WO2008088094A1

WO2008088094A1 - Structure of gas valve for fuel tank

Info

Publication number: WO2008088094A1
Application number: PCT/KR2007/000240
Authority: WO
Inventors: Do-Seong Han
Original assignee: Do-Seong Han
Priority date: 2007-01-15
Filing date: 2007-01-15
Publication date: 2008-07-24

Abstract

The invention concerns a gas valve structure for a fuel tank. The structure is provided in a fuel tank of a vehicle to discharge only gas generated from fuel but to block fuel. The invention is characterized in that the upper part of the closer (40) provided on a floater (30) is shaped a plate and is integrated with a hemisphere-shaped support (43) at the front end of a shaft extending toward the lower part of the closer, while the closer (40) can move upward/downward, forward/ backward or to the right/left, and can be slanted at any angle and achieve free movement with respect to the floater (30).

Description

Description STRUCTURE OF GAS VALVE FOR FUEL TANK

Technical Field

[1] The present invention relates to a gas valve used for a fuel tank in a vehicle for discharging only gas generated from fuel but for blocking fuel, and more particularly to a gas valve structure for a fuel tank capable of closing an orifice hole located above a closer by means of the closer on a general floater in order to guarantee stable sealing in valve operation and to allow the floater smoothly to operate at a high pressure in the tank.

[2]

Background Art

[3] Generally, the fuel contained in a fuel tank of a vehicle rapidly evaporates. The evaporation of fuel is furthermore accelerated with increasing ambient temperature or vibration and movement of the vehicle in running. Accordingly, overpressure occurs in the tank. Therefore, overpressure must be removed continuously.

[4] Typically, at least one discharge valve is provided for a fuel tank. The gas discharged from the at least one discharge valve is captured in a canister, then sucked into an engine to re-burn and thus to prevent gas from being discharged to the outside.

[5] Actually, because of a vehicle running on a slope area or on an unpaved road as well as in case of sudden stop and sudden turning, etc., a lot of movement of fuel occurs and gas is thus generated in the fuel tank. Such movement of fuel often pushes up and raises a floater equipped in the gas valve. In this case, when an unstable situation occurs in the overall structure while rising/falling of the floater repeats, i.e., the floater sometimes does not fall at a certain time in the structure that, as conventionally used, a cone-shaped closure is equipped on a floater and an orifice hole above the closure is also cone-shaped to allow the orifice hole to be closed with the closer.

[6] In order to cope with such an aforementioned situation, the gas is typically discharged into the air with a separate safety device, but it is not desirable in that the gas is discharged directly into the air without any measure and thus pollutes atmospheric environment. In other words, perfect and stable sealing of the float valve which is a primary safety device and is very important is required.

[7] In the prior art technology proposed to solve the problems, the published Korea

Patent No. 2004-0100008 (application No. 10-2003-0032202) discloses a dual material valve in which a key configuration of the technology is that an inserter is provided in an orifice hole of a valve housing and closing of the inserter of the orifice hole is controlled by a closer provided on a float valve. In this case, however, although the floater goes upward due to elastic force of the spring located on the lower part of the floater and the orifice hole is thereby closed, the closer stays to be fixed with the floater without movement. As a result, slanting or movement depending on the clearance present between the floater and the housing is disadvantageously not considered in the structure.

[8] That is, with the structure by the aforementioned prior art technology, stable sealing is kept only when the floater rises/falls vertically in parallel with the housing, due to the structure of the floater and the housing surrounding it. However, in fact, movement of the floater with respect to the housing cannot be completely prevented. In the end, with the aforementioned technology, each different pressure acts on each contact location when the closer contacts the orifice hole, so that partial side wear occurs on the lower part of the orifice hole in an extreme case, causing fuel leaking. Because of such structural problems, it is known that a metallic inserter is provided in the orifice hole to reduce wear in the prior art technology.

[9] In addition to the problem of increased weight resulting from the metal structure of the prior art technology, another problem is the high price of the parts made by injection molding for the inserter.

[10]

Disclosure of Invention

Technical Problem

[11] The invention was conceived to solve the aforementioned problems.

[12] It is an object of the present invention to provide a gas valve structure for a fuel tank which can rapidly cope with circumstances at any angle to implement stable sealing while carrying out smooth opening/closing of a valve at high pressure in the fuel tank, by allowing a closer to move freely independently of a floater, the closer selectively sealing an orifice hole above the floater in the fuel tank.

[13] It is another object of the invention to provide a gas valve structure for a fuel tank which blocks fuel from entering a canister although the fuel leaks from the orifice hole, by providing a partition for stopping direct communication between the orifice hole and the discharge pipe in the valve cap.

