Abstract: The present invention relates to an electrochemical cell comprising a solid electrolyte conductive for O.sup.2- anions in contact with an anode and a cathode of identical or different composition, the electrolyte solid being comprised of a composition derived from Bi.sub.4 V.sub.2 O.sub.11 of which at least one of the cationic constituent elements is substituted by at least one substituting element chosen such that the gamma phase structural type of Bi.sub.4 V.sub.2 O.sub.11 is maintained, as well as the equilibrium of charges, at least one of the anode or the cathode including two parts, a first part being of a mixed electronic and ionic conductive material in contact with the solid electrolyte, the second part being an electronic conductive material superposed on the first part. The invention equally relates to the use of the electrochemical cell with a view towards the separation or the extraction of oxygen.

Abstract: A method and apparatus are disclosed for measuring atmospheric pressure in conjunction with an air-fuel ratio sensor of the type comprising a concentration cell with atmospheric air and exhaust electrodes on opposite sides of a solid-state electrolyte having oxygen ion conductivity. During an atmospheric pressure measuring cycle, oxygen ions are pumped from the atmospheric air electrode to the exhaust electrode, in a quantity which is either predetermined at a fixed value, or is sufficient to bring the cell to an equilibrium state. Atmospheric pressure is then calculated from measured emf of the cell, using an experimentally derived functional relationship. In a second embodiment, ions are pumped until a predetermined change of the concentration cell emf is achieved, and atmospheric pressure is determined based on the amount of time required to achieve such change. The atmospheric pressure measuring mode is operated on a time shared basis with the air-fuel ration detection mode.

Abstract: A gas sensor includes a sensor element having one end portion exposed to gas to be measured. A plurality of electrodes are provided on the other end portion of the sensor element. A plurality of terminal contacts are resiliently held in electrical contact with the electrodes, respectively, in such a manner that the terminal contacts hold the other end portion of the sensor element therebetween. The electrodes are so provided on the sensor element that the terminal contacts abut against the electrodes to prevent the sensor element from being moved axially and laterally.

Abstract: A boron nitride ceramic is used as a high temperature gasket material to prevent gas leakage between an exhaust gas oxygen sensor and the exhaust system of an internal combustion engine.

Abstract: A diagnostic apparatus applied to internal combustion engine exhaust gas sensors employing electrochemical polarographic principles indicates sensor operation relative to a current limiting operating region in which a sensor output signal indicates oxygen concentration in the exhaust gas. A sensor drive signal is controllably perturbed and sensor sensitivity monitored by monitoring the sensor response to the perturbation. Current limiting operation may be diagnosed and indicated when the sensor response indicates an insensitivity to the perturbation.

Abstract: A small-sized highly accurate gas sensor, which is excellent in its reliability of electric connections between contacts and fixtures while being freed from any damage, includes a base member; a detecting unit mounted on the base member for detecting a gas concentration; electrodes mounted on the detecting unit; cylindrical contacts buried integrally in an end portion of the base member; and electric leads interposed between the cylindrical contacts and the electrodes. Contacting fixtures for external lead wires are fitted in and contact the cylindrical contacts so that they are connected to the cylindrical contacts.

Abstract: Disclosed herein is a gas sampling system for analyzing the oxygen partial pressure in a gas carburizing atmosphere. The system is appropriate for remote sensing of gas when the probe can't be fitted in the heat treating apparatus. Sooting of the sampled gas tube and probe is eliminated by use of ceramic, non-catalytic surfaces in the measuring vessel. A ceramic feed pipe, with a small diameter, introduces the gas to be measured into the vessel and increases the velocity of the gas to avoid sooting.

Abstract: A sensor system accurately measures nitrogen oxide (NO.sub.x) in a gas mixture via the use of at least one electrochemical sensing cell and differential pulse voltammetry (DPV). The sensor system has a sensor with an electrochemical sensing cell for producing an electrical signal (current, voltage, etc.) indicative of an amount of the nitrogen oxide within the gas mixture. The sensing cell has an electrolyte interposed between an anode electrocatalyst and a cathode electrocatalyst. Significantly, a DPV mechanism is connected to the sensing cell for enhancing the sensitivity and selectivity of the electrolyte associated with the sensing cell.

