Air control valve for fuel cell

An air control valve apparatus for a fuel cell, which controls air that flows into or out of a fuel cell stack, includes a valve housing having an air flow path fluidically-communicating with the fuel cell stack; a valve member configured to selectively open or close the air flow path; a trapping portion provided in the valve housing, disposed adjacent to an internal surface of the valve member, and configured to trap foreign substances discharged from the fuel cell stack; and a siphon guide tube connected between the trapping portion and the outside of the valve member and configured to selectively discharge the foreign substances trapped by the trapping portion to the outside of the valve member, improving stability and reliability.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No. 10-2021-0096663 filed on Jul. 22, 2021, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an air control valve apparatus for a fuel cell, and more particularly, to an air control valve apparatus for a fuel cell, which is capable of minimizing accumulation of foreign substances and improving stability and reliability.

Description of Related Art

A fuel cell system refers to a system that continuously produces electrical energy by a chemical reaction of continuously supplied fuel. Research and development are consistently performed on the fuel cell system as an alternative capable of solving global environmental issues.

Based on types of electrolytes used for the fuel cell system, the fuel cell system may be classified into a phosphoric acid fuel cell (PAFC), a molten carbonate fuel cell (MCFC), a solid oxide fuel cell (SOFC), a polymer electrolyte membrane fuel cell (PEMFC), an alkaline fuel cell (AFC), a direct methanol fuel cell (DMFC), and the like. Based on operating temperatures, output ranges, and the like as well as types of used fuel, the fuel cell systems may be applied to various application fields related to mobile power, transportation, distributed power generation, and the like.

Among the fuel cells, the polymer electrolyte membrane fuel cell is applied to the field of a hydrogen vehicle (hydrogen fuel cell vehicle) being developed to substitute for an internal combustion engine.

The hydrogen vehicle includes a fuel cell stack that produces electricity through an oxidation-reduction reaction between hydrogen and oxygen. The hydrogen vehicle is configured to travel as a motor is operated by electricity produced by the fuel cell stack.

Meanwhile, the hydrogen vehicle is provided with an air control valve configured to control air to be introduced into the fuel cell stack and to control air discharged from the fuel cell stack.

A valve member (valve disc) of the air control valve operates to open an air flow path while the vehicle operates, and the valve member operates to close the air flow path when the vehicle does not operate.

Meanwhile, if foreign substances (e.g., condensate water and corroded substances in the fuel cell stack) are accumulated at the periphery of the valve member in the air control valve, the performance in opening or closing the valve member and the performance in sealing the valve member deteriorate.

Because the foreign substances accumulated at the periphery of the valve member are frozen in the winter season when an atmospheric temperature is low, the valve member is difficult to normally open or close.

Therefore, recently, various studies have been conducted to minimize the accumulation of foreign substances at the periphery of the valve member and ensure a smooth operation of the valve member, but the study results are still insufficient. Accordingly, there is a need to develop a technology to minimize the accumulation of foreign substances and ensure the smooth operation of the valve member.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing an air control valve apparatus for a fuel cell, which is capable of minimizing accumulation of foreign substances at the periphery of a valve member and improving stability and reliability.

The present invention has been made in an effort to minimize accumulation of foreign substances at the periphery of a valve member and minimize disability of the valve member caused by frozen foreign substances.

The present invention, in various aspects thereof, has also been made in an effort to improve performance in opening or closing a valve member and performance in sealing the valve member.

The objects to be achieved by the embodiments are not limited to the above-mentioned objects, but also include objects or effects which may be understood from the solutions or embodiments described below.

Various aspects of the present invention provide an air control valve apparatus for a fuel cell, which controls air that flows into or out of a fuel cell stack, the air control valve apparatus including: a valve housing having an air flow path fluidically-communicating with the fuel cell stack; a valve member movably mounted to the valve housing and configured to selectively open or close the air flow path; a trapping portion provided in the valve housing, disposed adjacent to an internal surface of the valve member, and configured to trap foreign substances discharged from the fuel cell stack; and a siphon guide tube connected between the trapping portion and the outside of the valve member and configured to selectively discharge the foreign substances trapped by the trapping portion to the outside of the valve member through the siphon guide tube.

