| 摘要 |
<P>PROBLEM TO BE SOLVED: To precisely detect an abnormality of an oxygen sensor all the time, without being affected by the temperature characteristic of an element impedance, as to a deterioration detector for the oxygen sensor. <P>SOLUTION: A voltage V is impressed to the oxygen sensor 10, and an element impedance real value Rsr=V/I of a sensor element 12 is calculated based on a relation with respect to a current I flowing therein. An element temperature estimation value Tex of the oxygen sensor 10 is calculated based on items affecting a temperature of the sensor 10. An abnormality of the oxygen sensor 10 is judged based on the propriety of considering a relation between the element impedance real value Rsr and the element temperature estimation value Tex as a relation according to a normal temperature characteristic. <P>COPYRIGHT: (C)2004,JPO |