Abstract: A sensor for measuring sulphur dioxide in flue gases comprises a sensing electrolyte of doped .beta.-alumina or doped NASICON. The dopant serves to increase conductivity at grain boundaries in the sensing element or at the electrode interface, thereby to increase the rate of depolarisation. Preferred dopants are copper silver and nickel.

Abstract: The invention is directed to an arrangement for detecting the oxygen content in the exhaust gas of an internal combustion engine. The arrangement includes a concentration measuring cell operating pursuant to the Nernst principle. The concentration measuring cell has a measuring electrode, a solid electrolyte and a reference electrode and a series circuit which includes a direct voltage source and a series resistor. The series circuit connects the measuring electrode to the reference electrode. The measuring electrode communicates with the exhaust gas of the internal combustion engine and is connected to the reference electrode via the solid electrolyte. The reference electrode communicates with the reference gas volume. The reference gas volume is partitioned from the exhaust gas and from the ambient air so that a particle exchange between the reference gas volume and the exhaust gas as well as between the reference gas volume and the ambient air is at least made more difficult.

Abstract: To shorten the time during which oxygen concentration cannot be detected, the temperature of an oxygen concentration sensor is detected by negatively biasing the sensor using a bias control circuit. A microcomputer estimates a saturated current thereof at one time before the current flowing through the sensor section ends rising based on a current detected by a current detecting circuit at that time. Further, the sensor is positively biased right after the elapse of a negative bias voltage application period by the bias control circuit. The microcomputer determines the air-fuel ratio based on the current flowing through the sensor at that time. The period in which the negative bias is applied is variably set appropriately by the microcomputer in response to changes of engine temperature and intake air amount. Furthermore, to activate the sensor quickly, the temperature of the sensor section is detected and a heater is controlled based thereon.

Abstract: A sensor element for determining concentration of at least one constituent of a gas mixture operates on an electro-chemical measuring process and includes a gas measuring chamber; a pair of electrodes and an electrode chamber located between the pair of electrodes; and a diffusion conduit adjoining the electrode chamber and having a gas input which connects with the gas measuring chamber, having a gas output which connects with the electrode chamber, and having at least one cross-sectional area including a height, w, and a length, L, which height, w, has a preselected minimum value, and which length, L, has a value which is equal to or greater than the preselected minimum value of the height, w.

Abstract: A non-catalytic metal is used as an inner electrode of a heated exhaust gas oxygen sensor to eliminate the negative shift produced in the sensor emf when rich exhaust leaks into the reference compartment.

Abstract: A planar polarographic sensor for determining the lambda value of gas mixtures, for use with exhaust gases in internal combustion engines, includes a planar ceramic carrier sheet having an outer pumping electrode and an inner pumping electrode respectively arranged on opposite planar sides thereof, and a diffusion barrier. The outer and inner pumping electrodes, and the diffusion barrier are arranged on the planar ceramic carrier sheet so that the measuring gas is fed via the diffusion barrier to the inner pumping electrode. The sensor has front and side edge faces. The diffusion barrier is configured as a diffusion layer at least partially covering the inner pumping electrode and exposed at least at one edge face of the sensor to the measuring gas. A diffusion-free planar region of the sensor is provided with an equalizing layer having the same thickness as the diffusion layer, and the equalizing layer is disposed in the same plane with and adjacent to the diffusion layer.

Abstract: An oxygen concentration detection apparatus for an internal combustion engine is capable of starting feedback control of an air-fuel ratio in the shortest time possible after the engine has been started, thereby preventing the blackening of an oxygen concentration sensor 1, incorrect determination of the air-fuel ratio immediately after start of the current supply to a heating element 20, and damage to the oxygen concentration sensor 1 due to a temperature rise of the heating element 20 when the engine is cold started. A heating state of the heating element 20 of a variable resistance type, which heats the oxygen concentration sensor 1, is detected so that the current supply to an oxygen pumping device 18 is controlled in accordance with the detected state of the heating element 20.

Abstract: A sensor arrangement for determining at least one of gas components and gas concentrations of gas mixtures including CO, NO.sub.x and HC in exhaust gases of internal combustion engines, includes a measuring element which has a sensitive region; and a pump cell that includes a solid electrolyte and inner and outer pump electrodes which are opposingly disposed at least on the solid electrolyte and which effect an oxygen transfer to the measuring element, wherein the pump cell and the measuring element are spatially separated from one another, are located in different temperature zones during operation of the sensor arrangement, and are connected to one another by a diffusion segment through which oxygen can diffuse from the pump cell to the measuring element.

