JP3535338B2 - Fuel cut-off device for fuel tank - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cutoff device which is arranged in a path provided for the purpose of allowing vaporized fuel to escape from a fuel tank to a canister and which prevents liquid fuel from flowing into the canister.

[0002]

2. Description of the Related Art A fuel cutoff device is a device arranged in a path provided for the purpose of allowing vaporized fuel to escape from a fuel tank to a canister, and has a purpose of preventing liquid fuel from flowing into the canister. Is proposed. This fuel cutoff device normally connects the fuel tank and the canister, but when the fuel tank is filled by refueling, the communication between the fuel tank and the canister is cut off, the pressure in the fuel tank is increased, and the refueling gun The auto stop function of is activated.

The fuel cutoff device shown in US Pat. No. 5,535,772 is a fill limit valve in a tubular skirt.
(fill-limit valve) and rollover valve (rollove
It has two types of valves called r valves. When the liquid fuel level in the fuel tank rises due to refueling, the fill limit valve that rises as the liquid level rises
nlet port) is closed. The cylinder has a lower and upper side wall aperture, except for the inlet.
However, since the pressure in the fuel tank rapidly rises due to the closing of the intake port of the fill limit valve, the first auto stop can be activated. When refueling is repeated, the liquid fuel further raises the liquid level and flows into the cylinder from the wall surface opening, raises the rollover valve to the upper opening (aperature), and reaches the canister.
The (intermediate passageway portion) is completely closed to prevent the outflow of liquid fuel during superfueling.

[0004]

In recent years, ORVR has been used in the United States.
(Evaporation fuel evaporation regulation at the time of refueling) has been enforced, and the operation timing or the number of times of operation of the fuel cutoff device for the automatic stop function of the refueling gun is being reviewed. It is generally known that the vaporized amount of vaporized fuel is higher immediately after the auto stop function of the fuel gun is activated than during refueling. However, in ORVR it is necessary to wait a certain time until refueling restarts after the automatic stop is activated, so additional refueling (after the first automatic stop works,
Near full tank (ORVR regulates to be 95% or more of the nominal tank capacity)
The amount of vaporized fuel vaporized will increase every time the fuel is repeatedly supplied. Therefore, it is necessary to reduce the number of auto-stops in order to suppress the evaporation of vaporized fuel within the range that satisfies ORVR.

In order to reduce the number of times of automatic stop, it is sufficient to first make the amount of fuel supply at which automatic stop operates be as close to full as possible. However, in the fuel cutoff device shown in the above-mentioned US Pat. No. 5,535,772, the rise of the fill limit valve that closes the intake port to activate the first automatic stop is proportional to the rise of the liquid level in the fuel tank. Therefore, there is a problem that the operation timing of the auto stop varies depending on the movement of the fill limit valve. Factors that affect the movement of the fill limit valve are (1) slide resistance generated between the outer surface of the valve that moves up and down by buoyancy and the inner surface of the cylinder,
(2) In addition to the sudden pressure change in the fuel tank due to the approach of the valve to the intake port, (3) (related to (2)) the valve sticking to the intake port, etc., (4) Behavioral stability is also involved.

In addition, since the refueling speed generally varies, the movement of the fill limit valve becomes more complicated and the operation timing of the auto stop becomes unstable. Further, the variation in the fuel supply rate also affects the variation in the number of times the automatic stop is operated during the additional refueling, and as a result, the evaporation amount of the fuel vapor increases. Therefore, consider the structure of a fuel cutoff device that ensures and stabilizes the operation timing at which the autostop first starts in the fuel cutoff device and operates the first autostop with a refueling amount of at least 95% that is as close to full as possible. I chose

[0007]

[Means for Solving the Problems] As a result of study, the developed one is mounted on the end of the path connecting the fuel tank and the canister to enable the liquid fuel to flow in and out. A first valve and a second valve that are interlocked vertically are housed together, and a first valve seat and a second valve seat that are independently opened at the end of the path are individually opened and closed. The first valve moves up and down later or later than the second valve by fitting the hooking part provided on one side into the other regulation groove, and the side surface hole of this casing has a small inflow resistance. Is a fuel cutoff device for a fuel tank in which a bottom hole having a large inflow resistance is provided on the bottom surface of the casing, and when the fuel is refueled, the liquid fuel is mainly flown into the casing to raise the float and close the valve.

