Fuel cell system and fuel cell system control method

A fuel cell system comprising:

• a fuel cell;
• a fuel processor configured to process a raw fuel to produce a fuel gas for the fuel cell;
• an oxidant gas heater configured to heat an oxidant gas for the fuel cell;
• a combustor configured to combust the raw fuel to produce a combustion gas for use in heating the fuel processor and the oxidant gas heater;
• a first fuel injector configured to supply the raw fuel to the fuel processor and to adjust a flow rate of the raw fuel supplied to the fuel processor;
• a second fuel injector configured to supply the raw fuel to the combustor and to adjust a flow rate of the raw fuel supplied to the combustor;
• and
• a controller configured to control the first fuel injector and the second fuel injector, and configured to control a power generation state during warm-up of the fuel cell;
• wherein the controller is configured to:
• execute the warm-up of the fuel cell, which comprises, upon the fuel cell reaching a power generation start temperature, controlling the first fuel injector and the second fuel injector so as to cause the fuel cell to perform power generation for heating the fuel cell,
• after the warm-up of the fuel cell, execute rated operation of the fuel cell, which comprises controlling the first fuel injector and the second fuel injector so as to cause the fuel cell to perform power generation for supplying power to an external device,
• wherein (i) a raw fuel total flow rate of the flow rate of the raw fuel supplied from the first fuel injector to the fuel processor and the flow rate of the raw fuel supplied from the second fuel injector to the combustor during the warm-up of the fuel cell, is greater than (ii) the flow rate of the raw fuel supplied from the first fuel injector to the fuel processor during the rated operation of the fuel cell,
• wherein, during the warm-up of the fuel cell, before a temperature of the fuel processor reaches a lower limit temperature, the raw fuel is supplied from the second fuel injector to the combustor without being supplied from the first fuel injector to the fuel processor, and
• wherein, during the warm-up of the fuel cell, after the temperature of the fuel processor reaches the lower limit temperature, the raw fuel is supplied from the first fuel injector to the fuel processor and from the second fuel injector to the combustor.