Abstract: An ejector has a variable nozzle structure and is installed in a fuel cell recirculation line to supply new hydrogen and a recirculation gas. The ejector includes: a first housing having a first hole through which hydrogen is supplied and an orifice through which the hydrogen is discharged; a second housing disposed in the first housing and having a second hole into which the hydrogen passing through the first hole flows; and a poppet penetrating a third hole defined at one side of the second housing. The poppet is configured to adjust an area of a space opened by the orifice discharging the hydrogen. The hydrogen flowing into the second housing is discharged through a space between the other side opposite to the one side of the second housing and the poppet to move to the orifice.

Abstract: A fuel cell system includes: a supply flow path configured to supply reactant gas; a first branch flow path branching off from an outlet end of the supply flow path and configured to guide the reactant gas to a first fuel cell stack; a second branch flow path branching off from the outlet end of the supply flow path and configured to communicate with the first branch flow path and guide the reactant gas to a second fuel cell stack; and an inlet area change part disposed in a boundary zone between the first branch flow path and the second branch flow path and configured to selectively change inlet areas of the first and second branch flow paths. Efficiency in discharging condensate water is increased and performance and operational efficiency are improved.

Abstract: An ejector has a two-stage nozzle structure. The ejector is installed on a fuel cell recirculation line to supply new hydrogen and a recirculation gas. The ejector includes a housing having a first orifice defined therein and a poppet that is disposed in the housing and having a second orifice defined therein. A damage prevention member is disposed on a surface of the poppet to contact an inner surface of the housing, in which the damage prevention member contacts or is separated from the inner surface of the housing based on a pressure applied to the poppet.

Abstract: An ejector has a variable nozzle structure and is installed in a fuel cell recirculation line to supply new hydrogen and a recirculation gas. The ejector includes: a first housing having a first hole through which hydrogen is supplied and an orifice through which the hydrogen is discharged; a second housing disposed in the first housing and having a second hole into which the hydrogen passing through the first hole flows; and a poppet penetrating a third hole defined at one side of the second housing. The poppet is configured to adjust an area of a space opened by the orifice discharging the hydrogen. The hydrogen flowing into the second housing is discharged through a space between the other side opposite to the one side of the second housing and the poppet to move to the orifice.

Abstract: A solenoid valve includes a valve housing having a first space that communicates with an inlet flow path and a second space that communicates with an outlet flow path. A solenoid is provided in the valve housing to surround the first space. A flow path guide is provided in the first space and has an inflow path communicating with the first space. A plunger is rectilinearly moved in the flow path guide by the solenoid. A valve member is connected to the plunger and opens or closes the outlet flow path based on a plunger movement. A spring member provides elastic force allowing the valve member to move in a direction in which the valve member blocks the outlet flow path. A fluid guide part is formed in the plunger and guides a fluid, supplied into the inflow path via the first space, selectively to the second space.

Abstract: A method of measuring a water level in a water trap of a fuel cell system, the method including outputting a detected water level of a capacitive level sensor having a plurality of electrodes in the water trap. The method includes resetting a reference output value of each electrode and determining the water level depending on the speed at which water is introduced while detecting the water level in the water trap depending on an output value measured by the plurality of electrodes. Thereby, the influence of temperature and electrode differences is removed.

Abstract: A discharge valve is provided in a recirculation line through which gas discharged from a fuel cell stack recirculates to the stack. The discharge valve opens or closes a discharge line through which a fluid in the recirculation line is discharged. The discharge valve includes a valve body connected to the discharge line and a drive part disposed in the valve body to be movable vertically. A diaphragm is coupled to a lower end of the drive part and selectively opens or closes the discharge line based on the vertical movement. The drive part switches between a closed state in which the discharge line is closed by the diaphragm, a first opened state in which the discharge line is opened to a first opening degree, and a second opened state in which the discharge line is opened to a second opening degree greater than the first opening degree.

Abstract: A solenoid valve includes a valve housing having a first space that communicates with an inlet flow path and a second space that communicates with an outlet flow path. A solenoid is provided in the valve housing to surround the first space. A flow path guide is provided in the first space and has an inflow path communicating with the first space. A plunger is rectilinearly moved in the flow path guide by the solenoid. A valve member is connected to the plunger and opens or closes the outlet flow path based on a plunger movement. A spring member provides elastic force allowing the valve member to move in a direction in which the valve member blocks the outlet flow path. A fluid guide part is formed in the plunger and guides a fluid, supplied into the inflow path via the first space, selectively to the second space.

Abstract: A discharge valve is provided in a recirculation line through which gas discharged from a fuel cell stack recirculates to the stack. The discharge valve opens or closes a discharge line through which a fluid in the recirculation line is discharged. The discharge valve includes a valve body connected to the discharge line and a drive part disposed in the valve body to be movable vertically. A diaphragm is coupled to a lower end of the drive part and selectively opens or closes the discharge line based on the vertical movement. The drive part switches between a closed state in which the discharge line is closed by the diaphragm, a first opened state in which the discharge line is opened to a first opening degree, and a second opened state in which the discharge line is opened to a second opening degree greater than the first opening degree.

