upper portion of the inner, with emissions hole d is provided to communicate with the evaporation tube c, and float e is accommodated to float by the inflow of liquid fuel, the tank main body by turning Toka inclination of the vehicle When the fuel liquid level in a changes and the fuel liquid flows into the casing b, the float e rises by buoyancy, so that the seal portion e1 provided on the upper surface of the float b closes the discharge hole d, Prevent fuel liquid from leaking out through evaporative tube c
It is configured. Here, f in the same figure shows a canister into which the evaporated fuel gas is sent via the evaporation tube c.

However, with such a fuel cutoff device, the buoyancy of the float e by the fuel liquid causes the discharge hole d
Is closed to prevent undesired outflow of the fuel liquid, but if the gas pressure in the tank body a increases due to the closed state, the float e keeps the discharge hole d closed. And a so-called stick phenomenon occurs. In order to prevent such an undesired state, the weight of the float e is increased.
So that the result in large-type in.

[0004] In the conventional example shown in ibid Figure 4, such to eliminate the difficulties, in the state in which the float e is closing the discharge hole d by providing the relief valve g the casing b, the tank body a When the gas internal pressure becomes higher than the set value,
The relief valve g opens to allow the fuel vapor in the tank body a to escape from the evaporator tube c, thereby eliminating the stick phenomenon.

However, also in the above-described conventional example, the relief valve g is for avoiding the stick phenomenon of the float e.
The float e receives the internal gas pressure in the tank body a
It must be set lower than the pressure (stick pressure) that strongly contacts d . Therefore, if the stick pressure of the float e is set to be low, the valve opening pressure of the relief valve g is also set to be low.
It is difficult to lower the stick pressure to a value higher than a desirable level.

Therefore, even in the above-mentioned conventional example, it is impossible to fundamentally solve the problems such as an increase in the size and weight of the float e. Accordingly, Japanese Patent Application No. 3-14220 has already proposed a fuel cut-off device capable of fundamentally eliminating the occurrence of the stick phenomenon.
In this case, as clearly shown in FIG. 5, when the gas pressure of the tank main body a, that is, the tank internal pressure is increased by the evaporated fuel gas from the fuel liquid in the tank main body a, the casing is pushed up by the spring h, and b
, The valve body m which has closed the valve port k of the valve seat j opened at the upper end thereof in the valve housing i protruding from the valve housing i is pushed down. The gas is sequentially discharged from the inside of the valve housing i to the canister f through the communication hole e2 of the float e and the valve port k, through the evaporative tube c.

Further, when the fuel liquid in the tank body a infiltrates into the casing b as described above, buoyancy acts on the float e in which the guide cavity n is fitted in the valve housing i, so that the float h is reduced. The valve element m completely closes the valve port k due to the spring force of, and the outflow of the fuel liquid is prevented. Further, even in the blocking state, even if the tank internal pressure in the tank main body a becomes large, the tank internal pressure exerts an action of pressing the valve body m against the spring force of the spring h. The stick phenomenon as described above has no room for occurrence, and the danger that the gas pressure rises while the float e closes the valve port k can be drastically eliminated.

[0008]

However, according to the above proposal, although the stick phenomenon can be surely eliminated and the effect is effective, the number of springs h pushing up the valve element m is one. By the spring force generated by the spring h, not only the evaporative fuel gas is released in accordance with the pressurization, but also the fuel liquid blocking action when the fuel liquid enters the casing b is performed. Even at the time of rollover when turning over, the fuel liquid is completely prevented from leaking.

As is known, in order to prevent the fuel liquid from leaking at the time of the rollover, a considerably large spring force must be held by the spring h. On the other hand, the fuel liquid is prevented from flowing out due to fluctuations. in this case, although much of the power spring force is not required, which also was essential to relatively large power spring force, and in order to control the timely release of the vaporized fuel gas may be a soluble become small power spring force spring but Ru Nodea, if an attempt is satisfied with one of the spring these each of the three conditions, must use a spring with a large power spring force become eventually allowed.

For this reason, when using the above-mentioned fuel cut-off device, a spring having a considerably large spring force is used. However, in the case of a spring, the spring force varies, and for example, the degree of the dispersion is ± 10%. %, 2 g if the spring force is about 10 g.
On the other hand, a variation of only about 30 g would result in a variation of as much as 6 g if the weight is 30 g, and the absolute value of the variation becomes considerably large. As a result, if a spring having a large spring force is used to control the evaporated fuel gas, which requires only a spring having the smallest spring force, it is difficult to perform desirable control due to the variation.