This is to improve safety and reliability of the air control valve apparatus for a fuel cell.

That is, if foreign substances (e.g., condensate water and corroded substances in the fuel cell stack) are accumulated at the periphery of the valve member in the air control valve, the performance in opening or closing the valve member and the performance in sealing the valve member deteriorate. Because the foreign substances accumulated at the periphery of the valve member are frozen in the winter season when an atmospheric temperature is low, the valve member is difficult to operate normally (open or close).

However, according to the exemplary embodiment of the present invention, the foreign substances at the periphery of the valve member may be trapped by the trapping portion and then discharged to the outside of the valve member through the siphon guide tube. Therefore, it is possible to obtain an advantageous effect of minimizing the accumulation of foreign substances and the frozen foreign substances at the periphery of the valve member and improving operational stability and sealability of the valve member.

The trapping portion may have various structures configured for trapping the foreign substances in the air flow path.

For example, the trapping portion may include: a trapping hole provided in the valve housing and disposed adjacent to the internal surface of the valve member; and a trapping wall disposed between the valve member and the trapping hole to guide the foreign substances to the trapping hole.

The trapping hole may have a cross-sectional area that gradually decreases from an inlet thereof toward an outlet thereof.

Since the cross-sectional area of the trapping hole gradually decreases from the inlet toward the outlet of the trapping hole as described above, the foreign substances trapped in the trapping hole may be naturally guided along a wall surface of the trapping hole to the siphon guide tube connected to the outlet of the trapping hole.

According to the exemplary embodiment of the present invention, the air control valve apparatus for a fuel cell may include an inclined guide portion provided on an internal surface of the trapping wall and configured to guide the foreign substances to the trapping hole.

Since the inclined guide portion is provided on the internal surface of the trapping wall as described above, the foreign substances attached to the internal surface of the trapping wall (or the foreign substances moved downwards along the internal surface of the valve member) may be naturally moved downwards along the inclined guide portion to the trapping hole. Therefore, it is possible to obtain an advantageous effect of further improving efficiency in trapping the foreign substances.

Furthermore, the air control valve apparatus for a fuel cell may include a seating portion provided on an external surface of the trapping wall, wherein the valve member is selectively seated on the seating portion.

The siphon guide tube may have various structures configured for moving (discharging) the foreign substances based on the siphon principle.

For example, the siphon guide tube may include: a trapping tube connected to an outlet of the trapping hole to receive the foreign substances therein; and a discharge tube having a first end portion connected to the trapping tube and a second end portion externally exposed of the valve member. The trapping tube may have a ‘U’-shaped cross-section.

According to the exemplary embodiment of the present invention, an inlet of the trapping hole may have a first cross-sectional area, and an outlet of the siphon guide tube may have a second cross-sectional area smaller than the first cross-sectional area.

This is to inhibit a reverse flow of the foreign substances trapped in the trapping hole.

That is, when the air flow path is blocked by the valve member at the same time when the operation of the fuel cell stack is stopped, a negative pressure may be applied into the air flow path, and the internal pressure (negative pressure) in the air flow path may cause a reverse flow of the foreign substances trapped in the trapping hole.

However, according to the exemplary embodiment of the present invention, the cross-sectional area (the second cross-sectional area) of the outlet of the siphon guide tube may be smaller than the cross-sectional area (the first cross-sectional area) of the inlet of the trapping hole. Therefore, it is possible to obtain an advantageous effect of inhibiting a reverse flow of the foreign substances trapped in the trapping hole when the negative pressure is applied into the air flow path.

A ratio of the cross-sectional area (the first cross-sectional area) of the inlet of the trapping hole to the cross-sectional area (the second cross-sectional area) of the outlet of the siphon guide tube may be 5:4.

According to the exemplary embodiment of the present invention, the air control valve apparatus for a fuel cell may include a sealing portion configured to seal a gap between the air flow path and the valve member.

The sealing portion may have various structures configured for closing (sealing) the gap between the air flow path and the valve member.

For example, the sealing portion may include a first sealing member disposed on the internal surface of the valve member and configured to come into contact with the seating portion.

