| 摘要 |
PROBLEM TO BE SOLVED: To obtain an air-fuel ratio detecting sensor whose structure is simple and which can detect an air-fuel ratio value precisely by a method wherein the sensor is provided with a pumping cell composed of a diffusion barrier, with a sensing cell composed of a plurality of electrodes and with an air duct. SOLUTION: An air-fuel ratio detecting sensor is provided with a pumping cell which is composed of a first solid electrolyte 44 coming into contact with a combustion exhaust gas, of two electrodes 45a, 45b which move oxygen to a specific direction and of a diffusion control barrier 46, with a sensing cell which is composed of two electrodes used to measure an internal electromotive force and with an air duct 43 which is situated between the sensing cell and the pumping cell. In this manner, in the air-fuel ratio detecting sensor of a flat board type, the sensor can be manufactured easily as the flat board type, and it can be heated easily. On the other hand, when the sensor is provided with a drive circuit in which the output voltage of the sensing cell is input to the applied voltage of the pumping cell, an air-fuel ratio value can be detected over a wide region and in a simple circuit configuration. |
