| 摘要 |
PURPOSE:To adjust quickly the partial pressure of the gas in a diffusion chamber and to improve the responsiveness of a sensor by disposing an oxygen concn. cell and oxygen pump element so as to face each other via a space therebetween and forming the space to a specific size thereby constituting the diffusion chamber. CONSTITUTION:The oxygen concn. cell element 2 and the oxygen pump element 3 are disposed to face each other via the space therebetween. Said space is constituted as the diffusion chamber 1. The space of the diffusion chamber 1 is formed to a 0.2-0.01mm range. Passage forming bodies 9, 17 are provided to each of the element 2 and the element 3 and atm. passages 10, 18 are formed on the side opposite from the diffusion chamber 1. The oxygen in the diffusion chamber is put into or out of the passage 18 by the element 3 so that the specified electromotive force of the element 2 by the difference in the concn. between the oxygen in the exhaust gas of the diffusion chamber 1 and the oxygen in the passage 10 is maintained. The air-fuel ratio is detected from the current value of the element 3 in this stage. Since the chamber 1 can be made small and the electrode of the oxygen pump element can be increased, the air-fuel ratio sensor having the good responsiveness is obtd. by adjusting quickly the partial pressure of the gas in the diffusion chamber. |