In the fuel cutoff device of the present invention, the liquid fuel in the fuel tank whose liquid level rises beyond the bottom surface of the casing is
The float suddenly rises by flowing into the casing from the side hole all at once, and one of the first valve or the second valve is closed prior to the other to achieve a rapid increase in tank internal pressure and activate the first automatic stop. . Since this auto stop is determined by the total amount of refueling in the fuel tank that reaches the side hole rather than the refueling speed, the operation timing is stable. The float then slowly rises at a height that follows the liquid level, enabling additional refueling. Then, when the fuel tank is full, the float sufficiently rises to close both the first valve and the second valve, and it is possible to prevent the liquid fuel from flowing into the canister. Since the valve seats of the first valve and the second valve are independent of each other, for example, there is no concern that the behavior of the first valve when the valve is closed affects the second valve,
A stable closed valve state can be maintained.

The operation of the float is related to the difference in inflow resistance between the bottom hole and the side hole. That is, the inflow resistance of the bottom hole is determined so that the liquid fuel flows into the casing later than the liquid level rise in the fuel tank due to refueling, and the inflow resistance of the side hole is conversely determined by the liquid level rise in the casing. Determine that the liquid fuel flows into the tank faster.
Since the inflow resistance is approximately proportional to the opening area, the side surface hole is relatively large and the bottom surface hole is relatively small.

Ultimately, it is desirable that the bottom hole be closed when the liquid level rises. Therefore, in the above apparatus, a hollow valve for opening and closing the bottom hole is housed and a valve case opened downward is formed integrally with the casing. It is preferable that the hollow valve, which rises in the valve case as the liquid level rises during refueling, closes the bottom hole to allow the liquid fuel to flow into the casing from the side hole to raise the float and close the valve.
In this case, the size of the inflow resistance in the bottom hole does not matter, but the bottom hole has a role as an outlet for discharging the liquid fuel from the casing.

Since the liquid fuel does not flow into the hollow valve, the buoyancy is not impaired and the hollow valve is highly responsive to the rise in the liquid level.
Besides, the valve case is the orbit of the hollow valve, and also protects the hollow valve from ripples on the liquid surface, and in particular keeps the hollow valve from closing the bottom hole and preventing the hollow valve from leaving the device. Have. Such a hollow valve can surely and quickly rise as the liquid level rises to close the bottom hole. When the bottom hole is closed, the liquid fuel flows into the casing only through the side hole, and the float is suddenly raised to activate the automatic stop. Therefore, the operation timing can be stabilized as described above. Since the inflow resistance of the bottom hole is irrelevant, the inflow resistance of the side hole, that is, the opening shape or area is determined only in consideration of the fact that the liquid fuel flows into the casing faster than the liquid level rises.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 (excluding Fig. 3)
Is a hollow valve 13 which opens and closes the bottom hole 12 by providing a large opening side hole 2 having a small inflow resistance on the side surface of the casing 1 and a large opening bottom hole 12 having a small inflow resistance on the bottom surface of the casing 1. FIG. 1 is a sectional view showing an operating condition of a fuel cutoff device 14 of the present invention, which is housed in a valve case integrally formed with a casing 1. FIG. 1 shows a liquid level 6 in a fuel tank 5.
2 does not reach the fuel cutoff device 14, FIG. 2 shows a state in which the liquid level 6 in FIG. 1 rises and exceeds the bottom hole 12 but does not reach the side surface hole 2, and FIG. 4 shows the liquid level 6 in FIG. Has reached the side surface hole 2, FIG. 5 shows the state in which the liquid level 6 in FIG. 4 has crossed over the side surface hole 2, and in this example a 100% full state.

