| 摘要 |
In a fuel cell system (10), an anode exhaust gas discharge pipe (50) is full of hydrogen at the start of operation of a fuel cell (20). As time passes when the fuel cell (20) is operating, the concentration of impurities within the anode exhaust gas discharge pipe (50) increases. When the hydrogen concentration is less than a reference concentration for opening a valve, an upstream cut-off valve (61) closes and a downstream cut off valve (62) opens. As a result, the impurity concentration in the anode gas discharge pipe (50) quickly drops and is restored to the level that it was at the start of operation of the fuel cell (20). This sudden drop in the impurity concentration is caused by a pressure difference between the pressure in the anode exhaust gas pipe (50) and the pressure of the outside air, and the concentration gradient. |