The sealing portion may include a second sealing member disposed on the valve member, spaced from the first sealing member, and configured to come into contact with the seating portion.

As described above, according to the exemplary embodiment of the present invention, the gap between the valve member and the seating portion (the gap between the air flow path and the valve member) may be sealed by the dual sealing structure including the first sealing member and the second sealing member, in the state in which the valve member is accommodated on the seating portion. Therefore, it is possible to obtain an advantageous effect of improving the sealing performance implemented by the valve member and minimizing the leakage of air through the gap between the valve member and the seating portion.

According to various exemplary embodiments of the present invention, the air control valve apparatus for a fuel cell may include the sealing portion configured to seal the gap between the air flow path and the valve member. The sealing portion may include the first sealing member disposed on the internal surface of the valve member and configured to come into contact with the seating portion, and the second sealing member disposed on the seating portion and configured to come into contact with the internal surface of the valve member.

For example, the second sealing member may be provided in a form of a closed loop and accommodated in the first sealing member.

Since the second sealing member provided in a form of a closed loop is disposed in the first sealing member as described above, the gap between the valve member and the seating portion may be sealed by the triple sealing structure. Therefore, it is possible to obtain an advantageous effect of further improving the sealing performance implemented by the valve member and more effectively inhibiting the leakage of air through the gap between the valve member and the seating portion.

According to the exemplary embodiment of the present invention, the air control valve apparatus for a fuel cell may include a through-hole provided in the trapping wall, one end portion of the through-hole may be exposed to an internal surface of the trapping wall, and the other end portion of the through-hole may be exposed to an external surface of the trapping wall.

As described above, since the through-hole is provided in the trapping wall, foreign substances accumulated between the valve member and the external surface of the trapping wall may be trapped in the trapping hole. Therefore, it is possible to obtain an advantageous effect of further improving the efficiency in trapping the foreign substances. Furthermore, it is possible to minimize the accumulation of the foreign substances between the valve member and the valve housing and effectively remove the foreign substances accumulated between the valve member and the valve housing.

The through-hole may be inclined downwardly from the external surface of the trapping wall toward the internal surface of the trapping wall.

DETAILED DESCRIPTION

Hereinafter, various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical spirit of the present invention is not limited to various exemplary embodiments described herein but may be implemented in various different forms. One or more of the constituent elements in the exemplary embodiments may be selectively combined and substituted for use within the scope of the technical spirit of the present invention.

Furthermore, unless otherwise specifically and explicitly defined and stated, the terms (including technical and scientific terms) used in the exemplary embodiments of the present invention may be construed as the meaning which may be commonly understood by the person with ordinary skill in the art to which various exemplary embodiments of the present invention pertains. The meanings of the commonly used terms such as the terms defined in dictionaries may be interpreted in consideration of the contextual meanings of the related technology.

Furthermore, the terms used in the exemplary embodiments of the present invention are for explaining the embodiments, not for limiting the present invention.

In the exemplary embodiment, unless particularly stated otherwise, a singular form may also include a plural form. The expression “at least one (or one or more) of A, B, and C” may include one or more of all combinations that can be made by combining A, B, and C.

Furthermore, the terms such as first, second, A, B, (a), and (b) may be used to describe constituent elements of the exemplary embodiments of the present invention.

These terms are used only for discriminating one constituent element from another constituent element, and the nature, the sequences, or the orders of the constituent elements are not limited by the terms.

Furthermore, when one constituent element is referred to as being ‘connected’, ‘coupled’, or ‘attached’ to another constituent element, one constituent element may be connected, coupled, or attached directly to another constituent element or connected, coupled, or attached to another constituent element through yet another constituent element interposed therebetween.

Furthermore, the expression “one constituent element is provided or disposed above (on) or below (under) another constituent element” includes not only a case in which the two constituent elements are in direct contact with each other, but also a case in which one or more other constituent elements are provided or disposed between the two constituent elements. The expression “above (on) or below (under)” may mean a downward direction as well as an upward direction based on one constituent element.

