Patent ID: 8071248

Claim:
A method of operating a fuel cell system, comprising: providing a fuel inlet stream from a fuel source into a fuel inlet conduit: measuring, using a senor, a first water-to-fuel ratio of the fuel inlet stream in the fuel inlet conduit; providing a quantity of water into the fuel inlet conduit downstream from the sensor if the first water-to-fuel ratios is less than a predetermined water-to-fuel ratio; and providing the fuel inlet stream into a fuel cell stack, wherein the fuel inlet stream comprises a second water-to-fuel ratio that is substantially equal to the predetermined water-to-fuel ratio; wherein the step of providing the quantity of water downstream from the sensor comprises at least one of: providing liquid water into the fuel inlet conduit downstream from the sensor and upstream from a heat exchanger in which the water and the fuel are vaporized; or providing water vapor into the fuel inlet conduit downstream from the sensor and downstream from the heat exchanger in which the water and the fuel are vaporized.