JPH04365627A - Float valve of fuel tank - Google Patents

Abstract

PURPOSE:To surely prevent the floating-up of a float body due to the evaporated fuel without increasing the dimensions and weight of the float body. CONSTITUTION:The first float 27 which floats up and closes a gas discharge hole 25 when the fuel supply quantity reaches a prescribed value is accommodated into a casing 4 connected to the side edge part of the tank body 1 of a vent tube 3, and a flap 30 and a spring 28 for maintaining the attitude of the flap 30 are arranged at the position perpendicular to an evaporated fuel passage 31. When the inflow quantity of the evaporated fuel into the casing 4 increases over a prescribed value, the flap 30 tilts against the spring 28, and the shift in the valve closing direction of the first float 2 is regulated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a float valve that regulates the amount of fuel supplied by floating a float body.

0002

[Prior Art] Conventionally, this type of float valve
Something like the one shown in FIG. 7 has been devised.

The float valve shown in the figure has a casing 4 disposed at the end of the tank body 1 side of a vent tube 3 that communicates the upper space of the tank body 1 and the canister 2, and a gas discharge hole is provided in the casing 4. It has a basic structure in which a float body 6 that can close the gas discharge hole 5 is housed, and the float body 6 does not open the gas discharge hole 5 until the fuel liquid level in the tank body 1 reaches a predetermined height during fuel refueling. The vaporized fuel generated in the tank body 1 is released from the vent tube 3 to the canister 2, and when the fuel level reaches a predetermined height, the float body 6 floats up and closes the gas discharge hole 5.
As a result, the upper part of the tank body 1 is sealed to prevent the liquid level from rising further in the tank body 1. In addition, in FIG. 7, 7 is an on-off valve that opens the vent tube 3 in conjunction with the insertion operation of the refueling gun 8 into the filler tube 9, and 10 is a valve that connects the upper space of the tank body 1 with another canister 11 for refueling. The evaporative tube 12, which supplies and discharges gas within the tank body 1 at other times, is a check valve for maintaining the inside of the tank body 1 at a predetermined pressure.

[0004] This similar structure is, for example,
This is shown in Publication No. 5727 and the like.

[0005]

[Problems to be Solved by the Invention] However, in the case of the above-mentioned conventional float valve, if refueling is started when the internal pressure of the tank body 1 has increased significantly due to heat-resistant running, etc.
When the vent tube 3 is first opened, there is a possibility that vaporized fuel may suddenly flow into the casing 4 due to the large pressure difference between the tank body 1 and the vent tube 3 side, causing the float body 6 to float. At this time, if the weight of the float body 6 is light, it is possible that the float body 6 may block the gas exhaust hole 5 due to floating due to the evaporated fuel.
Conventionally, in order to deal with this, the float body 6 had to be made larger and heavier. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a float valve for a fuel tank that can reliably prevent the float body from floating due to evaporated fuel without increasing the size and weight of the float body.

[0007]

[Means for Solving the Problems] As a means for solving the above-mentioned problems, the present invention provides a system in which, when the amount of fuel supplied reaches a predetermined amount, the float body housed in the casing floats up and blocks the gas discharge hole. In the float valve for a fuel tank, a regulating means is provided in the casing for regulating the displacement of the float body in the valve closing direction when the flow rate of the inflowing evaporative fuel exceeds a predetermined amount.

[0008]

[Operation] When refueling is started when the internal pressure of the tank body has significantly increased due to heat-resistant driving, etc., and the flow rate of evaporated fuel flowing into the casing exceeds a predetermined amount, only then the regulating means is activated in the valve closing direction of the float body. to prevent the float body from completely blocking the gas exhaust hole.

[0009]

[Embodiment] Next, an embodiment of the present invention will be described based on FIGS. 1 to 4. Note that the same reference numerals are used for the same parts as in the conventional one shown in FIG.

First, the float valve 10 according to the present invention
The overall outline of the fuel tank that adopts 0 will be explained below.

In FIG. 2, 1 is a tank body of a fuel tank, and 9 is a filler tube for supplying fuel to the tank body 1. A shutter 14 is provided at the upper end of the filler tube 9 to prevent evaporated fuel from being directly discharged into the atmosphere when the filler cap 13 is opened, and a shutter 14 is provided at the upper end of the filler tube 9 to prevent evaporated fuel from being directly discharged into the atmosphere when the filler cap 13 is opened.
A sealing member 15 is provided to prevent evaporated fuel from being discharged into the atmosphere from the gap between the two.