[14]

Advantageous Effects

[15] With the gas valve structure for a fuel tank according to the invention as described above, the support provided on the lower end of the closer that executes sealing is shaped a hemisphere and supported by the inner bottom of the floater while the closer can freely move in any direction and also not be released from the floater. That is, since the closer can move upward/downward, forward/backward and to the right/left at any angle and can perform independent movement such as slanting, rapid, stable and optimum sealing can be effectively achieved.

[16] Also, although fuel is discharged through the orifice hole, the discharged fuel is primarily blocked by means of the partition, and falls by means of its self-weight to return to the tank, so that fuel discharged into a canister can be prevented. Therefore the invention has an advantage that performance deterioration of a canister can be prevented and atmospheric environment can also be protected accordingly.

[17]

Brief Description of the Drawings

[18] These and other features, aspects, and advantages of the present invention will become apparent from the following description, illustrated in the accompanying drawings, in which like components are referred to by like reference numerals. The various features of the drawings may not be to scale. In the drawings:

[19]

[20] Fig. 1 is a schematic cross section of a gas valve structure for a fuel tank according to one embodiment of the invention;

[21] Fig.2 is an enlarged view of the part A shown in Fig.1 ;

[22] Fig.3 shows a state of operation of the gas valve structure according to a first embodiment of the invention;

[23] Fig.4 is a schematic cross section of a gas valve structure according to a second embodiment of the invention; and

[24] Fig.5 is a cross section of the gas valve structure, cut along the line B-B shown in

Fig.4.

[25]

Best Mode for Carrying Out the Invention

[26] The invention to achieve the aforementioned object consists in a gas valve structure for a fuel tank, characterized in that the top of a closer 40 provided on a floater 30 is shaped a plate, and in that a support 43 shaped a hemisphere is integrated at the front end of a shaft extending toward the lower part of the closer 40 while the closer 40 can freely move upward/ downward, forward/backward, and to the right/left, at any angle and can freely rotate, with respect to the floater 30.

[27] Another object of the invention consists in a partition 14 for blocking direct flow of fuel from the orifice hole 12 to the discharge pipe 11 in the valve cap 10.

[28] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[29] Fig. 1 is a schematic cross section of a gas valve structure for a fuel tank according to one embodiment of the invention, and Fig.2 is an enlarged view of the part A shown in Fig.l.

[30] Referring to Fig.l, the gas valve 1 for a fuel tank consists of a valve cap 10, a housing 20, a floater 30 and a closer 40.

[31] The valve cap 10 has a discharge pipe 11 communicating with a canister (not shown) on its top left, an orifice hole 12 in the center of the lower part thereof and a flange 13 on the lower circumference thereof. The housing 20 is coupled to the lower part of the valve cap 10 and has an inlet 21 communicating with the inside of the fuel tank (not shown) on the lower end.

[32] The floater 30 is equipped operable to rise/fall in the housing 20, wherein a spring

31 is provided on the inner side of the lower part of the floater 30, wherein the spring is supported by the internal bottom of the housing 20. In the top center of the floater, there are provided a guide pipe 32 whose top is vertically punched, and a support chamber 33 communicating with the pipe 32.

[33] The closer 40 in the invention is provided, on top thereof, with a closing plate 41 for closing the orifice hole 12, which, at the front end of a shaft extending toward the bottom of the closer 40, is integrated with a support 43. The support 43 is placed in the support chamber 33. A cross section of the support 43 in a certain direction is shaped a circular arc (preferably, a semicircle). Here, it is preferred that the extending shaft 42 can rise/fall in the guide pipe 32 (see Fig.2).

[34] The gas valve 1 configured as described above is attached on top of a fuel tank by means of the flange 13. Then, when the pressure in the tank rises due to the gas resulting from fuel evaporation, pressure occurs toward the inlet 21 of the housing 20. In this case, the floater 30 is pushed up, the gas in the tank is led into the housing 20 through the inlet 21 and is then discharged to the orifice hole 12 to move to and be collected in the canister through the discharge pipe 11.

[35] In this case, when fuel raises the floater 30 because of fuel flow in the tank, the fuel flows into the housing 20 through the inlet 21, and the floater 30 thereby rises, so that the closer 40 placed on the floater 30 closes the orifice hole 12.

[36] That is, when the floater 30 rises, the support 43 at the end of the closer 40 supported by the bottom of the support chamber 33 rises accordingly. Therefore, the closing plate 41 of the close 40 contacts the lower part of the orifice hole 12 to achieve sealing, so that fuel cannot flow into the discharge pipe 11.

[37] Referring to Fig.2, the structure of the closer 40 with respect to the floater 30 will now be described in more detail.

[38] First, the outer diameter of the closer shaft 42 is smaller than the inner diameter of the guide pipe 32. The length of the shaft 42 is made longer than the height of the guide pipe 32. The lower part of the support 43 is shaped, e.g., a hemisphere, and its outer diameter is bigger than the inner diameter of the guide pipe 32.

