GASEOUS HYDROGEN CONCENTRATION DETECTOR

摘要

PROBLEM TO BE SOLVED: To provide a gaseous hydrogen concentration detector with no output fluctuation due to an existence of carbon monoxide acting as interfering gas in gaseous hydrogen concentration detection and a condition of a measuring portion of a reformed gas main stream of a fuel cell system, easily attachable to the fuel cell system, and capable of accurately measuring in a wide concentration range. SOLUTION: The gaseous hydrogen concentration detector includes a pair of current collecting plates 2 having passages 14 opened to gas to be detected arranged to contact respective faces not contacting an electrolyte film 20 of a pair of catalytic electrodes 21 and 22 arranged to contact both faces of the electrolyte film 20 having hydrogen ion conductivity, and a surrounding body 25 having a function of trapping carbon monoxide provided around respective entrances of the passages opened to the gas to be detected. Current is detected changing in response to gaseous hydrogen concentration in the gas to be detected taken in from the passages by a hydrogen ion transporting function from one of the catalytic electrodes toward another of the catalytic electrodes.