A fuel cell system mounted on a vehicle includes a fuel cell, a humidity sensor configured to detect a humidity in a vehicle cabin of the vehicle, a cathode off-gas exhaust passage through which cathode off-gas emitted from the fuel cell is exhausted to outside the vehicle, an introducing port for cathode off-gas, provided in the cathode off-gas exhaust passage, a cathode off-gas introducing unit configured to introduce cathode off-gas emitted from the fuel cell, into the vehicle cabin of the vehicle via the introducing port, and a cathode off-gas introducing amount control unit configured to control an amount of the cathode off-gas introduced into the vehicle cabin of the vehicle in accordance with a humidity in the vehicle cabin of the vehicle, detected by the humidity sensor.

A reaction device comprising: a first flow path to which a fuel gas is supplied; a second flow path to which a gas containing oxygen is supplied; a hydrogen permeable membrane that separates the first flow path and the second flow path and allows hydrogen contained in the fuel gas supplied to the first flow path to permeate toward the second flow path; and a catalyst that is provided in the second flow path and promotes oxidation reaction between the oxygen and hydrogen passing through the hydrogen permeable membrane, wherein the hydrogen permeable membrane comprises a barium zirconium oxide membrane.

A fuel cell system includes a fuel cell stack, an anode system apparatus, a control unit, an anode outlet temperature sensor, and a purge valve. In a method of starting operation of the fuel cell system at low temperature, a control unit compares a predetermined freezing temperature threshold value with an anode outlet temperature detected by an anode outlet temperature sensor. Then, the control unit performs low temperature control to place the purge valve in the constantly open state in the case where the temperature is not higher than the freezing temperature threshold value, and performs normal control for switching opening/closing of the purge valve in the case where the temperature exceeds the freezing temperature threshold value.

A method for humidifying a reactant in a fuel cell system is provided having a fuel cell stack, which is fluidically connected to a humidifier, wherein the humidifier comprises a membrane, on whose surface channels are formed. At least one of the channels is associated with a storage element for temporary storing of liquid water, the method involving the following steps: extracting the liquid water from the fuel cell stack and feeding the liquid water to the humidifier, admitting at least part of the liquid water into the storage element and temporarily storing the part therein, at least partially emptying the storage element by evaporating of the liquid water and humidifying of the reactant being supplied to the fuel cell stack by means of the evaporated liquid water, wherein the liquid water is extracted from the fuel cell stack both at the anode side and at the cathode side. A fuel cell system for carrying out the method is also provided.

Methods and systems are described for optimizing water discharge in fuel cell vehicles. The system includes a fuel cell stack, a blower for purging water from the fuel cell stack and a controller. The controller detects that an ambient temperature satisfies a threshold temperature. The controller determines the fuel cell vehicle is approaching a stopping location. The controller calculates a water discharge time prediction necessary to purge excess water from the fuel cell stack while the fuel cell vehicle is operating in response to detecting that the ambient temperature satisfies the threshold temperature and the fuel cell vehicle is approaching the stopping location. The water discharge time prediction is calculated based on the blower operating while the fuel cell stack is in at least one of an idle state and a stopped state as the fuel cell vehicle approaches the stopping location.

The present disclosure generally relates to systems and methods for using a relative humidity sensor in a cathode exhaust stream of a fuel cell stack to optimize the performance and efficiency of the fuel cell stack.

A system for controlling purge operation of a fuel cell assembly includes a controller and one or more sensors configured to obtain respective sensor data. The fuel cell stack is configured to receive a stack coolant. The controller is configured to execute a first purge mode when at least one of a first enabling condition and a second enabling condition is met. The first purge mode defines a first group of setpoints, including a relatively low cathode stoichiometric ratio. The controller is configured to switch to a second purge mode when the coolant temperature is above a minimum warm-up temperature and a third mode when a relative humidity value of a stack cathode output falls below a threshold humidity. The second purge mode defines a second group of setpoints, including a relatively high cathode stoichiometric ratio.

Provided is an apparatus for soft-sensing a fuel cell system. The apparatus includes: a connecting unit detachable from a control unit for being connected to an outside of a stationary fuel cell system; a collecting unit connected to the connecting unit and receiving data of the stationary fuel cell system; a quality variable predicting unit connected to the collecting unit and predicting a quality variable of the stationary fuel cell system based on the received data; and a monitoring unit connected to the quality variable predicting unit and outputting the predicted quality variable. The quality variable predicting unit is configured to predict the quality variable predictable including at least any one of a concentration of carbon monoxide in a reformed gas at a rear end of a fuel converting system, and a concentration of methane in the reformed gas at the rear end of the fuel converting system.

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.

Various embodiments of the present application are directed to methods of measuring a mass flow rate of at least one exhaust gas constituent in an exhaust gas of a fuel cell. In one example embodiment, the method includes the steps of measuring a volumetric flow rate of the exhaust gas; using a gas sensor to determine a concentration of the at least one exhaust gas constituent, and calculating the mass flow rate of the exhaust gas constituent using the volumetric flow rate of the exhaust gas and the determine concentration of the at least one exhaust gas constituent.