Electrochemical analyzer determines methane concentration in combustion engine exhaust gases by controlled, high-temperature, oxidation with oxygen in a cell with two chambers

摘要

A two-chamber cell, e.g. constructed of zirconia cermet with platinum electrodes, receives exhaust gases via a diffusion channel (14) into a first chamber (12), heated to approximately 450[deg]C, which is provided with an electrochemical oxygen pump (26). Following oxidation of nitrogen oxides, carbon monoxide, hydrogen and higher-hydrocarbons, and adjustment to constant lambda value, a part of the product gases pass via a second diffusion channel (16) into a chamber (18), maintained at a higher temperature 500-1000[deg]C, preferably 700[deg]C. From the required oxidizing oxygen flow rate to chamber (18), as provided by a second electrochemical pump (28), the methane content is calculated. Independent claims are included for two-chamber, methane measurement cells.