JP2006097538A - Fuel shut-off valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel shut-off valve 10 making automatic stop function at a predetermined liquid level of a fuel tank, preventing overfeeding of oil and preventing fuel from overflowing from an oil filling port after automatic stop. <P>SOLUTION: The fuel shut-off valve 10 is provided with a casing 20 and a float mechanism 50 having a float 51. In the casing 20, a first communication hole 31a is formed, and a second communication hole 33a of which opening area is narrower than that of the first communication hole 31a is formed above the first communication hole 31a. When fuel reaches the predetermined liquid level of the fuel tank FT by oil filling, the communication hole 31a is immersed, which increases internal pressure of the fuel tank FT. Due to pressure difference between the internal pressure of the fuel tank FT and pressure inside a valve chamber 30S, the float 51 is raised by fuel flowing into inside of the valve chamber 30S. Due to this, a second valve element 57 closes a connection passage 35b and a first valve element 53a opens the second communication hole 33a. In addition, when the pressure inside the valve chamber 30S is declined and the float 51 is lowered, the second communication hole 33a is closed by the first valve element 53a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cutoff valve that is attached to an upper part of a fuel tank and that opens and closes a connection passage that connects the inside and outside of the fuel tank to cut off communication between the fuel tank and the outside.

  Conventionally, patent document 1 etc. are known as this kind of a fuel cutoff valve. The fuel cutoff valve includes a casing and a float housed in a valve chamber of the casing. A first communication hole that is buried at a predetermined liquid level is formed in the casing. The first communication hole is formed in an opening area narrower than the first communication hole and above the first communication hole, and communicates the valve chamber and the fuel tank. Two communication holes are formed.

In the configuration of the fuel shut-off valve, when the fuel in the fuel tank reaches a predetermined liquid level (auto-stop liquid level) due to refueling, the first communication hole is buried, and the tank internal pressure in the fuel tank increases to stop refueling. Enable auto-stop function. The increase in the tank internal pressure raises the liquid level in the valve chamber, so that the float rises and closes the connection passage to the canister side. At this time, since the second communication hole is open, air is passed from the fuel tank to the valve chamber, the pressure difference between the valve chamber and the fuel tank is eliminated, the fuel level in the valve chamber is lowered, and the float is lowered. To do. In this state, since ventilation to the canister is ensured through the second communication hole and the connection passage, supercharging can be performed up to a liquid level exceeding a predetermined liquid level. However, depending on the specifications of the fuel tank system, there is a request to eliminate such supercharging and stop refueling at a predetermined liquid level.
JP-A-8-105571

  The present invention is based on solving the above-mentioned problems of the prior art, and makes the auto-stop function at a predetermined liquid level of the fuel tank and prevents supercharging, and further prevents fuel from overflowing from the fuel filler port after auto-stop. An object of the present invention is to provide a fuel cutoff valve that can be used.

The present invention made to solve the above problems
In a fuel cutoff valve that is mounted on the upper part of the fuel tank and that opens and closes a connection passage that connects the inside and outside of the fuel tank to cut off communication between the fuel tank and the outside.
A valve chamber that communicates the inside of the fuel tank and the connection passage, and is disposed so as to be buried when the fuel liquid level in the fuel tank reaches a predetermined liquid level, and communicates the valve chamber and the fuel tank. A casing having a first communication hole and a second communication hole having an opening area narrower than the first communication hole and disposed above the first communication hole and communicating the valve chamber and the fuel tank;
A float that is housed in the valve chamber and moves up and down by increasing or decreasing buoyancy according to a fuel liquid level in the valve chamber; and a first valve body that is provided in the float and closes the second communication hole when the float is in a lowered position; A float mechanism provided with the second valve body provided in the float and closing the connection passage when the float is in the raised position;
With
The float mechanism is
When the fuel liquid level reaches the predetermined liquid level and the first communication hole is buried, the float rises to the raised position due to an increase in buoyancy due to the fuel flowing into the valve chamber, whereby the second valve Close the connection passage with a body and open the second communication hole with the first valve body,
When the float is in the raised position, when the pressure in the valve chamber is reduced by ventilation through the second communication hole, the float is lowered to the lowered position, and the connection passage is formed by the second valve body. The second communication hole is configured to be opened and closed with the first valve body;
It is characterized by.

