Abstract: An adjustable fuel delivery regulation assembly is provided which can be disposed within a direct oxidation fuel cell system, or the fuel reservoir or fuel tank that supplies such a system. One embodiment of the fuel delivery regulation assembly is a shutter assembly, which includes two correspondingly perforated components. The two components can be positioned relative to one another such that the apertures in each component are aligned in certain ways. In an open position, the apertures are substantially fully aligned to permit full fuel flow. In a closed position, the apertures are offset such that there is no opening; thereby fuel flow is restricted. Intermediate positions allow adjustments in the amount of fuel flow proportional to the size of the openings. In accordance with another embodiment of the invention, a set of rotatably mounted slotted rods is inserted into a housing through which fuel can flow through openings in the housing.

Abstract: Apparatus and methods for the generation of water in a direct oxidation fuel cell. Water, in addition to carbon dioxide and heat, is produced when carbonaceous fuel or fuel solution is oxidized in the presence of air and a suitable catalyst. This oxidation reaction is performed on a surface that allows for the introduction of oxygen in the presence of a catalyst. Water produced can then be directly added to the fuel solution thereby diluting the fuel solution to a desired concentration, or may be separately and then later added to fuel solution for the normal fuel cell operations depending on the permeability of the membrane to water.

Abstract: A fuel cell diffusion layer providing a preferential path by which liquid reactants or byproducts may be supplied to or removed from a direct oxidation fuel cell is described. The modified diffusion layer will be typically on the cathode side of the fuel cell and its use is to eliminate or minimize flooding of the cathode diffusion layer area, which is a performance limiting condition in direct methanol fuel cells. In accordance with one embodiment of the invention, the diffusion layer includes a substrate that is coated with a microporous layer. A pattern may be embossed into the diffusion layer, to create preferential flow paths by which water will travel and thereby be removed from the cathode catalyst area. This avoids cathode flooding and avoids build up of potentially destructive pressure by possible cathodic water accumulation.