METHOD OF ESTIMATING HYDROGEN CONCENTRATION, AND FUEL CELL SYSTEM

摘要

PPROBLEM TO BE SOLVED: To provide a fuel cell system, in which appropriate purge time for hydrogen off gas can be decided, without providing a new hydrogen gas sensor in a fuel cell system provided with a hydrogen circulating path and carrying out reuse of unreacted hydrogen in fuel cell. PSOLUTION: The fuel cell system 10 is provided with the hydrogen-circulating path 17, in which the hydrogen not used in the fuel cell 11 is merged with hydrogen supplied from a hydrogen tank 22 and supplied to the fuel cell 11 and is constituted so that the hydrogen-circulating pump 18 is provided in the hydrogen-circulating path 17. The hydrogen-circulating pump 18 is constituted to feed out the gas by compressing the gas. The hydrogen-circulating pump 18 is driven by a motor M, and an invertor 24 is provided with a current sensor SA for detecting current (motor current) flowing in the motor M. A control apparatus 25 decides the purging time for the gas in the hydrogen circulating path 17, by estimating the hydrogen concentration in the hydrogen circulating path 17, based on the motor current value, corresponding to load of the pump and the opening and the closing of a purge valve 21 is controlled. PCOPYRIGHT: (C)2006,JPO&NCIPI