OXYGEN SENSOR FOR INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To reduce a voltage applied to an oxygen pump part while enabling oxygen concentration to be detected by arranging end parts of a couple of measurement electrodes on an insulation member in a hollow part. CONSTITUTION:The hollow part 14 is formed of a substrate 11 and a stabilized zirconia plate 12 inside the abutting part B at the tip side of an insulation substrate 11. The couple of measurement electrodes 15 and 16 are provided successively while passing through the substrate 11 and an oxygen concentration detection part 17 is formed at the tip parts of the electrodes 15 and 16. Further, pump electrodes 18 and 19 are provided on the internal and external surfaces of the plate 12 above the detection part 17 to form the oxygen pump part 20. A fine gap A for admitting exhaust gas into the hollow part 14 is formed at the contacting part B between the substrate 11 and plate 12 by polishing. Thus, the gap A for admitting the exhaust into the hollow part 4 is formed on the contacting surface C, so the total flow rate sectional area of the gap A is reduced and the amount of exhaust gas admitted into a detection part 17 through the contacting surface C is reduced. Therefore, when the amount of oxygen in the hollow part 4 is controlled, the voltage applied between the electrodes 18 and 19 is lowered.