JPH09105363A - Fuel tank device - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To secure an air layer in the tank main body at the time of refueling, and to perform degassing even when a small pressure acts on the tank main body while traveling, Provided is a fuel tank device capable of suppressing an increase in pressure in a tank body as compared with a conventional one. SOLUTION: A fuel tank 21 is a tank body 22.
And a filler tube 23 connected to the tank body 22 to supply fuel, the filler tube 23 and the tank body 22 are connected via a vent tube 28, and the tank body 22 is further connected. A second check valve 26 connected to a canister 27 via a tube 25, provided with a first check valve 26 on the connection tube 25, and opened on the drain side of the canister 27 with a valve opening pressure higher than the valve opening pressure of the first check valve 26. Check valve 32
And a valve portion 32a of the second check valve 32
The orifices 32d and 32e are provided in the.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel tank device used for vehicles, ships and the like, and more particularly to preventing over-fueling at the time of refueling fuel and guiding evaporative gas to the canister side even when the pressure in the tank body is low. The present invention relates to a fuel tank device capable of being operated.

[0002]

2. Description of the Related Art A conventional device of this type is shown in FIG. In the figure, reference numeral 1 is a fuel tank of a vehicle, which is configured by connecting a filler tube 3 to a tank body 2 and by a vent tube 4.
The upper part of the tank body 2 and the upper part of the filler tube 3 are connected.

A pair of float valves 5 are arranged on the upper surface 2a of the tank body 2, and the float valves 5 are connected to a canister 8 by a tube 7 via a check valve 6.

The canister 8 is connected to an intake manifold of an engine (not shown) via a negative pressure tube 9, and an intake valve 10 and a canister 8 which are opened only when outside air is drawn into the canister 8. An exhaust valve 11 is provided which is opened only when exhausted from.

In this structure, when refueling is performed, the refueling nozzle is inserted from the refueling port of the filler tube 3 to refuel. The fuel flows from the filler tube 3 into the tank main body 2, while the gas containing the fuel component in the tank main body 2 (hereinafter referred to as “vapor”) flows into the vent tube 4
Through the filler tube 3 to the top. Then, when the liquid level reaches the lower end of the vent tube 4, degassing cannot be performed, so that the supply of fuel into the tank body 2 is stopped and the fuel accumulates in the filler tube 3.

When the tank is full, the maximum height difference H between the liquid level inside the tank body 2 and the liquid level inside the filler tube 3 is 500 m.
Therefore, the pressure acting on the inside of the tank body 2 becomes about 27 mmHg. Therefore, in order to secure an air layer in the tank body 2, the valve opening pressure of the check valve 6 is set to be larger than 27 mmHg. In the state where the air layer is not secured, it is considered that the fuel directly flows to the canister 8 side due to turning of the vehicle or the like.

On the other hand, when the pressure in the tank body 2 becomes larger than 27 mmHg when the vehicle is running, the tank body 2 is
The vapor inside is guided to the canister 8 via the check valve 6, where the fuel component is adsorbed and released to the atmosphere via the exhaust valve 11.

An example of this type is described in US Pat. No. 5,099,880.

[0009]

However, in such a conventional one, the pressure in the tank body 2 is prevented from rising as much as possible, and the fuel is blown out when the filler cap (not shown) is opened. Although there is a request to suppress it, in order to secure an air layer in the tank body 2,
Since the opening pressure of the check valve 6 cannot be reduced so much, it has been difficult with the conventional structure to secure an air layer in the tank body 2 and keep the tank body 2 at a small pressure.

Therefore, according to the present invention, it is possible to secure an air layer in the tank main body at the time of refueling, and to perform degassing even when a small pressure acts on the tank main body while traveling, An object of the present invention is to provide a fuel tank device capable of suppressing the pressure rise in the tank body to be lower than before.

[0011]

SUMMARY OF THE INVENTION The invention described in claim 1 has been made in view of the above problems, and a fuel tank is provided with a fuel tank, and a filler tube connected to the tank body to supply fuel. And the filler tube and the tank body are connected via a vent tube, and the tank body is connected to a canister via a connection tube, and the connection tube has a first
A fuel tank in which a check valve is provided, a second check valve that opens with a valve opening pressure higher than the valve opening pressure of the first check valve is provided on the drain side of the canister, and an orifice is provided in the valve portion of the second check valve. It is characterized by being a device.

According to such a construction, when refueling, first, the refueling nozzle is inserted from the refueling port of the filler tube to refuel. The fuel flows into the tank body from the filler tube, while the vapor in the tank body escapes to the filler tube side via the vent tube. When the liquid level reaches the lower end of the vent tube, degassing cannot be performed, so the supply of fuel into the tank body is stopped and the fuel accumulates in the filler tube.

