Abstract:
A method of and fuel cell system for limiting an amount of a fuel crossing over a membrane in a fuel cell, the method including determining an appropriate molecular ratio of the fuel and water for a fuel-water mixture 503; and controlling an amount of the fuel-water mixture that is available to an anode side of the membrane 507 in the fuel cell according to an amount of the fuel that will be electro-oxidized by the fuel cell. The fuel cell system includes a fuel cell membrane 103 having an anode layer 107, a cathode layer 109, and an electrolyte layer 111 where the cathode layer is exposed to an oxygen source, and a fuel delivery system 105 including a fuel chamber 119 disposed around and proximate to the anode layer at a side opposite to the electrolyte layer, the fuel delivery system implementing the method above.
Abstract:
A gas pressure regulator (100) includes a mechanical primary stage (102), preferably including a spring valve, and an electronic secondary stage (104), preferably including a micromachined pressure regulator, the combination of the mechanical primary stage and the electronic secondary stage suitable for relatively precise low pressure near zero flow rates with reasonable energy consumption rates, such as encountered when supplying fuel to a low power fuel cell system.