Abstract: A control device and associated methodology select from at least two on-line sensors to assure an accurate and reliable feedback input to control the heat treating conditions within a furnace. The device and methodology also serve to provide an "alert" or "early warning" of gradual degradation of sensor performance, before ongoing heat treating operations are adversely affected.

Abstract: The invention relates to a measuring sensor having an internal pump oxygen reference atmosphere which, in turn, has a device for compensating pressure which is so dimensioned that, on the one hand, mechanical damage because of overpressure in the reference volume is reliably prevented and, on the other hand, external influences on the composition of the pumped measured gas atmosphere are substantially excluded. The device for compensating for pressure is so dimensioned according to the invention that the particle exchange between ambient air and gas to be measured is opposed by a resistance which is defined by the limit current principle.

Abstract: The invention is directed to a method of operating an exhaust-gas probe having a pumped reference atmosphere in a relatively closed volume. In this method, the oxygen ion current, which carries the pump current Ip to the reference atmosphere, is temporarily increased under specific conditions. In this way, an adulteration of the reference atmosphere can be more rapidly eliminated. This adulteration can occur because of fuel particles which diffuse in.

Abstract: A solid state electrochemical cell is provided for performing electrocheml measurements on a solid electrolyte at high temperatures. The solid state electrochemical cell includes a noble metal working electrode, a lithium alloy reference electrode, and counter electrode, and a solid solution of lithium germanium oxide and lithium vanadium oxide as the solid electrolyte.

Abstract: An electrochemical measuring probe for determining the oxygen content of gases, in particular of exhaust gases of internal combustion engines, whose measuring probe body consists essentially of a solid electrolyte, for example stabilised ZrO.sub.2 and whose electrode exposed to the gas to be measured is a cermet electrode which is coated with a finely porous ion-conducting covering layer composed of an ion-conducting supporting matrix material having no sintering activity of the type standard for cermet electrodes the covering layer is covered by a porous protective layer. The ion-conducting porous covering layer appreciably increases the activity of the cermet electrode.

Abstract: This sensor, which is of the oxygen pump type, makes it possible to generate an electric signal representative of the oxygen content of a gas, linearly dependent on this oxygen content, made of a solid electrolyte plate (3), one of whose faces is partly covered by a cathode (1) impervious to oxygen to be brought into the presence of the said gas, and whose other face is covered by an anode (2) to be brought into the presence of a reference gas. Under the effect of the difference in potential prevailing between the two electrodes (1, 2), there appears at the surface of the solid electrolyte an area (I) in which the molecular oxygen contained in the said gas is transformed into negative ions. The electrons captured by the oxygen during this transformation produce the said electric signal.

Abstract: The invention relates to a measuring sensor having pump reference for measuring the oxygen content of gas mixtures, particularly exhaust gases of internal combustion engines. The sensor includes a measuring cell (A) and a reference cell (B) each having a pair of electrodes, with one of each respective pairs of electrodes being common to the two cells, and having a fixed electrolyte. Reference cell (B) has defined therein an internal oxygen reference zone which is hermetically sealed from the gas mixture and which is connected to the atmosphere by way of a pressure-equalization line. The measuring cell (A) and the reference cell (B) can be heated by heating apparatus to a temperature at which the fixed electrolyte has an ionic conductivity which is sufficiently high.

Abstract: An oxygen concentration detector provides high durability by increasing the thermal stability of coating layers applied to an electrode face thereof. A catalyst layer is formed on an outer surface of an electrode at the analysis gas side of a partition wall made of an ion oxygen conductive ceramic for generating electromotive force according to the difference between the concentration of oxygen in the analysis gas and the concentration of oxygen in the reference gas. The catalyst layer is composed of heat resistant ceramic particles and a particulate metallic catalyst made of platinum, rhodium or the like, supported by the surface of the heat resistant ceramic particles. The catalyst layer is formed so that the catalyst is supported by the heat resistant support particles. The support particles are heat treated to grow to a particle size so that particle growth can be restrained when the support particles are exposed to the exhaust gas from an internal combustion engine.