Abstract: Disclosed are a chemochromic nanoparticle, a method for manufacturing the chemochromic nanoparticle, and a hydrogen sensor comprising the chemochromic nanoparticle. In particular, the chemochromic nanoparticle has a core-shell structure such that the chemochromic nanoparticle and comprises a core comprising a hydrated or non-hydrated transition metal oxide; and a shell comprising a transition metal catalyst.

Abstract: A fuel supply valve is provided. The fuel supply valve includes a housing of the valve, a plunger and a hollow part. A cavity where the plunger moves is formed at one side of the housing and a contact area is formed between the housing and the plunger based on the movement of the plunger. Accordingly, fuel flow in the cavity is limited by the contact.

Abstract: An apparatus for discharging a condensate of a fuel cell stack, the apparatus includes a condensate storage container for storing the condensate from the fuel cell stack, a condensate level detector for detecting a condensate level in the condensate storage container, a discharge valve configured to be opened and closed to discharge the condensate from the condensate storage container, and a control unit for setting a condensate discharge level differently according to currents of the fuel cell stack, and for controlling the discharge valve to be opened when a condensate level measured by the condensate level detector reaches the condensate discharge level.

Abstract: The present invention provides a method of outputting a level of a capacitive level sensor which may be provided in a water trap of a fuel cell system and the method of outputting a level of a capacitive level sensor including a level sensor including a plurality of electrodes for measuring capacitance, and an upper electrode and a lower electrode which are able to be disposed adjacent to each other in the level sensor, including: (a) measuring a change in an output value of the lower electrode; and (b) measuring a change in an output value of the upper electrode.

Abstract: A fuel cell system including a hydrogen shut-off valve and a hydrogen supply valve connected therewith, the fuel cell system including: a holder capable of accommodating the hydrogen supply valve, wherein the holder includes a rupture part which may be formed at one point between the hydrogen supply valve and the hydrogen shut-off valve, and the hydrogen shut-off valve may be accommodated in one or more extended ends of the holder, and when the rupture part is cut off by external shock the hydrogen shut-off valve and the hydrogen supply valve are disconnected from each other.

Abstract: A method of measuring a water level in a water trap of a fuel cell system, the method including outputting a detected water level of a capacitive level sensor having a plurality of electrodes in the water trap. The method includes resetting a reference output value of each electrode and determining the water level depending on the speed at which water is introduced while detecting the water level in the water trap depending on an output value measured by the plurality of electrodes. Thereby, the influence of temperature and electrode differences is removed.

Abstract: An anode discharge valve for a fuel cell system includes a valve main body which is installed in a hydrogen recirculation line of a fuel cell stack; a drive shaft which is rotatably installed in the valve main body, and coupled to an opening member which selectively opens a hydrogen discharge port by being rotated; and a mechanism which is connected to a hydrogen inlet port of the valve main body so as to form a hydrogen inflow path, and operates to rotate the drive shaft as a pressure of hydrogen inflowing through the hydrogen inflow path increases.

Abstract: A recycling system in which anode off gas of a fuel cell is recycled to a stack includes a purge flow path purging the anode off gas passing through the stack, and a sprayer spraying pure gas supplied from a fuel tank to the stack. The sprayer is disposed on a path where the anode off gas passing through the stack is discharged, the purge flow path is spaced a certain distance from the sprayer, and the anode off gas passing through the stack is mixed with the pure gas by suction force of the sprayer to be introduced to the stack, thereby being recycled.

Abstract: An apparatus for discharging a condensate of a fuel cell stack, the apparatus includes a condensate storage container for storing the condensate from the fuel cell stack, a condensate level detector for detecting a condensate level in the condensate storage container, a discharge valve configured to be opened and closed to discharge the condensate from the condensate storage container, and a control unit for setting a condensate discharge level differently according to currents of the fuel cell stack, and for controlling the discharge valve to be opened when a condensate level measured by the condensate level detector reaches the condensate discharge level.

Abstract: The present invention provides a method of outputting a level of a capacitive level sensor which may be provided in a water trap of a fuel cell system and the method of outputting a level of a capacitive level sensor including a level sensor including a plurality of electrodes for measuring capacitance, and an upper electrode and a lower electrode which are able to be disposed adjacent to each other in the level sensor, including: (a) measuring a change in an output value of the lower electrode; and (b) measuring a change in an output value of the upper electrode.

Abstract: A valve for a fuel cell serves to discharge a fluid in a fuel cell system to the outside or other locations of the fuel cell system. The valve is mounted with a pressure transmission unit which is connected between a valve flow path unit having an inner flow path for moving a fluid and a solenoid unit for generating power for opening and closing the inner flow path of the valve flow path unit, and transmits pressure between the valve flow path unit and the solenoid unit, so as to minimize an operating load of the solenoid unit by minimizing a pressure difference between the valve flow path unit and the solenoid unit, regardless of factors such as working pressure and a temperature in the fuel cell system.