Abstract: In an exemplary embodiment, the present invention provides an exhaust constituent sensor comprising a planar sensing element securely held in place within a tubular shield by disposing a high temperature mat support between the tubular inner shield and the planar sensing element. The high temperature mat support comprises suitable mat material, e.g., ceramic fibers or metal mesh, and preferably, comprises silica fibers, alumina fibers, alumina fibers with vermiculite, or any other suitable mat material providing the desired support, strength, and thermal and electrical insulating properties described herein. It is within the scope of the invention that the high temperature mat support may be in the form of a fibrous material or a more rigid perform structure, wherein in both instances, the high temperature mat support is adapted to be disposed concentrically around the planar sensing element for secure packaging thereof.

Abstract: A gas sensor is provided for measurement of oxygen and/or the air-to-fuel lambda ratio and hydrocarbons and/or carbon monoxide in gas mixtures. To reliably measure a plurality of gaseous components, the sensor is provided with a reference electrode representing a constant oxygen partial pressure, an oxygen ion-conducting solid electrolyte, and at least two measuring electrodes, the measuring electrodes and the reference electrode being mounted directly on the solid electrolyte and having electrical leads for connection and for take-away of electrical measurement signals. The solid electrolyte (1) is constructed with a measurement gas side exposed to the gas mixture and a reference gas side separated from the gas mixture.

Abstract: Disclosed are a gas sensor and a nitrogen oxide sensor each comprising a first diffusion rate-determining section for giving a predetermined diffusion resistance to a measurement gas to be introduced into a first chamber, the first diffusion rate-determining section being formed with a slit having a laterally extending aperture formed at a front end portion of a second spacer layer to make contact with the lower surface of a second solid electrolyte layer in which the aperture is formed to extend with an identical aperture width up to the first chamber, and a slit having a laterally extending aperture formed at a front end portion of the second spacer layer to make contact with the upper surface of a first solid electrolyte layer in which the aperture is formed to extend with an identical aperture width up to the first chamber.

Abstract: A gas sensor in the form of a mixed-potential sensor in which the influence of temperature-dependent interference is reduced. An improved temperature control is provided with the help of a temperature sensor mounted on the surface of the electrolytic substrate.

Abstract: The present invention is directed to a stable, non-hazardous solution for calibrating oxidation-reduction potential (ORP) measurement cells. The redox standard calibration solution of the present invention consists essentially of an aqueous solution containing the triiodide/iodide redox couple. In a preferred embodiment, the solution of the present invention consists essentially of an aqueous solution containing up to about 0.01 moles per liter of iodine (I2) and at least about 1 mole per liter of potassium iodide. In a most preferred embodiment, the solution of the present invention consists of an aqueous solution of 4 molar potassium iodide (KI) and 0.0067 molar iodine (I2).

Abstract: Chemical sensors for detecting the activity of a molecule or analyte of interest is provided. The chemical sensors comprise and array or plurality of chemically-sensitive resistors that are capable of interacting with the molecule of interest, wherein the interaction provides a resistance fingerprint. The fingerprint can be associated with a library of similar molecules of interest to determine the molecule's activity.

Abstract: A plate-shaped sensor element is proposed, in particular for determining the oxygen level in exhaust gases of internal combustion engines. The sensor element has at least one measuring cell with an oxygen-ion-conducting solid electrolyte and a heating element, the measuring cell and the heating element being connected with an electrical insulation layer. The material of the insulation layer is made of at least one crystalline, non-metallic material and at least one glass-forming material, a glazing filled with the crystalline, non-metallic material being formed when the sensor element is sintered.

Abstract: Electrodes carrying FAD-dependent enzymes on their surface are enclosed. The FAD is modified to include a functional group or moiety which affects the properties of the enzyme. The functional group or moiety can be a binding moiety through which the FAD-enzyme complex is immobilized onto the electrode; it can be an electron mediator group for transferring electrons between the electrode and the FAD; or it can be a photoisomerizable group which can undergo photoisomerization which yields a change in the rate of the electrically induced catalytic activity of the enzyme. The electrodes can be used in electrochemical systems for deforming analytes in liquid medium or for recordal of optical signals.

Abstract: A total of a most adjacent spacing distance in an axial direction between an outer gas-introducing hole of an outer protective cover and a slit provided at a flange of an intermediate protective cover and a most adjacent spacing distance in the axial direction between the slit of the intermediate protective cover and an inner gas-introducing hole of an inner protective cover is at least not less than 10 mm. Gaps for avoiding accumulation of water due to boundary tension are provided in a radial direction between the outer protective cover and the intermediate protective cover and in the radial direction between the outer protective cover and the inner protective cover.

Abstract: A gas sensor including a detection element having a front-end portion, a detection portion formed at the front-end portion of the detection element, and a protector that covers the detection portion. The protector includes a first portion having a first sidewall and a second portion having a second sidewall disposed outside the first portion. The first sidewall has an axial front end and a tapering portion. The tapering portion is formed from the axial front end of the first sidewall. The side portion has a front-end surface provided with a first gas outlet, and the second portion has a front-end surface provided with a second gas outlet. Furthermore, at least one gas inlet is formed to the sidewall of the second portion opposite the tapering portion, and plural gas inlets are formed on the sidewall of the first portion.