When the tank is full, pressure acts on the inside of the tank body due to the difference in height between the liquid level inside the tank body and the liquid level inside the filler tube. This opening pressure is set so that the first check valve is opened by this pressure, and the vapor in the tank body escapes into the canister through the first check valve, but inside the tank body An air layer can be secured. That is, in this case, the pressure acting on the second check valve does not become larger than the valve opening pressure of this valve (in other words, the valve opening pressure is set so as not to become larger), so the second check valve is closed. Stay in the state. Therefore, the vapor in this tank body is
After the fuel component is adsorbed in the canister, it is released to the atmosphere through the orifice of the second check valve. In this case, since the flow rate of the orifice is very small, the amount of vapor passing through the orifice is small during the waiting time in the normal additional oil supply, and therefore the liquid level in the filler tube does not drop so much. Therefore, the refueling person determines that the tank is full and does not continue refueling, does not overfill, and can secure an air layer in the tank body.

On the other hand, in the state without engine purge,
Due to the evaporation of the fuel, the pressure in the tank body rises and the second
1st set to open pressure smaller than check valve
When the opening pressure of the check valve is exceeded, the first check valve opens and the vapor in the tank body is introduced into the canister. Here, after the fuel component is adsorbed, it is released to the atmosphere through the orifice of the closed second check valve. In this case, since the vapor generated by the evaporation of the fuel contains approximately 100% of the fuel component, the vapor component flowing to the orifice side becomes very small because the fuel component is adsorbed by the canister. Therefore, even if the second check valve is not opened and the second check valve is allowed to escape to the atmosphere through the small-diameter orifice, the pressure increase in the tank main body can be suppressed to be lower than in the conventional case.

The invention described in claim 2 is characterized in that, in addition to the configuration described in claim 1, the first check valve is provided near a canister.

According to this structure, since the first check valve is provided in the vicinity of the canister, the effect of reducing the pressure inside the tank body is improved. That is, while the vapor containing approximately 100% of the fuel component is filled between the tank body and the first check valve, the vapor is filled before the first check valve, that is, from the canister side to the drain side. , Vapor with low fuel content is full. Therefore, when the first check valve is near the tank body, the connecting tube between the first check valve and the canister is filled with vapor having a low fuel component content. Therefore, even if this vapor passes through the canister, the amount of the adsorbed fuel component is small, so that the pressure in the tank main body does not decrease unless it directly escapes from the orifice to the atmosphere. However, since the flow rate of gas passing through the orifice is small, the responsiveness of lowering the pressure in the tank body is poor. On the other hand, when the first check valve is provided in the vicinity of the canister as in this claim, the first check valve is opened, so that the vapor containing almost 100% of the fuel component is immediately formed. By flowing into the canister and adsorbing the fuel component by the activated carbon in the canister, the volume is reduced and the pressure in the tank body can be lowered in a short time. This is an improvement over the case where it is not near the canister.

According to the invention described in claim 3, in addition to the structure described in claim 1 or 2, the orifice enables a gas flow from the canister side to the atmosphere side, and the orifice side allows the gas to flow from the atmosphere side to the canister side. It is characterized by being set to open and close with a one-way valve that blocks the flow.

According to this structure, even if the second check valve provided with the orifice is provided outside the vehicle, the one-way valve is provided so that the orifice is closed. It is possible to prevent the flow of water and dust from the nozzle to the canister side through the orifice.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

1 to 4 show an embodiment of the present invention.

First, the structure will be described. In the figure, reference numeral 21 is a fuel tank of a vehicle, which is constructed by connecting a filler tube 23 to a tank body 22, and a vent tube 28 forms an upper portion of the tank body 22 and the filler tube 23. Is connected to the upper part of.

A pair of float valves 24 are provided on the upper surface 22a of the tank body 22, and the float valves 24 are connected to the canister 27 via the connecting tube 25 and the first check valve 26.

The first check valve 26 is arranged above the canister 27, and a diaphragm 26b is arranged in the case 26a along a substantially horizontal direction to form a case 26a.
The diaphragm 26b is formed by defining the inside of the diaphragm up and down.
A first chamber 26c is formed on the upper side and a second chamber 26d is formed on the lower side. Then, the connection tube 25 is exposed to the second chamber 26d, and the projecting tube 26e projecting from the canister 27 is inserted into the second chamber 26d.
The protruding tube 26e is opened and closed by a diaphragm 26b which is urged downward by a spring 26f. The first chamber 26c is opened to the atmosphere through the opening 26g, and the opening pressure of the first check valve 26 is set to about 10 mmHg.