When fuel is supplied to a fuel tank using the fuel shut-off valve according to the present invention and reaches a predetermined liquid level in the fuel tank, the first communication hole is buried to increase the tank internal pressure in the fuel tank, Due to the pressure difference between the tank internal pressure and the valve chamber, the float is raised to the raised position by the fuel flowing into the valve chamber, thereby closing the connection passage by the second valve body and opening the first communication hole by the first valve body. At this time, an automatic stop for stopping the fuel supply of the fuel gun can be activated by detecting the increase in the tank internal pressure by the sensor or detecting that the fuel in the filler pipe has reached the fuel gun. In this state, even if the connection passage is closed, the second communication hole is opened, so that the tank internal pressure also decreases due to the ventilation from the inside of the fuel tank to the valve chamber through the second communication hole, so that the pressure from the fuel filler port is reduced. The overflow of fuel can be prevented.
The fuel shutoff valve closes the second communication hole connected to the canister by lowering the float after reaching the predetermined liquid level by refueling with the refueling gun, so that the inside of the fuel tank is connected to the canister side. Therefore, it is possible to prevent supercharging by the fuel gun.

  As a preferred aspect of the present invention, the first valve body can be configured to be formed on the lower surface of the upper flange portion of the float, and the second communication hole is formed on the upper portion of the casing. The structure which penetrates and is formed in the made flange can be taken.

  In order to further clarify the configuration and operation of the present invention described above, preferred embodiments of the present invention will be described below.

(1) Schematic configuration of fuel cutoff valve 10 FIG. 1 is a cross-sectional view showing a fuel cutoff valve 10 attached to an upper portion of a fuel tank of an automobile according to an embodiment of the present invention. In FIG. 1, the surface of the fuel tank FT is formed of a composite resin material containing polyethylene, and a mounting hole FTb is formed in the tank upper wall FTa. A fuel shut-off valve 10 is attached to the tank upper wall FTa in a state where the lower part thereof enters the attachment hole FTb. The fuel shut-off valve 10 controls the outflow to the canister when the fuel in the fuel tank FT rises to a predetermined liquid level FL1 during refueling, functions as an auto stop, and further prevents supercharging.

(2) Configuration of Each Part of Fuel Shutoff Valve 10 The fuel cutoff valve 10 includes a casing 20, a float mechanism 50, and a spring 58 as main components. The casing 20 includes a case main body 30, a case upper lid 35, and a lid body 40, and a space surrounded by the case main body 30 and the case upper lid 35 is a valve chamber 30 </ b> S. The float mechanism 50 supported by the housing is housed.

  FIG. 2 is an exploded cross-sectional view of the fuel cutoff valve 10. The case main body 30 has a cup shape surrounded by a side wall portion 31 and a bottom wall portion 32, and has an upper portion as an opening. A flange 33 projects from the upper portion of the side wall portion 31 in the radial direction, and an upper joint portion 34 is formed upward from the outer peripheral portion of the flange 33. The upper joint portion 34 supports the upper opening of the case body 30 so as to cover the case upper lid 35 with the case upper lid 35. The case body 30 is formed with a communication hole for connecting the valve chamber 30S into the fuel tank FT. As communication holes, a first communication hole 31 a is formed in the side wall portion 31, a second communication hole 33 a is formed in the flange 33, and a third communication hole 32 a is formed in the bottom wall portion 32. The first communication hole 31a is arranged so that the upper end thereof coincides with the predetermined liquid level FL1 (see FIG. 1). The second communication holes 33a are circular openings arranged above the predetermined liquid level FL1 and having a smaller ventilation area than the first communication holes 31a, and are arranged at four locations in the circumferential direction at intervals of 90 °. A seal portion 33b that protrudes from the upper surface of the flange 33 is formed on the periphery of the opening of the second communication hole 33a so as to surround the second communication hole 33a.

  The case upper lid 35 is provided with an umbrella-shaped upper lid body 35a, the central portion thereof is a connection passage 35b, and the lower peripheral edge portion of the opening is a seal portion 35c. Moreover, the opening peripheral part of the upper part of the connection channel | path 35b is the barrier 35d for returning a fuel. Further, the outer peripheral end of the upper lid main body 35 a is a holding end 35 e and is formed so as to be fitted to the fitting portion 34 a of the case main body 30.

  The lid body 40 includes a lid body 41, a tube body portion 42 projecting laterally from the center of the lid body 41, and a flange 43 formed on the outer periphery of the lid body 41, and these are integrally formed. . The tube portion 42 is formed with a lid side passage 42a. One end of the lid side passage 42a is connected to the valve chamber 30S of the case body 30 through the connection passage 35b, and the other end is on the canister (not shown) side. Connected to. An inner welding end 43b for welding the upper end of the case body 30 is formed at the lower portion of the lid body 41, and an outer welding portion 43a that is welded to the tank upper wall FTa of the fuel tank FT is formed at the lower end portion of the flange 43. Is formed.