The present invention is intended to solve the above-mentioned defects of the prior art. In the prior art shown in FIG. 5, the valve element m is pushed up by the spring h, and the normal time valve is thereby released. Instead of closing the valve port k by the body m, the spring h is pressed down by the weight of the float e, and thereby the valve port k is held in the open state. Therefore, during normal times, the fuel vapor in the tank body a enters the valve housing n through the valve port k, but the umbrella valve responds separately to the fluctuation of the gas internal pressure of the fuel vapor. Thus, a gas on-off valve formed is provided to deal with an abnormal increase in the gas internal pressure.

As described above, the above-mentioned gas on-off valve is exclusively used for controlling the evaporated fuel gas.
In the case of infiltration into the inside of the tank or at the time of rollover, the outflow of the fuel liquid is prevented by another source of generation corresponding to the above-mentioned spring h. The internal pressure allows the evaporative fuel gas to be always opened and closed at a predetermined pressure value,
It is an object of the present invention to improve its reliability, thereby helping to prevent a more desirable stick phenomenon, and to realize its weight reduction and miniaturization with high accuracy.

[0013]

The present invention SUMMARY OF THE INVENTION In order to achieve the above object, a casing communicating <br/> communication port is disposed In the upper part that is pierced in the tank body, the casing from the outlet communicates through the evaporation tube to the tank body outside of the canister is attached to the lower, the full <br/> funnel housed so as to be movable up and down movement within the cable <br/> Shin grayed becomes, to the casing bottom wall axis from cardiac position Ue突by a cylindrical valve housing is to fit the tubular guide sinus that opens to the downward in the axis of the float
The Rukoto, the float lifting movably der Rutotomoni, the float top plate portion formed by a directly on the guide sinuses, provided an actuating projection which under collision In the communication hole and the axis, This actuation projection is formed on the upper end of the valve housing
Is loosely fitted to the valve port of the valve seat, and within the valve housing
It is formed at a position that separates the inside of the
A gate valve opening is opened in the gate valve seat, and this gate valve seat and its
In the higher-level between the valve body interior to the valve housing by interposing a Ekitome spring for fuel fluid cutoff, in a normal state pressed by the contact between supra actuating projection of the valve body is a float Then , the valve opening of the valve seat is opened, and when the float is in the fuel liquid, the spring force of the liquid stop spring is increased so that the valve body closes the valve opening of the valve seat by floating of the float. The generated fuel gas having a predetermined pressure is bubbled into the gate valve seat through the gate valve port.
It is intended to provide a fuel shut-off device of the fuel tank, characterized in that from the Ujingu Ru flow freely der gas on-off valve is provided into the outlet.

[0014]

[Function] When the inside of the tank body is at a normal tank pressure, the operating projection of the float pushes down the valve body inside the valve housing against the spring force of the liquid stop spring,
Accordingly, a valve port in the communication hole and the valve seat of the float, holds the tank body and the valve housing in communication with the tank pressure of a result tank body, the gas on-off valve by an umbrella valve or the like Has been applied.

Therefore, when the gas internal pressure becomes larger than a predetermined value due to the evaporated fuel gas in the tank body,
The above-mentioned gas on-off valve is opened and the gate valve opening of the gate valve seat is
The inside of the valve housing communicates with the outlet, whereby the fuel vapor is discharged to the canister via the evaporative tube, thereby preventing abnormal pressure rise in the tank body.

Next, if the fuel liquid in the tank body enters the casing through the communication port due to turning or fluctuation of the vehicle,
The float becomes lighter due to the buoyancy acting thereon, and the float rises due to the force of the liquid stopping spring , which leads to the valve plug closing the valve opening of the valve seat. Infiltration into the valve housing is prevented, and there is no leakage of the fuel liquid. Also, at the time of rollover as known,
Since the valve body is pushed downward by the spring force of the liquid stop spring, the valve port of the valve seat is closed by the valve body, and at this time, the outflow of the fuel liquid is maintained in a shut-off state.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to FIGS. 1A and 1B and FIGS. 2 and 3. As is known, a fuel shut-off device X according to the present invention has a tank body in which a fuel liquid R is stored. At the upper part in T , it is attached via a bracket B or the like, and the evaporated fuel gas generated in the tank body T is discharged to the canister F outside the tank body T via the evaporation tube E. In FIG. 3 , FT indicates a filler tube, and BT indicates a belt tube.

