JPH03224825A - Fuel shutoff valve device for fuel tank - Google Patents

Abstract

PURPOSE:To enable easy discharge of vapor by making afloat a float valve when a vehicle is inclined or otherwise, for closing a valve seat and preventing an outflow of fuel, and releasing an orifice around the valve seat with a valve body, whenever necessary. CONSTITUTION:A valve casing 1 is provided in a tank body 12 and in addition, a float valve 6 is provided within the valve casing 1 via a spring 7. Also, a valve seat 5 is so formed as to oppose the valve part 6a of the float valve 6 at an upper wall separating the outlet 4 of the valve casing 1 from the housing part of the float valve 6. In this case, a plurality of orifices 8 are formed around the valve seat 5. Furthermore, a valve body 9 for concurrently opening and closing the valve seat 5 and the orifices 8 are laid at the rear side of the valve seat 5. In the aforesaid construction, the valve body 9 is opened whenever necessary, thereby discharging outside the air and generated vapor in the tank body 12.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fuel cutoff valve device for a fuel tank mounted on a vehicle such as an automobile.

BACKGROUND OF THE INVENTION Some fuel tanks for automobiles are known to be equipped with a fuel cutoff valve device to prevent the fuel within the tank body from flowing out when the automobile is tilted or overturned. As this fuel cutoff valve device, for example, Utility Model Application No. 62-7527
As shown in Publication No. 8, even when the float valve is closed, when the internal pressure of the tank body exceeds a predetermined value, the valve seat itself is raised to open the passage and allow paper to be guided into the paper passage. In addition, a valve seat itself is known to have a valve function for discharging paper. Specifically, the valve seat is loaded with a spring inside the valve casing, and another positive pressure valve is built into the valve seat itself.
It is designed to simultaneously take measures against paper discharge when the float valve sticks and against paper discharge during fuel refueling.

Problems to be solved by the invention A valve seat is movably incorporated into a valve casing,
Furthermore, since another positive pressure valve is movably incorporated into the valve seat itself, the structure becomes complicated and is disadvantageous in terms of cost. It is necessary to change the opening pressure of the valve seat itself and the opening pressure of the positive pressure valve built into the valve seat, and to do this, the pressure receiving area of the valve seat, the pressure receiving area of the positive pressure valve, and each valve must be changed. High precision is required for setting the spring constant of the set spring, which becomes increasingly disadvantageous in terms of cost. Therefore, the present invention has a simple structure that can simultaneously take measures against paper discharge when the valve seat is blocked by a float valve and against paper discharge during fuel refueling, and also allows easy setting of two different valve opening pressures. The present invention provides a fuel cutoff valve device for a fuel tank that allows for

Means for Solving the Problem A float valve is floated by the inflow of fuel into a valve casing disposed within the tank body, and the float valve closes the valve seat to block the outflow of fuel to the outside. In the structure, an orifice is provided around the valve seat, and the valve seat and the orifice are simultaneously closed on the back side of the valve seat,
In addition, a valve body is provided that simultaneously opens the valve seat and orifice when the internal pressure of the tank body exceeds a predetermined value.

When the vehicle tilts or falls and the fuel in the tank body flows into the valve casing, the float valve floats and closes the valve seat, blocking the flow of fuel to the outside.

When the vehicle is in its normal position, when the tank internal pressure that acts on the valve body through the valve seat and orifice exceeds a predetermined value due to refueling or temperature rise, the valve body opens and removes the paper inside the tank body. It is discharged to the outside through these valve seats and orifices. Further, even when the valve seat is closed by the float valve, an increase in the internal pressure of the tank acts on the valve body through the orifice, opens the valve body, and discharges the paper to the outside through the orifice.

Example Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In Fig. 1.2, ■ is a valve casing made of resin placed inside the tank body 12, and its peripheral wall forms a paper inlet hole 2, and the bottom wall allows inflowing fuel into the tank body 12. A drain hole 3 for return is formed. Reference numeral 6 denotes a float valve made of a resin material disposed inside the valve casing 1, and the float valve 6 uses a spring 7 to balance its buoyancy and its own weight. A valve seat 5 is formed on the earthen wall that separates the outlet 4 of the valve casing 1 from the housing portion of the float valve 6, facing the central valve portion 6a of the float valve 6. A plurality of orifices 8 are formed around the sheet 5.