Abstract: Herein described is an exhaust gas sensor that is used to detect gas concentration in a “lean only” exhaust stream. The gas sensor comprises a single cell within a dielectric substrate. The cell has an electrolyte with an inner and outer electrode disposed against opposite sides of the electrolyte. A porous protective layer is disposed against the outer electrode. Gases can enter and exit the galvanic cell through the porous protective layer. A voltage is applied across the electrodes, and ions are actively pumped out of the cell. The applied current can be used to determine a specific gas concentration in the exhaust stream.

Abstract: It is intended to avoid invasion of oxygen through any route except for an introducing port for a measurement gas so that the amount of oxide or inflammable gas contained in the measurement gas may be measured highly accurately. Insulative layers are provided for respective lead wires at positions corresponding to portions at which the temperature of the oxygen ion-conductive solid electrolyte is increased due to heat generation effected by a heater. Each of the insulative layers is formed to have a pattern in which one end is exposed to a first chamber or a second chamber, and the other end terminates at a position separated by a predetermined distance from a corresponding through-hole. At least the lead wires, which lead to an auxiliary pumping electrode and a detecting electrode, are densified. Preferably, the insulative layers for these lead wires are also densified.

Abstract: A process for operating an electrochemical measuring cell (1) is described, with which it is possible to carry out gas concentration measurements already shortly after switching on the measuring cell (1). The process includes the steps that potential voltage pulses are applied to the measuring cell (1) in a state of readiness of the measuring cell (1), in which the potential voltage is switched off. A system and device are also described.

Abstract: An improved structure of an oxygen sensing element installed in an oxygen sensor designed to measure an oxygen content in gases is provided. The structure includes a cup-shaped solid electrolyte body, an inner electrode, and an outer electrode. The solid electrolyte body has a portion exposed to the gases which has a given length. The inner electrode is formed on an inner wall of the solid electrolyte body and exposed to air. The outer electrode is formed on an outer wall of the solid electrolyte body and exposed to the gases through a protective layer. The oxygen content in the gases is measured based on output signals from the inner and outer electrodes. The outer electrode occupies an area on the outer wall of the solid electrolyte body within a range of 80% of the given length of the gas-exposed portion of the solid electrolyte body and has a thickness ranging from 1.2 to 3.0 &mgr;m.

Abstract: A method of measuring oxygen and/or the air-to-fuel lambda ratio and hydrocarbons and/or carbon monoxide in gas mixtures using a gas sensor is provided. To reliably measure a plurality of gaseous components, the sensor is provided with a reference electrode representing a constant oxygen partial pressure, an oxygen ion-conducting solid electrolyte, and at least two measuring electrodes, the measuring electrodes and the reference electrode being mounted directly on the solid electrolyte and having electrical leads for connection and for take-away of electrical measurement signals. The solid electrolyte is constructed with a measurement gas side exposed to the gas mixture and a reference gas side separated from the gas mixture.

Abstract: A measuring device (e.g., an electrochemical sensor) has a sensor element arranged at a measuring point, the sensor element being arranged in a housing, which is linked via electrical connecting lines to an evaluation circuit away from the measuring point, and the electrical connecting lines being routed, at least in the vicinity of the measuring point, in a protective device. Provision is made that the protective device is joined, with a force-locking and form-locking fit, to the housing via an attachment device, which embraces (surrounds) the housing and the protective device, to form a sealing seat.

Abstract: The present invention is an exhaust sensor seal and a method for making the same. A talc disk disposed between two support disks forms a talc assembly where at least one of which is metal. As pressure is applied to the assembly, the talc is forced into any voids in the sensing end of the exhaust sensor body from exhaust gases.

Abstract: A method for determining the concentration of a substrate in a sample solution using an electrode system comprising a working electrode, a counter electrode, and a reaction layer which contains at least an oxidoreductase and an electron mediator and is formed on the electrode system to electrochemically measure a reduced amount of the electron mediator resulting from enzyme reaction in the reaction layer, wherein a third electrode is formed as an interfering substance detecting electrode. A current flowing between the counter electrode and the third electrode is measured which is taken as a positive error. Subsequently, voltage application between the counter electrode and the third electrode is released and a voltage for oxidizing the reduced form electron mediator is applied between the working electrode and the counter electrode to measure a current flowing between the two electrodes.

Abstract: A multilayered air-fuel ratio sensing element comprises a solid electrolytic substrate having oxygen ion conductivity. A measuring gas sensing electrode is provided on one surface of the solid electrolytic substrate so as to be exposed to a measuring gas. A reference gas sensing electrode is provided on another surface of the solid electrolytic substrate so that the reference gas sensing electrode is exposed to a reference gas introduced into a reference gas chamber. The measuring gas sensing electrode is covered by a porous diffusive resistor layer. And, a hollow space is provided between the measuring gas sensing electrode and the porous diffusive resistor layer.

Abstract: An electrochemical sensor for insertion into slag for determining the activity of a metal oxide in the slag is disclosed. The sensor includes a reference electrode comprising a mixture of a metal alloy and a metal oxide, the metal alloy and the metal oxide each being exposed on a surface of the reference electrode. The sensor also includes at least one oxide electrode comprising a mixture of a metal alloy and a metal oxide different from the mixture of the reference electrode, the metal alloy and the metal oxide of the oxide electrode each being exposed on a surface of the oxide electrode. The sensor further includes a refractory housing holding the reference electrode and each oxide electrode. The reference electrode and each oxide electrode extend from the refractory housing such that the surface of the reference electrode and the surface of the oxide electrode are each in direct contact with the slag when the sensor is inserted into the slag.