| 摘要 |
PROBLEM TO BE SOLVED: To accurately calculate an air/fuel ratio from an air/fuel ratio sensor by detecting the characteristic change in the air/fuel ratio sensor that deteriorates with elapsed time and accurately judging the deterioration of the air/fuel ratio sensor. SOLUTION: The control device of an air/fuel ratio sensor for detecting current that is proportional to oxygen concentration in gas to be detected from the element 2 by applying voltage to the sensor element 2 of the air/fuel ratio sensor 1 is provided with a means 100 for detecting an AC impedance by applying high-frequency and low-frequency AC voltages to the element 2, a temperature adjustment means 100 for controlling the temperature of the element 2 to the target temperature based on the high-frequency impedance, and the means 100 for detecting the characteristic change of the element 2 based on the low-frequency impedance. |
