Abstract: A multi-gas sensor device for the detection of dissolved hydrocarbon gases in oil-filled electrical equipment. The device comprising a semiconductor substrate, one or more catalytic metal gate-electrodes deposited on the surface of the semiconductor substrate operable for sensing various gases, and an ohmic contact deposited on the surface of the semiconductor substrate. The semiconductor substrate comprises one of GaN, SiC, AlN, InN, AlGaN, InGaN and AlInGaN. A method for sensing gas in an oil-filled reservoir of electrical equipment, comprising providing a sensor device, immersing the sensor device in the oil-filled reservoir, allowing the gases emitted from the oil to interact with the one or more catalytic metal gate-electrodes, altering the gas as it contacts the catalytic metal gate-electrodes and altering the sensitivity of the sensor.

Abstract: A flat limiting-current sensor 10 includes a solid electrolyte substrate 22, a negative electrode 34a and a positive electrode 32a. The negative and positive electrodes 34a and 32a, respectively, are disposed on the same side of the solid electrolyte substrate 22. A voltage of 0.8 V is applied between the negative electrode 34a and the positive electrode 32a in order to determine oxygen concentration. The ratio between the area of the negative electrode 34a and the area of the positive electrode 32a is set to 1:2, thereby reducing element resistance to 74% that of the case where the negative electrode and the positive electrode assume the same area. Thus, the measurement accuracy of the flat limiting-current sensor 10 is improved.

Abstract: In a limiting current type oxygen sensor, a plane cathode layer and a plane anode layer are arranged on both sides of a solid electrolyte layer, and a porous diffusion layer for controlling gaseous diffusion rate is arranged on the other side of the cathode layer. Additionally, the cathode layer has a bonding pad portion for connecting electrically to an external lead wire. A part of the bonding pad is in contact with the solid electrolyte layer, and the other part of the bonding pad is exposed to an atmosphere of the sensor. A patterned gas barrier film is disposed in between a boundary between the part of the bonding pad being in contact with the patterned solid electrolyte layer and the other part of the bonding pad exposed to the atmosphere, and surroundings thereof so as not to expose the boundary directly to the atmosphere.

Abstract: A gas sensing element and related manufacturing method are disclosed with a solid electrolyte body having one surface formed with a measuring-gas-side electrode and the other surface formed with a reference-gas-side electrode, wherein a measuring-gas-side lead portion is formed on the solid electrolyte body in connection with the measuring-gas-side electrode and a reference-gas-side lead portion is formed on the solid electrolyte body in connection with the reference-gas-side electrode. A dense protective layer is formed on the solid electrolyte body so as to cover the measuring-gas-side lead portion, and a porous protective layer is laminated on the dense protective layer so as to cover the measuring-gas-side electrode, wherein the relationship is established as QB?0.8 QA where QB represents a porosity rate of a base end region of the measuring-gas-side lead portion in an area spaced from the base end of the dense protective layer by a distance of approximately 0.

Abstract: In an oxygen sensor that measures a limiting current of when a voltage is applied between pumping electrodes, and also performs a rich/lean judgment based on an electromotive force generated between one of the pumping electrodes and a reference electrode, an oxygen supply voltage for supplying oxygen to the reference electrode is applied, and the reference electrode is covered with a dense layer.

Abstract: The oxygen sensor of the present invention has excellent durability capable of effectively preventing contamination with lead or the like for a detection electrode even in low temperature exhaust gases, and having stable response over a long period of time. The contamination preventive layer provided in the sensor device comprises composite powders having coarse powders covered therearound with fine powders, and hollows not filled with fine powders are scattered in gaps among the composite powders. Both the coarse and fine powders comprise ceramic powders. Further, it is particularly preferred that the ceramic powders are powders of a titania powder having a peak at 1 ?m or less and a composite ceramic powder containing alumina such as spinel having a peak at 10 ?m or more.

Abstract: A two-step chemical treatment method for chemically conditioning a sensor element comprising an electrolyte in ionic communication with a first electrode and a second electrode is described. The method comprises treating at least a portion of a sensor element with a first solution comprising an inorganic base, a carbonate salt and an acid salt; heating the sensor element; treating at least a portion of the sensor element with a second solution comprising an inorganic base and a carbonate salt; and drying the sensor element. The gas sensors comprising the two-step treated sensor elements have reduced lean shift, green effect, sensor output amplitude drop, and the light-off time is improved.

Abstract: The present invention is a method and apparatus for measuring the total NOx concentration in a gas stream utilizing the principles of a NOx sensor, i.e., mixed potential sensor. The exhaust gas is first conditioned by a catalyst assembly that converts the various species of nitrogen oxide gases present to a fixed steady state concentration ratio of NO2/NO, where NO2 is approximately 0–10% of the total NOx concentration present in the gas exhaust, thereby enabling the NOx sensor to generate a meaningful and reproducible determination of the concentration of total NOx present in the gas being measured. The catalyst assembly also functions to oxidize any unburned combustibles such as CH4, CO, etc., and remove potential contaminants such as SO2.