[0018] The fuel shut-off device X, the upper the communication port 1a are decorated secured by a bracket B in the tank body T
It has a casing 1 penetrating therethrough, and an outlet 2 provided below the casing 1 and connected to a lower portion of the bottom wall 1b, and the outlet 2 is a canister outside the tank body T as described above. F, Evaporation tube E
Are communicated through.

Furthermore, having a float 3 in the above casing 1 is fitted so as to be movable up and down movement <br/>, from a central axial position of the bottom wall 1b of the casing 1, a valve according to a cylindrical shape, or the like housing 1c are Ue突, the tubular <br/> guide sinus 3a which is opened downward in the axial position of the float 3, the elevation motion self <br/> to said valve housing 1c It is fitted so that it exists. The float top plate portion 3b formed just above the guide cave 3a with respect to the float 3
Are provided with a communication hole 3c and an operation projection 3d which is provided at an axial center position and protrudes downward. The operation projection 3d is formed at the upper end of the valve housing 1c.
It is loosely fitted to the opening of the valve port 1e to the valve seat 1d.

In the present invention, the gate valve seat 4a for partitioning between the valve housing 1c and the outlet 2 is provided.
A gate valve opening 4b is opened, and the gate valve seat 4a and the valve housing 1c are interposed.
Between the valve body 5a formed on a sphere or the like which is furnished to a higher-level definitive, the Ekitome spring 5b is interposed a cutoff of fuel liquid R. Here, the liquid stop spring 5
When the inside of the tank body T is in a normal state,
By the valve body 5a is pressed by the above-mentioned actuating projection 3d of the float 3, the communication hole 3c, valve port 1e mentioned above
When the inside of the valve housing 1c is in communication and the float 3 is in the fuel liquid R and receiving buoyancy, the valve element 5a is set to close the valve port 1e of the valve seat 1d. .

Furthermore, in the present invention In the gate valve seat 4a having the above partition valve port 4b, evaporated fuel gas generated in the tank body T, via a partition valve port 4b, the valve housing 1c It becomes freely communicating into the outlet 2 from the inner
A gas on-off valve 6 that operates as described above is provided. here,
As the gas on-off valve 6 shown in FIG. 1, a known umbrella valve is adopted, which is inserted through a shaft hole of the gate valve seat 4a so that a retaining bulging portion 6a is located above the gate valve seat 4a. Ba
The umbrella portion 6 is expanded in the
b in outlet 2 below gate valve seat 4a.
It is connected continuously. The umbrella portion 6b is inverted due to an increase in the internal pressure due to the evaporated fuel gas in the valve housing 1c.
As a result, the fuel vapor flows into the outlet 2 through the gate valve opening 4b of the gate valve seat 4a.

Here, an umbrella valve is used as the gas on-off valve 6, but a valve as shown in FIG. 2 may be used. In this case, a gate valve at the gate valve seat 4a is used. 4b the gas stop valve body 6c disposed on the lower side of which, to <br/> pushed up so that the gas stop spring 6d which is disposed below them, in the normal state at which the partition valve body 6c closes the gate valve opening 4b by the spring force of the gas stop spring 6d.

Here, in the embodiment shown in FIG. 2 , a known negative pressure valve 7 is provided at the base of the outlet 2 so that the gas internal pressure at the outlet 2 is reduced by the pressure of the tank body T. When it becomes larger than the gas internal pressure,
The negative pressure valve body 7a resists the spring force of the negative pressure spring 7b,
It is depressed so as to open the negative pressure valve port 7c, so that the tank body T and the inside of the outlet 2 communicate with each other through the discharge port 7d.

Since the present invention can be configured as described above, if the inside of the tank body T is in a normal state as understood from FIG. 1, the valve body 5a is connected to the valve port 1e.
Is not closed, and the evaporated fuel gas in the tank body T has entered into the valve housing 1c. In this case, the tank internal pressure is increased, lever which reaches the certain pressure value, the gas-off valve 6 is then opened, the evaporated fuel gas via a partition valve port 4b,
It is released to the outlet 2-evaporation tube E-canister F, and the inside of the tank body T is not brought into an abnormally pressurized state. At this time, since the gas on-off valve 6 can adopt an extremely small spring force, the dispersion of the spring force is reduced, and a highly responsive and highly accurate opening and closing can be performed in response to the rise and fall of the gas pressure. Is achieved.

