Patent Description:
The present disclosure relates to a fuel cell system, and more particularly, to a fuel cell system that are capable of reducing a hydrogen concentration in exhaust gas discharged from a fuel cell stack.

A fuel cell vehicle (e.g., a hydrogen fuel cell vehicle) is configured to autonomously generate electricity by means of a chemical reaction between fuel (hydrogen) and air (oxygen) and travel by operating a motor.

In general, the fuel cell vehicle includes a fuel cell stack configured to generate electricity by means of an oxidation-reduction reaction between hydrogen and oxygen, a fuel supply device configured to supply fuel (hydrogen) to the fuel cell stack, an air supply device configured to supply the fuel cell stack with air (oxygen) which is an oxidant required for an electrochemical reaction, and a thermal management system (TMS) configured to remove heat, which is generated from the fuel cell stack and power electronic parts of the vehicle, to the outside of the system and control temperatures of the fuel cell stack and the power electronic parts.

Further, discharge water (condensate water) and exhaust gas (e.g., unreacted hydrogen), which are produced during the operation of the fuel cell stack, may be discharged to the outside through an exhaust pipe.

Recently, various attempts have been made to apply the fuel cell system to construction machines (e.g., excavators) as well as passenger vehicles (or commercial vehicles).

Meanwhile, hydrogen may be contained in the exhaust gas discharged from the fuel cell stack (e.g., the exhaust gas discharged during a purge process for adjusting a hydrogen concentration in the fuel cell stack). When a hydrogen concentration in the exhaust gas increases to a certain level or higher, the risk of explosion increases. Accordingly, regulations are defined to force the hydrogen concentration in the exhaust gas discharged from the fuel cell to be at a predetermined level or lower.

The passenger vehicle operates mainly for the purpose of traveling, and it is possible to dilute the exhaust gas (reduce the hydrogen concentration in the exhaust gas) using outside air introduced into the vehicle while the vehicle travels (using vehicle-induced wind introduced when the vehicle travels).

In contrast, in the case of the construction machine used in a stationary state in an indoor construction site such as a construction site in a factory or warehouse, it is difficult to use the vehicle-induced wind, which makes it difficult to sufficiently dilute the exhaust gas. In particular, the exhaust gas stagnates at a particular position (e.g., in a power pack), which causes an increase in the risk of occurrence of an accident (risk of explosion).

Therefore, recently, various studies have been conducted to effectively reduce a hydrogen concentration in the exhaust gas discharged from the fuel cell stack, but the study results are still insufficient. Accordingly, there is a need to develop a technology to effectively reduce the hydrogen concentration in the exhaust gas discharged from the fuel cell stack. <CIT> discloses a fuel cell system with the features of the preamble of claim <NUM>. <CIT> and <CIT> disclose further fuel cell systems.

The present disclosure has been made in an effort to provide a fuel cell system and an exhaust gas treatment device that are capable of reducing a hydrogen concentration in exhaust gas discharged from a fuel cell stack.

In particular, the present disclosure has been made in an effort to reduce a hydrogen concentration in exhaust gas discharged from a fuel cell stack even under a condition in which vehicle-induced wind cannot be used.

The present disclosure has also been made in an effort to simplify a structure and improve spatial utilization and a degree of design freedom.

The present disclosure has also been made in an effort to improve safety and reliability.

The present disclosure has also been made in an effort to simplify a manufacturing process and reduce costs.

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

The invention provides a fuel cell system according to the appended claims.

This is to reduce the hydrogen concentration in the exhaust gas discharged from the fuel cell stack.

That is, hydrogen may be contained in the exhaust gas discharged from the fuel cell stack (e.g., the exhaust gas discharged during a purge process for adjusting a hydrogen concentration in the fuel cell stack). When a hydrogen concentration in the exhaust gas increases to a certain level or higher, the risk of explosion increases. Therefore, the hydrogen concentration in the exhaust gas discharged from the fuel cell needs to be maintained at a predetermined level or lower.

The passenger vehicle operates mainly for the purpose of traveling, and it is possible to dilute the exhaust gas using outside air introduced into the vehicle while the vehicle travels (using vehicle-induced wind introduced when the vehicle travels). In contrast, in the case of the construction machine used in a stationary state in an indoor construction site such as a construction site in a factory or warehouse, it is difficult to use the vehicle-induced wind, which makes it difficult to sufficiently dilute the exhaust gas. In particular, the exhaust gas stagnates at a particular position, which causes an increase in the risk of occurrence of an accident (risk of explosion).

However, according to the embodiment of the present disclosure, a part of the air, which is supplied to the fuel cell stack through the air supply line, is supplied to the discharge adapter configured to discharge the exhaust gas, such that the discharge adapter may discharge the exhaust gas and the air together. Therefore, it is possible to obtain an advantageous effect of reducing a hydrogen concentration in the exhaust gas discharged to the outlet of the discharge line even under a condition in which vehicle-induced wind cannot be used.

Among other things, according to the embodiment of the present disclosure, the exhaust gas (hydrogen) and the air are mixed by the discharge adapter. Therefore, it is possible to obtain an advantageous effect of reducing the hydrogen concentration of the exhaust gas and reducing the risk of explosion.

Moreover, according to the embodiment of the present disclosure, it is not necessary to additionally provide a separate fan (an air supply fan) for forcibly supplying the air to reduce the hydrogen concentration in the exhaust gas discharged from the fuel cell. Therefore, it is possible to obtain an advantageous effect of simplifying the structure and improving the degree of design freedom and the spatial utilization.

According to the exemplary embodiment of the present disclosure, the fuel cell system may include an air compressor connected to the air supply line and configured to compress the air to be supplied to the fuel cell stack.