Reference numeral 9 denotes a valve body disposed on the back side of the valve seat 5 and formed in a size that blocks the valve seat 5 and the orifice 8 at the same time. When the internal pressure exceeds a predetermined value, these valve seats 5. The second recess 8 is opened at the same time.

The spring force F of the spring 10 is F=k C (1, -Q l) k - Spring constant f
f,...The free length of the spring ρ1... is obtained as the bullet length of the spring, so the spring force F of this spring 10,
The relationship between the pressure receiving area S of the valve body 9 and the internal pressure P of the tank body 12 is set as k(Qo-12+)≦sp.

On the other hand, since the pressure receiving area S of the valve body 9 is obtained as the opening area S of the valve seat 5 and the opening area S6 of the orifice 8, when the float valve 6 is away from the valve seat 5 (when the float valve is open) ) in valve body 9
The valve opening pressure P of the valve body 9 and the valve opening pressure PC of the valve body 9 when the valve seat 5 is closed by the float valve 6 (when the float valve is closed) are obtained respectively. Therefore, the opening pressure Po when the float valve is opened and the opening pressure Pc when the float valve is closed are the valve seat opening area S, n
It can be arbitrarily and easily set by changing the ratio of the orifice opening area S8 and the orifice opening area S8.

A negative pressure valve 11 is attached to the earth wall of the valve casing 1, which opens when the internal pressure of the tank body 12 becomes negative due to fuel consumption, and introduces atmospheric air into the tank body I2 from the paper passage 13.

According to the structure of the above embodiment, when the vehicle tilts or falls and fuel flows into the valve casing 1, the float valve 6 floats and comes into contact with the valve seat 5, thereby closing the valve seat 5. Therefore, the incoming fuel pressure does not act on the valve body 9 through the valve seat 5, and the outflow of fuel to the outside is reliably blocked.

On the other hand, when the vehicle is in its normal position, by refueling,
Alternatively, the internal pressure of the tank body 12 reaches the predetermined valve opening pressure P due to paper generation due to a rise in fuel temperature. If the tank internal pressure exceeds the valve seat 5. It acts on the valve body 9 through the orifice 8 to open the valve body 9. As a result,
Air and generated paper within the tank body 12 are discharged to the outside of the tank body 12, and are adsorbed into a canister (not shown) via the paper passage I3. Furthermore, when the fuel level is inclined and the float valve 6 is blocking the valve seat 5, such as when the vehicle is turning, if the internal pressure of the tank body 12 increases due to the generation of paper, the inside of the valve casing 1 Even if the fuel returns to the tank body 12, the float valve 6 may receive this internal pressure and remain closed to the valve seat 5. In such a state, when the internal pressure of the tank body rises to the valve opening pressure Pc, which does not reach the bursting pressure of the tank body 12 but is high to a certain extent,
This internal pressure of the tank body acts on the valve body 9 through the orifice 8 to open the valve body 9. Therefore, also in this case, the paper inside the tank body I2 can be discharged to the outside of the tank body 12 through the orifice 8, thereby lowering the internal pressure of the tank body I2 and protecting the tank body.

Effects of the Invention As described above, according to the present invention, when the vehicle is tilted, etc., the float valve floats to close the valve seat and prevent the fuel from flowing out. It is possible to perform normal paper ejection using a float valve and paper ejection when the valve seat is blocked by a float valve, and the opening pressure of the valve body, which differs in these paper discharge modes, can be controlled by a single valve body configuration. Seat opening area,
It can be easily set by changing the ratio of the orifice opening area, and is very advantageous in terms of structure and cost.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a schematic sectional view of a fuel tank showing the arrangement of the device of the embodiment. 1... Valve casing, 5... Valve seat, 6
...Float valve, 8..Orifice, 9..Valve body.

Claims (1)

[Claims] (1) A structure in which a float valve is floated by the inflow of fuel into a valve casing disposed in a tank body, and the float valve closes a valve seat to block external outflow of fuel. An orifice is provided around the valve seat, and a valve is provided on the back side of the valve seat that simultaneously closes the valve seat and the orifice, and simultaneously opens the valve seat and the orifice when the internal pressure of the tank body exceeds a predetermined value. A fuel cutoff valve device for a fuel tank, characterized in that a fuel cutoff valve device is provided with a body.