Thermal shock resistant oxygen detector for engine exhaust gas - has zirconium oxide electrolyte tube with specified ratio of area to vol. in exhaust gas

摘要

O2 detector for measuring the O2 partial pressure in engine exhaust gas uses a solid Zr oxide electrolyte tu be, which is closed at one end and has inner and outer electrode coatings, the inner electrode being in contact with a reference gas, whilst the outer one is contacted with the exhaust gas by placing the closed end of the tube in the exhaust pipe. The ratio of the external area of the detector pt. placed in the exhaust gas to its vol. is min. 10 (cm2/cm3) and the outside dia. over the entire length of the detector pt. is max. 6mm, so that the Zr oxide electrolyte is protected against damage due to a sudden exhaust gas temp. change. The resistance to thermal shock is improved.