The discharge adapter may have various structures capable of discharging the air and the exhaust gas together.

According to the invention, the discharge adapter includes: an adapter body having a discharge flow path communicating with the discharge line; an air inlet port provided in the adapter body and connected to the bypass line; and an adapter guide disposed on the adapter body and configured to define an air injection flow path separated from the discharge flow path and communicating with the air inlet port.

According to the exemplary embodiment of the present disclosure, the fuel cell system may include a valve unit connected to the discharge line and configured to selectively open or close the discharge line, and the discharge adapter may be connected to the valve unit.

The valve unit may have various structures capable of selectively opening or closing the discharge line. For example, the valve unit may include: a valve housing having a valve flow path communicating with the discharge line; and a valve member configured to selectively open or close the valve flow path.

According to the exemplary embodiment of the present disclosure, the adapter guide may be provided in the form of a continuous ring in a circumferential direction of the adapter body, and the air injection flow path may be provided in the form of a continuous ring in the circumferential direction of the adapter body.

In particular, an outlet of the discharge flow path and an outlet of the air injection flow path may be directed in the same direction.

According to the exemplary embodiment of the present disclosure, an inlet of the air inlet port may have a first cross-sectional area, and an outlet of the air injection flow path may have a second cross-sectional area smaller than the first cross-sectional area.

As described above, according to the embodiment of the present disclosure, the cross-sectional area of the outlet of the air injection flow path is smaller than the cross-sectional area of the inlet of the air inlet port. Therefore, a discharge velocity of the air discharged through the air injection flow path may be higher than an inflow velocity of the air introduced into the air inlet port. As a result, a pressure in the outlet region of the air injection flow path may be lower than a pressure in the valve flow path.

As a result, a pressure difference between the external pressure (the pressure in the outlet region of the air injection flow path) and the internal pressure (the internal pressure of the valve flow path) enables air adjacent to the periphery of the outlet of the air injection flow path to enter (move to) the outlet region of the air injection flow path where the pressure is relatively low. Therefore, the air injected through the air injection flow path and the air adjacent to the periphery of the outlet of the air injection flow path may be mixed in the exhaust gas discharged through the discharge flow path. Therefore, it is possible to obtain an advantageous effect of more effectively reducing the hydrogen concentration in the exhaust gas.

In particular, the air injection flow path may have a cross-sectional area that gradually decreases from an inlet end to an outlet end of the air injection flow path.

Since the air injection flow path has a cross-sectional area that gradually decreases from the inlet end to the outlet end as described above, the velocity (flow velocity) of the air passing through the air injection flow path may further increase. Therefore, it is possible to further increase the discharge velocity of the air discharged through the air injection flow path.

More particularly, the air injection flow path may have a streamlined cross-sectional shape.

As described above, according to the embodiment of the present disclosure, the air injection flow path has a streamlined cross-sectional shape having a cross-sectional area that gradually decreases from the inlet end to the outlet end. Therefore, the velocity of the air passing through the air injection flow path may gradually increase, and the pressure in the outlet region of the air injection flow path may more effectively decrease. As a result, it is possible to obtain an advantageous effect of maximizing the inflow amount of air to be introduced into the exhaust gas at the periphery of the outlet of the air injection flow path.

According to the exemplary embodiment of the present disclosure, the fuel cell system may include an inlet hole provided in the adapter body and configured to communicate with the discharge flow path and allow air outside the adapter body to be introduced thereinto.

As described above, according to the embodiment of the present disclosure, the inlet holes are provided in the adapter body, and the air outside the adapter body is introduced into the adapter body (the discharge flow path) through the inlet holes. Therefore, it is possible to obtain an advantageous effect of more effectively reducing the hydrogen concentration in the exhaust gas discharged through the discharge flow path.

In particular, the inlet hole may be provided in plural, and the plurality of inlet holes may be spaced apart from one another in a circumferential direction of the adapter body. Since the plurality of inlet holes is spaced apart from one another at uniform intervals in the circumferential direction of the adapter body as described above, the air may be uniformly introduced into the adapter body in the circumferential direction of the adapter body. Therefore, it is possible to obtain an advantageous effect of further improving efficiency in mixing the exhaust gas and the air.

According to the exemplary embodiment of the present disclosure, the fuel cell system may include a sealing member interposed between the valve housing and the discharge adapter.

Since the sealing member is provided between the valve housing and the discharge adapter as described above, it is possible to obtain an advantageous effect of minimizing leakage of the exhaust gas through the gap between the valve housing and the discharge adapter and improving safety and reliability.

According to the exemplary embodiment of the present disclosure, the fuel cell system may include: a fastening flap extending from an end of the discharge adapter and disposed to surround an outer peripheral surface of an outlet port of the valve housing; and a clamp member configured to lock the fastening flap to the outlet port.

In particular, according to the exemplary embodiment of the present disclosure, the fuel cell system may include a cut-out slit provided in the fastening flap. As described above, according to the embodiment of the present disclosure, the cut-out slit is provided in the fastening flap. Therefore, the cut-out slit may improve dynamic properties of the fastening flap relative to the discharge adapter (the properties that enable the fastening flap to move relative to the discharge adapter in the radial direction of the discharge adapter based on one end of the fastening flap connected to the discharge adapter).

According to the exemplary embodiment of the present disclosure, the fuel cell system may include: a catching protrusion provided on the outer peripheral surface of the outlet port; and a catching groove provided in an inner peripheral surface of the fastening flap and configured to accommodate the catching protrusion.