[39] As a result, the closer 40 cannot be released from the upper part of the floater 30, while, because the length of the shaft 42 is longer than the guide pipe 32, the closer 40 can rise/fall. Also, since the diameter of the shaft 42 is smaller, it can move and slant upward/downward and to the left/right at any angle. If the shaft 42 and the guide pipe 32 are shaped round, relative rotation of the closer can also be achieved.

[40] Therefore, as shown in Fig.2, although the floater 30 rises while it slants at any angle with respect to the housing 20, the closer 40 can rise vertically due to the feature of the shape and movability of the support 43. Since the closing plate 41 is kept in parallel with the lower end of the orifice hole 12 eventually, the full contact area receives uniform pressure, so that stable sealing can be achieved.

[41] Also, the closer structure that allows the closer to be slanted and go upward/ downward, forward/backward and to the left/right at any angle with respect to the floater 30 also allows independent movement of the closer with respect to the floater, independently of movability of the floater 30 with respect to the housing 20. Therefore, although there is a high pressure in the tank, the closer 40 can rapidly and tightly close the orifice hole 12.

[42] As such, there are many alternatives of assembling the closer that can achieve independent and free movement with respect to a floater. One example is that the closer 40 is assembled by making a groove on a side line of the guide pipe 32 of the floater to insert the closer 40 from the side. If the assembled and finished structure is the same as described above, the invention can be compatible with various assembling alternatives.

[43] Fig.3 shows a state of operation of a gas valve structure according to one embodiment of the invention. The state shown in Fig.3 shows the state that a vehicle runs on a slanted road and the fuel tank is thus slanted. In this case, since there is more or less movement allowance between the housing 20 and the floater 30, there is a difference between the slanting angle of the housing and that of the floater.

[44] In this case, although the floater 30 is slanted and rises at a given angle with respect to the housing 20, the closer 40 can move independently with respect to the floater 30, so that rapid and stable sealing can be kept at the same state as shown in Fig.2.

[45] Fig.4 is a schematic cross section of a gas valve structure according to a second embodiment of the invention, and Fig.5 is a top cross section of the gas valve structure, cut along the line B-B shown in Fig.4.

[46] Referring to Figs.4 and 5, there is provided a partition 14 between the orifice hole

12 and the discharge pipe 11 in the valve cap 10. The partition is further provided with an opening 15 on the opposite side of the discharge pipe 11.

[47] With such a configuration, the fuel leaking despite the action of the closer 40 can be blocked from flowing directly into the discharge pipe 11, and detours through the opening 15. By the measure, the time that fuel stays in the valve cap 10 is extended, and the fuel can then return to the tank through the orifice hole 12 by means of its self- weight when the floater 30 returns to its original position.

[48] Exemplary embodiments of the invention have been explained above and are illustrated in the figures. However, the present invention is not limited to the exemplary embodiments described above, and it is apparent that variations and modifications can be effected by those skilled in the art within the spirit and scope of the present invention. Therefore, the exemplary embodiments should be understood not as limitations but as examples. The scope of the present invention is not determined by the above description but by the accompanying claims and variations and modifications may be made to the embodiments of the invention without departing from the scope of the invention as defined by the appended claims and equivalents.

[49] In the claims, any reference signs shall not be construed as limiting the claims. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim.

Claims

[1] A gas valve structure for a fuel tank, comprising: a valve cap 10 having a discharge pipe on the upper part thereof and an orifice hole 12 in the center of the lower part thereof; a housing 20 coupled to the lower part of the valve cap and having an inlet on the lower end thereof; and, a floater 30 capable of rising/falling in the housing and including a spring supported by the inner bottom of the housing, the spring being located inside of the lower part of the floater, characterized in that a closer 40 is provided which can close the orifice hole above the floater 30; in the center of the upper part of the floater, there are provided a guide pipe 32 whose top is vertically punched and a support chamber

33 communicating with the lower part of the pipe 32; and the closer 40 is provided with a closing plate 41 on top thereof, and is integrated with a support 43 at the front end of a shaft extending toward the lower part of the closer 40, wherein the support 43 is placed in the support chamber 33, and a cross section of the support in any direction is shaped a circular arc.

[2] The structure as claimed in claim 1, characterized in that the outer diameter of the closer shaft 42 is smaller than the inner diameter of the guide pipe 32, but the length of the shaft is longer than the height of the guide pipe 32, and in that the outer diameter of the support 43 is larger than the inner diameter of the guide pipe 32.

[3] The structure as claimed in claim 1 or 2, characterized in that, between the orifice hole 12 and the discharge pipe 11 in the valve cap 10, a partition having an opening 15 on the opposite side of the partition, seen from the end of the discharge pipe, is provided.

[4] The structure as claimed in claim 1, characterized in that between the orifice hole

12 and the discharge pipe 11 in the valve cap 10, a partition having an opening 15 on the opposite side of the partition, seen from the end of the discharge pipe, is provided.