| 摘要 |
PURPOSE:To keep the partial pressure of the oxygen in an internal reference oxygen source constant and to secure the detecting accuracy of an air-fuel ratio by stably discharging overflowing amount of the oxygen in the internal reference oxygen source into gas atmosphere to be measured through a high-diffusion resistance part, wherein the temperature is relatively low and stable, in an air-fuel ratio sensor having the internal reference oxygen source, wherein oxygen is contained by the current conduction of an element. CONSTITUTION:In an air-fuel ratio sensor 1, elements A and B, wherein porous electrodes (a)-(d) are provided in the front and rear surfaces of solid electrolyte plates 3 and 5, are arranged so as to face each other through a measuring gas chamber S. A shielding body 7 is laminated on the opposite side of the element A with respect to the measuring gas chamber S. An internal oxygen reference source R, wherein the oxygen in the measuring gas chamber S is drawn into the side of the porous electrode (a) by the current conduction of the element A, is formed. The overflowing amount of the reference oxygen in the internal oxygen reference source R is discharged into gas atmosphere to be measured by way of a porous lead part La as the high- diffusion resistance part, which is extending to the side of the end of the sensor connected to the porous electrode (a), a porous fixed layer 35, a filled-powder layer and a porous heat-resisting fixing agent 21. |