As shown in FIG. 1, the fuel cutoff device 14 of this embodiment has a large opening side hole having a small inflow resistance on each of the side surface and the bottom surface of the substantially cylindrical casing 1 fixed to the upper surface of the fuel tank 5. 2 and a large opening bottom hole 12 are provided,
The valve A that opens and closes the path 9 is integrated with the float 7.
It is composed of a (first valve) and a valve B (second valve) which moves up and down in conjunction with the valve A, thereby improving the responsiveness of the valve as a whole. A protrusion 8 is provided on the side surface of the float that is integrated with the valve A. The stopper 8 is fitted into a restriction groove 11 formed on the surface lowered from the valve B to interlock the two. I am trying to For example, when both the valve A and the valve B are closed, the valve B opens prior to the valve A as the float 7 descends, and then the hooking portion 8 pushes the lower end of the restriction groove 11 downward. The interlocking mode is shown in which the valve A is opened after the valve B. The valve A opens and closes the valve seat a, and the valve B opens and closes the valve seat b.

The hollow valve 13 housed in the valve case 15 which is integral with the casing 1 rises when the liquid level 6 in the fuel tank 5 reaches the bottom hole 12, and closes the bottom hole 12. Since the liquid fuel does not enter inside the hollow valve 13 and is laterally surrounded by the valve case 15 that also serves as a track, the hollow valve 13 can be quickly and accurately moved up and down without being affected by the ripple of the liquid level 6 or the like. can do. When refueling starts, the liquid level 6 in the fuel tank 5 rises.
Is not reaching the fuel cutoff device, the float 7 in the casing 1 descends and both valve A and valve B are open.
Path 9 to the canister (not shown) is open.

Eventually, the liquid surface 6 crosses the bottom surface hole 12 and the side surface hole 2
As shown in Figure 2,
Since the hollow valve 13 that has risen in the valve case 15 closes the bottom hole 12 and blocks the inflow of liquid fuel into the casing 1, only the liquid level 6 in the fuel tank surrounding the casing 1 continues to rise, but the float 7 still does not rise. Therefore, both the valve A and the valve B are still open. Bottom hole
Since 12 is closed by the hollow valve 13, the inflow resistance can be reduced, that is, the opening area can be increased, the liquid fuel remaining in the casing 1 can be easily discharged, and there is an advantage that there is no fear of clogging due to foreign matter or the like. .

FIG. 3 shows a fuel cutoff device 4 having a large opening side hole 2 with a small inflow resistance on the side surface of the casing 1 and a small opening bottom hole 3 with a large inflow resistance on the bottom surface. FIG. In the fuel cutoff device 4 having no hollow valve, a difference in inflow resistance is provided between the side surface hole 2 and the bottom surface hole 3, and the liquid fuel flowing from the bottom surface hole 3 having a small inflow resistance is supplied to the liquid surface 6 in the fuel tank 5. The rise of the float 7 is suppressed by making it smaller than the rise of the float 7.
The difference due to the presence or absence of the hollow valve is the difference in the regulation method of the float 7 when the liquid level 6 in the fuel tank 5 is between the bottom surface hole 3 and the side surface hole 2. That is, the fuel cutoff device 14
In FIG. 2, the hollow valve 13 completely blocks the inflow of liquid fuel into the casing 1 and does not raise the float 7 at all, whereas in the fuel shutoff device 4 (FIG. 3), the float 7
The only difference is that it suppresses the rise in. Therefore, the operation of the fuel cutoff device 4 without the hollow valve will not be described below.

When the liquid surface 6 in the fuel tank 5 reaches the side surface hole 2, the liquid fuel flows into the casing 1 at once through the side surface hole 2 having a small inflow resistance, and as shown in FIG. As a result of the liquid level 6 and the liquid level 10 in the casing 1 becoming equal and the float 7 rapidly rising, the valve B is first closed and the pressure in the fuel tank 5 is increased to activate the first automatic stop. Since the casing 1 also serves as an orbit for wrapping the float 7, the behavior of the float 7 is not disturbed, and liquid fuel does not enter the inside of the float 7 that is an air reservoir. Normally, the position of the side surface hole 2 is provided so that this auto stop operates when 95% or more of the fuel tank 5 is refueled. At this stage, only the valve B is closed, the valve A is kept open, and the passage 9 is in the open state although the ventilation resistance is increased, so that the canister (not shown) and the fuel tank 5 after the automatic stop operation are operated. The air permeability is secured and additional oil can be added.

