JP2000205071A - Fuel cutoff valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the flow of fuel into communicating passages positively and ensure a large capacity of fuel tanks. SOLUTION: A cover 32 connects to the upper end of a pressure port 52 via a pipe portion 48 and a tube 50. The lower end of the pressure port 52 is above the float point F of a float valve 20. With the float valve 20 submerged, if a subsidiary tank is filled up with fuel or a fuel tank is inclined, the fuel level L in the pressure port 52 rises accordingly to apply downward pressure P2 to a valve element 42, which in turn closes the interior of a wall 44 and a passage 46 reliably. Even when the fuel tank has a higher fill-up level, fuel in a liquid phase is positively prevented from flowing into a canister via a vapor line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cut-off valve, for example, provided between a fuel tank of an automobile and a vapor pipe to prevent fuel from entering the vapor pipe. .

[0002]

2. Description of the Related Art FIG. 5 shows an example of a conventional fuel cut-off valve 110.

In the fuel cut-off valve 110, a gap H is formed between the liquid level L and the fuel cut-off valve 110 when the fuel tank is filled with fuel and becomes full. Then, when the liquid level L of the fuel tank rises to a predetermined height or more due to tilting or falling of the vehicle, the float valve 112 rises by buoyancy, and the valve portion 114 closes the valve seat opening 116. This prevents the fuel from flowing into the canister through the communication passage 118 as a liquid.

As described above, in the conventional fuel cut-off valve 110, by forming the gap H when the fuel tank is full, it is possible to prevent the fuel from flowing into the canister from the communication passage 118 as a liquid. . Therefore, since it is necessary to set the full tank level at a sufficiently low position, a useless space is generated in the upper part of the fuel tank, and the capacity of the fuel tank becomes smaller than the size of the fuel tank itself.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention provides a fuel cut-off valve which can reliably prevent fuel from flowing into a communication passage and can secure a large capacity in a fuel tank. The challenge is to obtain.

[0006]

According to the first aspect of the present invention, when the liquid level in the fuel tank rises above a predetermined float point, the evaporative fuel is discharged by buoyancy. A first valve member that closes an outlet, a second valve member that is provided at the evaporative fuel discharge port, and that can close the evaporative fuel discharge port independently of the first valve member, and the liquid level is higher than the float point. Closing means for closing the evaporated fuel outlet by pressing the second valve member to the evaporated fuel outlet by a liquid pressure acting from the fuel in the fuel tank in a high state. .

Therefore, when the liquid level in the fuel tank rises above the float point, the first valve member rises due to buoyancy and closes the evaporated fuel outlet, so that the fuel does not flow into the evaporated fuel outlet.

When the liquid level is higher than the float point, the closing means presses the second valve member to the fuel vapor discharge port by the liquid pressure. For this reason, the fuel vapor outlet is
It is closed not only by the first valve member but also by the second valve member. In this state, even if the liquid level fluctuates, for example, when the fuel tank is tilted or tilted when the tank is full, the second valve member reliably closes the evaporated fuel outlet, and the fuel flows to the evaporated fuel outlet. There is no inflow.

Further, in order to prevent the fuel from flowing into the evaporative fuel discharge port as a liquid when the liquid level fluctuates, it is not necessary to set the fuel tank to a full liquid level low. Even with a small fuel tank, a large capacity can be ensured without generating useless space in the fuel tank.

According to a second aspect of the present invention, in the first aspect of the present invention, the second valve member is supported by the diaphragm mounted on the valve body, and the fuel vapor discharge port is closed. And a valve body movable between an open position to open the evaporated fuel discharge port and a closed position to open the evaporated fuel discharge port.

Accordingly, the pressing force of the closing means acts on the valve body, and the diaphragm is deformed, so that the valve body moves from the open position to the closed position. When the pressing force of the closing means decreases, the diaphragm is restored, and the valve body returns from the closed position to the open position.

As described above, by using the diaphragm valve as the second valve member, the evaporated fuel discharge port can be opened or closed with a simple configuration.

