Abstract: A sensor responsive to the partial pressure of oxygen and suitable for inclusion in an internal combustion engine exhaust gas environment is disclosed. The sensor is comprised of a ceramic material fabricated from an alloy of cobalt monoxide and magnesium oxide. The ceramic material exhibits, at elevated temperatures, a direct and generally linear change in the logarithm of its electrical resistance as a function of the partial pressure of oxygen. A body of the cobalt-magnesium monoxide ceramic material is supported by a housing formed of a compatible, nonreactive, ceramic material such as alumina. A pair of electrical leads communicate the sensor ceramic body with an external utilization device. The external utilization device may be arranged to measure the change in resistance of the ceramic sensor body in response to its environment.

Abstract: The present invention provides a sensor which is operative to sense the partial pressure of oxygen in the exhaust gases of combustion processes having air/fuel combustion mixture ratios in excess of the stoichiometric ratio. The sensor according to the present invention relies upon the direct and generally linear change in the logarithm of the resistance of cobalt monoxide ceramic material as a function of the partial pressure of oxygen in the environment of the sensor element at elevated temperatures for partial pressures of oxygen which coincide with the partial pressures of oxygen in the exhaust gases of fuel-lean combustion mixtures. The present invention provides a generally cylindrical cobalt monoxide ceramic sensor element, supported within a housing formed of a compatible ceramic material such as alumina, and arranged so that the change in the electrical resistance between the ends of the cylinder of the sensing element may be measured.

Abstract: The present invention provides a sensor which is operative to sense the partial pressure of oxygen in the exhaust gases of combustion processes having air/fuel combustion mixture ratios in excess of the stoichiometric ratio. The sensor according to the present invention relies upon the direct and generally linear change in the logarithm of the resistance of cobalt monoxide ceramic material as a function of the partial pressure of oxygen in the environment of the sensor element at elevated temperatures for partial pressures of oxygen which coincide with the partial pressures of oxygen in the exhaust gases of fuel-lean combustion mixtures. The present invention provides a generally cylindrical cobalt monoxide ceramic sensor element, supported within a housing formed of a compatible ceramic material such as alumina, and arranged so that the change in the electrical resistance between the ends of the cylinder of the sensing element may be measured.