  The float mechanism 50 includes a float 51 and an upper float 55 disposed on the top of the float 51. The float 51 includes a float main body 52 having a buoyancy chamber 51 </ b> S opened downward, and a flange 53 from the top of the float main body 52. A valve portion 51 a protrudes from the center upper portion of the float 51. The outer peripheral lower surface of the collar portion 53 is a first valve body 53a that opens and closes the second communication hole 33a by being attached to and detached from the seal portion 33b of the case body 30. In addition, the flange portion 53 is formed with an engagement hole 53b for preventing the upper float 55 from being pulled out. A guide protrusion 52 a is formed on the lower outer periphery of the float body 52. The guide protrusions 52a are provided on the side wall of the float main body 52 so as to protrude in the shape of ribs in the vertical direction at eight locations in the circumferential direction at equal intervals. The float 51 is supported by a spring 58 that spans between the bottom wall portion 32 and the upper surface of the buoyancy chamber 51S.

  The upper float 55 is a valve for improving the restart valve characteristics, and is supported on the upper part of the float 51 so as to be movable up and down. A communication hole 55b that is opened and closed by the valve portion 51a is formed at the center of the disc 55a. ing. The lower end of the communication hole 55b is a seal portion 55c. In addition, an engaging claw 55d that protrudes into and engages with the engaging hole 53b of the flange 53 is provided at the lower end of the outer periphery of the circular plate 55a. A rubber second valve element 57 is attached to the upper part of the upper float 55, and the second valve element 57 is attached to and detached from the seal portion 35c.

(3) Operation of the fuel cutoff valve 10 Next, the operation of the fuel cutoff valve 10 will be described. As shown in FIG. 1, when fuel is supplied into the fuel tank FT by refueling, the fuel vapor accumulated in the upper portion of the fuel tank FT as the fuel level in the fuel tank FT rises is reduced to the bottom wall portion 32. The third communication hole 32a and the first communication hole 31a of the side wall 31 enter the valve chamber 30S and escape from the valve chamber 30S to the canister side through the connection passage 35b and the lid side passage 42a. As shown in FIG. 3, when the fuel liquid level FL in the fuel tank FT reaches the predetermined liquid level FL1, the fuel closes the first communication hole 31a, thereby increasing the tank internal pressure in the fuel tank FT. When the sensor detects the increase in the tank internal pressure, an auto-stop functioning to stop the fueling of the fueling gun is activated. In this state, the differential pressure between the tank internal pressure and the pressure in the valve chamber 30S increases, and the fuel level rises in the valve chamber 30S. When the fuel liquid level in the valve chamber 30S reaches the height h1, the balance between the buoyancy of the float 51 and the upward force due to the load of the spring 58 and the downward force due to the dead weight of the float 51 and the upper float 55, When the former exceeds the latter, the float 51 and the upper float 55 rise together, and the second valve body 57 is seated on the seal portion 35c and closes the connection passage 35b. Thereby, at the time of refueling to the fuel tank FT, it is possible to escape the fuel vapor from the fuel tank FT and to prevent the fuel from flowing out of the fuel tank FT.

When the flange portion 53 is separated from the seal portion 33b due to the rise of the float 51, the first valve body 53a opens the second communication hole 33a, and the valve chamber 30S communicates with the inside of the fuel tank FT. The second communication hole 33a acts as a passage for releasing a high tank internal pressure to the valve chamber 30S. Then, the pressure in the valve chamber 30S is regulated so as to be balanced with the tank internal pressure through the ventilation of the second communication hole 33a, thereby reducing the fuel level in the valve chamber 30S. When the fuel liquid level in the valve chamber 30S decreases, the float 51 descends with its buoyancy reduced, so the valve portion 51a is separated from the seal portion 55c and opens the communication hole 55b. That is, since the valve portion 51a of the float 51 is conical and has a small pressure receiving area, the force of closely contacting the periphery of the communication hole 55b is weak and does not prevent the float 51 from descending. Therefore, the float 51 descends quickly and opens the communication hole 55b. Due to the communication of the communication hole 55b, the pressure below the upper float 55 becomes the same pressure as in the vicinity of the connection passage 35b. As the tank internal pressure decreases and the pressure difference decreases, the force with which the valve portion 51a comes into close contact with the seal portion 55c is weakened, so that the float 51 is smoothly lowered as shown in FIG. In this manner, the upper float 55 functions to promote the improvement of the restart valve characteristic that allows the float 51 to be opened smoothly. Moreover, since the state where the tank internal pressure has increased does not continue for a long time, it is possible to prevent the fuel from the fuel filler port from gradually overflowing.
When the float 51 and the upper float 55 are lowered, the connection passage 35b is opened, and when the float 51 is lowered, the first valve body 53a is seated on the seal portion 33b, thereby closing the second communication hole 33a (see FIG. 1 state). By closing the second communication hole 33a, the passage connected to the canister is closed and the inside of the fuel tank FT is sealed with respect to the canister side, so that the supercharging by the fuel gun can be prevented.

