JPH05330350A - Fuel outflow preventer of fuel tank for vehicle - Google Patents

Abstract

PURPOSE:To reduce the internal pressure in a fuel tank excepting in time of tank fullness and prevent any outflow due to vibration at the time of car running from occurring. CONSTITUTION:A fuel outflow valve 8 installed on top of a fuel tank 1 is provided with a valve element 10 and a float 11. In, if an oil level reaches the vicinity of lower end of a vapor bypass tube 7, this valve element 10 is pushed up by the float 11, thereby closing a passage 9 of the valve 8. In this case, a check valve 4A inserted with a vent tube 2 to be interconnecting this passage 9 of the valve 8 to an engine 13 is made to set its valve opening pressure lower than ever before.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel outflow prevention device for a vehicle fuel tank.

[0002]

2. Description of the Related Art As shown in FIG.
A vapor tube connected to the upper space of the fuel tank 1 communicates with an intake pipe of an engine (not shown) through a vaporized fuel adsorption canister 3 so that the vaporized fuel adsorbed by the adsorbent of the canister 3 is used when the vehicle is running. Inhale.

Reference numeral 4 is a check valve arranged in the middle of the vapor tube 2, 5 is a filler tube, 6 is a filler cap, and 7 is a vapor bypass tube. When refueling, the filler cap 6 is opened to refuel from the filling port of the filler tube 6, but the check valve 4 does not open due to the pressure difference of the fuel height H from the lower end of the vapor bypass tube 7 when the tank is full. Since the check valve 4 was set to a high opening / closing pressure, the fuel level in the tank during refueling did not exceed the level 1a determined by the lower end position of the vapor bypass tube 7 even when the tank was full.

[0004]

In recent years, however, there are some areas where the regulation other than when the tank is full is moving to "reduce the internal pressure of the fuel tank". In order to clear this regulation, the check valve 4 is opened. It has become necessary to set the valve pressure low.

As described above, since the valve opening pressure of the check valve 4 becomes low, the fuel level immediately after refueling to full tank becomes high up to the A side of FIG. When the vehicle is parked on a sloping ground, the fuel reaches the passage 9 through which the vapor passes, and the pressure in the fuel tank rises as the temperature rises, so that the fuel leaks slightly even if the fuel outflow prevention valve 8 is closed.

Since the opening pressure of the check valve is low, fuel (gasoline) passes through the check valve 4,
There is a problem that the deterioration of the canister is accelerated by flowing into the canister 3.

In the worst case, when the vehicle rolls over, fuel leaks out of the canister. Therefore, it is an object of the present invention to provide a fuel outflow prevention device for a fuel tank, which is capable of clearing the above regulations and solving such problems.

[0008]

In order to achieve the above object, a fuel tank (1) provided with a filler tube (5) and a vapor bypass tube (7), and a fuel outflow prevention valve ( 8) and a fuel outflow prevention valve (8) having a vent tube (2) communicating with the engine and a fuel outflow prevention valve (8) including a float (11). The liquid level of 1) is set so that the float (11) rises near the lower end of the vapor bypass tube (7) and the passage (9) of the fuel outflow prevention valve (8) is closed.

The fuel outflow prevention valve (8) is attached to the float (1
A valve body (10) separately arranged above 1) may be provided.
Further, an elastic body (1) is provided between the float (11) and the valve body (10).
It is effective to insert 9).

[0010]

1 is a first embodiment of the present invention, 1 is a fuel tank, 5 is a filler tube, 6 is a filler cap,
Numeral 7 is a vapor bypass tube which facilitates refueling by allowing the vapor to escape from here during refueling. Reference numeral 8 denotes a fuel outflow prevention valve provided in the upper portion of the fuel tank 1, which includes a passage 9, a valve body 10 that opens and closes the passage 9, and a float 11 that operates the valve body 10.

At the lower part of the passage 9, the fuel tank 1
The vent tube 2 is communicated with the intake pipe of the engine 13 through the check valve 4A, the evaporated fuel adsorption canister 3 and the electromagnetic valve 12 at the upper part. 14 is an electronic control unit (E
CU).

The canister 3 has a tank port 3a, an atmosphere port 3b and a purge port 3c, which are connected as well known in the drawing. Check valve 4 of the first embodiment
In A, the valve opening pressure is set to be lower than that in the prior art of FIG. 5 so as to clear the fuel tank internal pressure regulation.

When the liquid level of the fuel tank 1 during refueling approaches the lower end of the vapor bypass tube 7, the float 11 pushes up the valve body 10 to close the passage 9 of the fuel outflow prevention valve 8.