Referring toFIGS.1to10, an air control valve100according to the exemplary embodiment of the present invention includes a valve housing110having an air flow path112fluidically-communicating with a fuel cell stack10, a valve member120configured to selectively open or close the air flow path112, a trapping portion130provided in the valve housing110, disposed adjacent to an internal surface of the valve member120, and configured to trap foreign substances discharged from the fuel cell stack10, and a siphon guide tube140connected to the trapping portion130and configured to selectively discharge the foreign substances trapped by the trapping portion130to the outside of the valve member120.

The air control valve100according to the exemplary embodiment of the present invention may be used to control air to be introduced into the fuel cell stack10and to control air to be discharged from the fuel cell stack10.

For reference, the air control valve100according to the exemplary embodiment of the present invention may be applied to various fuel cell vehicles (e.g., passenger vehicles or commercial vehicles), ships, mobility vehicles in aerospace fields, or the like to which the fuel cell stack10may be applied. The present invention is not restricted or limited by the types and properties of the subjects to which the air control valve100is applied.

The fuel cell stack10refers to a kind of power generation device that generates electrical energy through a chemical reaction of fuel (e.g., hydrogen). The fuel cell stack may be configured by stacking several tens or hundreds of fuel cells (unit cells) in series.

The fuel cell may have various structures configured for producing electricity by an oxidation-reduction reaction between fuel (e.g., hydrogen) and an oxidant (e.g., air).

For example, the fuel cell may include: a membrane electrode assembly (MEA) having catalyst electrode layers in which electrochemical reactions occur and which is attached to two opposite sides of an electrolyte membrane through which hydrogen ions move; a gas diffusion layer (GDL) configured to uniformly distribute reactant gases and transfer generated electrical energy; a gasket and a fastener configured to maintain leakproof sealability for the reactant gases and a coolant and maintain an appropriate fastening pressure; and a separator (bipolar plate) configured to move the reactant gases and the coolant.

In the fuel cell, hydrogen, which is fuel, and air (oxygen), which is an oxidant, are supplied to an anode and a cathode of the membrane electrode assembly, respectively, through flow paths in the separator such that the hydrogen is supplied to the anode, and the air is supplied to the cathode.

The hydrogen supplied to the anode is decomposed into hydrogen ions (protons) and electrons by catalysts in the electrode layers provided at two opposite sides of the electrolyte membrane. Only the hydrogen ions are selectively transmitted to the cathode through the electrolyte membrane, which is a cation exchange membrane, and at the same time, the electrons are transmitted to the cathode through the gas diffusion layer and the separator which are conductors.

At the cathode, the hydrogen ions supplied through the electrolyte membrane and the electrons delivered through the separator meet oxygen in the air supplied to the cathode by an air supply device, generating a reaction of producing water. As a result of the movement of the hydrogen ions, the electrons flow through external conductive wires, and the electric current is generated as a result of the flow of the electrons.

The valve housing110has therein the air flow path112through which air flows. The valve housing100is mounted in the vehicle (fuel cell vehicle).

The valve housing110may be variously changed in shape and structure in accordance with required conditions and design specifications. The present invention is not restricted or limited by the shape and the structure of the valve housing110.

The air flow path112includes a first flow path through which the air is supplied to the fuel cell stack10, and a second flow path through which the air is discharged from the fuel cell stack10. For example, in the valve housing110, the first flow path and the second flow path may be individually separated (partitioned) by a partition wall.

Furthermore, the valve housing110is provided with a first port connected to an air inlet port of the fuel cell stack10, and a second port connected to an air discharge port of the fuel cell stack10.

For example, the first port may communicate with the first flow path, and the air to be supplied to the fuel cell stack10may flow through the first port. Furthermore, the second port may communicate with the second flow path, and the air discharged from the fuel cell stack10may flow through the second port.

Furthermore, the valve housing110may be provided with a bypass flow path configured to connect the first flow path and the second flow path and allow the air introduced into the first flow path to selectively flow to the second flow path.

The valve member120is configured to selectively open or close the air flow path112by being rotated by a drive unit (e.g., a motor or solenoid).

Hereinafter, an example will be described in which the valve member120opens or closes the air flow path112(e.g., the second flow path) through which the air is discharged from the fuel cell stack10.

The valve member120may have various structures configured for opening or closing the air flow path112. The present invention is not restricted or limited by the structure and shape of the valve member120.