The catching protrusion provided on the outer peripheral surface of the outlet port is accommodated in the catching groove provided in the inner peripheral surface of the fastening flap when the fastening flap is disposed to surround the outer peripheral surface of the outlet port of the valve housing as described above. Therefore, it is possible to obtain an advantageous effect of stably maintaining an assembled state of the fastening flap and inhibiting the discharge adapter from separating from the valve housing.

Another exemplary embodiment of the present disclosure, which is not part of the claims, provides an exhaust gas treatment device including: a valve unit disposed in a discharge line for discharging exhaust gas discharged from a fuel cell stack and configured to selectively open or close the discharge line; and a discharge adapter connected to the valve unit and configured to discharge, to the outside, the exhaust gas together with air to be supplied to the fuel cell stack.

According to the exemplary embodiment of the present disclosure, the valve unit may include: a valve housing having a valve flow path communicating with the discharge line; and a valve member configured to selectively open or close the valve flow path.

According to the exemplary embodiment of the present disclosure, the discharge adapter may include: an adapter body having a discharge flow path communicating with the valve flow path; an air inlet port provided in the adapter body and configured to allow the air to be introduced thereinto; and an adapter guide disposed on the adapter body and configured to define an air injection flow path separated from the discharge flow path and communicating with the air inlet port.

According to the exemplary embodiment of the present disclosure, the exhaust gas treatment device may include: an inlet hole provided in the adapter body and configured to communicate with the discharge flow path and allow air outside the adapter body to be introduced thereinto.

According to the embodiment of the present disclosure described above, it is possible to obtain an advantageous effect of reducing a hydrogen concentration in the exhaust gas discharged from the fuel cell stack.

In particular, according to the embodiment of the present disclosure, it is possible to obtain an advantageous effect of reducing the hydrogen concentration in the exhaust gas discharged from the fuel cell stack even under the condition in which the vehicle-induced wind cannot be used.

In addition, according to the embodiment of the present disclosure, it is possible to obtain an advantageous effect of simplifying the structure and improving the spatial utilization and the degree of design freedom.

In addition, according to the embodiment of the present disclosure, it is possible to obtain an advantageous effect of improving safety and reliability.

In addition, according to the embodiment of the present disclosure, it is possible to obtain an advantageous effect of simplifying the manufacturing process and reducing the costs.

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

In addition, unless otherwise specifically and explicitly defined and stated, the terms (including technical and scientific terms) used in the embodiments of the present disclosure may be construed as the meaning which may be commonly understood by the person with ordinary skill in the art to which the present disclosure 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.

In addition, the terms used in the embodiments of the present disclosure are for explaining the embodiments, not for limiting the present disclosure.

In the present specification, 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.

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

These terms are used only for the purpose of 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.

Further, when one constituent element is described 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 still another constituent element interposed therebetween.

In addition, 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 to <FIG>, an exhaust gas treatment device <NUM> according to an embodiment of the present disclosure includes: a valve unit <NUM> disposed in a discharge line <NUM> through which exhaust gas EG discharged from a fuel cell stack is discharged, the valve unit <NUM> being configured to selectively open or close the discharge line <NUM>; and a discharge adapter <NUM> connected to the valve unit <NUM> and configured to discharge, to the outside, the exhaust gas EG together with air AG1 supplied to the fuel cell stack.

For reference, the exhaust gas treatment device <NUM> according to the embodiment of the present disclosure may be applied to treat the exhaust gas EG discharged from a fuel cell system <NUM> applied to mobility vehicles such as automobiles, ships, and airplanes. The present disclosure is not restricted or limited by types and properties of subjects (mobility vehicles) to which the exhaust gas treatment device <NUM> is applied.

Hereinafter, an example will be described in which the exhaust gas treatment device <NUM> according to the embodiment of the present disclosure is applied to the fuel cell system <NUM> provided in a construction machine (e.g., an excavator).

According to the exemplary embodiment of the present disclosure, the fuel cell system <NUM> includes: an air supply line <NUM> configured to supply the air to the fuel cell stack; the discharge line <NUM> connected to the fuel cell stack and configured to guide the exhaust gas EG discharged from the fuel cell stack; the discharge adapter <NUM> connected to the discharge line <NUM> and configured to discharge the exhaust gas EG to the outside; and a bypass line <NUM> having one end connected to the air supply line <NUM> and the other end connected to the discharge adapter <NUM>, the bypass line <NUM> being configured to selectively allow the air AG1 to flow from the air supply line <NUM> to the discharge adapter <NUM>.

The air supply line <NUM> is connected to a fuel cell stack <NUM> to supply the air to the fuel cell stack <NUM>.

The air supply line <NUM> may have various structures capable of supplying the air to the fuel cell stack <NUM>. The present disclosure is not restricted or limited by the structure of the air supply line <NUM>.

Referring to <FIG>, according to the exemplary embodiment of the present disclosure, the fuel cell system <NUM> may include an air compressor <NUM> connected to the air supply line <NUM> and configured to compress the air to be supplied to the fuel cell stack <NUM>.

The air compressor <NUM> compresses the air supplied through the air supply line <NUM> and supplies the air to the fuel cell stack <NUM>.

More specifically, the air compressor <NUM> may compress the air so that the air to be supplied to the fuel cell stack <NUM> may have a sufficient pressure that enables the air to pass through a flow path in the fuel cell stack <NUM>.

Various air compressors <NUM> capable of compressing air may be used as the air compressor <NUM>. The present disclosure is not restricted or limited by the type and structure of the air compressor <NUM>. For example, the air compressor <NUM> may be configured to compress and supply the air using a centrifugal force generated by a rotation of a rotor (not illustrated).

