IC engine exhaust air=fuel ratio sensor with oxygen concn. cell solid electrolyte and pump - controls supply of heater power on condition that pump current is interrupted and removes condition after period of time period after supply of power.

摘要

The oxygen concn. cell and pump elements (11b, 11c) consist of solid electrolyte conducting oxygen ions, and are respectively provided with an electrode. The sensor (1) also has a heater (12) for heating the two elements (11a, 11b), a pump control unit for the current flowing in the pump element, so that the voltage of the cell element assumes a predetermined value. A pump current evaluation unit determines the pump current. A pump switch-off unit interrupts the supply of pump current. A supply unit delivers power to the heater, and first and second timers control the interruption of the pump current. A control unit activates the supply of power by the power supply unit to the heater, if the pump current is interrupted. It also curtails the interruption of the pump current, during a predetermined time duration in predetermined intervals. This results after the activation of the power supply to the heater with the help of the first timer. USE/ADVANTAGE - IC engine. Determines activation point of sensor with increased precision, without causing any deterioration of sensor characteristics. It can determine anomalies of sensor. Does not require additional components for determining of cell and pump voltage.