Parkhurst & Wendel
Method and system for detecting deterioration of exhaust gas control catalyst
 A system for detecting deterioration of an exhaust gas control catalyst provided in an exhaust gas passage through which a combustion exhaust gas is discharged, including a processing zone communicating with a portion of the passage which is downstream of the catalyst and a pumping cell including an oxygen ion conductive solid electrolyte layer and a pair of electrodes one of which is exposed to the processing zone, wherein the pumping cell pumps oxygen out of the processing zone so as to control oxygen partial pressure in the processing zone which corresponds to a monitor voltage, at a value at which the combustible gas component within the processing zone cannot be burned, and the oxygen concentration in the combustion exhaust gas is obtained based on a pumping current flowing between the pair of electrodes of the pumping cell, whereby the degree of deterioration of the catalyst is determined on the basis of the obtained oxygen concentration. 
NGK Insulators, Ltd.
Y Y G F F
Y10T Y02T G01N F01N F01N
additional additional inventional inventional additional
Nobuhide Noriyuki
Kato Ina