Oxygen sensor and oxygen sensor control device

The oxygen sensor control device according to claim 11, further comprising:

• lean operation continuation time detection means for detecting a continuation time of lean operation that is a time in which an air-fuel ratio is lean relative to a theoretical air-fuel ratio during a predetermined operation period of the internal combustion engine;
• and
• voltage application time period setting means for setting a voltage application time period in accordance with the continuation time of lean operation,
• wherein the unidirectional voltage is voltage in a direction that makes the atmosphere electrode negative and makes the exhaust electrode positive, and
• wherein the voltage application control means, in accordance with the voltage application time period, applies the voltage between the atmosphere electrode and the exhaust electrode.

The oxygen sensor control device according to claim 11, further comprising:

• rich operating state detection means for detecting a rich operating state that is a state in which an operating state of the internal combustion engine is in a predetermined high speed and high load operating range and in which an air-fuel ratio is in a rich amount increasing range;
• and
• wherein the unidirectional voltage is voltage in a direction to make the atmosphere electrode positive and make the exhaust electrode negative, and
• wherein the voltage application control means, when the rich operating state is detected, applies the voltage between the atmosphere electrode and the exhaust electrode.

An oxygen sensor control device controlling an electromotive force-type oxygen sensor disposed in an exhaust passage of an internal combustion engine, the oxygen sensor comprising:

• a solid electrolyte;
• an atmosphere electrode that is disposed on one face side of the solid electrolyte and contacts with atmosphere when disposed in the exhaust passage;
• and
• an exhaust electrode that is disposed on a face on an opposite side to the one face of the solid electrolyte and contacts with exhaust gas when disposed in the exhaust passage;
• the oxygen sensor being subjected to an activation process that applies a unidirectional voltage between the atmosphere electrode and the exhaust electrode,
• the control device comprising:
• voltage application control means for applying a voltage in the same direction as the unidirectional voltage between the atmosphere electrode and the exhaust electrode in accordance with operating state of the internal combustion engine.

An oxygen sensor control device controlling an electromotive force-type oxygen sensor disposed in an exhaust passage of an internal combustion engine, the oxygen sensor comprising:

• a solid electrolyte;
• an atmosphere electrode that is disposed on one face side of the solid electrolyte and contacts with atmosphere when disposed in the exhaust passage;
• and
• an exhaust electrode that is disposed on a face on an opposite side to the one face of the solid electrolyte and contacts with exhaust gas when disposed in the exhaust passage;
• the oxygen sensor being subjected to an activation process that applies a unidirectional voltage between the atmosphere electrode and the exhaust electrode,
• the control device applying a voltage in the same direction as the unidirectional voltage between the atmosphere electrode and the exhaust electrode in accordance with operating state of the internal combustion engine.