| 摘要 |
PURPOSE:To prevent electrodes from being locally deteriorated, and thereby stabilize electricity generation performance by detecting potential at the inlet and outlet port sides of a reaction gas passage, and thereby turning over the flow direction of reaction gas in the reaction gas passage when the difference in potential between both of the port sides comes up to a specified level. CONSTITUTION:As operating time passes on, detected potential from a voltage sensor 41 located at the inlet port side for reaction gas becomes lower, and detected potential from a voltage sensor 42 located at the outlet port side becomes higher so that the difference in potential between both of them is thereby increased. When the difference comes up to a specified level, a controller 44 opens valves 22 and 23, and 32 and 33 based on signals from a potential difference detector 43 so that the switch-over of exciting current is made in order to close valves 21 and 14, and 31 and 34. Which thereby permits the flow direction of combustion gas 27 in a reaction gas passage to be turned over to the direction indicated by a solid arrow head line 27B, and also permits the flow direction of an oxidizing agent 37 to be turned over to the direction indicated by a dotted arrow head line 37B. As a result, the distribution of reaction gas concentration in a fuel passage and an oxdizing agent passage and the distribution of output current density can almost completely be equalized so that electricity generation characteristics can thereby be stabilized. |
