| 摘要 |
PURPOSE:To provide a limit current type oxygen sensor in which deterioration of the oxygen sensor can be self-diagnosed using a single power supplly voltage value. CONSTITUTION:Cathode electrode membranes 2a, 3a are disposed in a space defined by the barrier wall of a spiral spacer, a sealing plate 5, and a solid electrolyte 1 and communicated with an oxygen diffusion path 6. Anode electrode membranes 2b, 3b are formed oppositely to the cathode electrode membranes on the opposite sides of an oxygen ion conductive planar solid electrolyte 1 to obtain an oxygen sensor having two sets of electrode. A means 10 detects a current value when two sets of electrodes are driven simultaneously by applying a voltage from a power supply 8 and a current value when only one set of electrodes is driven by a switch means 9. Means 12 compares two current values and a means 13 decides whether the oxygen sensor deteriorated or not by deciding whether the current value is within a preset region. When the oxygen sensor deteriorated, a means 14 delivers an alarm. |
