A control device of a fuel cell system does not execute feedback control of an air valve in a case where a first condition in which a valve opening degree command value calculated by the control device is less than a command value threshold and a second condition in which a valve opening degree measurement value measured by an air valve opening degree sensor is less than a measurement value threshold are satisfied, and executes the feedback control of the air valve in a case where the first condition or the second condition is not satisfied.

A method and a device for detecting internal carbon deposition of a solid oxide fuel cell system. The method comprises the following steps: adjusting a temperature in a reformer of the solid oxide fuel cell system so that a mixed gas discharged from the reformer is at a detection temperature; sampling the mixed gas; detecting a gas sample to obtain a mole fraction of each gas, and calculating an equilibrium constant K1 of a Boudouard reaction according to the obtained mole fraction; calculating an equilibrium constant K2 of the Boudouard reaction according to thermodynamics; comparing K1 and K2, if K1 is less than K2, determining that there will be no carbon deposition in the solid oxide fuel cell system; and if K1 is greater than K2, determining that there will be carbon deposition in the solid oxide fuel cell system. By using the method, a carbon deposition condition in the solid oxide fuel cell system can be detected to effect early warning regarding the solid oxide fuel cell system and take preventive measures

A method for purging the hydrogen feed anode circuit of a fuel cell, whereby hydrogen is fed at a nominal pressure to the inlet of the cell, characterized in that at predetermined periodicity the following steps are repeated: instruction is given to open the hydrogen purge valve arranged on the outlet of the anode circuit; the pressure of hydrogen is measured at the inlet to the anode circuit of the cell, and the measured value is compared with a predetermined threshold pressure value; and the purge valve is closed when the measured pressure is equal to or lower than the predetermined threshold pressure value.

In a fuel cell vehicle and a method of controlling the fuel cell vehicle, when a gas pressure in a high pressure tank becomes less than a first threshold pressure, the SOC of an energy storage device is increased to a margin SOC. When the gas pressure becomes a second threshold pressure which is lower than the first threshold pressure, the amount of fuel released from the high pressure tank is limited to prevent the occurrence of buckling, and limit the travel driving force by the motor to a required limit. At the time of limiting the travel driving force, electrical energy of the energy storage device is used to provide assistance in a manner that the travel driving force by the motor becomes the travel driving force of the required limit.

A method for controlling a fuel cell system having a hydrogen fuel injector/ejector and a control system, includes determining a hydrogen fuel consumption rate associated with a selected power level at steady state, determining a modeled hydrogen fuel flow rate associated with the selected power level and the injector/ejector, determining a modeled effective flow area associated with the injector/ejector, determining a true effective flow area of the injector/ejector, and using the effective flow area to calculate or adjust a command signal, an estimation or an estimation error of at least one of a hydrogen fuel flow rate, an anode leak rate and an anode exhaust valve flow rate.

A method for at least partially compensating for a temperature-induced rise in pressure in a fuel-cell system includes providing a fuel-cell system that has an anode supply path that establishes a fluidic connection between a fuel-cell stack and at least one fuel-source, and an anode-side stack shut-off valve in the anode supply path, the anode-side stack shut-off valve prohibiting the supply of fuel to the fuel-cell stack from an anode section of the anode supply path. The fuel-cell system also has an excess-pressure valve in the anode section, the excess-pressure valve conducting fuel away out of the anode section if the pressure in the anode section exceeds a tripping pressure. In the shut-down state, the pressure in the anode section rises due to warming of the fuel. The anode-side stack shut-off valve is opened to relieve the pressure before the rising pressure in the anode section reaches the tripping pressure.

A fuel cell system includes a fuel cell generating electric power by a reaction between a fuel gas and an oxidant gas, an injector supplying the fuel gas to the fuel cell, a discharge line in which an off-gas discharged from the fuel cell flows, an ejector recirculating the off-gas flowing in the discharge line to the fuel cell using a flow of the fuel gas from the injector, a discharge valve discharging the off-gas flowing in the discharge line to the outside, and a control device controlling supply of the fuel gas by the injector and opening and closing of the discharge valve. When supply of the fuel gas by the injector is stopped, the control device opens the discharge valve while the off-gas is recirculated to the fuel cell and closes the discharge valve before supply of the fuel gas by the injector is restarted.

A system for estimating a concentration of hydrogen in a fuel cell is provided. The system includes a hydrogen supply line supplying the hydrogen to the fuel cell and a time measurement sensor measuring a time duration from a point in time when an operation of the fuel cell ends to a point in time when the fuel cell restarts. A controller estimates an amount of air introduced into the fuel cell during the time duration using the measured time duration and estimates a concentration of hydrogen in the hydrogen supply line at the time of restarting the fuel cell based on the measured time duration and the estimated amount of introduced air.

A fuel cell system and method, the system including a hotbox, a fuel cell stack disposed in the hotbox, an anode tail gas oxidizer (ATO) disposed in the hotbox, and a fuel exhaust processor fluidly connected to the hotbox. The fuel exhaust processor includes a first hydrogen pump configured to extract hydrogen from the anode exhaust received from the fuel cell stack and to output the hydrogen to a first hydrogen stream provided to the fuel cell stack, a second hydrogen pump configured to extract hydrogen from anode exhaust output from the first hydrogen pump and to output the hydrogen to the first hydrogen stream, and a third hydrogen pump configured to extract hydrogen from anode exhaust output from the second hydrogen pump and to output the hydrogen to a second hydrogen stream provided to the ATO.

In a method of operating a fuel cell system, a stable-period voltage difference is calculated in a state where output power of the fuel cell stack is stable. Thereafter, a voltage difference is calculated during power generation. Then, it is determined whether or not the change amount of the voltage difference with respect to the stable-period voltage difference has exceeded a predetermined threshold value. When it is determined that the change amount has exceeded the predetermined threshold value, electric power is generated with the supply amount of the anode gas to the fuel cell stack being increased.