Abstract: A method and a system for diagnosing a failure of a temperature sensor for a fuel cell are provided. The method includes calculating a heating value that is generated at a fuel cell stack during a predetermined diagnosis time and then calculating a temperature variation of the fuel cell stack from the calculated heating value. A failure of a temperature sensor configured to measure a temperature of the fuel cell stack is then detected based on the calculated temperature variation of the fuel cell stack.

Abstract: A water removing system and method of a fuel cell vehicle using impedance are provided. The system measures measure the low frequency impedance of a fuel cell stack when a fuel cell system is stopped in a low temperature condition, and adjusts the air supply amount and supply time for removing the water supercharged into the fuel cell stack using the measured low frequency impedance. Thus, air is prevented from being unnecessarily supercharged into the fuel cell stack and at the same time, the water remaining in the fuel cell stack is removed.

Abstract: A water removing system and method of a fuel cell vehicle using impedance are provided. The system measures measure the low frequency impedance of a fuel cell stack when a fuel cell system is stopped in a low temperature condition, and adjusts the air supply amount and supply time for removing the water supercharged into the fuel cell stack using the measured low frequency impedance. Thus, air is prevented from being unnecessarily supercharged into the fuel cell stack and at the same time, the water remaining in the fuel cell stack is removed.

Abstract: A water removing system and method of a fuel cell vehicle using impedance are provided. The system measures measure the low frequency impedance of a fuel cell stack when a fuel cell system is stopped in a low temperature condition, and adjusts the air supply amount and supply time for removing the water supercharged into the fuel cell stack using the measured low frequency impedance. Thus, air is prevented from being unnecessarily supercharged into the fuel cell stack and at the same time, the water remaining in the fuel cell stack is removed.

Abstract: An apparatus and method for controlling hydrogen purging are provided. The hydrogen purging control apparatus includes a purge valve that is disposed at an outlet on an anode side of a fuel cell stack and is configured to adjust an amount of emission of hydrogen containing impurities. Additionally, a controller is configured to adjust an opening and closing cycle of the purge valve based on a required output or an output current of the fuel cell stack.

Abstract: A method and a system for controlling hydrogen supply for a fuel cell are provided. The method includes calculating a target hydrogen supply pressure, which is a target pressure value of hydrogen supplied to a fuel cell stack based on a required output. A fuel supply valve (FSV) duty is then adjusted based on the calculated target hydrogen supply pressure and modes are determined based on the FSV duty or actual hydrogen supply pressure measurements of a sensor. A hydrogen supply pressure measurement is calculated according to each of the determined modes and the FSV duty is corrected based on the calculated target hydrogen supply pressure and the hydrogen supply pressure measurement.

Abstract: A water removing system and method of a fuel cell vehicle using impedance are provided. The system measures measure the low frequency impedance of a fuel cell stack when a fuel cell system is stopped in a low temperature condition, and adjusts the air supply amount and supply time for removing the water supercharged into the fuel cell stack using the measured low frequency impedance. Thus, air is prevented from being unnecessarily supercharged into the fuel cell stack and at the same time, the water remaining in the fuel cell stack is removed.

Abstract: An apparatus and method for controlling hydrogen purging are provided. The hydrogen purging control apparatus includes a purge valve that is disposed at an outlet on an anode side of a fuel cell stack and is configured to adjust an amount of emission of hydrogen containing impurities. Additionally, a controller is configured to adjust an opening and closing cycle of the purge valve based on a required output or an output current of the fuel cell stack.

Abstract: An apparatus and method for controlling hydrogen purging are provided. The hydrogen purging control apparatus includes a purge valve that is disposed at an outlet on an anode side of a fuel cell stack and is configured to adjust an amount of emission of hydrogen containing impurities. Additionally, a controller is configured to adjust an opening and closing cycle of the purge valve based on a required output or an output current of the fuel cell stack.

Abstract: A method and a system for diagnosing a failure of a temperature sensor for a fuel cell are provided. The method includes calculating a heating value that is generated at a fuel cell stack during a predetermined diagnosis time and then calculating a temperature variation of the fuel cell stack from the calculated heating value. A failure of a temperature sensor configured to measure a temperature of the fuel cell stack is then detected based on the calculated temperature variation of the fuel cell stack.

Abstract: A system and method for controlling charging of a low-voltage battery are provided. The method includes determining a state of charge of the low-voltage battery of a vehicle based on a voltage of the low-voltage battery and determining a state of charge of the low-voltage battery based on a magnitude of consumed power of a low-voltage direct current (DC) converter (LDC) providing charged power to the low-voltage battery during a period in which vehicle start-up is performed. A charged voltage of the low-voltage battery is then set based on a determination result of the state of charge of the low-voltage battery.