For reference, the fuel cell stack <NUM> refers to a kind of power generation device that generates electrical energy through a chemical reaction of fuel (e.g., hydrogen), and 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 capable of producing electricity by means of 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) (not illustrated) 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) (not illustrated) configured to uniformly distribute reactant gases and transfer generated electrical energy; a gasket (not illustrated) and a fastener (not illustrated) configured to maintain leakproof sealability for the reactant gases and a coolant and maintain an appropriate fastening pressure; and a separator (bipolar plate) (not illustrated) configured to move the reactant gases and the coolant.

More specifically, 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, thereby creating 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.

Meanwhile, the electrolyte membrane of the membrane electrode assembly needs to be maintained at a predetermined humidity or higher so that the fuel cell stack <NUM> normally operates.

To this end, the air supplied along the air supply line <NUM> may pass through a humidifier <NUM>, and the air to be supplied to the fuel cell stack <NUM> along the air supply line <NUM> may be humidified while passing through the humidifier <NUM>. In this case, the humidification of air is defined as a process of increasing the humidity of the air.

For example, the humidifier <NUM> may be configured to humidify air (dry air) to be supplied to the fuel cell stack <NUM> using air (moist air) discharged from the fuel cell stack <NUM>.

The humidifier <NUM> may have various structures capable of humidifying the dry air using the air (moist air) discharged from the fuel cell stack <NUM>. The present disclosure is not restricted or limited by the structure of the humidifier <NUM>.

According to the exemplary embodiment of the present disclosure, the humidifier <NUM> is disposed between the air compressor <NUM> and the fuel cell stack <NUM>. The humidifier <NUM> may include an inflow gas supply port (not illustrated) through which inflow gas (dry air) is introduced (supplied), an inflow gas discharge port (not illustrated) through which the (humidified) inflow gas having passed through the interior of the humidifier <NUM> is discharged, a moist air supply port (not illustrated) through which moist air discharged from the fuel cell stack <NUM> is supplied, and a moist air discharge port (not illustrated) through which the moist air, which has humidified the inflow gas, is discharged to the outside.

The inflow gas supplied through the inflow gas supply port may be humidified by the moist air while passing through a humidification membrane (e.g., a hollow fiber membrane) (not illustrated) disposed in the humidifier <NUM>. Then, the inflow gas may be supplied to the fuel cell stack <NUM> through the inflow gas discharge port.

Further, the moist air (or the condensate water) discharged from the fuel cell stack <NUM> may be supplied to the moist air supply port, humidify the inflow gas in the humidifier <NUM>, and then be discharged to the outside through the moist air discharge port.

According to the exemplary embodiment of the present disclosure, the fuel cell system <NUM> may include an air control valve <NUM> configured to control the air entering and exiting the fuel cell stack <NUM> (the air to be introduced into the fuel cell stack and the air to be discharged from the fuel cell stack).

Various valves capable of selectively blocking the air entering and exiting the fuel cell stack <NUM> may be used as the air control valve <NUM>. The present disclosure is not restricted or limited by the type and structure of the air control valve <NUM>. For example, the air control valve <NUM> may include a first valve member (not illustrated) and a second valve member (not illustrated) that are configured to open or close a first port (not illustrated) through which the air is supplied to the fuel cell stack <NUM> and a second port (not illustrated) through which the air is discharged from the fuel cell stack <NUM>.

The discharge line <NUM> is connected to the fuel cell stack <NUM> to discharge, to the outside, the exhaust gas EG (e.g., air and hydrogen) discharged from the fuel cell stack <NUM>.

The discharge line <NUM> may have various structures capable of guiding the exhaust gas EG discharged from the fuel cell stack <NUM>. The present disclosure is not restricted or limited by the structure of the discharge line <NUM>.

For example, the exhaust gas EG discharged along the discharge line <NUM> may pass through the humidifier <NUM>. The air (dry air) introduced into the humidifier <NUM> may be humidified by the exhaust gas EG (moist air contained in the exhaust gas) passing through the humidifier <NUM>.

The discharge adapter <NUM> is configured to discharge, to the outside, the exhaust gas EG together with the air AG1 supplied to the fuel cell stack <NUM>. The bypass line <NUM> connects the air supply line <NUM> and the discharge adapter <NUM> (the discharge line) and selectively allows the air AG1 to flow from the air supply line <NUM> to the discharge adapter <NUM>.

This is to reduce the hydrogen concentration in the exhaust gas EG discharged through the discharge line <NUM>.

That is, hydrogen may be contained in the exhaust gas EG discharged from the fuel cell stack <NUM> (e.g., the exhaust gas discharged during a purge process for adjusting a hydrogen concentration in the fuel cell stack). When a hydrogen concentration in the exhaust gas EG increases to a certain level or higher, the risk of explosion increases. Therefore, the hydrogen concentration in the exhaust gas EG discharged from the fuel cell needs to be maintained at a predetermined level or lower.

In the embodiment of the present disclosure, a part of the air AG1, which is to be supplied to the fuel cell stack <NUM> along the air supply line <NUM>, is supplied to the discharge adapter <NUM> through the bypass line <NUM>. Therefore, it is possible to obtain an advantageous effect of reducing the hydrogen concentration in the exhaust gas EG discharged through the discharge line <NUM>.

Among other things, according to the embodiment of the present disclosure, the exhaust gas EG (e.g., hydrogen) discharged through the discharge line <NUM> and the air AG1 supplied through the bypass line <NUM> are mixed by the discharge adapter <NUM>. Therefore, it is possible to obtain an advantageous effect of reducing the hydrogen concentration in the exhaust gas EG and reducing the risk of explosion even under a condition in which vehicle-induced wind cannot be used (e.g., in a state in which a construction machine is stationary).

