| 摘要 |
PURPOSE:To make possible the detection of air-fuel ratios even in regions other than theroretical air-fuel ratio by controlling the diffusion of the gas molecules up to the electrode surface of exhaust gas and at the same time forcefully flowing electric current in solid electrolytes thereby controlling the oxygen partial pressure of the electrode surface. CONSTITUTION:Oxygen ion conductive solid electrolytes 4 and 5 are provided respectively between the 1st electrode 1 and 2nd electrode 2 as well as between the 2nd electrode 2 and 3rd electrode 3. A dense solid electrolyte is used for the solid electrolyte 4 and a porous solid electrolyte for the solid electrolyte 5. A voltage measuring device 7 is connected by means of a lead wire 6a to the 1st electrode 1 and 2nd electrode 2 and a DC electric power source 9 is connected to the 2nd electrode 2 and 3rd electrode 3 by way of a lead wire 6b and double-pole double-throw switch 8. Thereupon, active or inert material is used catalytically for the electrodes 1-3 and the polarities connecting to the DC power source are changed, by which various air-fuel-ratio-electromotive force characteristics may be obtained and the detection of the air-fuel ratios in regions other than theoretical air-fuel ratio is made possible. |
