Abstract: An oxygen sensor element with a ceramic heater, having a cylindrical element body formed of an oxygen ion permeable solid electrolyte with one end closed, inner and outer electrodes formed on the inner and outer surfaces of the element body, and an electrode protective layer covering at least one of the inner and outer electrodes, the ceramic heater including a bar-like ceramic core member, a ceramic covering layer which covers the outer surface of the ceramic core member and a heating member disposed in the interface between the core member and the covering layer.

Abstract: An oxygen sensor element having an oxygen ion-permeable solid electrolyte having a tabular or columnar shape and electrode layers formed on the solid electrolyte. At least one of the electrode layers is composed of a fired body having a uniform structure consisting of 100 weight parts of a metal and 0.1 to 10 weight parts of a glass which consists of the following materials in molar amounts: SiO.sub.2, 62-75%; ZrO.sub.2, 7-11%; R.sub.2 O, 13-23%; R'O, 1-10%; Al.sub.2 O.sub.3, 0-4%; B.sub.2 O.sub.3, 0-6%; Fe.sub.2 O.sub.3, 0-5%; CaF.sub.2, 0-2%; and TiO.sub.2, 0-4%; wherein R.sub.2 O is Na.sub.2 O which is substantially pure or is substituted by Li.sub.2 O within 2 mole percent thereof, and R'O is an oxide selected from the group consisting of the alkaline-earth metal oxides, ZnO and MnO. Disclosed also is a method of producing the oxygen sensor element.

Abstract: An oxygen concentration detector provided with an oxygen concentration sensor further provided with an oxygen ionic conductor, a cathode placed on one surface of the oxygen ionic conductor, an anode placed on the other surface of the oxygen ionic conductor, and a layer convering the cathode for regulating the diffusion of oxygen gas toward the cathode. Temperature compensation is applied to the output of the detector which is inherently influenced by the temperature of the sensor. More specifically, an oxygen concentration detector is provided with the foregoing oxygen concentration sensor, and voltage or current is alternatively supplied to the sensor to measure a limiting current of the sensor and internal resistance of the sensor, and the current or the voltage produced by the foregoing application of voltage or current, and a temperature compensation is applied to the detected magnitude of limiting current according to the internal resistance of the sensor.

Abstract: A leanness sensor has a sensor element made of an oxygen-permeable solid electrolyte and having a cylindrical form or a form like a vessel closed at one end thereof. The sensor element is provided with metallic electrodes formed on the inner and outer surfaces thereof. An inner metallic member and an outer metallic member are mounted on the sensor element and electrically connected to the metallic electrodes. The sensor element is fixed to the inner side of the end portion of a cylindrical insulating tube.

Abstract: A lean sensor for sensing oxygen concentration in exhaust emissions, including a sensor element consisting of a tabular solid electrolyte having opposed sides provided with electrodes with at least one surface thereof coated with a porous coating layer, an element fixing plate having an element fitting hole to which the element is fitted, and a pair of heat-resistant insulating support plates having opposing windows and clamping therebetween the element fixing plate together with the sensor element disposed in the windows. In this way, it is possible precisely to locate the element in relation to the plate and to improve the bonding strength and reliability while reducing the size of the sensor as a whole.

Abstract: An oxygen sensing element capable of measuring partial pressures of oxygen in sample gases, which element has a solid electrolyte member having totally embedded therein a means for providing a reference partial pressure of oxygen composed of a sintered product of a finely divided metal or metal-metal oxide mixture and having a lead-out wire connected thereto is prepared by a method wherein: p1 (a) a part of the finely divided solid electrolyte material is compression-molded to form a provisional solid electrolyte member having a hole;(b) a provisional product of the reference oxygen partial pressure-providing means is formed in the hole of the provisional solid electrolyte member from the finely divided metal or metal-metal oxide mixture;(c) the remaining part of the finely divided solid electrolyte material is piled up on the provisional reference oxygen partial pressure-providing means product, followed by compression molding the piled up solid electrolyte material to form an integrated structure comprising

Abstract: A catalyst supported oxygen sensor element detecting the oxygen concentration in exhaust gas from vehicle engines is composed of a tubular container of a solid ion-conductive electrolyte with the one end portion thereof closed, an inner electrode being positioned on the inner circumference of the container, an outer electrode being positioned on the outer circumference, a protective layer of a refractory material being provided on the outer circumference of the outer electrode, a catalyst layer being provided on the outer circumference of the protective layer, and optionally provided on the outer circumference of the catalyst layer, and a method of manufacturing the same.