For example, the valve member120may have a shape corresponding to a cross-sectional shape (e.g., a quadrangular cross-sectional shape) of the air flow path112. According to various exemplary embodiments of the present invention, the valve member may have a different shape from the air flow path.

Referring toFIG.2, the trapping portion130is provided in the valve housing110and disposed adjacent to the internal surface of the valve member120to trap foreign substances discharged from the fuel cell stack10.

For reference, in the exemplary embodiment of the present invention, the foreign substances discharged from the fuel cell stack10may be defined as a concept including both condensate water made as moisture vapor discharged from the fuel cell stack10is condensed, and corroded substances in the fuel cell stack10.

For example, when the operation of the fuel cell stack10is stopped, the valve member120closes the air flow path112. When the operation of the fuel cell stack10is stopped (the air flow path is closed by the valve member) in a state in which an interior of the air flow path112is filled with moisture vapor (e.g., moisture vapor at 65° C. to 80° C.) discharged from the fuel cell stack10, an internal temperature of the air flow path112is decreased such that the moisture vapor with which the interior of the air flow path112is filled is condensed, and the condensate water is generated.

If the foreign substances are accumulated in the air flow path112(particularly, the condensate water is accumulated at the periphery of the valve member), the valve member120is difficult to smoothly open or close. Therefore, it is necessary to minimize the accumulation of the foreign substances in the air flow path112.

Accordingly, according to the exemplary embodiment of the present invention, the trapping portion130may be disposed adjacent to the internal surface of the valve member120, and the foreign substances in the air flow path112may be trapped by the trapping portion130. Therefore, it is possible to obtain an advantageous effect of minimizing the accumulation of the foreign substances, which affect the operation of opening or closing the valve member120, at the periphery of the valve member120.

The trapping portion130may have various structures configured for trapping the foreign substances in the air flow path112. The present invention is not restricted or limited by the structure of the trapping portion130.

For example, the trapping portion130may include a trapping hole132provided in the valve housing110and disposed adjacent to the internal surface of the valve member120, and a trapping wall134disposed between the valve member120and the trapping hole132.

The trapping hole132may be provided in a form of a recessed hole (or groove) having a trapping space configured for trapping the foreign substances. The trapping hole132may be provided in a bottom portion of the air flow path112and disposed maximally adjacent to the internal surface of the valve member120.

The trapping hole132may be variously changed in structure and shape in accordance with required conditions and design specifications. The present invention is not restricted or limited by the structure and shape of the trapping hole132.

For example, the trapping hole132may have an approximately circular shape. According to various exemplary embodiments of the present invention, the trapping hole may have a quadrangular shape or other shapes.

The trapping hole132may have a cross-sectional area that gradually decreases from an inlet (an upper end portion based onFIG.2) thereof toward an outlet (a lower end portion based onFIG.2) thereof.

Since the cross-sectional area of the trapping hole132gradually decreases from the inlet toward the outlet of the trapping hole132as described above, the foreign substances trapped in the trapping hole132may be naturally guided along a wall surface of the trapping hole132to the siphon guide tube140connected to the outlet of the trapping hole132.

The trapping wall134is disposed between the valve member120and the trapping hole132and partially covers a lower end portion (based onFIG.1) of the valve member120.

Since the trapping wall134is disposed between the valve member120and the trapping hole132as described above, it is possible to obtain an advantageous effect of minimizing the introduction of the foreign substances to the lower end portion of the valve member120.

The air control valve100for a fuel cell may include an inclined guide portion134aprovided on an internal surface of the trapping wall134(a right surface of the trapping wall based onFIG.2) and configured to guide the foreign substances to the trapping hole132.

Since the inclined guide portion134ais provided on the internal surface of the trapping wall134as described above, the foreign substances attached to the internal surface of the trapping wall134(or the foreign substances moved downwards along the internal surface of the valve member) may be naturally moved downwards along the inclined guide portion134ato the trapping hole132. Therefore, it is possible to obtain an advantageous effect of further improving efficiency in trapping the foreign substances.

