| abstract |
The present invention relates to improving the overall efficiency of a fuel cell system by reducing parasitic power consumption. A controller is programmed to decrease oxidant stoichiometry until oxidant starvation is detected or until oxidant stoichiometry is about one. When oxidant starvation is detected, the oxidant stoichiometry is increased until oxidant starvation is no longer detected. The fuel cell system employs a sensor for detecting an operational characteristic such as voltage output, or oxygen or hydrogen concentration in the cathode exhaust stream. The controller uses the operational characteristic to calculate oxidant stoichiometry or to determine when there is oxidant starvation at the cathode. |