| 摘要 |
PROBLEM TO BE SOLVED: To shorten the temperature rising time by a heater, to stably detect the air-fuel ratio of an engine in an early stage, and to improve the manufacturing workability. SOLUTION: An air-fuel ratio detection element 21 comprises a hollow rod- shaped heater unit 22, a solid electrolyte layer 27 formed on the outer circumference of the heater unit 22, first and second electrodes 28 and 29 which are formed on the outer circumference of the solid electrolyte layer 27 and apply the pump voltage Vp from a DC power source 35 to the solid electrolyte layer 27, a reference electrode 30 formed on the outer circumference of the slid electrolyte layer 27 separately from the electrodes 28 and 29, and a diffusion layer 31 which covers the solid electrolyte layer 27 and the electrodes 28-30. The diffusion zone 31 comprises a first diffusion zone 32 formed by using a means of the curved surface printing, or the like, and a second diffusion zone 33 formed on the outer circumferential side thereof by performing the plasma thermal spraying of a ceramic material. |