Abstract: A process and system for removing trace amounts of oxygen as an impurity in inert gases is disclosed. The process and system involve an electrochemical cell containing an oxygen ion transporting, solid state metal oxide electrolyte having a high thermodynamic potential and having only one thermodynamically stable valence state for the metal ion component of the electrolyte. The electrolyte is coated with a perovskite anode and a metallic cathode. Operation is conducted at high voltages, e.g., 1.5 volts and above, at elevated temperatures. Purification of inert gases to an oxygen content of about 1 ppm is readily achievable.

Abstract: Oxygen-sensor element comprises reference-gas-side and detection-gas-side electrodes on both surfaces of a solid-electrolyte body, and a porous protective layer on the surface of the detection-gas-side electrode, wherein at least a part (including at least a surface layer) of said porous protective layer is formed by a granular texture of a grain size of 0.1 to 0.5 .mu.m formed mainly of a nonstoichiometric compound of a transition metal oxide (TiO.sub.x), and a catalyst for having gas components of the gas to be measured react is carried in at least a part (including at least a surface layer) of the porous protective layer. Oxidation reaction of gas components is improved to prevent deterioration of the responsive property.

Abstract: A solid electrolyte sensor device for determining gas concentrations in measurement gases, with a sensor formed by a solid electrolyte which is arranged between at least two electrodes. The electrodes are permeable to gas and at least one of the electrodes faces the measurement gas. An electrical device is also provided for detecting and processing concentration-dependent sensor output values. For the purpose of permanently preventing disruptive adsorption of measurement gas components on the sensor or on the corresponding sensor electrode, an adjustable oxygen source is arranged in the vicinity of the sensor electrode which faces the measurement gas so that oxygen or oxygen radicals can be introduced into the measurement gas via this oxygen source for the oxidation of the measurement gas.

Abstract: An electrochemical measuring sensor is proposed for determining the oxygen content in exhaust gases which has a base body made of an ion-conducting solid electrolyte in the form of a tube closed at one end, an inner electrode, an outer electrode disposed on the external surface of the probe block and having a conductor track on the connection side which has a covering layer, a ceramic protective layer and a metallic sealing ring for sealing the reference space from the exhaust gas space and for making an electrical contact to the housing in which the measuring sensor is to be inserted. The electrochemical covering layer covering the conductor track is brought down on the reference side of the probe block to below the metallic sealing ring and the track is formed with uncovered lateral extensions making electrical contact with the ring. This makes it possible to significantly prolong the service life of the measuring sensor.

Abstract: An electrocatalytic device for sensing gases. The gas sensing device includes a substrate layer, a reference electrode disposed on the substrate layer comprised of a nonstoichiometric chemical compound enabling oxygen diffusion therethrough, a lower reference electrode coupled to the reference electrode, a solid electrolyte coupled to the lower reference electrode and an upper catalytically active electrode coupled to the solid electrolyte.

Abstract: The invention includes an automotive exhaust gas sensor including an inside belleville design, wherein a belleville spring is located inside a middle shell sub-assembly and below an upper insulator. The design provides for improved interior loading pressures with improved resiliency for a self-contained air reference source exhaust gas sensors.

Abstract: An exhaust gas sensor which is exposed to exhaust gas, includes a measuring electrode; and a porous ceramic coating provided on the measuring electrode and comprised of at least two layers, a first porous ceramic layer which is provided on the measuring electrode and at least a second porous ceramic layer which is provided on the first porous ceramic layer and which is directly exposed to the exhaust gas, wherein the first porous ceramic layer contains getter substances for removal of substances that are harmful to the measuring electrode, and wherein the second porous ceramic layer is provided with one of a diffusion resistance or a catalytic effect relative to exhaust gas constituents such that, at the boundary of the first and second porous ceramic layers, a gas composition is present in use which is comprised of one of oxidizable or reducible gas constituents and which sets a control position for the exhaust gas sensor.

