NOx GAS SENSOR METHOD AND DEVICE

摘要

The present invention is a method and apparatus for measuring the total NO_x concentration in a gas stream utilizing the principles of a NO_x sensor (22), i.e., mixed potential sensor (22). The exhaust gas is first conditioned by a catalyst assembly (12) that converts the various species of nitrogen oxide gases present to a fixed steady state concentration ratio of NO₂/NO, where N0₂ is approximately 0 - 10% of the total NO_x concentration present in the gas exhaust, thereby enabling the NO_x sensor to generate a meaningful and reproducible determination of the concentration of total NO_x present in the gas being measured. The catalyst assembly (12) also functions to oxidize any unburned combustibles such as CH₄, CO, etc., and remove potential contaminants such as SO₂.