Abstract: A method and a system for controlling hydrogen supply for a fuel cell are provided. The method includes calculating a target hydrogen supply pressure, which is a target pressure value of hydrogen supplied to a fuel cell stack based on a required output. A fuel supply valve (FSV) duty is then adjusted based on the calculated target hydrogen supply pressure and modes are determined based on the FSV duty or actual hydrogen supply pressure measurements of a sensor. A hydrogen supply pressure measurement is calculated according to each of the determined modes and the FSV duty is corrected based on the calculated target hydrogen supply pressure and the hydrogen supply pressure measurement.

Abstract: The present invention relates to a method and system for controlling a stop mode of a fuel cell. In particular, the present invention provides a method and system for controlling a stop mode of a fuel cell which are characterized by calculating the degree of deterioration of a fuel cell, determining a stopping voltage in accordance with the calculated degree of deterioration, and controlling an output voltage of the fuel cell to be the determined stopping voltage.

Abstract: A method for controlling startup of a fuel cell vehicle is provided. The disclosed method includes detecting generation of a startup command from a vehicle and supplying hydrogen to a fuel cell by opening a hydrogen valve. Additionally, the method includes detecting whether a fuel cell voltage has increased after supply of hydrogen, and a first startup of consuming generated electric power of the fuel cell through connection of a load device to the fuel cell, supplying air to the fuel cell through opening an air valve and adjusting the fuel cell voltage to be maintained at a predetermined level or less through adjustment of a bus stage voltage of a power converter when the controller determines that the fuel cell voltage has increased after supply of hydrogen.

Abstract: A system and method for emergency starting of a fuel cell vehicle is provided. In particular, a high-voltage converter, a balance of power (BOP), and a controller are included in the system. The high-voltage converter is configured such that one side thereof is connected to a high-voltage battery via a battery switch and the other side thereof is connected in parallel to a plurality of fuel cells. The BOP is connected in parallel to the high-voltage converter and the fuel cells. The controller is configured to control the power supplied from the high-voltage battery to the BOP without conversion by connecting the battery switch upon the failure of the high-voltage converter or high-voltage battery.

Abstract: An emergency start method for a fuel cell-powered vehicle includes starting the vehicle and detecting an abnormal state of a power supply system of an air blower upon the start of the vehicle. If the power supply system of the air blower is in the abnormal state, an air-check valve of a fuel cell opens. Hydrogen is supplied to the fuel cell, and the air blower operates with power generated from the fuel cell and an emergency start system.

Abstract: A method for controlling startup of a fuel cell vehicle is provided. The disclosed method includes detecting generation of a startup command from a vehicle and supplying hydrogen to a fuel cell by opening a hydrogen valve. Additionally, the method includes detecting whether a fuel cell voltage has increased after supply of hydrogen, and a first startup of consuming generated electric power of the fuel cell through connection of a load device to the fuel cell, supplying air to the fuel cell through opening an air valve and adjusting the fuel cell voltage to be maintained at a predetermined level or less through adjustment of a bus stage voltage of a power converter when the controller determines that the fuel cell voltage has increased after supply of hydrogen.

Abstract: A system and method for controlling charging of a low-voltage battery are provided. The method includes determining a state of charge of the low-voltage battery of a vehicle based on a voltage of the low-voltage battery and determining a state of charge of the low-voltage battery based on a magnitude of consumed power of a low-voltage direct current (DC) converter (LDC) providing charged power to the low-voltage battery during a period in which vehicle start-up is performed. A charged voltage of the low-voltage battery is then set based on a determination result of the state of charge of the low-voltage battery.

Abstract: A method for diagnosing a current sensor of a fuel cell system includes calculating an estimated duty value of a hydrogen pressure control valve, corresponding to a sensing value of the current sensor, while operating the fuel cell system. The estimated duty value is compared with an actual duty value where the hydrogen pressure control valve is controlled during the operation of the fuel cell system, thereby calculating an error value between the estimated duty value and the actual duty value. The error value is compared with a critical value in a normal range, thereby determining whether a failure occurs in the current sensor. The hydrogen pressure control valve controls a pressure of hydrogen supplied to a fuel cell stack of the fuel cell system.

Abstract: An emergency start device of a fuel cell vehicle having a motor as a driving source is provided and includes a fuel cell that supplies power to a motor and an air blower that supplies air to the fuel cell. A high voltage battery supplies power to the air blower and a direct current (DC) converter increases an output of the high voltage battery to transfer the output to the air blower. In addition, a first switch transfers or intercepts an output of the high voltage battery to the air blower. By directly transferring a voltage of the high voltage battery to the air blower, the fuel cell is driven, when the DC converter fails while driving by the high voltage battery.