According to a third aspect of the present invention, in the second aspect of the present invention, the closing means includes a pressure port provided above the float point and opened downward, A communication pipe that communicates with the pressure port, applies hydraulic pressure applied to the pressure port to the valve body, and moves the valve body from the open position to the closed position.

Therefore, when the liquid level becomes higher than the float point, the opening of the pressure port is closed, and the inside of the communication pipe is sealed. When the liquid level further rises, the liquid pressure acting on the pressure port acts on the valve body through the communication pipe. As a result, the valve moves from the open position to the closed position, and the fuel vapor outlet is closed. Conversely, when the liquid level drops and becomes lower than the float point, the opening of the pressure port is opened, and the inside of the communication pipe communicates with the outside, so that the liquid pressure does not act on the valve body, and the valve body is moved from the closed position. Return to open position.

As described above, the closing means can be constituted only by providing the pressure port and the communication pipe.

[0016]

FIG. 1 shows a fuel cut-off valve 10 according to one embodiment of the present invention. The fuel cut-off valve 10 is attached to an upper wall 12 of a fuel tank of an automobile to prevent the fuel in the fuel tank from directly flowing into a canister (not shown) as a liquid. Used in
In the drawings, the overall image of the fuel tank is not shown.

The fuel cutoff valve 10 has a case 14 formed in a substantially cylindrical shape. Case 14
A flange 18 extending radially outward is formed at the upper end of the case. When the case 14 is inserted into the mounting hole 16 of the upper wall 12, the flange 18 comes into contact with the upper wall 12 and 14
Is positioned. In this state, the case 14 protrudes into the fuel tank.

In the case 14, a float valve 20 is arranged. The float valve 20 has an outer diameter of the case 1
4 and slightly smaller than the inner diameter of the case 14.
It has a predetermined shape so as to be lower than the height of the inner method. The float valve 20 and the bottom plate 14 of the case 14
A support spring 56 for urging the float valve 20 upward is provided between the support spring 56 and the valve spring A. For this reason, as shown in FIGS.
When the fuel flows into the case 14 from the fuel port 22 formed in the side plate 14B and the liquid level L in the case 14 rises above the float point F, the buoyancy from the fuel and the urging force from the support spring 56 Thereby, the float valve 20 rises.

At the center of the upper surface of the float valve 20, a substantially conical valve portion 24 protruding upward is formed. The upper plate 14 of the case 14 corresponds to the valve portion 24.
C has an opening 2 penetrating the upper plate 14C in the thickness direction.
6 are formed. In the normal state, the opening 26 is open, but when the float valve 20 rises, the valve 24
Enters the opening 26 and the opening 26 is closed.

The flange 18 is formed with a through hole 28 penetrating the flange 18 in the thickness direction (horizontal direction).
The through hole 28 communicates with the canister via a vapor pipe (not shown).

A flat cylindrical mounting cylinder 30 is formed upward from the outer periphery of the flange 18. Mounting tube 3
At 0, a cover 32 is attached.

The cover 32 is formed in a disk shape having substantially the same diameter as the mounting cylinder portion 30, and a substantially cylindrical flange 34 is formed downward from the outer periphery thereof. Then, the protrusion 36 formed on the outer periphery of the flange portion 18 and the concave portion 38 formed on the outer periphery of the flange 34 mesh with each other without any gap, and the cover 32 is attached to the case 14 in close contact.

Further, a gap is formed between the flange 34 and the flange 18 at a constant interval inside the projection 36 and the recess 38. In this gap, the diaphragm 40
Is pinched and fixed. The diaphragm 40 is formed in an annular shape from a material that can be elastically deformed, and a substantially circular valve body 42 is attached to a central hole. Therefore, the diaphragm 40 is elastically deformed as the valve body 42 moves up and down. Note that the diaphragm valve of the present invention includes a diaphragm 40 and a valve element 42.

On the other hand, on the upper plate 14C of the case 14, an annular wall body 44 (the horizontal sectional area of this inner method is A1) is provided upright so as to surround the opening 26. Between the wall body 44 and the mounting cylinder 36 is a flow path 46 through which the evaporative gas in the fuel tank flows. And
Normally, as shown in FIG. 1, the elasticity of the diaphragm 40 holds the valve body 42 at a position (open position) apart from the upper end of the wall body 44. However, as shown in FIG. When the valve body 42 descends, the valve body 42 comes into a position (closed position) in close contact with the upper end of the wall body 44, and closes the inside and outside of the wall body 44.

