Robert Boschgmbh

Robert Bosch Gmbh

Tobias Falkenau

Timo Bosch

Christopher Bruns

The invention relates to a method for operating a fuel cell system with at least one fuel cell which is supplied with hydrogen via an anode path and oxygen via a cathode path, wherein anode exhaust gas exiting the fuel cell is recirculated, but from time to time a part of the anode exhaust gas is introduced into an exhaust gas path, which conducts the cathode exhaust gas, by purging the exhaust gas out of the anode path, and wherein the hydrogen concentration of the exhaust gas is measured in the exhaust gas path using a hydrogen sensor. According to the invention, the hydrogen and/or nitrogen concentration of the anode gas in the anode path before the last purge is calculated on the basis of the measured hydrogen concentration, the quantity of gas introduced into the exhaust gas path from the cathode path and from the anode path, and the quantity of hydrogen which is freshly supplied to the anode path. The invention further relates to an analysis unit for a fuel cell system for carrying out the method according to the invention.

Method for operating a fuel cell system, and analysis unit for a fuel cell system

A device () for determining the H2 concentration of a fluid in an exhaust gas line () of a fuel cell system () includes a sensor () arranged in a pipe section (), and the pipe section has an inflow opening () and an outflow opening (). An installation element () divides exhaust gas arriving through the inflow opening () into a first volumetric flow which flows through a first pipe volume (V) and at least one additional volumetric flow which flows through at least one additional pipe volume (V). A purge line () opens into the first pipe volume (V) between the inflow opening () and the H2 sensor (). The sensor () measures the H2 concentration of the exhaust gas in the first pipe volume (V).

Device for determining the hydrogen concentration of an exhaust gas in an exhaust gas line of a fuel cell system, and fuel cell system

A fuel cell system () for providing electrical energy. The system () comprises a fuel cell stack (), an anode subsystem () with a proportional valve () for dosing a volume of gas to be fed to the fuel cell stack (), a purge valve () for discharging gas from the anode subsystem () into an exhaust-gas path () of the fuel cell system (), and a control unit () for controlling the proportional valve () and the purge valve (). The control unit () is configured to use an electrical control current that is fed to the proportional valve () to readjust for a purging operation to draw conclusions regarding a hydrogen concentration in a gas that is fed to the purge valve (), wherein the control unit () is furthermore configured to adjust the fuel cell system () in a manner dependent on the determined hydrogen concentration.

Growing community of inventors

Esslingen, Germany

Tobias Falkenau