A scheme of a fuel feeding sub-sect

A scheme of a fuel feeding sub-section in a direct hydrogen FCS for automotive application is shown in Fig. 4.2. Pressure regulation sub-system design has the objective to regulate inlet pressure to assure the hydrogen flow rate necessary to the chemical reaction. The inlet pressure and fuel purge represent the main parameters to be controlled in both operative modes, however, the role of the purge valve is different for the two possible configurations. In a dead-end configuration and when air is used as oxidant, nitrogen tends to crossover from the cathode flow field through the electrolyte to the anode side. As fuel is consumed in the fuel cell, the concentration of nitrogen in the anode compartment increases, thus accumulating therein and negatively impacting the performance of the fuelcell [5].