Next, when the fuel liquid R infiltrates into the casing 1 as described above, buoyancy acts on the float 3 so that the valve body 5a closes the valve port 1e by the spring force of the liquid stopping spring 5b. The fuel liquid R in the tank body T is prevented from flowing into the valve housing 1c. And
By the blocking condition persists, even if such a gas in pressure in the tank body T is increased, since the gas pressure becomes pressing the float 3, it is not that the stick phenomenon such as occurs .

[0026]

As described above, the present invention can completely prevent the occurrence of the stick phenomenon and solve the problems such as an increase in the size of the float and an increase in the weight, as well as the valve opening which is pushed up by the liquid stop spring. In a normal state, it is opened without being closed, and in this state, a separately provided gas opening / closing valve is used to release the fuel vapor gas in a timely manner so that the tank internal pressure due to the gas in the tank body does not become excessive. The liquid stop spring does not participate in the adjustment of the tank internal pressure, and only allows the gas on / off valve to perform the adjustment. Therefore, the gas on / off valve needs to have a large spring force to prevent the fuel liquid from flowing out. It is Ru without. As a result, the variation in the spring force of the gas on-off valve can be reduced, so that the gas on-off valve can always be released with high reliability at a desired gas internal pressure, and of course, the fluctuation of the vehicle and the roll It is also possible to improve the reliability in preventing the fuel liquid from flowing out at the time of overrun .

[Brief description of the drawings]

FIG. 1 shows a fuel cut-off device for a fuel tank according to the present invention, in which (A) is a vertical front view in a normal state, and (B) is a longitudinal sectional front view in a fuel liquid immersion state.

FIG. 2 is a vertical front view of a normal state showing another embodiment of the fuel cutoff device.

FIG. 3 is a schematic vertical front view of a tank body to which the fuel cutoff device according to the present invention is attached.

4 is a vertical sectional front view showing a fuel cutoff equipment is a conventional example of the fuel tank.

FIG. 5 is a vertical sectional front view showing a fuel cutoff device as a conventional example of different types of fuel tanks.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 1a Communication port 1b Bottom wall 1c Valve housing 1d Valve seat 1e Valve port 2 Outlet 3 Float 3a Guide hole 3b Float top plate part 3c Communication hole 3d Operating projection 4a Partition valve seat 4b Partition valve port 5a Valve body 5b Liquid spring 5b 6 Gas on-off valve E Evaporation tube F Canister R Fuel liquid T Tank body

Claims (1)

(57) [Claims] A casing 1. A are arranged be in the upper portion of the tank body communicating <br/> communication port that has been pierced through the evaporation tube to the tank body outside of the canister is attached to the lower portion of the casing and an outlet in communication with Te, consists of a full <br/> funnel housed so as to be movable up and down movement within the cable <br/> thin grayed, Ue突in-cylinder from the bottom wall axis position of the casing the Jo of the valve housing, to fit the tubular guide sinus that opens to the downward in the axis of the float
The Rukoto, the float lifting movably der Rutotomoni, the float top plate portion formed by a directly on the guide sinuses, provided an actuating projection which under collision In the communication hole and the axis, This actuation projection is formed on the upper end of the valve housing
Is loosely fitted to the valve port of the valve seat, and within the valve housing
It is formed at a position that separates the inside of the
A gate valve opening is opened in the gate valve seat, and this gate valve seat and its
In the higher-level between the valve body interior to the valve housing by interposing a Ekitome spring for fuel fluid cutoff, in a normal state pressed by the contact between supra actuating projection of the valve body is a float Then , the valve opening of the valve seat is opened, and when the float is in the fuel liquid, the spring force of the liquid stop spring is increased so that the valve body closes the valve opening of the valve seat by floating of the float. The generated fuel gas having a predetermined pressure is bubbled into the gate valve seat through the gate valve port.
The fuel shut-off device of the fuel tank, characterized in that from the Ujingu Ru flow freely der gas on-off valve is provided into the outlet.