The bypass line <NUM> may be connected in various manners in accordance with required conditions and design specifications. The present disclosure is not restricted or limited by the structure for connecting the bypass line <NUM>.

For example, according to the exemplary embodiment of the present disclosure, the fuel cell system <NUM> may include a supply adapter <NUM> provided on the air compressor <NUM>. The bypass line <NUM> may be connected to the air supply line <NUM> through the supply adapter <NUM>.

According to another embodiment of the present disclosure, the bypass line may be connected directly to the air supply line without separately providing the supply adapter.

The supply adapter <NUM> may have various structures capable of being connected to the air compressor <NUM>. The present disclosure is not restricted or limited by the structure and shape of the supply adapter <NUM>.

For example, referring to <FIG>, the supply adapter <NUM> may include a first supply port <NUM> communicating with the air supply line <NUM>, and a second supply port <NUM> communicating with the bypass line <NUM>.

For example, the first supply port <NUM> and the second supply port <NUM> may each have a straight shape. According to another embodiment of the present disclosure, the first supply port and the second supply port may each have a curved shape or other shapes.

Hereinafter, an example will be described in which the supply adapter <NUM> has three second supply ports <NUM> that communicate with the first supply port <NUM> and are disposed in an approximately 'T' shape.

For reference, <FIG> illustrates an example in which only two second supply ports <NUM>, among the three second supply ports <NUM>, are connected to the bypass lines <NUM>. However, the bypass lines <NUM> may be substantially and respectively connected to the second supply ports. According to another embodiment of the present disclosure, the supply adapter may have two or less second supply ports or four or more second supply ports.

In particular, an on-off valve <NUM> for selectively opening or closing the second supply port <NUM> may be integrally provided on a lateral portion of the supply adapter <NUM>.

Various valve means capable of selectively opening or closing the second supply port <NUM> may be used as the on-off valve <NUM>. The present disclosure is not restricted or limited by the type and structure of the on-off valve <NUM>. For example, a typical solenoid valve, a butterfly valve, or the like may be used as the on-off valve <NUM>.

With this configuration, in a state in which the on-off valve <NUM> closes the second supply port <NUM>, the air compressed by the air compressor <NUM> may be supplied to the fuel cell stack <NUM> through the first supply port <NUM>. In contrast, in a state in which the on-off valve <NUM> opens the second supply port <NUM>, a part of the air compressed by the air compressor <NUM> is supplied to the fuel cell stack <NUM> through the first supply port <NUM>, and another part AG1 of the air compressed by the air compressor <NUM> may be supplied to the bypass line <NUM> through the second supply port <NUM> (see <FIG>).

The discharge adapter <NUM> may have various structures capable of discharging the air AG1 and the exhaust gas EG. The present disclosure is not restricted or limited by the structure of the discharge adapter <NUM>.

For example, referring to <FIG>, the discharge adapter <NUM> includes an adapter body <NUM> having a discharge flow path 222a communicating with the discharge line <NUM>, air inlet ports <NUM> provided in the adapter body <NUM> and connected to the bypass lines <NUM>, and an adapter guide <NUM> provided in the adapter body <NUM> and configured to define an air injection flow path 226a separated from the discharge flow path 222a and communicating with the air inlet port <NUM>.

Hereinafter, an example will be described in which the fuel cell system <NUM> includes the valve unit <NUM> connected to the discharge line <NUM> to selectively open or close the discharge line <NUM>, and the discharge adapter <NUM> is connected to the valve unit <NUM>. According to another embodiment of the present disclosure, the discharge adapter may be connected directly to the discharge line without the valve unit.

The valve unit <NUM> may have various structures capable of selectively opening or closing the discharge line <NUM>. The present disclosure is not restricted or limited by the structure of the valve unit <NUM>.

For example, the valve unit <NUM> may include a valve housing <NUM> having a valve flow path 212a communicating with the discharge line <NUM>, and a valve member <NUM> configured to selectively open or close the valve flow path 212a.

For example, the valve housing <NUM> may have a hollow cylindrical shape and include the valve flow path 212a having an approximately straight shape.

A typical solenoid valve, a butterfly valve, or the like, capable of opening or closing the valve flow path 212a, may be used as the valve member <NUM>. The present disclosure is not restricted or limited by the type and structure of the valve member <NUM>.

With this configuration, in a state in which the valve member <NUM> opens the valve flow path 212a, the exhaust gas EG discharged from the fuel cell stack <NUM> may be discharged to the outside through the valve flow path 212a. In contrast, in a state in which the valve member <NUM> closes the valve flow path 212a, the discharge of the exhaust gas EG through the valve flow path 212a may be blocked.

The adapter body <NUM> may have various structures having the discharge flow path 222a communicating with the discharge line <NUM>. The present disclosure is not restricted or limited by the structure and shape of the adapter body <NUM>.

For example, the adapter body <NUM> may have a circular cross-section with an approximately hollow cylindrical shape, and an approximately straight discharge flow path 222a may be defined along the interior of the adapter body <NUM>. According to another embodiment of the present disclosure, the adapter body may have a quadrangular cross-sectional shape or other cross-sectional shapes. Alternatively, the discharge flow path may have a curved shape or other shapes.

The air inlet port <NUM> is provided in the adapter body <NUM> and connected to (communicates with) the bypass line <NUM>.

For example, the adapter body <NUM> may have two air inlet ports <NUM>, and the bypass lines <NUM> may be respectively connected to the air inlet ports <NUM>. According to another embodiment of the present disclosure, the adapter body may have a single air inlet port or three or more air inlet ports.

For example, the air inlet port <NUM> may be perpendicularly connected to the adapter body <NUM>. The air AG1 introduced into the air inlet port <NUM> through the bypass line <NUM> may be discharged to the outside of the adapter body <NUM> through the air injection flow path 226a.

