A method of shutting down operation of a fuel cell system is disclosed, comprising a fuel cell stack, the method comprising the sequential steps of: i) ceasing a supply of fuel to the fuel cell stack; ii) closing a shut-off valve on an exhaust line in fluid communication with a cathode system of the fuel cell system, the cathode system comprising a cathode fluid flow path passing through the fuel cell stack; iii) pressurizing the cathode system with an air compressor in fluid communication with a cathode air inlet port in the fuel cell stack; and iv) ejecting water from the cathode flow path.

A fuel cell assembly comprising an enclosure having a fuel cell stack mounted therein. The fuel cell stack has an inlet face for receiving coolant/oxidant fluid and an outlet face for expelling said coolant/oxidant fluid. The fuel cell stack further includes a pair of end faces extending transversely between the inlet face and outlet face. The enclosure defines a flow path for the coolant/oxidant fluid that is configured to guide the coolant/oxidant fluid to the inlet face, from the outlet face, and over at least one of the end faces.

Various embodiments of the present disclosure are directed to methods and systems for determining at least one actual value of a controlled variable of a conditioning unit for a reactant of a fuel cell. In one example embodiment, the method steps for determining the at least one actual value of a controlled variable includes: measuring a measured value of the actual value of the at least one controlled variable, calculating a model value of the at least one controlled variable using a model of the conditioning unit, calculating a model value of the actual value of the at least one controlled variable using a sensor model, calculating a correction value for the at least one controlled variable, and calculating the actual value of the at least one controlled variable as the sum of the correction value and of the model value of the at least one controlled variable.

A method of monitoring operation of a reactor system includes causing a chemical reaction to occur within an assembly of the reactor system, and measuring a chemical composition of one or more reactants of the chemical reaction with spatial resolution at a plurality of points along a path within the assembly using a sensor system structured to implement distributed sensing. The sensor system includes an optical fiber sensing member provided at least partially within the assembly, wherein the optical fiber sensing member comprises a functionalized optical fiber based sensor device structured to exhibit a change in one or more optical properties in response to changes in the chemical composition of the one or more reactants.

A fuel cell system includes: a fuel cell stack; a coolant circulation path through which coolant for cooling the fuel cell stack flows; a cathode gas supply flow path that is connected to an inlet of the fuel cell stack, and in which a compressor that supplies cathode gas to the fuel cell stack is arranged; an intercooler that is arranged between an outlet of the compressor and the inlet of the fuel cell stack in the cathode gas supply flow path, is connected to the coolant circulation path, and cools cathode gas discharged from the compressor with use of the coolant; and a regulating valve that is arranged in the cathode gas supply flow path, and regulates a pressure between the outlet of the compressor and the inlet of the fuel cell stack when the fuel cell stack is being started at low temperature.

A fuel cell system in a vehicle has a cathode and an anode. A compressor has an inlet and an outlet, the outlet being configured to outlet a compressed air from the compressor. A bypass line is configured to return the compressed air from the outlet to the inlet such that the air returns to the compressor in a loop. A valve is located downstream of the compressor and is operable in a plurality of modes. In a first mode, the valve is configured to block the air from the cathode and return the air via the bypass line. In a second mode, the valve is configured to direct at least some of the air to the cathode. The valve can also be configured to operate in a third mode in which the air is sent to the cathode without going through the bypass line.

A fuel cell system includes a fuel cell configured to be supplied with fuel and air to generate electricity, a reformer configured to reform the fuel to be supplied to the fuel cell, a heat source device configured to heat an off-gas discharged from the fuel cell to produce a heating gas and configured to heat the reformer, a fuel cell heating device configured to heat the air to be supplied to the fuel cell using the heating gas, a fuel cell temperature acquisition unit configured to acquire a temperature of the fuel cell, and a reformer temperature acquisition unit configured to acquire a temperature of the reformer. The fuel cell system includes a controller configured to, in a warm-up operation to perform a warm-up of the reformer and a warm-up of the fuel cell, control at least one of the heat source device and the fuel cell heating device based on the temperature of the reformer and the temperature of the fuel cell to adjust at least one of a heating amount of the off-gas and a heating amount of the air by the heating gas.

A method for identifying and mapping a maximum instantaneous stall torque capability of a fuel cell cathode valve includes: maintaining a temperature of an electric motor at a predetermined temperature, wherein the predetermined temperature is equal to or less than a freezing point of water (0° C.), and the electric motor includes motor brushes, commutator poles, a stator, a rotor rotatable with respect to the stator, and a shaft coupled to the rotor; locking the shaft of the electric motor such that the shaft is incapable of rotating, thereby fixing the shaft at a locked position; mounting the shaft of the electric motor to a dynamometer; supplying electrical energy to the electric motor; monitoring an instantaneous stall torque of the electric motor; and monitoring a rotor electrical resistance.

A fuel cell device is provided, including a media system for supplying fluid media to electrochemical units of the fuel cell device and/or for discharging fluid media from the electrochemical units of the fuel cell device, wherein the media system includes at least one valve to which, in a standard operating state of the fuel cell device, an electrical standard input power is suppliable in order to maintain the valve in a desired valve state. The fuel cell device is able to be reliably started with as little effort as possible, even under frost conditions. The fuel cell device is switchable into a heating operating state in which an electrical heating input power that is greater than the electrical standard input power is suppliable to the at least one valve.

A system and method for controlling operation of a fuel cell are provided. The method includes estimating an effective catalyst amount within a fuel cell stack and monitoring a change in the estimated effective catalyst amount according to time. An irreversible degradation state of the fuel cell stack is determined based on the monitored change in the estimated effective catalyst amount.