Abstract: A solid pole oxygen sensor wherein an oxygen sensor element is composed of a solid pole with one end of a lead wire buried therein; an internal electrode formed on the outside surface of the solid pole; a solid electrolyte enclosing the electrode to constitute a solid pole assembly as a column with a projection at its top; and a platinum electrode separated from the lead wire. The oxygen sensor element is so secured to an almost cylindrical ceramic insulator by means of adhesive or the like that the upper top side of the oxygen sensor element having the projection is matched to a recess at the tip of the cylindrical ceramic insulator and a pair of electroconductive zones provided on the side wall of the cylindrical ceramic insulator are electrically connected with the platinum electrode and the lead wire. A process of manufacturing a solid oxygen sensor is also disclosed.

Abstract: In an oxygen concentration cell having metal electrodes formed on both inner and outer wall surfaces of its solid electrolyte vessel and a solid pole as a reference oxygen partial pressure source made of a metal alone or a mixture of a metal and an oxide of the metal filled in said vessel, a method of activating said oxygen concentration cell by heat-treating the cell so as to diffuse the metal of said reference oxygen partial pressure source into said metal electrode on the inner wall or into said solid electrolyte through the metal on the inner wall surface and the oxygen concentration cell produced by this method.

Abstract: An oxygen sensor with an oxygen sensor element having an outer protective layer of alumina, acting as getters with respect to catalyst poisons, particularly phosphorus, in exhaust gases, formed on the outer surface of a catalyst layer of platinum or a mixture of platinum and rhodium which is coated on an electrode protective layer provided on the outer electrode of an oxygen sensor element. Such an outer protective layer is additionally provided on the inner wall of the inner louver of the oxygen sensor having a double louver structure. A method of manufacturing an oxygen sensor with an oxygen sensor element comprising the steps of coating such an outer alumina protective layer onto the outer surface of said catalyst layer formed on an electrode protective layer provided onto the outer electrode of an oxygen sensor element and additionally coating such an alumina protective layer onto the inner wall of the inner louver of an oxygen sensor having a double louver structure.

Abstract: A protective layer of a refractory material deposited on a metal electrode layer of an oxygen sensing element is improved by a process comprising forming the protective layer onto the surface of the metal electrode layer by plasma spray coating the surface of the metal electrode layer, first with a refractory material powder at a position of a prescribed distance from a plasma spray coating device and at a prescribed electric power, and second, with a refractory material powder having the same particle size and composition as said refractory material powder used in the first plasma spray coating at a position of a distance greater than said prescribed distance and/or at an electric power lower than said prescribed electric power.

Abstract: Low temperature operability of an oxygen sensing element, which comprises a solid electrolyte member composed of sintered material, and a means for providing a reference oxygen partial pressure, composed of a sintered product of a finely divided metal or metal-metal oxide mixture powder and being completely embedded within the solid electrolyte member, is improved by the incorporation of from 0.5 to 10% by weight, based on the total weight of the sintered product, of a finely divided platinum group metal powder in the sintered product of the reference oxygen partial pressure-providing means.

Abstract: The high temperature durability of an oxygen sensing element, which comprises a solid electrolyte member composed of sintered material, and a means for providing a reference oxygen partial pressure, composed of a sintered product of a finely divided metal or metal-metal oxide mixture powder and being completely embedded within the solid electrolyte member, is improved by incorporating in the finely divided metal or metal-metal oxide mixture powder an antisintering material and a pore-forming material capable of subliming or being decomposed, thereby to generate gas upon sintering. The amounts of the antisintering material and the pore-forming material are from 5 to 70% by weight and from 20 to 80% by weight, respectively, based on the total weight of these additives-incorporated metal or metal-metal oxide mixture. The low temperature operation capability of the oxygen sensing element is improved by further incorporating therein a minor amount of a platinum group metal.

Abstract: The present invention relates to an oxygen concentration detector to be used in a system which can simultaneously dispose of the three harmful elements in automotive emissions, i.e., unburnt hydrocarbons (unburnt HC), carbon monoxide (CO) and nitrogen oxides (NOx) through reaction with catalyst. In said detector an oxygen concentration cell comprises a solid electrolyte of a special ceramic material characterized by oxygen ion-conductivity; and the oxygen concentration of a measured gas can be analyzed by measuring the electromotive force generated through a difference in the oxygen partial pressure between the measured gas and a reference gas.