EXHAUST GAS SENSOR

摘要

An exhaust gas sensor electrical circuit is improved by the provision of circuit means for inhibiting reduction in the magnitude of the change in voltage signal produced in the sensor circuitry. The reduction in magnitude change would otherwise result from prolonged exposure of the sensor ceramic elements to exhaust gases produced by combustion of a rich air/fuel mixture or a lean air/fuel mixture. The sensor has a titania or other exhaust gas sensing element responsive to temperature and to the partial pressure of oxygen. A second metal oxide ceramic element also is responsive to exhaust gas sensor temperature, but is more slowly responsive to the partial pressure of oxygen in the exhaust gases. Prolonged exposure of the second element in the sensor to rich-mixture exhaust gases or to lean-mixture exhaust gases can lead to a temporary but substantial loss of output signal magnitude from the sensor in the absence of the inhibiting means of the improved circuitry.