Abstract: A gas or fluid pressure or force sensor is disclosed consisting of a fluid-tight housing containing a supply of electrochemically active gas and an electrolytic membrane disposed to divide the housing into two chambers. The electrolytic membrane has one or more pervious electrodes disposed on each side of and in contact with the membrane. A flexible bellows or diaphragm is disposed to form one wall of the fluid-tight housing and provide the contacting surface for transferring a force or pressure to the sensor. A controller is connected to display measurements and to permit automatic sensor calibration, differential pressure-induced diffusion compensation, temperature compensation and sensor chamber pressure control. The disclosed force sensor is useful for application to robotic manipulators and the basic device is useful for measurement of the gas partial-pressure of a selected gas.

Abstract: A solid electrolyte gas-sensing device comprising a solid electrolyte layer (a) and a reference electrode layer (b) and a working electrode layer (c) with the solid electrolyte layer (a) being an intermediate layer therebetween, said working electrode layer (c) having a mixture layer (d) in the interface between said solid electrolyte layer (a) and said working electrode layer (c), the mixture layer (d) being formed from a metal salt which shows dissociation equilibrium with a gas to be measured and an electron-conducting substance, the mixture layer (d) containing 0.5 to 14% by volume of the electron-conducting substance.

Abstract: An oxygen sensing apparatus for detecting an oxygen concentration of a gas is disclosed. The apparatus includes a first electrochemical cell having an oxygen-ion conductive solid electrolyte body and a reference and a measuring electrode, for producing an electromotive force which corresponds to the oxygen concentration of the gas. A reference-gas chamber formed around the reference electrode is provided with a reference gas by an oxygen pumping action of the first electrochemical cell. The apparatus further includes a second electrochemical cell including a solid electrolyte body and a pair of electrodes, one disposed in a measurement-gas chamber formed around the measuring electrode, and the other exposed in an external space. The measurement-gas chamber is provided with an oxygen gas by an oxygen pumping action of the second electrochemical cell to feed oxygen from the external space into the measurement-gas chamber.

Abstract: A conduit defined by an oxygen ion permeable wall formed of zirconia or other materials and having gas permeable electrodes disposed on an inner and outer surface of the wall. The electrodes are configured to form two oxygen pumps that share an electrode on the inner surface in order to minimize interference with gas flowing through the conduit, yet allow a number of operations to be performed on the gas as it flows. The conduit can be used as a getter for removal of oxygen from even reactive gases. The conduit can also be used as a pump for injecting a known quantity of oxygen to the gas, the oxygen supplied from air outside the conduit. The upstream pump can be used as a getter and the downstream pump for oxygen injection, thereby providing a known concentration of oxygen gas or oxidants, such as water vapor, in the gas exiting the conduit. The conduit can contain a pair of sensor electrodes on the inner and outer surface downstream of the other electrodes.

Abstract: An oxygen concentration measuring device capable of significantly shortening the period of time during which oxygen concentration cannot be measured. When measuring the temperature of a sensor main body, a microcomputer determines the temperature of the sensor main body by estimating a saturation current starting from a current detected by a current detecting circuit in a period of time before current flowing through the sensor main body finishes rising, after the sensor main body has been negatively biased by a bias control circuit. The sensor main body is positively biased by the bias control circuit directly after the period of time has lapsed. The microcomputer determines an air fuel ratio by using current in a period of time before current flowing through the sensor main body due to the positive bias finishes decreasing.

Abstract: An exhaust sensor having a substrate including first and second portions, the first portion comprising a dielectric material, the second portion comprising an electrolyte material and a transition zone interposed between the first and second portions. The transition zone includes an increasing concentration of the dielectric material in the direction of the first portion of the substrate and an increasing concentration of the electrolyte material in a direction towards the second portion of the substrate. The invention also includes a method of making such an exhaust sensor substrate including the steps of co-depositing first and second amenable compositions, the first composition comprising a dielectric material and the second composition comprising an electrolyte material. The co-deposited compositions are fired together to form the substrate having first, second and transition portions as described above.

Abstract: A humidity sensing device comprising a solid electrolyte evidencing proton conductivity includes a composite comprising HZr.sub.2 P.sub.3 O.sub.12 /ZrP.sub.2 O.sub.7. The humidity sensing device is operative over a temperature range from 350.degree.-600.degree. C.

