Abstract: The invention relates to a liquid separator (17) for a gas flow charged with liquid, having an inner volume (21) which has at least one baffle element (23) and a collection area (24) for the separated liquid. The invention is characterized in that a heat-conducting element (30) made of a material having good heat conductivity is arranged in the collection area (24) and protrudes in the direction of the at least one baffle element (23) into the gas flow (25) in the inner volume (21), wherein the baffle element (23) is made from a material which conducts heat less well than the heat-conducting element (30).

Abstract: A method for starting a fuel cell in a fuel cell system, at temperatures below the freezing point of water, includes, in a first step, that the hydrogen concentration in the anode is increased; after which, in a second step, an anode pressure is increased for a fixed period of time, and while air is supplied to the cathode, the maximum possible current is drawn from the fuel cell, and after which, in a third step, the fuel cell is switched in a load-free manner and the anode pressure is reduced. After the third step, the second step and the third step are repeated successively until a sufficient performance of the fuel cell for its normal operation is reached.

Abstract: A method for preparing a fuel cell system in a vehicle for starting, for which purpose a starting preparation routine is carried out after the vehicle has been shut down depending on a temperature limit value. In the method, in the event that the fuel cell had not reached its normal operating temperature during the previous operation and a temperature falls below the predetermined temperature limit value, the fuel cell system is operated until it has reached its normal operating temperature and after which the starting preparation routine is subsequently carried out.

Abstract: A method for the start preparation of a fuel cell system in a vehicle having a fuel cell and a system bypass where an air flow is conveyed by parts of the fuel cell system in order to dry the fuel cell. In a first temporal phase of the method, a larger part of the air flow is led through the fuel cell and a smaller part of the air flow is led through the system bypass, after which, in a second temporal phase, a larger part of the air flow is led through the system bypass and a smaller part of the air flow is led through the fuel cell.

Abstract: A method for the start preparation of a fuel cell system in a vehicle having a fuel cell and a system bypass where an air flow is conveyed by parts of the fuel cell system in order to dry the fuel cell. In a first temporal phase of the method, a larger part of the air flow is led through the fuel cell and a smaller part of the air flow is led through the system bypass, after which, in a second temporal phase, a larger part of the air flow is led through the system bypass and a smaller part of the air flow is led through the fuel cell.

Abstract: A method for preparing a fuel cell system in a vehicle for starting, for which purpose a starting preparation routine is carried out after the vehicle has been shut down depending on a temperature limit value. In the method, in the event that the fuel cell had not reached its normal operating temperature during the previous operation and a temperature falls below the predetermined temperature limit value, the fuel cell system is operated until it has reached its normal operating temperature and after which the starting preparation routine is subsequently carried out.

Abstract: A method for starting a fuel cell in a fuel cell system, at temperatures below the freezing point of water, includes, in a first step, that the hydrogen concentration in the anode is increased; after which, in a second step, an anode pressure is increased for a fixed period of time, and while air is supplied to the cathode, the maximum possible current is drawn from the fuel cell, and after which, in a third step, the fuel cell is switched in a load-free manner and the anode pressure is reduced. After the third step, the second step and the third step are repeated successively until a sufficient performance of the fuel cell for its normal operation is reached.

Abstract: A method for power control of a fuel cell system in a vehicle is disclosed. The requested fuel cell system power by the vehicle is converted into a power request made of the fuel cell by an expected power of auxiliary drives of the fuel cell system at the requested fuel cell system power being added to the requested fuel cell system power. A media supply of the fuel cell which corresponds to the power request made of the fuel cell is requested. The electrical loading of the fuel cell with current is performed in accordance with a model of the cathode dynamics such that a control variable of the control operation is matched to the media dynamics, and the power release is performed such that the fuel cell is loaded only when the adequate media supply is ensured.

Abstract: A method for flushing a fuel cell system during a power-down cycle includes conveying air by an air conveying device through a cathode space of a fuel cell and releasing the conveyed air through an exhaust air line. An outlet valve is cyclically closed and opened during the power-down cycle, where an opening duration depends on an amount of air that is conveyed and the outlet valve connects an anode discharge line to the exhaust air line. The conveyed air is guided from a delivery side of the air conveying device directly to the exhaust air line at least in part through a system bypass.

Abstract: A method for controlling the pressure on the cathode side of a fuel cell system is disclosed. The fuel cell system has at least one fuel cell, an air conveying device which is arranged on a common shaft with an expander, and a system bypass which connects the pressure-side outlet of the air delivery device to the pressure-side inlet of the expander via a system bypass line and a system bypass valve. The system bypass valve is opened in order to increase the pressure in the fuel cell.