FIG. 2 shows a part of the second embodiment of the present invention. The fuel outflow prevention valve 8 provided at the upper portion of the fuel tank 1 has a valve body 11a integrally formed on the upper end of a float 11, and at the time of refueling, The liquid level is the lower end 7 of the vapor bypass tube 7.
When reaching the vicinity of a, the valve body 11a is integrally formed on the upper end of the float 11, and when the liquid level reaches near the lower end 7a of the vapor bypass tube 7 during refueling, the float 11
Is set to close the passage 9.

Reference numeral 15 is a compression spring provided between a float 11 and a cylindrical stopper 16 attached to the lower end of the cylindrical case of the fuel outflow valve 8 for closing the passage 9 by pressing the float against the passage 9 when the vehicle rolls over. It is a thing.

The float 11 has a cylindrical shape that opens downward. The lower opening serves to ensure that the air inside the float escapes when the vehicle rolls over, the buoyancy of the float disappears, and the float closes the passage 9 securely.

Numeral 8a is a hole formed in the outer periphery of the upper part of the case of the fuel outflow prevention valve 8 for allowing vapor to escape. 4B
Is a one-way valve for preventing damage when the tank internal pressure becomes lower than the atmospheric pressure, and the valve opening pressure is set to 500 to 1000 mmAg. Also, 4C is a one-way valve for preventing tank damage when the tank internal pressure becomes higher than the atmospheric pressure, and is 500 to 1000.
The valve opening pressure is set to mmAg.

Since these one-way valves 4B and 4C are provided in parallel with the passage 9, it is not necessary to lower the valve opening pressure as in the check valve 4A of FIG. 1 and the conventional check valve 4 of FIG. The valve opening pressure is set to the same level.

In FIG. 2, 1A is an air chamber above the fuel tank. FIG. 3 is a main part of the third embodiment of the present invention. A small hole 11a is formed in the bottom surface of the float 11, and when the pressure becomes low due to the temperature change of the tank during long-term suspension, the air in the float is discharged from this hole 11a. It escapes to reduce the buoyancy and opens the passage 9 to prevent the tank internal pressure from rising.

Reference numeral 17 is a spring for urging the valve body 10 upward, and is set to have a load slightly smaller than the weight of the valve body 10. FIG. 4 shows another embodiment of the fuel outflow prevention valve 8 used in the present invention, in which 18 is a compression spring interposed between the valve case and the retainer 19, and 19 is inserted between the valve body 10 and the float 11. The elastic body (compression spring)
As a result, the force of the float 11 does not act directly on the valve body 10 and acts as a cushion, so that the valve body 10 can be used as a passage
It is possible to prevent the seal portion (valve seat) from being worn by colliding with the valve seat portion and causing a sealing failure.

Further, in the second to fourth embodiments shown in FIGS. 2 to 4, fuel does not flow out of the canister at the time of rollover.

[0022]

Since the fuel outflow prevention device of the present invention is constructed as described above, the vapor escapes from the vapor bypass tube well, and the fuel refueling time is shortened.

In addition, the distance from the liquid level when the tank is full to the fuel outflow prevention valve can be increased, so that even during long-term parking on a slope,
Since the fuel does not flow into the canister, deterioration of the canister can be prevented.

Further, in the case where an elastic body is provided between the float and the valve body, vibration durability can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a main part of a third embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a main part of a fourth embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a conventional technique.

FIG. 6 is a schematic configuration diagram of a conventional technique.

[Explanation of symbols]

 1 Fuel Tank 2 Vent Tube 5 Filler Tube 7 Vapor Bypass Tube 8 Fuel Outflow Prevention Valve 9 Passage 10 Valve Body 11 Float 19 Elastic Body

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location F16K 31/18 Z 7001-3H

Claims (3)

[Claims] 1. A fuel outflow prevention device comprising: a fuel tank having a filler tube and a vapor bypass tube; a fuel outflow prevention valve provided at an upper portion of the fuel tank; and a vent tube communicating the fuel prevention valve with an engine. The fuel flow prevention valve is provided with a float, and the liquid level of the fuel tank is set so that the float rises near the lower end of the vapor bypass tube to close the passage of the fuel flow prevention valve. Tank fuel spill prevention device. 2. The fuel outflow prevention device for a vehicle fuel tank according to claim 1, wherein the fuel outflow prevention valve includes a valve element separately arranged above the float. 3. The fuel outflow prevention device for a vehicle fuel tank according to claim 2, wherein an elastic body is interposed between the float and the valve body.