| 摘要 |
PURPOSE:To obviate the cooling of electrodes by an exhaust gas and to prevent the defect of electrode activity by introducing the exhaust has into the 2nd electrode after the gas is directly warmed by a diffusion rate-determining layer at also used as a heater. CONSTITUTION:The atm. air is introduced as a reference gas into the space of an atm. air introducing part 12 and is brought into direct contact with the electrode 13. On the other hand, the circumference is covered with the exhaust gas of an internal combustion engine. The diffusion rate-determining layer 22 used as the heater has a prescribed resistance value and, therefore, generates heat when current is passed to lead wires 20 and 21. The exhaust gas is heated and diffusion rate-determined by the diffusion rate-determining layer 22 in this way and is then successively permeated through an insulating layer 19, a porous layer 18 and a hole 17a into an aperture 16a of a reaction chamber part 16 where the gas comes into contact with the electrode 15. The oxygen concn. in the exhaust gas is detected by utilizing the phenomenon that a flat plate 14 generates an electromotive force at the time of a large difference in the oxygen concn. between both surface thereof and does not generate the electromotive force at the time of a small difference. Therefore the exhaust gas which comes into contact with the electrode 15 is directly heater by the diffusion rate-determining layer 22, the defect of activity is prevented and the stable output is obtd. |