The adapter guide <NUM> is disposed outside the adapter body <NUM> to define the air injection flow path 226a separated from the discharge flow path 222a and communicating with the air inlet port <NUM>.

The adapter guide <NUM> may have various structures capable of defining the air injection flow path 226a. The present disclosure is not restricted or limited by the structure and shape of the adapter guide <NUM>.

For example, the adapter guide <NUM> may be disposed on an inner peripheral surface of the adapter body <NUM> and provided in the form of a continuous ring defined in a circumferential direction of the adapter body <NUM>. The air injection flow path 226a is provided in the form of a continuous ring defined in the circumferential direction of the adapter body <NUM> and disposed to surround the entire periphery of the discharge flow path 222a.

In particular, an outlet of the discharge flow path 222a and an outlet of the air injection flow path 226a may be directed in the same direction. For example, the outlet of the discharge flow path 222a may be disposed at a distal end (a left end based on <FIG>) of the adapter body <NUM>. The outlet of the air injection flow path 226a may be disposed at a distal end (a left end based on <FIG>) of the adapter guide <NUM> so as to be directed in the same direction as the outlet of the discharge flow path 222a.

As described above, according to the embodiment of the present disclosure, the adapter guide <NUM> has the discharge flow path 222a and the air injection flow path 226a, and the air AG1 (the air supplied through the bypass line) and the exhaust gas EG are discharged together through the adapter guide <NUM>, such that the exhaust gas EG discharged through the discharge flow path 222a may be mixed with the air AG1 supplied through the bypass line <NUM>. Therefore, it is possible to obtain an advantageous effect of reducing the hydrogen concentration in the exhaust gas EG.

More particularly, an outlet end of the discharge flow path 222a may be disposed at the distal end of the adapter body <NUM>. An outlet end of the air injection flow path 226a may be disposed at the distal end of the adapter guide <NUM> and provided on the same line as the outlet end of the discharge flow path 222a.

In this case, the configuration in which the outlet end of the discharge flow path 222a (the left end of the discharge flow path based on <FIG>) is provided on the same line as the outlet end of the air injection flow path 226a (the left end of the air injection flow path based on <FIG>) may mean that a start point from which the exhaust gas EG is discharged through the discharge flow path 222a is identical to a start point from which the air AG1 is discharged through the air injection flow path 226a.

Since the outlet end of the discharge flow path 222a and the outlet end of the discharge flow path 222a are provided on the same line as described above, the exhaust gas EG may be discharged through the discharge flow path 222a and then immediately mixed with the air AG1 discharged through the air injection flow path 226a.

In the embodiment of the present disclosure illustrated and described above, the example has been described in which the adapter guide <NUM> is provided in the form of a continuous ring to surround the entire inner peripheral surface of the adapter body <NUM>. However, according to another embodiment of the present disclosure, the adapter guide may partially surround a part of the inner peripheral surface of the adapter body.

According to the exemplary embodiment of the present disclosure, an inlet of the air inlet port <NUM> may have a first cross-sectional area, and the outlet of the air injection flow path 226a may have a second cross-sectional area smaller than the first cross-sectional area.

This is to increase a discharge velocity of the air AG1 discharged through the air injection flow path 226a and decrease a pressure in an outlet region of the air injection flow path 226a. In this case, the outlet region of the air injection flow path 226a may be understood as a region in which the air AG1 is injected through the outlet of the air injection flow path 226a (an outer region adjacent to the outlet of the air injection flow path).

In addition, according to the Bernoulli's theorem, it can be seen that a pressure of the fluid (air) decreases as the velocity (flow velocity) of the fluid (air) moving along the flow path (air injection flow path) increases. That is, according to the Bernoulli's theorem, it can be seen that when a flow rate Q of a fluid (air) supplied to a flow path (air injection flow path) is constant, a cross-sectional area of the flow path (air injection flow path) is inversely proportional to a velocity (flow velocity) of the fluid (air) moving along the flow path (air injection flow path).

As described above, according to the embodiment of the present disclosure, the cross-sectional area (e.g., A2) of the outlet of the air injection flow path 226a is smaller than the cross-sectional area (e.g., A1) of the inlet of the air inlet port <NUM> (A2 < A1). Therefore, the discharge velocity (e.g., V2) of the air AG1 discharged through the air injection flow path 226a may be higher than an inflow velocity (e.g., V1) of the air introduced into the air inlet port <NUM> (V2 > V1). As a result, a pressure (hereinafter, referred to as an 'external pressure') (e.g., P2) in the outlet region of the air injection flow path 226a may be lower than a pressure (hereinafter, referred to as an 'internal pressure') (e.g., P1) in the valve flow path 212a (P2 < P1). For example, when the internal pressure of the valve flow path 212a (a discharge pressure of the exhaust gas) is a first pressure P1, the pressure in the outlet region of the air injection flow path 226a may be a second pressure P2 lower than the first pressure.

As a result, a pressure difference between the external pressure (the pressure in the outlet region of the air injection flow path) and the internal pressure (the internal pressure of the valve flow path) (the external pressure of the air injection flow path is lower than the internal pressure of the valve flow path) enables air AG2' adjacent to the periphery of the outlet of the air injection flow path 226a to enter (move to) the outlet region of the air injection flow path 226a where the pressure is relatively low.

Therefore, the air AG1 injected through the air injection flow path 226a and the air AG2' adjacent to the periphery of the outlet of the air injection flow path 226a may be mixed in the exhaust gas EG discharged through the discharge flow path 222a. Therefore, it is possible to obtain an advantageous effect of more effectively reducing the hydrogen concentration in the exhaust gas EG.

