| 摘要 |
PROBLEM TO BE SOLVED: To provide an element resistance detector for oxygen sensor capable of detecting the element resistance of an oxygen concentration sensor at a low cost while satisfactorily keeping the detecting precision of oxygen concentration. SOLUTION: An A/F sensor 10 is provided in an engine exhaust pipe, and a current I corresponding to the oxygen concentration in exhaust gas is carried thereto accompanying the application of a voltage. A regulating resistor R10 is connected in series to the A/F sensor 10. A prescribed voltage is applied to the serial circuit of the A/F sensor 10 and the regulating resistor R10 by operational amplifiers OP2 and OP2, and the element current I carried to the A/F sensor 10 is detected by a current detecting resistor R9. The applied voltage to the serial circuit of the A/F sensor 10 and the regulating resistor R10 is swept, and the resistance value of the A/F sensor 10 and the regulating resistor R10 is detected from the voltage change at that time and the current change accompanying it.
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