Abstract: An oxygen sensor capable of accelerating electrochemical reactions and practically working at a low temperature comprises a solid electrolyte 5, and an outer electrode 31 and an inner electrode 32, provided on the surfaces of the solid electrolyte 5, wherein mixed conductors 11 and 12 capable of adsorbing oxygen molecules and conducting an ionization reaction are provided between the solid electrolyte 5 and the outer electrode 31 and between the solid electrolyte 5 and the inner electrode 32, respectively. The mixed conductors 11 and 12 are porous and have a higher oxygen ion conductivity than that of the solid electrolyte 5 and an electron conductivity substantially equivalent to the oxygen ion conductivity and are made of a fluorite-type oxide or a perovskite-type oxide.

Abstract: An arrangement determines a voltage which indicates the lambda value of an air/fuel mixture supplied to a combustion engine generating exhaust gas during the operation thereof. The arrangement includes a two-cell oxygen probe mounted in the exhaust gas flow of the engine. The two-cell oxygen probe has an exhaust-gas space for the exhaust gas and an ambient-air space for ambient air. The oxygen probe has a pump cell having two electrodes and a sensing cell having two electrodes. A switchover stage outputs a voltage indicating the electric pump current through the pump cell when a control to the lambda value deviating from one is to be made and outputs that Nernst voltage which is taken off between the electrodes of the sensing cell facing into the ambient air and one of the remaining ones of the electrodes when a control to the lambda value one is to be made. For controlling to the lambda value one, the Nernst voltage supplies a significantly more precise signal than the voltage derived from the pump current.

Abstract: An electrochemical measuring sensor for the determination of the air/fuel ratio in exhaust gases of internal combustion engines both in the low-fuel and also in the fuel-rich range with a sensor element with an electrochemical oxygen concentration cell and an oxygen pumping cell with solid electrolyte base is proposed, in which the sensor element is arranged in a housing, capable of insertion in the exhaust gas pipe, in a manner such that the electrodes of the electrochemical oxygen concentration cell and of the oxygen pumping cell of the sensor element in the measuring sensor are situated outside the exhaust gas pipe, the communication with the atmosphere taking place via openings in the housing and the communication with the exhaust gas taking place via a diffusion slit. The sensor element is characterized by a particularly simple construction, free oxygen being available to the oxygen pumping cell both in the lean and also in the rich lambda range.

Abstract: A sensor for determining the stoichiometric air to fuel ratio (A/F) at the intake of an internal combustion engine is based on a capacitive device in the exhaust stream which can be used to measure the change in the workfunction of an appropriate material which occurs at the stoichiometric point and which forms one of the two interacting elements of the capacitor. To measure A/F over an extended range about stoichiometry the material whose workfunction changes is made the working electrode of an oxygen concentration cell using a solid electrolyte. Oxygen pumping to and from that surface can change the magnitude of the workfunction allowing for a feedback control method for keeping the workfunction constant despite changes in the A/F so that the required pump current becomes a measure of the A/F.

Abstract: A method of monitoring, while on board an automotive vehicle, one or more of catalyst performance, engine misfire, and combustion quality, the vehicle having an internal combustion engine equipped with a catalyst for converting noxious emissions of the engine, comprising: (i) exposing at least one pair of EGO sensors to substantially the same emissions either exiting from the engine or from the catalyst, one of the EGO sensors having its electrode highly catalytic, and the other sensor having its electrode low-to-noncatalytic; (ii) comparing the outputs of the sensor electrodes (amplitude, frequency, or phase shift) to determine if there is a sufficient differential to indicate a misfire or poor combustion in the case of the sensors being located downstream of the engine exhaust but upstream of the catalyst, or indicating poor catalyst efficiency in the case of the sensors being placed substantially immediately downstream of the catalyst. The catalyst may be a three-way catalyst (or an oxidation catalyst).

Abstract: A method of monitoring, while on board an automotive vehicle, one or more of catalyst performance, engine misfire, and combustion quality, the vehicle having an internal combustion engine equipped with a catalyst for converting noxious emissions of the engine, comprising: (i) exposing at least one pair of EGO sensors to substantially the same emissions either exiting from the engine or from the catalyst, one of the EGO sensors having its electrode highly catalytic, and the other sensor having its electrode low-to-noncatalytic; (ii) comparing the outputs of the sensor electrodes (amplitude, frequency, or phase shift) to determine if there is a sufficient differential to indicate a misfire or poor combustion in the case of the sensors being located downstream of the engine exhaust but upstream of the catalyst, or indicating poor catalyst efficiency in the case of the sensors being placed substantially immediately downstream of the catalyst. The catalyst may be a three-way catalyst (or an oxidation catalyst).

