FLUID DENSITY DETECTION DEVICE AND FLUID DENSITY DETECTION METHOD

摘要

PPROBLEM TO BE SOLVED: To measure density of a fluid with high precision even in a severe environment in the case the density of the fluid is detected in order to detect concentration of each component included in the fluid exhausted from a fuel cell. PSOLUTION: The fuel cell system returns the fuel gas exhausted from the fuel cell 1 to the fuel cell 1 through a reflux line 2, and comprises a pressure sensor PSSB1/SBto detect pressure fluctuation of the fuel gas caused by opening and closing of a purge valve 4 and an operating means (20) which obtains an acoustic velocity C of pressure fluctuation by measuring the time difference from opening and closing of the purge valve 4 till detection of the pressure fluctuation by the pressure sensor PSSB1/SB. Thereby, by a simple structure, the acoustic velocity C of the pressure fluctuation generated when a part of the fuel gas is discharged to the outside of the recirculation system is obtained, and the density of the fuel gas can be calculated. PCOPYRIGHT: (C)2007,JPO&INPIT