SENSOR ELEMENT AND METHOD FOR DETERMINING NITROGEN OXIDES

摘要

Disclosed is a sensor element for determining gas components in gas mixtures, especially NOX in the exhaust gases of internal combustion engines, comprising a first and second electrochemical concentration cell. The concentration cells comprise a first and second electrode (31, 33, 35). Free oxygen is determined by means of the first cell and the sum of free oxygen and the oxygen resulting from the decomposition of the gas components or consumed thereby is determined by the second cell. A diffusion resistor (23) is disposed upstream from the first electrode (31) of the concentration cell in the direction of flow of the gas mixture. Said resistor substantially corresponds to a diffusion resistor disposed upstream from the first electrode (33) of the second concentration cell.