The canister 27 is a negative pressure tube 2
A tube 30 having a bifurcated bifurcated portion 30a, 30b is connected to the engine (not shown) via 9. The tip end opening of the one branch portion 30a faces the inside of a closed cross section of a front side member (not shown) on the intake side and is open to the atmosphere. And
An intake valve 31 is provided in the one branch portion 30a.

In the intake valve 31, the valve body 31a is biased by the spring 31b, and the opening 31c is opened and closed by the valve body 31a. This valve body 31
The a is opened only when the inside pressure of the canister 27 becomes negative, and the outside air is sucked into the canister 27.

The tip end opening of the other branch portion 30b is
It is opened to the atmosphere outside the vehicle, and a second check valve 32 is arranged at this branch portion 30b.

As shown in FIG. 2, in the second check valve 32, the valve portion 32a is biased to the left side in the drawing by the spring 32b, and the opening 32 is formed by the valve portion 32a.
c is opened and closed. The valve opening pressure of the chuck valve 32 is set to 27 mmHg. In the valve portion 32a, a rubber member 32g that opens and closes the opening 32c is held by the moving member 32h.
Orifices 32d and 32e having a diameter of 0.5 mm are formed in each of 2g and the moving member 32h, and one of the orifices 32e is opened and closed by an umbrella valve 32f as a "one-way valve". The umbrella valve 32f opens the orifice 32e when the gas flows from the canister 27 side to the atmosphere side, and closes the orifice 32e in the opposite case.

Next, the operation will be described.

First, when refueling, refueling is performed by inserting a refueling nozzle from the refueling port of the filler tube 23. The fuel flows from the filler tube 23 into the tank body 22, while the vapor in the tank body 22 escapes to the filler tube 23 side via the vent tube 28. Then, when the liquid level reaches the lower end of the vent tube 28, degassing cannot be performed, so that the supply of fuel into the tank body 22 is stopped and the filler tube 2
It collects in 3.

When the tank is fully filled, the maximum height difference H between the liquid surface of the tank body 22 and the liquid surface of the filler tube 23 becomes about 500 mm as shown in FIG. It becomes 27 mmHg. Due to this pressure, the first check valve 26 is opened, and the vapor in the tank body 22 passes through the first check valve 26 to escape into the canister 27, but the second check valve 32 is closed. It is possible to secure an air layer in the tank body 22. That is, in this case, the pressure acting on the second check valve 32 is
Since it does not become larger than the valve opening pressure of 2 (27 mmHg),
The second check valve 32 maintains the closed state. Therefore, the vapor in the tank body 22 is
After the fuel component is adsorbed inside the second check valve 32
Will be released to the atmosphere through the orifices 32d and 32e. In this case, when the height difference H is about 500 mm, the flow rate of the orifices 32d and 32e is 100 cc /
It is as small as about min. Therefore, in normal additional refueling, the waiting time is about 30 seconds, and the amount of gas passing through the orifices 32d and 32e is small within this time, so that the liquid level in the filler tube 23 is lowered so much. Absent. Therefore, the refueling person determines that the tank is full and does not continue refueling, does not overfill, and can secure an air layer in the tank body 22.

Then, even if a filler cap (not shown) is closed from this full state, if the pressure in the tank body 22 is higher than 10 mmHg, it will escape to the atmosphere via the orifices 32d and 32e, and the filler will be discharged. The fuel in the tube 23 flows into the tank main body 22 and becomes a little higher than the liquid level height shown in FIG. 1 as shown by the chain double-dashed line in the figure. The volumes of the main body 22 and the filler tube 23 and the height of the lower end 28a of the vent tube 28 are set.

On the other hand, as shown in FIG. 3, when the engine is not purged, the tank body 22 is caused by the evaporation of fuel.
When the internal pressure rises to 10 to 15 mmHg, the first check valve 26 opens and the vapor in the tank body 22 is introduced into the canister 27. Here, after the fuel component is adsorbed, the tube 30 and the orifices 32d and 32e
Is released into the atmosphere via. In this case, the vapor generated by evaporating the fuel contains approximately 100% of the fuel component, so that the fuel component is adsorbed by the canister 27, so that the vapor flowing to the tube 30 side becomes a trace amount. Therefore, even if the second check valve 32 is not opened and is released to the atmosphere through the small-diameter orifices 32d and 32e, the pressure increase in the tank body 22 can be suppressed to about 10 mmHg or less.