Abstract: A wide range oxygen sensor is provided which operates partially in the diffusion limited current mode to provide an output which is proportional to the oxygen partial pressure in a gas mixture which is sensed, such as the exhaust gas of an automotive internal combustion engine. The wide range oxygen sensor is constructed to have a planar structure with a single solid electrolyte layer that is shared by electrochemical storage, pumping and reference cells and which is deposited using known thermal deposition techniques. As a result, the wide range oxygen sensor of the present invention is characterized as being relatively low cost and readily producible under mass production conditions. Moreover, the wide range oxygen sensor is capable of rapidly and accurately sensing the exhaust gas oxygen partial pressure while the engine is operating in either the fuel-rich or fuel-lean condition to enable the evaluation of the air-to-fuel ratio of the precombustion fuel mixture.

Abstract: A probe for measuring oxygen potential, especially to determine the carboransfer properties of a furnace atmosphere containing the gases H.sub.2, CO, and CH.sub.4, with the probe having an oxygen ion conducting, solid measuring electrolyte with a contact electrode in the furnace atmosphere and a contact electrode in a reference medium that has a known oxygen concentration. To improve the accuracy of the measurement, an oxygen ion conductive compensation electrolyte in the form of a detachable solid body is connected between the contact electrode in the furnace atmosphere and the solid measuring electrolyte.

Abstract: An oxygen concentration detecting apparatus having, a pumping cell and a sensing cell, electrodes formed on both surfaces of each of the pumping and sensing cells, a related support structure forming a closed space by being connected with the pumping and sensing cells, an opening communicating between the closed space and the surrounding environment, an electromotive force detector for detecting an electromotive force generated between the electrodes of the sensing cell, a voltage source for applying a voltage between the electrodes of the pumping cell, a current detector for detecting as a signal representing the oxygen concentration a current flowing in the pumping cell when a voltage is applied between the electrodes of the pumping cell, and a controller for controlling the voltage so that the electromotive force is constant at a specified value at which value the above-mentioned current is 70% or less of the limiting current.

Abstract: A gas or fluid pressure or force sensor is disclosed consisting of a fluid-tight housing containing a supply of electrochemically active gas and an electrolytic membrane disposed to divide the housing into two chambers. The electrolytic membrane has one or more pervious electrodes disposed on each side of and in contact with the membrane. A flexible bellows or diaphragm is disposed to form one wall of the fluid-tight housing and provide the contacting surface for transferring a force or pressure to the sensor. A controller is connected to display measurements and to permit automatic sensor calibration, differential pressure-induced diffusion compensation, temperature compensation and sensor chamber pressure control. The disclosed force sensor is useful for application to robotic manipulators and the basic device is useful for measurement of the gas partial-pressure of a selected gas.

Abstract: Disclosed herein is a gas atmosphere sampling system for analyzing the oxygen partial pressure in a gas carburizing atmosphere. The system is appropriate for remote sensing of gas atmosphere when the probe can't be fitted in the heat treating apparatus. Sooting of the sampled gas tube and probe is eliminated by use of ceramic, non-catalytic surfaces in the measuring vessel. A ceramic feed pipe, with a small diameter, introduces the gas atmosphere to be measured into the vessel and increases the velocity of the gas atmosphere to avoid sooting.

Abstract: A sensor for determining the stoichiometric air to fuel ratio (A/F) at the input to the cylinders of an internal combustion engine which is based on measuring the change in the workfunction of a material which occurs when the oxidizing and reducing species in the adjacent gas phase are at or near their stoichiometric ratio. In one method the sensor includes a material which is capable of thermionically emitting alkali metal or other appropriate ions into an exhaust gas atmosphere where they are subsequently collected by a nearby collector electrode and the magnitude of the emission current is measured. The interaction of the emitting surface with the gas phase reversibly changes the workfunction of the emitting surface from large to smaller values as that gas phase is varied through the stoichiometric ratio with respect to the amounts of the oxidizing and reducing species in the gas.