An auxiliary power unit for an aircraft. It includes an air compressor coupled to an air-drawing device for drawing in air from outside the aircraft, the compressor supplying compressed air to a manifold. The manifold is configured to supply air to an environmental control system and a start-up module of at least one propulsion system of the aircraft running on hydrogen. The manifold is also configured to supply air to a fuel cell stack arranged to provide an electric generation function configured to power non-propulsive systems of the aircraft, the fuel cell stack also being supplied with hydrogen from a tank supplying hydrogen to the at least one propulsion system of the aircraft.

A fuel cell system may include: a reformer performing a reforming process of producing hydrogen gas from a gasified fuel; a burner supplying heat to the reformer; a stack generating electrical energy by generating an electrochemical reaction using reforming gas and air discharged from the reformer; a first supply pipe supplying external air to the burner; a second supply pipe supplying external air to the stack; a first storage tank storing a liquid fuel; a second storage tank supplying a gasified fuel to the reformer; and a fuel evaporator making a liquid fuel discharged from the first storage tank exchange heat with air flowing through the first supply pipe or air flowing through the second supply pipe, and sending a gasified gaseous fuel to the second storage tank.

A fuel cell system includes a fuel cell, an air supplier, an air passage connected to the fuel cell, air supplied from the air supplier flowing in the air passage, a bleed passage branched off from the air passage on a side upstream of the fuel cell and joining the air passage on a side downstream of the fuel cell, part of the air supplied by the air supplier flowing in the bleed passage in such a manner as to circumvent the fuel cell, a bleed valve provided in the bleed passage, the bleed valve regulating the amount of air flowing in the bleed passage, an air supplier control unit which controls the air supplier to supply a predetermined amount of air, a wetness reduction determination unit which determines whether or not it is necessary to reduce a degree of wetness of the fuel cell, and a bleed amount control unit which reduces an opening of the bleed valve when the degree of wetness of the fuel cell needs to be reduced.

The present disclosure relates to a fuel cell system including a discharge line configured to discharge exhaust gas, which is discharged from a fuel cell stack, to the outside, and a pneumatic branch line having an outlet end connected to the discharge line, and an inlet end connected to a pneumatic supply unit configured to supply air to a pneumatic part of a mobility vehicle, the pneumatic branch line being configured to selectively supply the air from the pneumatic supply unit to the discharge line, thereby effectively reducing a hydrogen concentration in the exhaust gas discharged from the fuel cell stack.

When it is determined that the vehicle is stopped, a control unit blocks communication between a first opening and a fuel cell by a first valve. When a fan is being driven and communication between the first opening and the fuel cell is blocked by the first valve, a second valve opens a third opening.

A fuel cell apparatus may include a stack, a reformer configured to generate reformed gas, a burner, a water supply tank configured to store cooling water, a burner air blower configured to draw in external air and then to blow the air, a vertex tube configured to convert the air into heated air and cooled air, a three-way valve configured to supply the air from the burner air blower selectively to the vertex tube or the burner, a first heat exchanger configured to exchange heat between the air discharged from the vertex tube and the cooling water, a second heat exchanger configured to exchange heat between the air discharged from the vertex tube and the reformed gas, and a four-way valve configured to supply the heated air and the cooled air to the first and second heat exchangers.

An airflow control method of an air control system for a fuel cell stack (FCS) includes opening a recirculation valve by a controller to recirculate air through a compressor to increase a temperature of the air prior to entering the FCS to offset a FCS temperature below a predetermined threshold in response to identification to a cold-start event. The recirculation valve may be arranged with the compressor to recirculate air therethrough. The FCS may be arranged with the compressor and recirculation valve to selectively receive air therefrom. A sensor may measure thermal conditions of the FCS. The controller may be programmed to receive signals from the sensor indicating thermal conditions of the FCS, and to operate the recirculation valve based on the signals to recirculate air through the compressor to increase a temperature of the air prior to entering the FCS.

A fuel cell apparatus may include a stack, a stack air blower configured to supply external air to the stack, a humidifier configured to extract moisture contained in exhaust air and to supply the extracted moisture to external air supplied to the stack, a first bypass channel configured to allow exhaust air to bypass the humidifier, a first three-way valve controlled to adjust the amount of exhaust air that bypasses the humidifier, and a humidity sensor configured to sense the humidity of external air. The fuel cell apparatus may also include a second bypass channel configured to allow external air to bypass the humidifier, a second three-way valve controlled to adjust the amount of external air that bypasses the humidifier, and a controller configured to control the first three-way valve and the second three-way valve depending on the sensed humidity value of the external air.

A high-temperature operating fuel cell system includes a reformer that produces a reformed gas from air and a raw material, an air supplier that supplies the air to the reformer, a fuel cell that generates electricity with the reformed gas and air, a combustor in which unutilized portions of the reformed gas and the air burn, a combustion exhaust gas path of a combustion exhaust gas, a depurator including a combustion catalyst for freeing the combustion exhaust gas of toxic substances, a heater that heats the combustion catalyst, and a controller. At start-up in a case of having detected an abnormal stoppage in which a purge operation is impossible, the controller first controls the heater so that the combustion catalyst is heated to a predetermined temperature and then controls the air supplier so that the high-temperature operating fuel cell system is purged by supplying the air to the reformer.

A method for no-purge starting up a fuel cell system is provided. The method includes calculating a nitrogen partial pressure from a target hydrogen concentration during driving that corresponds to a condition in which start-up without purging is possible and calculating a target hydrogen pressure satisfying the target hydrogen concentration from the calculated nitrogen partial pressure. Further, hydrogen is then supplied to the system based on the target hydrogen pressure.