In an exemplary embodiment of the present invention, the inclined guide portion134amay include a front inclined guide portion inclined downwardly from the trapping wall134toward the trapping hole132in a rearward direction, and a rear inclined guide portion inclined downwardly from the trapping wall134toward the trapping hole134in a forward direction, wherein a height of the rear inclined guide portion is lower than a height of the front inclined guide portion.

Furthermore, the air control valve100for a fuel cell may include a seating portion134bprovided on an external surface of the trapping wall134(a left surface of the trapping wall based onFIG.2) and configured to allow the valve member120to be accommodated thereon.

The seating portion134bmay have various structures on which the valve member120may be accommodated. The present invention is not restricted or limited by the structure and shape of the seating portion134b.

For example, the seating portion134bmay be provided in a form of a flat surface corresponding to an edge portion of the internal surface of the valve member120. The edge portion of the internal surface of the valve member120may come into contact with the seating portion134b, which makes it possible to more assuredly close the air flow path112.

The siphon guide tube140is connected to the trapping portion130and selectively discharges the foreign substances, trapped by the trapping portion130, to the outside of the valve member120.

One end portion (an inlet end) of the siphon guide tube140may be connected to the outlet of the trapping hole132, and the other end portion (an outlet end) of the siphon guide tube140may be externally exposed of the valve member120(e.g., a space at a side of an external surface of the valve member). The foreign substances trapped in the trapping hole132may be discharged to the outside of the valve member120along the siphon guide tube140based on the siphon principle.

The siphon guide tube140may have various structures configured for moving (discharging) the foreign substances (e.g., condensate water) based on the siphon principle. The present invention is not restricted or limited by the structure of the siphon guide tube140.

For example, the siphon guide tube140may include a trapping tube142connected to the outlet of the trapping hole132and filled with the foreign substances, and a discharge tube144having one end portion connected to the trapping tube142and the other end portion externally exposed of the valve member120.

Hereinafter, an example will be described in which the trapping tube142has an approximately ‘U’-shaped cross-section and is connected to the outlet of the trapping hole132, and the discharge tube144has a straight shape in a horizontal direction and is connected to the outlet end portion of the trapping tube142.

According to various exemplary embodiments of the present invention, the trapping tube may have an ‘S’ shape, a ‘W’ shape, or other shapes, and the discharge tube may have a curved shape or other shapes.

Referring toFIG.3, foreign substances DW in the air flow path112may be trapped in the trapping hole132. When a level of the foreign substances DW trapped in the trapping hole132is increased to a predetermined level or higher, the foreign substances DW accommodated in the trapping hole132may be discharged to the outside of the valve member120along the siphon guide tube140, as illustrated inFIG.4.

The siphon guide tube140may continuously discharge the foreign substances DW until the level of the foreign substances DW in the trapping hole132becomes lower than a height of the outlet end portion of the discharge tube144. When the level of the foreign substances DW in the trapping hole132becomes lower than the height of the outlet end portion of the discharge tube144, the discharge of the foreign substances DW may be stopped.

Furthermore, since the interior of the siphon guide tube140is filled with the foreign substances DW, a flow of air through the siphon guide tube140may be blocked in the state in which the discharge of the foreign substances DW is stopped.

In other words, when the amount of foreign substances DW accumulated in the air flow path112(in the valve member) is increased to a predetermined degree or more (the level of the foreign substances trapped in the trapping hole is increased to a predetermined level or higher), the foreign substances may be discharged to the outside of the valve member120through the siphon guide tube140. In contrast, since the siphon guide tube140may be blocked by the foreign substances DW (seeFIG.3) in the state in which the discharge of the foreign substances DW is stopped, the state in which the valve member120closes the air flow path112(blocks the introduction of air into the air flow path) may be maintained.

In an exemplary embodiment of the present invention, the discharge tube144is positioned higher than the outlet of the trapping hole132.

Meanwhile, according to the exemplary embodiment of the present invention, the inlet of the trapping hole132has a first cross-sectional area, and the outlet of the siphon guide tube140has a second cross-sectional area smaller than the first cross-sectional area.

This is to inhibit a reverse flow of the foreign substances trapped in the trapping hole132.

