OXYGEN SENSOR PARTICULARLY FOR USE IN EXHAUST SYSTEM FOR AUTOMOTIVE ENGINES

摘要

A solid electrolyte tube closed at one end and two porous electrode layers respectively coated on the outer and inner surfaces of the electrolyte tube constitute a known oxygen concentration cell. A tubular metal shell encloses the electrolyte tube partly such that a closed end portion of the tube protrudes from the shell and that the outer electrode coating is locally in contact with the inside of the shell, and a metal tube is partly and fixedly inserted into the bore of the electrolyte tube to serve both as an inner conductor and as an air admitting conduit. To protect the open end of the electrolyte tube against splashing of water during use, an annular ceramic pad is placed on the open end face of the electrolyte tube allowing the metal tube to pass therethrough, and a tubular cap which is shaped to tightly sheathe the ceramic pad is fixed at one end to the shell to prevent the ceramic pad from parting from the end face of the electrolyte tube.