Patent ID: 8067122

Claim:
A fuel cell system comprising: a fuel cell configured to generate electric power by use of a fuel gas and an oxidizing gas; a fuel gas generator configured to generate the fuel gas by reforming a raw material through a reforming reaction; a combustor configured to supply heat to said fuel gas generator to promote the reforming reaction; a combustion fuel feeder configured to control a feed rate of combustion fuel to said combustor; an air feeder configured to supply air to said combustor; a fuel gas passage configured to supply the fuel gas from said fuel gas generator to said fuel cell; an off gas passage configured to supply part of the fuel gas from said fuel cell to said combustor, which part has been left without being used in the electric power generation; a bypass passage configured to connect said fuel gas passage and said off gas passage such that the fuel gas generated by said fuel gas generator is supplied to said combustor, so as to bypass said fuel cell; a switching valve configured to switch a destination of the fuel gas generated in said fuel gas generator between said fuel cell and said bypass passage; and a controller, wherein an inside of said fuel cell is filled with the raw material before said controller controls said switching valve so as to switch from said bypass passage to said fuel cell to supply the fuel gas generated in said fuel gas generator to said fuel cell, and wherein said controller controls said combustion fuel feeder so as to reduce the feed rate of the combustion fuel to said combustor when controlling said switching valve so as to switch from said bypass passage to said fuel cell to supply the fuel gas generated in said fuel gas generator to said fuel cell.