FUEL CELL ADAPTIVE PURGE DRAIN VALVE CONTROL

A fuel cell system for a vehicle includes an anode manifold, a drain valve, and a controller. The controller adjusts the duration for which the drain valve remains open or closed based on changes in the anode pressure slope associated with the valve's operation. The system, for example, increases the duration that the drain valve remains closed in response to a change in the anode pressure slope following an opening command and adjusts the duration that the valve remains open based on changes in the slope resulting from a closing command.