| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a sensor drive circuit equipped with a function for previously sensing an output decrease of a limiting current oxygen concentration sensor and discriminating a normal sensor and an abnormal sensor. <P>SOLUTION: An oxygen concentration measurement apparatus is provided with a limiting current oxygen sensor element, the oxygen sensor drive circuit having a means for measuring an output current to a voltage applied to the limiting current oxygen sensor element, a discharging circuit for discharging a charge accumulated in the sensor element and a circuit for measuring the discharged charge and a peak voltage so as to determine a deterioration diagnosis. <P>COPYRIGHT: (C)2004,JPO |
