| 摘要 |
PROBLEM TO BE SOLVED: To provide a heater-embedded oxygen sensor solving a possible problem of instability occurred in any output such as an electromotive force due to temperature distribution presence in a sensing part although a heating resistive element circumferentially built in the sensing part enables more rapid temperature up than a conventional indirect heating means. SOLUTION: In the heater-embedded oxygen sensor, a reference electrode 3 is formed on an inner face of a cylindrical tube 2 made of ceramic solid electrolyte with its one end sealed, a measuring electrode 4 is formed on an outer face position of the cylindrical tube 2 opposed to the reference electrode 3, and a ceramic insulating layer 6 locating a heating resistive element 8 at least along lengthwise direction of the cylindrical tube on the measuring electrode 4 is laminated to lower the heat value at the central part of the heating resistive element 8 in a lengthwise direction than the one at any other area. Specifically when the heating resistive element is tri-divided in a lengthwise direction, the following relational expression is obtained: a>b/2 where: a = gross area of the heating resistive element located at the central part and b = gross area of the section located at both ends. |
