| 摘要 |
PROBLEM TO BE SOLVED: To rapidly start the detection at gas to be measured after the supply of a current to a heater is started in a control device of an oxygen sensor. SOLUTION: In an oxygen sensor wherein an oxygen pump wherein a solid electrolyte layer is held between porous electrodes and an oxygen concn. measuring cell are provided in contact with a measuring gas chamber restricted in the dififusion of gas to be measured and a minute current is allowed to flow to the oxygen concn. measuring cell to allow the electrode on the side opposite to the measuring gas chamber to function as an internal oxygen reference source and the pump current flowing to the oxygen pumping cell is controlled so that the voltage between those electrodes becomes objective voltage to detect the concn. of oxygen from the pump current, the minute current is allowed to flow to the oxygen concn. measuring cell until a definite time ΔT is elapsed after the supply of a current to a heater is started (point t1 of time) and, thereafter, the supply of the minute current is cut off and, at the same time, the control of the pump current is started (point t2 of time). At a point t3 of time when the voltage across the electrodes of the oxygen concn. measuring cell can be controlled to objective voltage by the control of the pump current, the activation of the sensor is judged to resume the supply of a current of the minute current. |
