| 摘要 |
PURPOSE:To prevent a deterioration in endurance on severe heat cycle conditions while achieving an accurate air/fuel ratio control by coupling a protective layer to a base part of a sensor element through a spherical protrusion while an oxygen occluded material is contained in the protective layer. CONSTITUTION:A protective layer 4 comprising a heat resistant metal oxide is provided on a side exposed to an exhaust gas of a sensor element through an electrode 3. A body 1 of the sensor element is made up of a base part 1a and a plurality of spherical protrusions 1b. The layer 4 contains an oxygen occluded material. According to an oxygen sensor thus arranged, the protrusion 1b functions as wedge to allow the coupling of the layer 4 to the body 1 firmly. As a result, there is no deterioration in endurance such as peeling even under severe heat cycle conditions. Thus, an action of a material 4a contained in the layer 4 can be delivered sufficiently for a long period of time, thereby achieving an accurate air/fuel control in accelerated and normal operations. |
