Patent ID: 6824661
Filing Date: 2004-11-30
Classification: G01N

Abstract:
A combined sensor for measuring oxygen content and NOx content in a gas, said sensor comprising;a partial enclosure defining a gas passage, an inlet portion, and an outlet portion; a diffusion barrier disposed between said inlet portion and said outlet portion, wherein said diffusion barrier defines a diffusion-limited portion of said gas passage on a side of said diffusion barrier opposite said inlet portion and a barrier between said diffusion-limited portion of said gas passage and said inlet portion of said gas passage; an oxygen sensor disposed in said inlet portion on a side of said diffusion barrier opposite said diffusion-limited portion of said gas passage, wherein said oxygen sensor is configured to provide a signal indicative of oxygen partial pressure in said inlet portion; a sensor body disposed in said partial enclosure on a side of said diffusion barrier opposite said inlet portion, wherein said sensor body comprises a plurality of non-dissociative oxygen-porous electrode layers and a plurality of dissociative oxygen-porous electrode layers, and said dissociative oxygen-porous electrode layers comprise a material selected to catalyze dissociation of NOx into nitrogen and oxygen; an oxygen content electrical signal output coupled to said plurality of non-dissociative oxygen-porous electrode layers for generating an indication of background oxygen within said diffusion limited portion of said gas passage; and a NOx content electrical signal output coupled to said plurality of dissociative oxygen-porous electrode layers.