In particular, the air injection flow path 226a may have a cross-sectional area that gradually decreases from the inlet end to the outlet end.

For example, based on <FIG>, the air injection flow path 226a may have a cross-sectional area that gradually decreases from the right end to the left end.

Since the air injection flow path 226a has a cross-sectional area that gradually decreases from the inlet end to the outlet end as described above, the velocity (flow velocity) of the air AG1 passing through the air injection flow path 226a may further increase. Therefore, it is possible to further increase the discharge velocity (e.g., V2) of the air AG1 discharged through the air injection flow path 226a (decrease the pressure in the outlet region of the air injection flow path).

More particularly, the air injection flow path 226a may have a streamlined cross-sectional shape.

As described above, according to the embodiment of the present disclosure, the air injection flow path 226a has a streamlined cross-sectional shape having a cross-sectional area that gradually decreases from the inlet end to the outlet end. Therefore, the velocity of the air AG1 passing through the air injection flow path 226a may gradually increase, and the pressure in the outlet region of the air injection flow path 226a may more effectively decrease. As a result, it is possible to obtain an advantageous effect of maximizing the inflow amount of air AG2' to be introduced into the exhaust gas EG at the periphery of the outlet of the air injection flow path 226a (the exhaust gas discharged through the discharge flow path).

According to the exemplary embodiment of the present disclosure, the fuel cell system <NUM> may include inlet holes <NUM> provided in the adapter body <NUM> and configured to communicate with the discharge flow path 222a and allow air AG2 outside of the adapter body <NUM> to be introduced into the adapter body <NUM>.

For example, the inlet holes <NUM> may be provided in the adapter body <NUM> and disposed between the air inlet port <NUM> and the inlet end (the right end based on <FIG>) of the discharge flow path 222a.

According to another embodiment of the present disclosure, the inlet hole may be provided in the air inlet port of the outlet end of the discharge flow path or positioned at other positions.

The inlet hole <NUM> may have various structures capable of allowing the outside air AG2 of the adapter body <NUM> (the air outside the outer peripheral surface of the adapter body) to be introduced thereinto. The present disclosure is not restricted or limited by the structure and shape of the inlet hole <NUM>.

For example, the inlet hole <NUM> may be provided in the form of a long hole with a length longer than a width thereof. Alternatively, the inlet hole <NUM> may be provided in the form of a circular hole, a quadrangular hole, or the like.

As described above, according to the embodiment of the present disclosure, the inlet holes <NUM> are provided in the adapter body <NUM>, and the air AG2 outside the adapter body <NUM> is introduced (drawn) into the adapter body <NUM> (the discharge flow path) through the inlet holes <NUM> before the exhaust gas EG is discharged to the outside of the adapter body <NUM>. Therefore, it is possible to obtain an advantageous effect of more effectively reducing the hydrogen concentration in the exhaust gas EG finally discharged through the discharge flow path 222a.

In particular, the inlet hole <NUM> may be provided in plural, and the plurality of inlet holes <NUM> may be spaced apart from one another at uniform intervals in the circumferential direction of the adapter body <NUM>. Since the plurality of inlet holes <NUM> is spaced apart from one another at uniform intervals in the circumferential direction of the adapter body <NUM> as described above, the air AG2 may be uniformly introduced into the adapter body <NUM> in the circumferential direction of the adapter body <NUM>. Therefore, it is possible to obtain an advantageous effect of further improving efficiency in mixing the exhaust gas EG and the air AG2.

According to the exemplary embodiment of the present disclosure, the fuel cell system <NUM> may include a sealing member <NUM> interposed between the valve housing <NUM> and the discharge adapter <NUM>.

The sealing member <NUM> may have various structures capable of sealing a gap between the valve housing <NUM> and the discharge adapter <NUM>. The present disclosure is not restricted or limited by the structure of the sealing member <NUM>.

For example, the sealing member <NUM> may have an approximately ring shape and be interposed between the valve housing <NUM> and the discharge adapter <NUM>.

The sealing member <NUM> may be made of an elastic material such as silicone or urethane. The present disclosure is not restricted or limited by the material and properties of the sealing member <NUM>.

Since the sealing member <NUM> is provided between the valve housing <NUM> and the discharge adapter <NUM> as described above, it is possible to obtain an advantageous effect of minimizing leakage of the exhaust gas EG through the gap between the valve housing <NUM> and the discharge adapter <NUM> and improving safety and reliability.

Meanwhile, the structure for coupling the valve unit <NUM> and the discharge adapter <NUM> may be variously changed in accordance with required conditions and design specifications. The present disclosure is not restricted or limited by the structure for coupling the valve unit <NUM> and the discharge adapter <NUM>.

For example, referring to <FIG>, according to the exemplary embodiment of the present disclosure, the fuel cell system <NUM> may include: a fastening flap 222b extending from an end of the discharge adapter <NUM> and disposed to surround an outer peripheral surface of an outlet port 212b of the valve housing <NUM>; and a clamp member <NUM> configured to lock the fastening flap 222b to the outlet port 212b.

The fastening flap 222b may have various structures capable of surrounding the outer peripheral surface of the outlet port 212b of the valve housing <NUM>. The present disclosure is not restricted or limited by the structure of the fastening flap 222b.

For example, the fastening flap 222b may extend from the end of the discharge adapter <NUM> and have an inner peripheral surface that may come into close contact with the outer peripheral surface of the valve housing <NUM>.

In particular, according to the exemplary embodiment of the present disclosure, the fuel cell system <NUM> may include a cut-out slit 222c provided in the fastening flap 222b.