(4) Actions and effects of the embodiment The following actions and effects are exhibited by the configuration of the above embodiment.
(4) -1 When the fuel level in the fuel tank FT exceeds the predetermined liquid level FL1 that closes the first communication hole 31a by refueling, the tank internal pressure of the fuel tank FT rises, so that an automatic stop can be activated.

(4) -2 When the fuel level exceeds a predetermined level FL1 due to refueling, the fuel level in the valve chamber 30S rises and the float mechanism 50 closes the connection passage 35b, so that the fuel flows out to the canister. Can be prevented. At this time, the first valve body 53a opens the second communication hole 33a, and the internal pressure of the fuel tank FT is released to the valve chamber 30S side. Therefore, the pressure in the tank is lowered and the overflow of fuel from the fuel filler port is prevented. be able to.

(4) -3 After the fuel level reaches the predetermined level FL1 due to refueling and the auto-stop is activated, the fuel cutoff valve 10 has the second communication hole 33a connected to the canister by the lowering of the float 51 as the first valve body. Since the inside of the fuel tank FT is sealed with respect to the canister side by closing 53a, supercharging can be prevented.

  The present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the scope of the invention.

It is sectional drawing which shows the fuel cutoff valve attached to the upper part of the fuel tank of the motor vehicle concerning one Example of this invention. It is sectional drawing which decomposed | disassembled the fuel cutoff valve. It is explanatory drawing explaining operation | movement of a fuel cutoff valve. It is explanatory drawing explaining the operation | movement following FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cutoff valve 20 ... Casing 30 ... Case main body 30S ... Valve chamber 31 ... Side wall part 31a ... 1st communicating hole 32 ... Bottom wall part 32a ... 1st 3 communication holes 33 ... flange 33a ... 2nd communication hole 33b ... seal part 34 ... upper joint part 34a ... fitting part 35 ... case upper lid 35a ... upper lid body 35b. .. Connection passage 35c ... Seal part 35d ... Wall 35e ... Holding end 40 ... Lid body 41 ... Lid body 42 ... Tube part 42a ... Lid side passage 43 .. Flange 43a ... Outer weld 43b ... Internal weld end 50 ... Float mechanism 51 ... Float 51S ... Buoyancy chamber 51a ... Valve part 52 ... Float body 52a ... Guide Ridge 53 ... collar 53a ... first valve element 53b ... engagement hole 55 ... upper float 55a ... disc 55b ... communication hole 55c ... seal part 55d ... .Engaging claw 57 ... second valve body 58 ... spring FT ... fuel Link FTa ... tank on the wall FTb ... mounting holes

Claims (3)

In a fuel cutoff valve mounted on the upper part of the fuel tank (FT), which opens and closes a connection passage (35b) that connects the inside of the fuel tank (FT) and the outside to cut off communication between the fuel tank (FT) and the outside.
A valve chamber (30S) communicating between the fuel tank (FT) and the connection passage (35b), and disposed so as to be buried when the fuel level in the fuel tank reaches a predetermined level (FL1). A first communication hole (31a) that communicates between the valve chamber (30S) and the inside of the fuel tank (FT), and has an opening area narrower than the first communication hole (31a) and the first communication hole (31a). ) And a casing (20) having a second communication hole (33a) disposed above the valve chamber (30S) and communicating with the fuel tank (FT);
A float (51) which is housed in the valve chamber (30S) and moves up and down with increasing or decreasing buoyancy depending on the fuel level in the valve chamber (30S), and the float (51) provided in the float (51) is lowered. The first valve body (53a) that closes the second communication hole (33a) when in the position, and the connection passage (35b) provided in the float (51) when the float (51) is in the raised position. A float mechanism (50) comprising a second valve body (57) for closing;
With
The float mechanism (50)
When the fuel liquid level reaches the predetermined liquid level (FL1) and the first communication hole (31a) is buried, the float (51) is increased due to an increase in buoyancy due to the fuel flowing into the valve chamber (30S). Rises to the raised position, the second valve body (57) closes the connection passage (35b) and the first valve body (53a) opens the second communication hole (33a),
When the float (51) is in the raised position, when the pressure in the valve chamber (30S) is reduced by ventilation through the second communication hole (33a), the float (51) is moved to the lowered position. The second valve body (57) is opened, the connection passage (35b) is opened, and the second communication hole (33a) is closed by the first valve body (53a).
A fuel shut-off valve characterized by The fuel cutoff valve according to claim 1,
The said 1st valve body (53a) is a fuel cutoff valve currently formed in the lower surface of the collar part (53) of the upper part of the said float (51). The fuel cutoff valve according to claim 2,
The second communication hole (33a) is a fuel cutoff valve that is formed through a flange (33) formed in the upper part of the casing (20).

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