Moreover, in this case, since the first check valve 26 is provided in the vicinity of the canister 27, the pressure reducing effect in the tank body 22 is improved. That is, the tank main body 22 and the first check valve 26 are filled with the vapor containing substantially 100% of the fuel component, while the first check valve 26, that is, the tube 30 side, is filled with the vapor. , Vapor with low fuel content is full. Therefore, the first check valve 26
However, in the case where it is near the tank body 22 side, in the tube between the first check valve 26 and the canister 27,
This means that the vapor with a low content rate of the fuel component is full. Therefore, even if this vapor passes through the canister 27, the amount of the adsorbed fuel component is small, so that the pressure in the tank main body 22 does not decrease unless the vapor passes through the orifices 32d and 32e to the atmosphere. However, since the flow rate of the gas passing through the orifices 32d and 32e is small, the responsiveness of lowering the pressure inside the tank body 22 is poor. On the other hand, as in this embodiment, the first
When the check valve 26 is provided in the vicinity of the canister 27, the first check valve 26 is opened, so that the vapor containing approximately 100% of the fuel component immediately flows into the canister 27 and the inside of the canister 27. Since the fuel component is adsorbed by the activated carbon, the pressure is reduced in the tank main body 22 in a short time because the volume is reduced, and the pressure reducing effect is the first check valve 26.
Is improved in comparison with the case where is not near the canister 27.

Further, as shown in FIG. 4, the tank main body 22
When the internal pressure is 10 mmHg or less and the engine is being purged, a negative pressure acts on the canister 27 from the engine via the negative pressure tube 29. In this state, while the first check valve 26 maintains the closed state, the intake valve 3
1 is opened and the atmosphere is sucked into the canister 27, the fuel component is separated and sucked into the engine through the negative pressure tube 29.

Further, in this embodiment, since the open end of the one branch portion 30a faces the front side member of the closed cross-section structure (not shown), the outside air containing less dust can be sucked. On the other hand, since the end opening of the other branch portion 30b is directly exposed to the outside of the vehicle, there is a risk that water, dust, etc. due to splash will enter the second check valve 32 when the vehicle is traveling. However, since the orifice 32e is closed by the umbrella valve 32f,
Water and dust are prevented from entering the canister 27 side.

[0036]

As described above, according to the invention described in claim 1, it is possible to secure an air layer in the tank body at the time of refueling the fuel, and to keep the tank body in the tank body while traveling. Even if a small pressure is applied, the gas can be vented, and the pressure rise in the tank body can be suppressed to a lower level than before.

According to the invention described in claim 2, in addition to the effect described in claim 1, by providing the first check valve near the canister, it is possible to improve the pressure reducing effect in the tank main body. .

According to the invention described in claim 3, in addition to the effect described in claim 1 or 2, even if the second check valve provided with the orifice is arranged outside the vehicle, the one-way Since the orifice is closed by providing the valve, it is possible to prevent the flow of water and dust from the atmosphere side to the canister side through the orifice, which is a practically useful effect.

[Brief description of the drawings]

FIG. 1 is a schematic view of a fuel tank device according to an embodiment of the present invention during refueling.

FIG. 2 is a sectional view of a second check valve showing the same embodiment.

FIG. 3 is a diagram showing the same embodiment as FIG. 1 during vapor generation.
It is a schematic diagram corresponding to.

FIG. 4 is a schematic diagram corresponding to FIG. 1 during engine purging showing the same embodiment.

FIG. 5 is a schematic view of a fuel tank device showing a conventional example.

[Explanation of symbols]

 21 Fuel tank 22 Tank body 23 Filler tube 26 1st check valve 27 Canister 28 Vent tube 32 2nd check valve 32a Valve part 32d, 32e Orifice 32f Umbrella valve (one-way valve)

Claims (3)

[Claims] 1. A fuel tank has a tank main body and a filler tube connected to the tank main body to supply fuel, and the filler tube and the tank main body are connected via a vent tube. A second check valve in which a tank body is connected to a canister via a connection tube, a first check valve is provided in the connection tube, and a drain side of the canister is opened with an opening pressure higher than a valve opening pressure of the first check valve. Is provided
A fuel tank device in which an orifice is provided in a valve portion of the second check valve. 2. The fuel tank device according to claim 1, wherein the first check valve is provided near a canister. 3. The orifice is set so as to be opened and closed by a one-way valve that allows a gas flow from the canister side to the atmosphere side and blocks a flow from the atmosphere side to the canister side. The fuel tank device according to claim 1.