A tube portion 48 is formed from the cover 32 toward the outside in the radial direction. The distal end of the tube portion communicates with the upper end of the pressure port 52 via the tube 50.

The pressure port 52 is formed in a cylindrical shape with an open lower surface, and its upper wall 1 is positioned so that its lower end is located above the float point F of the float valve 20.
2 is attached to the mounting hole.

The size (content) of the pressure port 52
In the state where the liquid level L rises in the pressure port 52 and becomes equal to the height of the upper wall 12 of the case 14 (see FIG. 3), the decrease V1 in the internal volume causes the valve body 42 to descend. A sufficient and sufficient volume to be in close contact with the upper end of the wall body 44 (that is, an increase V2 in the volume of the upper space of the valve body 42, the diaphragm 40 and the valve body 42 shown by a solid line in FIG. 40 and the valve element 42). Therefore, V1 = V2 holds.

Next, the operation of the fuel cutoff valve 10 according to the present embodiment will be described.

In a normal state, that is, when the liquid level L of the fuel in the fuel tank is lower than the float point F as shown in FIG. 1, the float valve 20 does not rise and the opening 26 is opened. ing. Further, the liquid level L is lower than the lower end of the pressure port 52 and does not seal the pressure port 52, so that the liquid pressure does not act on the valve body 42 via the tube 50 and the tube portion 48. Therefore, the valve body 42 is held at a position (open position) apart from the upper end of the wall body 44 by the elasticity of the diaphragm 40. Accordingly, the evaporated gas in the fuel tank reaches the flow passage 46 from the opening 26 through the inside of the wall body 44, and further enters the canister via a vapor pipe (not shown).

Here, as shown in FIG. 2, when the liquid level in the case 14 rises above the float point F due to refueling, or when the vehicle moves, the fuel tank tilts,
When the liquid level substantially displaces above the float point F, the float valve 20 rises due to buoyancy, and the valve portion 24 closes the opening 26. For this reason, case 14
It is possible to prevent the fuel inside the tank from flowing into the canister from a vapor pipe (not shown) while remaining liquid.

In this state, the liquid level L is located below the lower end of the pressure port 52. Therefore, the hydraulic pressure does not act on the valve body 42, and the valve body 42 does not come into close contact with the upper end of the wall body 44.

As shown in FIG. 3, the liquid level L further rises,
When the float valve 14 is substantially in contact with the upper wall 12 of the case 14, the float valve 14 is submerged in the fuel. The lower end of the pressure port 52 is closed by the liquid level L, and the pressure port 5
Since the liquid level L has risen inside the tube 50, the liquid pressure
And acts on the valve body 42 through the pipe portion 48. Thereby, the valve body 42 moves downward while the diaphragm 40 is elastically deformed, and comes into close contact with the upper end of the wall body 44. The valve body 42 closes the space between the inside of the wall body 44 and the flow path 46.

Here, as shown in FIG. 4, for example, when the fuel is filled up to the upper surface of the sub tank connected to the fuel tank, or when the fuel tank is tilted, the liquid level L in the pressure port 52 rises. Try to climb further. That is,
The fuel head (water head) in the fuel tank is located above the upper wall 12 of the case 14. At this time,
The pressure P2 (P1 ≒ P2) substantially equal to the hydraulic pressure P1 in the pressure port 52 is applied to the tube 50 and the tube portion 4.
Acting on the valve element 42 via 8.