The cut-out slit 222c may have various structures in accordance with required conditions and design specifications. The present disclosure is not restricted or limited by the structure and shape of the cut-out slit 222c.

For example, the cut-out slit 222c may be provided by removing (cutting) a part of the fastening flap 222b in the longitudinal direction of the discharge adapter <NUM>. The cut-out slit 222c may be provided in plural, and the plurality of cut-out slits 222c may be spaced apart from one another in the circumferential direction of the discharge adapter <NUM>.

According to another embodiment of the present disclosure, the cut-out slit may be provided in the fastening flap in another direction. Alternatively, the cut-out slit may have a curved shape such as an 'S' shape or a 'C' shape.

As described above, according to the embodiment of the present disclosure, the cut-out slit 222c is provided in the fastening flap 222b. Therefore, the cut-out slit 222c may improve dynamic properties of the fastening flap 222b relative to the discharge adapter <NUM> (the properties that enable the fastening flap to move relative to the discharge adapter in the radial direction of the discharge adapter based on one end of the fastening flap connected to the discharge adapter).

The clamp member <NUM> may have various structures capable of locking the fastening flap 222b to the outlet port 212b of the valve housing <NUM>. The present disclosure is not restricted or limited by the structure of the clamp member <NUM>.

For example, the clamp member <NUM> may be made by winding a metal wire in the form of a coil (e.g., in the form of a coil spring).

According to another embodiment of the present disclosure, the clamp member may be configured by assembling a plurality of clamp bands each having a circular arc shape.

In particular, the fuel cell system <NUM> may include a catching protrusion 212c protruding from an outer peripheral surface of the outlet port 212b, and a catching groove 222d provided in an inner peripheral surface of the fastening flap 222b and configured to accommodate the catching protrusion 212c.

The catching protrusion 212c provided on the outer peripheral surface of the outlet port 212b is accommodated in the catching groove 222d provided in the inner peripheral surface of the fastening flap 222b when the fastening flap 222b is disposed to surround the outer peripheral surface of the outlet port 212b of the valve housing <NUM> as described above. Therefore, it is possible to obtain an advantageous effect of stably maintaining an assembled state of the fastening flap 222b (a state in which the fastening flap is disposed to surround the outer peripheral surface of the outlet port of the valve housing) and inhibiting the discharge adapter <NUM> from separating from the valve housing <NUM>.

Meanwhile, <FIG> is a block diagram for explaining a method of controlling the fuel cell system according to the embodiment of the present disclosure. Further, the parts identical and equivalent to the parts in the above-mentioned configuration will be designated by the identical or equivalent reference numerals, and detailed descriptions thereof will be omitted.

Referring to <FIG>, according to the exemplary embodiment of the present disclosure, the method of controlling the fuel cell system <NUM> may include a step S <NUM> of opening the valve unit <NUM>, a step S20 of opening the on-off valve <NUM>, a step S30 of increasing a rotational speed (RPM) of the air compressor <NUM>, a step S40 of closing the valve unit <NUM>, a step S50 of closing the on-off valve <NUM>, and a step S60 of restoring the air compressor <NUM> to a normal operation mode.

First, when it is determined that a hydrogen concentration in the exhaust gas EG discharged to the outside is higher than a preset reference concentration, the valve unit <NUM> is opened (the valve flow path is opened), and the on-off valve <NUM> is opened. As a result, a part of the air compressed by the air compressor <NUM> may be supplied to the fuel cell stack <NUM>, and another part of the air compressed by the air compressor <NUM> may be supplied to the bypass line <NUM>.

After the valve unit <NUM> and the on-off valve <NUM> are opened, the air compressor <NUM> performs a supercharging operation by increasing the RPM of the air compressor <NUM> (e.g., revolutions per minute of the rotor) by corresponding to a flow rate of the air flowing through the bypass line <NUM>. Since the RPM of the air compressor <NUM> is increased in the state in which the valve unit <NUM> and the on-off valve <NUM> are opened as described above, a sufficient amount of air may be supplied to the fuel cell stack <NUM> (an amount of air required for the normal operation of the fuel cell stack may be supplied) even under the condition in which the air AG1 is supplied through the bypass line <NUM>.

Thereafter, when it is determined that the hydrogen concentration in the exhaust gas EG is lower than the preset reference concentration, the valve unit <NUM> and the on-off valve <NUM> may be closed, and the air compressor <NUM> may be restored to the normal operation mode (the RPM of the air compressor may be decreased).

Claim 1:
A fuel cell system (<NUM>) comprising:
an air supply line (<NUM>) configured to supply air to a fuel cell stack (<NUM>);
a discharge line (<NUM>) connected to the fuel cell stack (<NUM>) and configured to guide an exhaust gas discharged from the fuel cell stack (<NUM>);
a discharge adapter (<NUM>) connected to the discharge line (<NUM>) and configured to discharge the exhaust gas to the outside of the fuel cell system (<NUM>); and
a bypass line (<NUM>) having one end connected to the air supply line (<NUM>) and the other end connected to the discharge adapter (<NUM>), the bypass line (<NUM>) being configured to selectively allow the air to flow from the air supply line (<NUM>) to the discharge adapter (<NUM>),
wherein the discharge adapter (<NUM>) comprises:
an adapter body (<NUM>) having a discharge flow path (222a) communicating with the discharge line (<NUM>);
an air inlet port (<NUM>) provided in the adapter body (<NUM>) and connected to the bypass line (<NUM>);
characterized by
an adapter guide (<NUM>) disposed on the adapter body (<NUM>) and configured to define an air injection flow path (226a) separated from the discharge flow path (222a) and communicating with the air inlet port (<NUM>).