Reference numeral 2 denotes a canister for adsorbing evaporated fuel, and this canister 2 is used to process evaporated fuel generated within the tank body 1 during refueling through the vent tube 3, and when not during refueling. Tank body 1
The evaporative fuel generated inside the evaporative tube 10 is also used for processing through the evaporative tube 10. That is, the vent tube 3 and the evaporative tube 10, which communicate with the upper space in the tank body 1, respectively, join together at the valve chamber 16 provided in contact with the outer periphery of the upper end of the filler tube 9.
and the canister 1 are connected to each other by a single supply/discharge tube 17, and when the switching valve 18 provided in the valve chamber 16 is operated in conjunction with the opening/closing operation of the shutter 14, either the vent tube 3 or the evaporative tube 10 is connected. One side communicates with canister 2. Note that when the shutter 14 is opened during refueling, the vent tube 3 communicates with the canister 2.

A float valve 100 according to the present invention is provided at the end of the vent tube 3 on the side of the tank body 1, and the float valve 100 has a portion near the upper end of the filler tube 9 connected to the canister 2. A sub-vent tube 19 for communication is connected to merge.

Reference numeral 20 denotes a fuel cutoff valve provided at the end of the evaporative tube 10 on the tank body 1 side. occlude the Evapotube 10
It is designed to prevent fuel from leaking outside.

Next, the float valve 100 will be explained in detail.

In FIG. 1, 4 is a float valve 10.
This casing 4 is fixedly installed on the upper wall of the tank body 1 via a bracket 21, and its interior is divided into an upper chamber 23 and a lower chamber 24 by a partition wall 22. ing. The partition wall 22 has a first gas exhaust hole 2 that communicates only the upper chamber 23 and the lower chamber 24.
5 is formed, and the upper chamber 23 is passed through this gas exhaust hole 25.
Gas such as evaporated fuel flows in and out between the lower chamber 24 and the lower chamber 24.

The lower chamber 24 is connected to the inside of the tank body 1 through a communication hole 26, and a first float 27, which is a float body, is accommodated therein together with a spring 28. Normally, the first float 27 opens the first gas discharge hole 25 due to its own weight, but when the liquid level of the fuel in the tank body 1 reaches a predetermined height during refueling, it rises due to buoyancy. A spherical seal portion 29 on the upper surface closes the first gas discharge hole 25, thereby sealing the upper space within the tank body 1.

A flap 30 made of metal or resin is rotatably attached to the lower surface of the peripheral edge of the first gas discharge hole 25 of the partition wall 22. This flap 30 is
It is biased by a spring 32 so that it faces perpendicularly to the passage 31 leading from the communication hole 26 of the lower chamber 24 to the first float 27, and under normal conditions it is perpendicular to the passage 31 and does not come into contact with the first float 27. However,
When a predetermined amount or more of vaporized fuel flows in from the communication hole 26, it comes into contact with the first float 27, which tilts and tries to float due to the force, thereby causing the first float 27 to move in the valve closing direction (upward direction). Regulate displacement. In this embodiment, the flap 30 and the spring 32 constitute a regulating means for regulating the displacement of the float body (first float 27) in the valve closing direction.

On the other hand, in the upper chamber 23 of the casing 4, the vent tube 3 and the sub-vent tube 19 are connected in communication, and a second float 33, which is a float main body, is housed together with a spring 34. 2nd float 33
is housed not directly above the first gas exhaust hole 25 of the partition wall 22, but at a position offset from this gas exhaust hole 25. Further, a second gas exhaust hole 35 is provided in the upper wall of the upper chamber 23 and communicates with the vent tube 3, and this gas exhaust hole 35 is normally open when no fuel flows into the upper chamber 23. When fuel flows into the upper chamber 23 and the second float 33 floats, it is closed by a spherical seal portion 36 on the upper surface of the second float 33. Furthermore, a flap 4 similar to that described above is provided on the lower surface of the peripheral edge of the second gas discharge hole 35 in the upper wall of the upper chamber 23.
0 is rotatably attached, and this flap 40
is biased by a spring 39 so as to face perpendicularly to a passage 38 extending from a communication hole 37 communicating with the sub-vent tube 19 to the second float 33 . This flap 40 also does not come into contact with the second float 33 under normal conditions, but when a predetermined amount or more of vaporized fuel flows in from the communication hole 37 or the first gas exhaust hole 25,
The force causes it to tilt and come into contact with the second float 33, thereby restricting the displacement of the second float 33 in the valve closing direction.

In the above configuration, when the refueling gun 8 is inserted into the upper end of the filler tube 9 to start refueling the tank body 1 as shown in FIG.
In the normal state where the internal pressure of the float valve 100 is not high, both the first float 27 and the second float 33 of the float valve 100 are lowered, as shown by the arrows in FIGS.
The evaporated fuel in the upper space of the tank body 1 is supplied to the float valve 1.
The vaporized fuel in the filler tube 9 enters the upper chamber 23 through the sub-vent tube 19, and the second gas flows from the upper chamber 23, respectively. Discharge hole 35, vent tube 3,
It passes sequentially through the supply/discharge tube 17 and is discharged into the canister 2.

