| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas sensor having a self-diagnostic function capable of promptly and reliably detecting whether or not it is a fault. SOLUTION: This gas sensor 10A comprises: a main pump cell 28 pumping oxygen in a first chamber 20; a feedback control system 38 comparing an oxygen partial pressure of the first chamber 20 with a first reference value and controlling the main pump cell 28 so as to set this oxygen partial pressure to be a specified value that NOx cannot be dissolved; an auxiliary pump cell 52 pumping oxygen in a second chamber 22; and a measuring pump cell 58 pumping oxygen generated by dissolving NOx. In this case, this sensor is also provided with a correction control system 70 controlling in correction the feedback control system 38 from a deviation between a pump current Ip1 flowing in the auxiliary pump cell 52 and a second reference value and making a constant oxygen concentration in the second chamber 22, and a self-diagnosing device comparing a value of the pump current Ip1 with a stipulated scope and carrying out a fault decision from the comparison results. |
