A solid oxide fuel cell system includes a fuel cell stack that generates electric power through a reaction between a fuel gas and an oxidizing gas; a combustor in which anode and cathode off-gases discharged from the fuel cell stack are burned by diffusion combustion; a temperature sensor that detects temperature of the anode off-gas flowing into the combustor; and a controller. When the system is in at least one of the following states during power generation, the controller instructs the system to perform a power-generation control action for preventing failed combustion reactions: the temperature of the anode off-gas, detected by the temperature sensor, is below a first predetermined temperature for a predetermined continuous period of time; the temperature of the anode off-gas decreases by not less than a predetermined second temperature range during a predetermined period of time.

Temperature control system and method for a fuel cell system are disclosed. The temperature control system includes a state detector, a control selector, a normal controller and an internal model controller. The state detector determines whether the fuel cell system is in a leakage condition based on a dynamic transfer function from an air flowrate provided to the fuel cell system to a fuel cell temperature. The control selector selects to switch between the normal controller and the internal model controller based on a determined result. The normal controller is configured for controlling an air flowrate of the fuel cell system which is not in the leakage condition. The internal model controller is configured for controlling the air flowrate of the fuel cell system in the leakage condition to control the fuel cell temperature. A fuel cell system with the temperature control system is also disclosed.

A fuel cell system includes a fuel cell, a first supply flow path, a second supply flow path, a recycle flow path, a circulator, a discharge flow path, a reservoir, a valve, and a controller. The controller opens the valve, determines an open time, for which the valve is opened to discharge the anode off gas, on the basis of the amount of water stored in the reservoir, the discharge time of water that flows through the discharge flow path to be discharged, and the discharge amount of the anode off gas that flows through the discharge flow path to be discharged, and closes the valve when an elapsed time for which the valve is opened reaches the open time.

A control method for a fuel cell system with a gas supplying device configured to supply fuel gas and oxidant gas to a fuel cell, includes a power generating operation step of performing a power generating operation for causing the fuel cell to generate power by controlling the fuel gas and the oxidant gas to be supplied to the fuel cell on the basis of a load required of the fuel cell. Further, the control method includes an autonomous operation step of performing an autonomous operation of the fuel cell when the load drops to or below a predetermined value. In the autonomous operation, power supply from the fuel cell system to the load is stopped and the fuel gas is passed to an anode of the fuel cell.

A fuel cell system comprises a solid oxide fuel cell which generates a power by receiving a supply of an anode gas and a cathode gas. The system comprises a cathode gas supply unit to supply the cathode gas to the fuel cell via a cathode gas supply route; a first burner arranged in the cathode gas supply route, a second burner to burn an anode off-gas and a cathode off-gas, which are discharged from the fuel cell; a first branch path which is branched out from an upstream of the first burner and joins to a downstream of the first burner in the cathode gas supply route; and a second branch path which is branched out from a downstream of the first burner in the cathode gas supply route and joins to a cathode off-gas discharge route through which the cathode off-gas is discharged from the fuel cell to the second burner.

A controller of a fuel cell system, when the fuel cell system is started up and thrown into warming-up operation, sets a rotating speed of the circulation pump to a reference rotating speed, subsequently repeatedly performs: (a) a process of acquiring the first temperature and the second temperature; and (b) a process of controlling the circulation pump by setting the rotating speed of the circulation pump in order that with the first temperature is within a predetermined temperature range, the rotating speed is made generally higher than the reference rotating speed with increasing temperature difference between the first temperature and the second temperature, and when a condition for rotating the circulation pump at the reference rotating speed is satisfied, the controller sets the rotating speed of the circulation pump to the reference rotating speed.

A fuel cell system comprises a fuel cell, a fuel gas supply pipe connected to a fuel gas inlet of the fuel cell, a circulation pipe connecting a fuel off gas outlet of the fuel cell and the fuel gas supply pipe, a hydrogen pump disposed on the circulation pipe, a water pump configured to deliver coolant discharged from the fuel cell to the hydrogen pump, an acquisition unit configured to obtain at least one parameter corresponding to temperature of fuel gas exhausted from the hydrogen pump, and a controller configured to switch between ON and OFF states of the water pump according to the parameter obtained by the acquisition unit.

A fuel cell system includes a fuel cell which generates electric power by using a hydrogen gas and an oxidizing gas, a hydrogen gas supply route where the hydrogen gas to be supplied to an anode of the fuel cell flows, an anode off-gas discharge route for discharging an anode off-gas discharged from the anode of the fuel cell to outside, an anode off-gas discharge valve provided to the anode off-gas discharge route, and a controller which causes the anode off-gas discharge valve to be opened when a temperature of any of the hydrogen gas supply route, the anode of the fuel cell, the anode off-gas discharge route, and the anode off-gas discharge valve becomes equal to or lower than a predetermined temperature.

This invention concerns a fuel cell system (100a; 100b; 100c) comprising a fuel cell stack (1) having an anode portion (2) and a cathode portion (3), a reformer (4) for supplying reformed anode gas to the anode portion (2), and an exhaust gas burner (5) for burning anode exhaust gas from the anode portion (2) and/or cathode exhaust gas from the cathode portion (3), wherein the reformer (4) is arranged at least in sections annularly around the exhaust gas burner (5), wherein an inner wall portion of the reformer (4) is arranged completely or at least substantially around an outer wall portion of the exhaust gas burner (5). The invention also concerns a method for operating a fuel cell system conforming to the invention (100a; 100b; 100c) and a motor vehicle (1000) with a fuel cell system conforming to the invention (100a; 100b; 100c).

A fuel cell system includes: a fuel cell that generates electricity using a fuel gas and an oxidant gas; a fuel gas supply path through which a fuel gas to be supplied to an anode of the fuel cell flows; a recycle gas path through which an anode off-gas emitted from the anode of the fuel cell is returned to the fuel gas supply path; a water reservoir that holds water separated from the anode off-gas flowing through the recycle gas path; a drainage path through which water stored in the water reservoir is drained; a valve provided on the drainage path; and a controller that determines, on the basis of a history of a flow rate of the anode off-gas, a length of time for which the valve continues to be opened for draining the water stored in the water reservoir.