When the continuous refueling is continued, the liquid level 10 in the casing 1 continues to rise together with the liquid level 6 in the fuel tank 5,
As can be seen in FIG. 5, the valve A is closed. By closing both valve A and valve B in this way, the fuel tank 5
The path 9 from the canister to the canister (not shown) is completely cut off to prevent the outflow of liquid fuel due to over-refueling after 100% refueling is completed. As described above, the fuel cutoff device of the present invention prevents a sudden flow of liquid fuel into the casing that occurs when the liquid level in the fuel tank and the liquid level in the casing that rises behind the liquid level coincide with each other. The operation is characterized in that the auto-stop is operated at a specific timing determined by the total amount of liquid fuel supplied to the fuel tank to create a closed valve state that allows the pressure in the fuel tank to rise.

[0019]

According to the fuel cutoff device of the present invention, the first automatic stop can be operated at substantially the same timing according to the amount of fuel supplied to the fuel tank, regardless of whether the fuel supply speed is slow or slow. Above all, the hollow valve has a great effect of making the timing constant. Since this hollow valve is housed in a valve case integrated with the casing,
The hollow valve is not deviated or damaged during transportation of the fuel cutoff device, and the fuel cutoff device can be handled in the same manner as before. In this way, the operation timing of the auto stop can be made as close as possible to the refueling amount which is close to 100%, and as a result, the number of times of refueling can be reduced. As a matter of course, when the tank is 100% full, it is possible to completely close the path from the fuel tank to the canister so that supercharging cannot be performed, and it becomes possible to provide a fuel cutoff device that satisfies ORVR.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which a liquid level in a fuel tank has not reached the fuel cutoff device in the fuel cutoff device of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the liquid level rises beyond the bottom hole but does not reach the side hole in the same fuel cutoff device.

FIG. 3 is a partial cross-sectional view corresponding to FIG. 2 in the fuel cutoff device having no hollow valve.

FIG. 4 is a cross-sectional view showing a state in which a liquid surface reaches a side surface hole in the fuel cutoff device.

FIG. 5 is a cross-sectional view showing a state in which the liquid level exceeds the side surface hole in the fuel cutoff device.

[Explanation of symbols]

1 casing 2 side holes 3 Small opening bottom hole 4 Fuel cutoff device without hollow valve 5 fuel tank 6 Liquid level in fuel tank 7 floats 8 hook Route to 9 canisters 10 Liquid level in casing 11 Regulated groove 12 Large bottom hole 13 Hollow valve 14 Fuel shutoff device with hollow valve 15 valve case

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yujiro Hayashi 8 Ome Industries Co., Ltd. at 1724 Kushiro, Soja City, Okayama Prefecture (72) Inventor Toshihiro Koyama 5-3-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Kogyo Co., Ltd. (56) Reference JP-A-6-297968 (JP, A) JP-A-2-112658 (JP, A) JP-A-7-257205 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) F02M 37/00 301 F02M 37/00 311 B60K 15/077 F16K 24/00 F16K 31/18

Claims (2)

(57) [Claims] 1. A float and a first valve and a second valve which are vertically linked to each other as the float moves up and down in a casing which is attached to an end of a path connecting a fuel tank and a canister to enable the inflow and outflow of liquid fuel. The first valve seat and the second valve seat that are independently opened at the end of the path are individually opened and closed. The first valve to move up and down earlier or later than the second valve, and the side surface of the casing has a side hole with a small inflow resistance, and the bottom surface of the casing has a bottom with a large inflow resistance. A fuel cutoff device for a fuel tank, characterized in that a surface hole is provided, and when refueling, liquid fuel is mainly flown into the casing from the side hole to raise the float and close the valve. 2. A float and a first valve and a second valve which are interlocked up and down as the float moves up and down in a casing which is attached to an end of a path connecting a fuel tank and a canister to allow inflow and outflow of liquid fuel. The first valve seat and the second valve seat that are independently opened at the end of the path are individually opened and closed. The first valve to move up and down earlier or later than the second valve by fitting it in, and a side surface hole with a small inflow resistance is provided on the side surface of the casing, and a bottom surface hole is provided on the bottom surface of the casing. Further, a hollow valve for opening and closing the bottom hole is housed and a valve case opened downward is integrally formed with the casing, and a hollow valve that rises in the valve case according to the liquid level rise at the time of refueling blocks the bottom hole. Liquid from the side hole to the casing. A fuel cutoff device for a fuel tank, characterized in that the float is raised by inflowing body fuel to close the valve.