Gas sensor processing apparatus

A gas sensor processing apparatus for processing an output of a gas sensor including a detection element which is formed of a solid electrolyte body, which has a pair of electrodes, and which detects the concentration of a specific gas, comprising:

• voltage shift means for shifting a detection element voltage produced between the electrodes of the detection element from a pre-shift voltage to a post-shift voltage different from the pre-shift voltage;
• recovery means for returning the detection element voltage from the post-shift voltage to the pre-shift voltage through self-discharge by an internal capacitor of the detection element after the end of a voltage shift period in which the detection element voltage is shifted by the voltage shift means;
• and
• deterioration index detection means for detecting a deterioration index representing the degree of deterioration of the detection element on the basis of a change in the detection element voltage in a recovery period in which the detection element voltage is returned to the pre-shift voltage by the recovery means;
• wherein, when the detection element is represented by an equivalent circuit, the detection element is equivalent to a series circuit between the electrodes thereof, the series circuit including a cell that generates an electromotive force in accordance with the concentration of the specific gas and an internal impedance composed of an internal resistor and an internal capacitor connected in parallel, and
• the post-shift voltage is greater than the electromotive force generated by the detection element.