In this state, when the buoyancy acting on the float valve 20 fluctuates due to the vertical movement of the liquid level L, the hydraulic pressure is applied to the valve element 42 temporarily upward (in a direction away from the opening 26). P1 may act. However, comparing the area A2 of the valve element 42 where the pressure P2 acts and the area A1 of the valve element 42 where the hydraulic pressure P1 acts, since the area A2 is larger, P2 × A2> P1 as a whole. × A1 (1) holds, and the force pressing the valve body 42 against the upper end of the wall body 44 is larger. For this reason, the inside of the wall body 44 and the flow path 46 are closed, and it is possible to reliably prevent the fuel in the case 14 from flowing into the canister from a vapor pipe (not shown) while remaining liquid. Also, the area A2
Is larger than the area A1, so that even if the liquid pressure P1 fluctuates due to the vertical movement of the liquid level L, the valve body 42 is securely pressed against the upper end of the wall body 44, and the fuel pipe remains in a liquid state. From flowing into the canister can be reliably prevented.

As described above, in the fuel cut-off valve 10 of the present embodiment, even when the float valve 20 is submerged, the fuel flows from the vapor pipe into the canister in a liquid state. Is reliably prevented. Thus, the full tank liquid level of the fuel tank can be set high (can be set to the level shown in FIG. 4), so that even if the fuel tank itself is made small, there is no useless space inside and the fuel tank is large. The tank capacity can be secured.

[0036]

According to the first aspect of the present invention, when the liquid level in the fuel tank rises above a predetermined float point, the fuel vapor outlet is closed by buoyancy. A first valve member, a second valve member provided at the evaporative fuel discharge port and capable of closing the evaporative fuel discharge port independently of the first valve member, and in a state where the liquid level is higher than the float point Closing means for closing the evaporated fuel outlet by pressing the second valve member to the evaporated fuel outlet by a liquid pressure acting from the fuel in the fuel tank. There is no inflow, and even with a small fuel tank, a large capacity can be ensured without creating useless space in the fuel tank.

According to a second aspect of the present invention, in the first aspect of the present invention, the second valve member is supported by the diaphragm mounted on the valve body and the diaphragm, and the evaporative fuel discharge port is closed. The diaphragm valve is constituted by a valve body movable between a closing position to be closed and an opening position to open the evaporated fuel outlet, so that the evaporated fuel outlet can be opened or closed with a simple configuration. Can be.

According to a third aspect of the present invention, in the second aspect of the present invention, the closing means includes a pressure port provided above the float point and opened downward, A communication pipe that communicates with the pressure port and causes the hydraulic pressure applied to the pressure port to act on the valve element to move the valve element from the open position to the closed position. The closing means can be constituted only by providing a tube.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a normal state of a fuel cut-off valve according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the liquid level has risen to a float point in the fuel cut-off valve according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a state in which a liquid level has risen to an upper wall of a fuel tank in the fuel cut-off valve according to one embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a state in which the liquid level of the fuel cutoff valve according to the embodiment of the present invention has risen above the upper wall of the fuel tank.

FIG. 5 is a sectional view showing a conventional fuel cut-off valve.

[Explanation of symbols]

 Reference Signs List 10 fuel cut-off valve 20 float valve (first valve member) 26 opening (evaporated fuel supply port) 40 diaphragm (second valve member) 42 valve body (second valve member) 48 tube (closing means) 50 tube ( Closing means) 52 pressure port (closing means)

Claims (3)

[Claims] 1. A first fuel tank is provided at an evaporative fuel outlet of a fuel tank, and closes the evaporative fuel outlet by buoyancy when the liquid level in the fuel tank rises above a predetermined float point.
A valve member, a second valve member provided at the evaporative fuel outlet, and capable of closing the evaporative fuel outlet independently of the first valve member, and in a state where the liquid level is higher than the float point, The hydraulic pressure acting on the fuel in the fuel tank
A fuel cutoff valve, comprising: a closing means for pressing a valve member against the evaporated fuel outlet to close the evaporated fuel outlet. A second valve member having a diaphragm attached to a valve body, a diaphragm supported by the diaphragm, and a closed position for closing the evaporated fuel outlet and an open position for opening the evaporated fuel outlet. The fuel cut-off valve according to claim 1, wherein the diaphragm valve is configured by: 3. The valve according to claim 3, wherein the closing means communicates a pressure port provided above the float point and opened downward, the valve body and the pressure port, and the hydraulic pressure applied to the pressure port is reduced. The fuel cut-off valve according to claim 2, further comprising: a communication pipe that acts on the valve body to move the valve body from the open position to the closed position.