| 摘要 |
PURPOSE:To provide an air-fuel ratio sensor which can sense the air-fuel ratio accurately without provision of any voltage sensor circuit for the element part and without leading to deterioration of the sensor and which can perform judgement of the activatedness precisely. CONSTITUTION:In the condition that the pump current to a pump element 11a of an air-fuel ration sensor part 1 is cut, the pump current cut is disengaged for a certain period of time at specified intervals by the first timer means from the time when current is fed to a heater 12 so as to conduct the current control, and thereby the pump current is cut when the pump current exceeds a certain level and also the second timer means is started. When the second timer means is timed up, judgement is passed that the element part 11 is activated, and the pump current cut is disengaged. |
