Patent ID: 7875377

Claim:
A fuel cell system comprising: a fuel cell configured to generate power by an electrochemical reaction of a fuel gas and an oxidant gas; a cathode discharge pipe connected to the fuel cell and configured to discharge oxidant offgas generated during power generation from the fuel cell; an anode drain opening in the fuel cell configured to discharge fuel offgas and moisture generated during power generation from the fuel cell via an anode drainpipe; a gas-liquid separator configured to receive the fuel offgas and the moisture from the anode drain opening via the anode drainpipe and to separate the fuel offgas and the moisture; a variable throttle valve forming an opening in a flow path of the fuel offgas between the gas-liquid separator and the cathode discharge pipe; and a controller configured to operate the variable throttle valve to restrict a flow rate of the fuel offgas and to establish a pressure difference in the anode drainpipe between the gas-liquid separator and the anode drain opening that causes the fuel offgas and the moisture to flow from the anode drain opening to the gas-liquid separator and the fuel offgas to flow from the gas-liquid separator to the variable throttle valve during power generation of the fuel cell.