Abstract: A method for flushing a fuel cell system during a power-down cycle includes conveying air by an air conveying device through a cathode space of a fuel cell and releasing the conveyed air through an exhaust air line. An outlet valve is cyclically closed and opened during the power-down cycle, where an opening duration depends on an amount of air that is conveyed and the outlet valve connects an anode discharge line to the exhaust air line. The conveyed air is guided from a delivery side of the air conveying device directly to the exhaust air line at least in part through a system bypass.

Abstract: A method for starting the normal operation of an electrical system with a fuel cell and a transducer from a stop mode is disclosed. The transducer absorbs the electrical power of the fuel cell, in which at least one reactant supply of the fuel cell was interrupted, where the interrupted reactant supply is resumed from a restart signal, and where a fuel cell voltage is prescribed and then regulated by the transducer. The prescribed fuel cell voltage is prescribed in a way that an electrical unloaded fuel cell supplied with reactants will exceed the prescribed fuel cell voltage in every case, and the current of the transducer necessary for maintaining the prescribed fuel cell voltage is measured, where the normal operation is released as of a prescribed current necessary to that effect.

Abstract: A method for power control of a fuel cell system in a vehicle is disclosed. The requested fuel cell system power by the vehicle is converted into a power request made of the fuel cell by an expected power of auxiliary drives of the fuel cell system at the requested fuel cell system power being added to the requested fuel cell system power. A media supply of the fuel cell which corresponds to the power request made of the fuel cell is requested. The electrical loading of the fuel cell with current is performed in accordance with a model of the cathode dynamics such that a control variable of the control operation is matched to the media dynamics, and the power release is performed such that the fuel cell is loaded only when the adequate media supply is ensured.

Abstract: A method for supplying air to a fuel cell (2), using a controllable air conveying device (7) which delivers an air mass flow for a cathode chamber (4) of the fuel cell (2), and using at least one air mass flow sensor (9, 18). The invention is characterized in that, for at least one location (19) in the air flow path which is situated at a distance from the at least one air mass flow sensor (9) in the flow direction, a computed estimate is made of the air mass flow present at that location.

Abstract: A method for starting the normal operation of an electrical system with a fuel cell and a transducer from a stop mode is disclosed. The transducer absorbs the electrical power of the fuel cell, in which at least one reactant supply of the fuel cell was interrupted, where the interrupted reactant supply is resumed from a restart signal, and where a fuel cell voltage is prescribed and then regulated by the transducer. The prescribed fuel cell voltage is prescribed in a way that an electrical unloaded fuel cell supplied with reactants will exceed the prescribed fuel cell voltage in every case, and the current of the transducer necessary for maintaining the prescribed fuel cell voltage is measured, where the normal operation is released as of a prescribed current necessary to that effect.

Abstract: A method for controlling the pressure on the cathode side of a fuel cell system is disclosed. The fuel cell system has at least one fuel cell, an air conveying device which is arranged on a common shaft with an expander, and a system bypass which connects the pressure-side outlet of the air delivery device to the pressure-side inlet of the expander via a system bypass line and a system bypass valve. The system bypass valve is opened in order to increase the pressure in the fuel cell.

Abstract: A fuel cell system includes a fuel cell with an anode chamber and a cathode chamber. The fuel cell system also includes a recirculation device that recirculates anode exhaust gas to the anode input, which includes a discharge line for discharging liquid and/or gas from the region of the recirculation device, and an air conveying device for supplying the cathode chamber with a supply air flow. A water separator, which is connected to the discharge line and through which at least a portion of the supply air flow passes, is situated between the air conveying device and the cathode chamber in the area of the supply air flow.

Abstract: A method for supplying air to a fuel cell (2), using a controllable air conveying device (7) which delivers an air mass flow for a cathode chamber (4) of the fuel cell (2), and using at least one air mass flow sensor (9, 18). The invention is characterized in that, for at least one location (19) in the air flow path which is situated at a distance from the at least one air mass flow sensor (9) in the flow direction, a computed estimate is made of the air mass flow present at that location.

Abstract: A method of operating a fuel cell system in a vehicle that is switchable to a temporary stop mode and restarted from the stop mode. When, in certain driving situations, it is required to switch to the stop mode, it is then checked whether the operating conditions of the fuel cell system allow a switch to the stop mode. If the switch is allowed it takes place. When a restart of the fuel cell system is required on the basis of the vehicle the settings of the stop mode are cancelled again. The switch to the stop mode involves, with further existing electric contacting of the fuel cell, the air mass flow conveyed by the air conveying device being switched off or reduced to a predefined value and the pressure of the combustion gas supplied being reduced to a predefined value.

Abstract: A method for supplying air to a fuel cell (2) by means of a controllable air-conveying device that delivers an air mass flow for a cathode chamber (4) of the fuel cell (2). The air-conveying device (7) is adjusted to a specified value of a pressure (psoll) in the air line and/or to a specified value of a pressure loss (?psoll) across a component of the air line.