Abstract: A method for controlling a fuel cell system includes steps of: (a) determining whether hydrogen (H2) is detected in an interior space of a stack enclosure in which a fuel cell stack is accommodated; (b) stopping power generation that is performed using the stack when it is determined in step (a) that the hydrogen is detected; (c) opening a purge valve to discharge gases circulating in an anode through the purge valve, and opening a condensate discharge valve to discharge condensate contained in a water trap through the condensate discharge valve; and (d) determining whether the hydrogen discharged through at least one of the purge valve and the condensate discharge valve in step (c) flows back to the interior space based on H2 concentration in the interior space.

Abstract: An apparatus for diagnosing a fuel cell and a vehicle system includes a measuring device that measures a stack voltage and a stack current from a fuel cell stack, and at least one processor that extracts a plurality of reference current points and a plurality of reference voltage points corresponding to the reference current points by analyzing the measured stack voltage and the measured stack current, calculates an abnormality degree of the fuel cell stack based on a reference signal waveform formed by using voltage differences between the reference voltage points, and determines an abnormal state of the fuel cell stack based on the calculated abnormality degree of the fuel cell stack.

Abstract: A method of controlling energy supply in a fuel cell vehicle includes storing an output current of a fuel cell as a pre-limited current when a cell voltage ratio reaches a minimum cell voltage ratio, setting a limited output current of the fuel cell as the pre-limited current when the cell voltage ratio reaches a hazard cell voltage ratio, connecting first and second high-voltage batteries to a main bus terminal in parallel when the cell voltage ratio reaches the hazard cell voltage ratio, and outputting a supplementary current from the second high-voltage battery by an insufficient amount of the output current of the fuel cell for the pre-limited current, and a system for performing the same.

Abstract: An apparatus and a method for controlling vehicle start-up modify a sequence order in which control units of the vehicle are started up to improve reliability. In operation, a processor determines whether a voltage of a low-voltage battery is less than a reference voltage when a start key is turned on, and determines a voltage classification level corresponding to the voltage of the low-voltage battery when the voltage of the low-voltage battery is less than or equal to the reference voltage. The processor then determines a sequence order in which to start up driving units of the vehicle including a power conversion device of the vehicle based on the determined voltage classification level, and controls startup of the vehicle by reflecting the determined sequence order of the power conversion device.

Abstract: A fuel cell control method includes calculating an amount of water in a humidifier using a production amount of water at a cathode of a fuel cell, a discharge amount of saturated vapor and a discharge amount of water at an anode, judging whether or not a vehicle is in a driving state using state information of the vehicle, judging humidity of air in the fuel cell stack upon judging that the vehicle is in the driving state, increasing RPM of an air blower and activating the air blower when the amount of water is greater than a first threshold and a second condition is satisfied, if first conditions are satisfied, and activating a heater when the amount of water is greater than a second threshold, if the first conditions are not satisfied.

Abstract: A fuel cell control method includes calculating an amount of water in a humidifier using a production amount of water at a cathode of a fuel cell, a discharge amount of saturated vapor and a discharge amount of water at an anode, judging whether or not a vehicle is in a driving state using state information of the vehicle, judging humidity of air in the fuel cell stack upon judging that the vehicle is in the driving state, increasing RPM of an air blower and activating the air blower when the amount of water is greater than a first threshold and a second condition is satisfied, if first conditions are satisfied, and activating a heater when the amount of water is greater than a second threshold, if the first conditions are not satisfied.

Abstract: A cooling pump driving system includes an electric water pump in a coolant passage line for circulating a coolant and having a variable rotation speed. A sensor disposed at an outlet side of the electric water pump checks a coolant pressure passing through the electric water pump. A controller including a reference value for the pressure change is configured to decrease a rotation speed of the electric water pump when the pressure change detected by the sensor is the reference value or higher.