In addition, when refueling is started when the internal pressure of the tank body 1 has increased significantly, such as immediately after a heat-resistant run, the gas may flow into the lower chamber 24 from the communication hole 26 or from the first gas discharge hole. The first float 27 and the second float 33 try to float upward due to a large flow of evaporated fuel flowing into the upper chamber 23 from 25 and the communication hole 37, but at this time, the flow rate of the evaporated fuel flowing into the casing 4 is larger than a predetermined amount, the flaps 30 and 40 tilt against the force of the springs 32 and 39, as shown by the chain lines in FIG. Therefore, the first float 27 and the second float due to evaporated fuel
Due to the floating of the float 33, the gas discharge holes 25, 3
A situation where 5 is blocked will no longer occur.

When the fuel level in the tank body 1 reaches a predetermined height, the float valve 10 is opened from the communication hole 26.
Fuel flows into the lower chamber 24 of No. 0, and as shown in FIG. 3, the first float 27 floats up and closes the first gas exhaust hole 25. As a result, the upper space in the tank body 1 is sealed, so only the liquid level in the filler tube 9 rises, and the evaporated fuel in the filler tube 9 subsides until the liquid level reaches its upper end. The gas continues to be discharged from the vent tube 19 into the canister 2 via the upper chamber 23, the second gas discharge hole 35, the vent tube 3, etc. When the liquid level in the filler tube 9 reaches the vicinity of its upper end, this is sensed by the auto-stop sensor a of the refueling gun 8, and refueling is stopped.

Furthermore, when the auto-stop sensor a is out of order or when additional refueling is performed, fuel passes through the sub-vent tube 19 connected to the vicinity of the upper end of the filler tube 9 and enters the upper chamber 23 of the float valve 100. This will result in an influx of water. When the liquid level of the fuel in the upper chamber 23 rises in this way, the second float 33 floats up and closes the second gas exhaust hole 35, as shown in FIG. Communication will be cut off. This prevents fuel from flowing out from the sub-vent tube 19 to the canister 2. When refueling is completed and the fuel in the tank body 1 is used, the first float 27 descends as the liquid level in the tank body 1 decreases, opening the first gas discharge hole 25 and opening the upper chamber 23. The fuel in the inner and sub-vent tubes 19 is supplied into the tank body 1 through the first gas discharge hole 25.

Furthermore, when the vehicle rolls over, the first float 27 and the second float 33 are lowered by their own weight and the force of the springs 28 and 34, and the first and second gas exhaust holes 25 and 33 are moved downwards. Since the hole 35 is closed, fuel will not leak out to the vent tube 3 side.

The embodiments of the present invention are not limited to those shown in FIGS. 1 to 4. For example, in the embodiment described above, two float bodies (first float 2
7 and the second float 33), but only one float body may be accommodated in the casing 4, and the regulating means may be a flap 41 as shown in FIG. The spring (corresponding to 32 in FIG. 1) may be omitted by forming the member 42 from a rubber material, or the member 42 may have an L-shaped cross section as shown in FIG.
is supported by a spring 43 that expands and contracts in the direction along the passage 31, and only when the amount of vaporized fuel flowing into the casing 4 exceeds a predetermined amount, the member 42 moves forward against the force of the spring 43 to close the float body. It is also possible to restrict the displacement of the first float 27 in the valve closing direction.

[0026]

As described above, the present invention provides a regulating means in the casing for regulating the displacement of the float body in the valve closing direction when the flow rate of the inflowing evaporated fuel exceeds a predetermined amount. It is possible to reliably prevent the float body from floating due to evaporated fuel without increasing the size and weight or adversely affecting the regulation of fuel supply amount.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is an overall schematic diagram showing the same embodiment.

FIG. 3 is a sectional view showing the same embodiment.

FIG. 4 is a sectional view showing the same embodiment.

FIG. 5 is a sectional view showing another embodiment of the present invention.

FIG. 6 is a sectional view showing another embodiment of the present invention.

FIG. 7 is an overall schematic diagram showing a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1...tank body, 3...vent tube, 4...casing, 25...first gas discharge hole (gas discharge hole), 27...first
Float (float body), 30... Flap (regulating means), 32... Spring (regulating means), 33... Second float (float main body), 35... Second gas exhaust hole (gas exhaust hole), 39... Spring ( regulation means), 40...flap (regulation means), 100...float valve.

Claims (1)

[Claims] Claim 1: In a float valve for a fuel tank, in which a float body housed in a casing floats up to close a gas discharge hole when the amount of fuel supplied reaches a predetermined amount, the evaporation flowing into the casing A float valve for a fuel tank, characterized in that a regulating means is provided for regulating the displacement of the float body in the valve closing direction when the flow rate of fuel becomes larger than a predetermined amount.