That is, when the air flow path112is closed by the valve member120at the same time when the operation of the fuel cell stack10is stopped, a negative pressure may be applied into the air flow path112, and the internal pressure (negative pressure) in the air flow path112may cause a reverse flow of the foreign substances trapped in the trapping hole132.

However, according to the exemplary embodiment of the present invention, the cross-sectional area (the second cross-sectional area) of the outlet of the siphon guide tube140may be smaller than the cross-sectional area (the first cross-sectional area) of the inlet of the trapping hole132. Therefore, it is possible to obtain an advantageous effect of inhibiting a reverse flow of the foreign substances trapped in the trapping hole132when the negative pressure is applied into the air flow path112.

A ratio of a cross-sectional area (the first cross-sectional area) A1of the inlet of the trapping hole132to a cross-sectional area (the second cross-sectional area) A2of the outlet of the siphon guide tube140may be 5:4.

For example, when the air flow path112is closed by the valve member120at the same time when the operation of the fuel cell stack10is stopped, an external pressure P2of the valve member120may be about 100 kPa (the atmospheric pressure), and a pressure in the air flow path112(an internal pressure of the valve member120) P1may be about 80 kPa.

Therefore, it is possible to implement the equilibrium between a force applied to the inlet of the trapping hole132and a force applied to the outlet of the siphon guide tube140by setting the ratio of the cross-sectional area (the first cross-sectional area) A1of the inlet of the trapping hole132to the cross-sectional area (the second cross-sectional area) A2of the outlet of the siphon guide tube140to 5:4 (100:80), on the contrary to the ratio (80:100, i.e., 4:5) of the pressure P1applied to the inlet of the trapping hole132to the pressure P2applied to the outlet of the siphon guide tube140. Therefore, even though the negative pressure is applied into the air flow path112, it is possible to inhibit the foreign substances trapped in the trapping hole132from flowing reversely into the air flow path112.

Referring toFIG.5,FIG.6,FIG.7,FIG.8, andFIG.9, according to the exemplary embodiment of the present invention, the air control valve100for a fuel cell may include a sealing portion150configured to seal a gap between the air flow path112and the valve member120.

The sealing portion150may have various structures configured for closing (sealing) the gap between the air flow path112and the valve member120. The present invention is not restricted or limited by the structure of the sealing portion150.

For example, referring toFIG.5andFIG.6, the sealing portion150may include a first sealing member152disposed on the internal surface of the valve member120and configured to come into contact with the seating portion134b.

For example, the first sealing member152may be provided in a form of an approximately quadrangular ring provided along the edge portion of the internal surface of the valve member120.

The first sealing member152may be made of an elastic material such as rubber, silicone, or urethane. The present invention is not restricted or limited by the material and properties of the first sealing member152.

The sealing portion150may include a second sealing member154disposed on the valve member120, spaced from the first sealing member152, and configured to come into contact with the seating portion134b.

For example, the second sealing member154may be disposed at a lower end portion of the internal surface of the valve member120and have an approximately straight shape.

The second sealing member154may be made of an elastic material such as rubber, silicone, or urethane. The present invention is not restricted or limited by the material and properties of the second sealing member154.

The first and second sealing members152and154may be manufactured separately from the valve member120and then attached (bonded) to the internal surface of the valve member120. According to various exemplary embodiments of the present invention, the first and second sealing members may be provided on the internal surface of the valve member by applying or printing an elastic material. Alternatively, the first and second sealing members may be provided on the valve member by injection molding.

For reference, in the exemplary embodiment of the present invention, the example has been described in which the second sealing member154is partially provided at the lower end portion of the internal surface of the valve member120. However, according to various exemplary embodiments of the present invention, like the first sealing member, the second sealing member may be provided in a form of a ring provided along the edge portion of the internal surface of the valve member.

As described above, according to the exemplary embodiment of the present invention, the gap between the valve member120and the seating portion134b(the gap between the air flow path and the valve member) may be sealed by the dual sealing structure including the first sealing member152and the second sealing member154in the state in which the valve member120is accommodated on the seating portion134b. Therefore, it is possible to obtain an advantageous effect of improving the sealing performance implemented by the valve member120and minimizing the leakage of air through the gap between the valve member120and the seating portion134b.

