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 fuel cell deterioration prevention system includes a cell voltage stability determination unit determining cell voltage stability according to a preset operating condition, a fuel cell deterioration diagnosing unit diagnosing deterioration of a fuel cell by changing and controlling a control variable pre-selected according to an operating condition and monitoring a resultant change in the cell voltage of the fuel cell, and a deterioration avoidance operation control unit performing a deterioration avoidance operation based on a diagnosis result of the fuel cell deterioration diagnosing unit.

A fuel cell system that generates electric power by supplying anode gas and cathode gas to a fuel cell includes a control valve adapted to control the pressure of the anode gas to be supplied to the fuel cell; a buffer unit adapted to store the anode-off gas to be discharged from the fuel cell; a pulsation operation unit adapted to control the control valve in order to periodically increase and decrease the pressure of the anode gas at a specific width of the pulsation; and a pulsation width correcting unit adapted to correct the width of the pulsation on the basis of the temperature of the buffer unit.

In order to improve estimation accuracy of a purging amount, a fuel cell system comprises a supply valve that controls a supply of an anode gas into an anode system, a purge valve that discharges an off-gas from the anode system, a pressure detecting unit configured to estimate or measures a pressure inside the anode system, and a purging amount estimating unit configured to estimate a purging amount of the off-gas discharged from the anode system through the purge valve based on a pressure change inside the anode system during a purge valve close duration in a supply valve open state and a pressure change inside the anode system during a purge valve close duration in a supply valve close state.

A valve device for controlling an air flow of a fuel cell stack includes: a housing connected to the fuel cell stack and including a plurality of manifolds formed therein; a disk rotatably provided in the housing to control the air flow of the fuel cell stack; and a central shaft provided at the center of the housing to rotate the disk.

A system for controlling gas flow in a fuel cell circuit includes a fuel cell stack, a pressure sensor, and a valve to adjust a flow of gas through the fuel cell circuit. The system further includes an ECU designed to estimate pressure values of the gas at multiple locations in the fuel cell circuit based on the detected pressure of the gas and based on flow resistance values (including at the valve), the estimated pressure values including an estimated sensor pressure value at a location of the pressure sensor. The ECU is further designed to determine a pressure deviation between the detected pressure and the estimated sensor pressure value. The ECU is further designed to adjust the flow resistance value of the valve to determine a final flow resistance value of the valve that causes the pressure deviation to reach or drop below a threshold deviation amount.

A controller according to an embodiment controls a hydrogen system including at least a hydrogen production system in which received power is planned in advance and a hydrogen production amount changes in accordance with the received power. The controller includes: a processor that calculates, in a preparation time period before a demand adjustment time period in which a target value of the received power is set in advance, a control command value such that input power to be inputted as the received power to the hydrogen production system matches the target value at a start of the demand adjustment time period; and a command controller that outputs the control command value calculated by the processor to the hydrogen production system.

A fuel cell system is provided that includes a fuel cell with an assembly of multiple individual cells, each of which has an anode section, an electrolyte membrane, and a cathode section, an anode gas supply, which leads to an anode gas inlet and includes a fuel cell and a fuel metering device, a cathode gas supply, and a passive anode gas recirculation device, which connects an anode gas outlet to the recirculation gas inlet of a mixer arranged in the anode gas supply. The fuel cell system is started up after a standstill in that in a first phase, the fuel cell is activated while fuel is supplied from the fuel source, and the anode recirculation is suppressed without actively blocking the anode gas recirculation device, and in a second phase, anode gas is recirculated in addition to the supply of fuel from the fuel source.

A fuel cell system comprising (i) at least one fuel cell stack (30) comprising at least one intermediate-temperature solid oxide fuel cell, and having an anode inlet (41) and a cathode inlet (61) and (ii) a reformer (70) for reforming a hydrocarbon fuel to a reformate, and a reformer heat exchanger (160); and defining: an anode inlet gas fluid flow path from a fuel source (90) to said reformer (70) to said fuel cell stack anode inlet (41); a cathode inlet gas fluid flow path from an oxidant inlet (140, 140′, 140″) through at least one cathode inlet gas heat exchanger (110, 150) to said reformer heat exchanger (160) to said fuel cell stack cathode inlet (61); wherein said at least one cathode inlet gas heat exchanger (110, 150) is arranged to heat relatively low temperature cathode inlet gas by transfer of heat from at least one of (i) an anode off-gas fluid flow path and (ii) a cathode off-gas fluid flow path; wherein said reformer heat exchanger is arranged for heating said anode inlet gas from said relatively high temperature cathode inlet gas to a temperature T.sub.3 at the anode inlet that is below a temperature T.sub.1 at the cathode inlet; and wherein oxidant flow control means (200) for controlled mixing of low temperature oxidant from the or each oxidant inlet (140, 140′, 140″) with high temperature cathode inlet gas to control a temperature T.sub.1 at the cathode inlet (61) relative to a temperature T.sub.3 at the anode inlet (41) and at a level higher than T.sub.3.

A pressurized air supply system supplies, to a pressurization object device, flowing air that includes at least one of compressed air, which is generated by compressing air supplied from an air supply source, or discharged air from a turbocharger compressor forming a turbocharger. The compressor is controlled such that a saturated steam temperature of the flowing air supplied from the air supply source to the pressurization object device is lower than a temperature in the pressurization object device, at startup.