In the exemplary embodiment of the present invention illustrated and described above, the example has been described in which both the first sealing member152and the second sealing member154are provided on the internal surface of the valve member120. However, according to various exemplary embodiments of the present invention, any one of the first sealing member and the second sealing member may be provided on the internal surface of the valve member, and the other of the first sealing member and the second sealing member may be provided on the seating portion.

That is, referring toFIGS.7to9, according to various exemplary embodiments of the present invention, the air control valve100for a fuel cell may include the sealing portion150configured to seal the gap between the air flow path112and the valve member120. The sealing portion150may include the first sealing member152disposed on the internal surface of the valve member120and configured to come into contact with the seating portion134b, and a second sealing member154′ disposed on the seating portion134band configured to come into contact with the internal surface of the valve member120.

For example, the first sealing member152may be provided in a form of an approximately quadrangular ring provided along the edge portion of the internal surface of the valve member120.

The second sealing member154′ may have various structures configured for cooperatively defining a sealing wall together with the first sealing member152. The present invention is not restricted or limited by the shape and structure of the second sealing member154′.

For example, the second sealing member154′ may be provided in a form of a closed loop (e.g., a quadrangular ring) and accommodated in the first sealing member152.

Since the second sealing member154′ provided in a form of a closed loop is disposed in the first sealing member152as described above, the gap between the valve member120and the seating portion134bmay be sealed by the triple sealing structure. Therefore, it is possible to obtain an advantageous effect of further improving the sealing performance implemented by the valve member120and more effectively inhibiting the leakage of air through the gap between the valve member120and the seating portion134b.

According to various exemplary embodiments of the present invention, the second sealing member disposed on the seating portion may be provided in a form of an open loop such as a straight shape or an arc shape.

According to the exemplary embodiment of the present invention, the air control valve100for a fuel cell may include a through-hole136provided in the trapping wall134. One end portion of the through-hole136may be exposed to an internal surface of the trapping wall134(a right surface of the trapping wall based onFIG.10), and the other end portion of the through-hole136may be exposed to an external surface of the trapping wall134(a left surface of the trapping wall based onFIG.10).

The through-hole136may be inclined downwardly from the external surface of the trapping wall134toward the internal surface of the trapping wall134. According to various exemplary embodiments of the present invention, the through-hole may be horizontally provided in the trapping wall.

To ensure the sealing performance of the sealing portion150, the other end portion of the through-hole136may be disposed inside the sealing portion150(on an upper portion of the sealing portion based onFIG.10). In some instances, the through-hole may be provided at the same height as the sealing portion.

As described above, according to the exemplary embodiment of the present invention, since the through-hole136is provided in the trapping wall134, foreign substances (condensate water or corroded substances) accumulated between the valve member120and the external surface of the trapping wall134(the left surface of the trapping wall based onFIG.10) may be trapped in the trapping hole132. Therefore, it is possible to obtain an advantageous effect of further improving the efficiency in trapping the foreign substances. Furthermore, it is possible to minimize the accumulation of the foreign substances between the valve member120and the valve housing110and effectively remove the foreign substances accumulated between the valve member120and the valve housing110.

Moreover, according to the exemplary embodiment of the present invention, since the through-hole136is provided in the trapping wall134, an additional flow path may be ensured to allow the air, which is blocked by the trapping wall134, to flow at the time of discharging the air. Therefore, it is possible to obtain an advantageous effect of improving the efficiency in discharging the air.

According to the exemplary embodiment of the present invention described above, it is possible to obtain an advantageous effect of minimizing the accumulation of foreign substances at the periphery of the valve member and improving stability and reliability.

According to the exemplary embodiment of the present invention, it is possible to obtain an advantageous effect of minimizing the accumulation of foreign substances at the periphery of the valve member and minimizing disability of the valve member caused by frozen foreign substances.

Furthermore, according to the exemplary embodiment of the present invention, it is possible to obtain an advantageous effect of improving stability and reliability.

Furthermore, according to the exemplary embodiment of the present invention, it is possible to obtain an advantageous effect of improving the performance (operational stability) in opening or closing the valve member and improving the sealing performance.