Abstract: There are provided glass-ceramics having a high lithium ion conductivity which include in mol %: P2O5 38–40% TiO2 25–45% M2O3 (where M is Al or Ga) ?5–15% Li2O 10–20% and contain Li1+X(Al, Ga)XTi2?X(PO4)3 (where 0<X<0.8) as a main crystal phases. There are also provided glass-ceramics having a high lithium ion conductivity which include in mol %: P2O5 ?26–40% SiO2 0.5–12% TiO2 ?30–45% M2O3 (where M is Al or Ga) ??5–10% Li2O ?10–18% and contain Li1+X+YMXTi2?XSiYP3?YO12 (where 0<X?0.4 and 0<Y?0.6) as a main crystal phase. There are also provided solid electrolytes for an electric cell and a gas sensor using alkali ion conductive glass-ceramics, and a solid electric cell and a gas sensor using alkali ion conductive glass-ceramics as a solid electrolyte.

Abstract: A contamination-resistant sensor element and methods for making the same are provided. A sensor element may include a contamination-resistant coating on at least a portion thereof. The coating may comprise gamma-delta alumina and lithium oxide and may have a thickness of about 100 to about 600 microns and a porosity of about 20 to about 70 percent. The method may include using gamma-delta alumina and lithium oxide to form a mixture, applying the mixture to at least a portion of a sensor element, and temperature treated the mixture to form a contamination-resistant coating on the surface of the measuring cell.

Abstract: An alumina sintered body having communicating pores of 400–1100 ? in average pore diameter and 4–16% in porosity and being obtainable by mixing first alumina particles 1 having a particle diameter of 0.2–0.7 ?m and a sphericity of 0.7–1.0 as an aggregate and second alumina particles having a particle diameter of 0.01–0.1 ?m as a pore forming material to embed a plurality of the second alumina particles 2 in the spaces between the first alumina particles 1, and sintering the mixture at a temperature of 1200–1400° C. The alumina sintered body can be used for a part for various gas permeable industrial materials inclusive of protective film for gas sensors, and the like.

Abstract: The present invention provides a gas sensor element and its production method, in which poisons are trapped in a porous protective layer to prevent them from reaching a measured gas side electrode, thereby making it possible to maintain a stable sensor output over a long period of time. The gas sensor element of the present invention is composed of a solid electrolyte 10, and a measured gas side electrode 12 that contacts a measured gas and a reference gas side electrode 11 that contacts a reference gas provided on said solid electrolyte 10; wherein, the above measured gas side electrode 12 is covered with a porous protective layer 14 composed of a heat-resistant metal oxide containing a getter, and the above getter is an alkaline silicate.

Abstract: The invention relates to an air/fuel ratio detection apparatus for a gas. This apparatus includes (a) a heater portion having an elongate cylindrical shape; (b) a solid electrolyte layer surrounding the heater portion and activated by heat to conduct oxygen ions therethrough; (c) a first electrode positioned between the heater portion and the solid electrolyte layer; (d) second and third electrodes in contact with an outer surface of the solid electrolyte layer and away from each other; (e) a first voltage applying device for applying a first voltage between the first and second electrodes; (f) a second voltage applying device for applying a second voltage between the first and third electrodes, the second voltage being higher than the first voltage; and (g) a diffusion layer made of a porous material and covering the second electrode to adjust transmission of the gas to the second electrode.

Abstract: A hydrogen sensor which may be employed in an overcharge/overdischarge detector for a battery and a hydrogen leakage detector for a fuel cell is provided. The hydrogen sensor includes a sensor element and a diffused resistor member. The gas to be measured passes through the diffused resistor member and reaches the sensor element. The sensor element outputs a signal indicative of the concentration of hydrogen contained in the gas as a function of a decrease in concentration of oxygen contained in the gas arising from reaction of the hydrogen on the oxygen. The diffused resistor member is so designed that speeds of diffusion of the hydrogen and the oxygen when passing through the diffused resistor member are different from each other for increasing the sensitivity of measurement of the concentration of hydrogen.

Abstract: A sensor element of a gas sensor is described, this sensor being used to determine the concentration of at least one component of a gas mixture, in particular in exhaust gases of internal combustion engines. It includes at least two electrodes which are situated in an internal gas space which is in direct contact with the gas mixture, the one electrode containing a first material and the second electrode containing a second material. The internal gas space contains a means which acts physically and/or chemically to prevent diffusion of metal between the electrodes.

Abstract: An apparatus and method for mounting a device to a pipe. The apparatus is particularly useful for the installation and/or replacement of retrofit sensors and injectors to the piping of engine exhaust systems and emission control systems, and is designed to be used on pipes of different dimensions.

Abstract: A coating system and a method for its manufacture are provided. An electrically conductive base coat and a porous overcoat lying over the base coat are arranged on a ceramic substrate. At least one additional deposited layer is arranged on the base coat in such a way that the additional layer is formed in the pores of the porous overcoat adjacent to the base coat. The additional layer is deposited either by currentless or electrolytic deposition. For electrolytic deposition of the additional layer, the ceramic substrate sintered with the base coat and the overcoat is submerged in an electrolytic bath and the base coat is connected as a cathode. The currentless deposition takes place from a solution of the metal to be deposited with the addition of a reducing agent.

Abstract: The oxygen concentration detector of the present invention includes a sensor element having a solid electrolyte and having an external electrode and an internal electrode provided on the external surface and the internal surface, respectively, and a heater provided adjacent to the internal surface of the sensor element, in which a high-emissivity layer consisting of a material having a high emissivity is provided on the internal surface of the sensor element and/or the surface of the heater.

Abstract: A gas sensing element includes a solid electrolytic substrate having oxygen ion conductivity, a measured gas side electrode provided on a surface of the solid electrolytic substrate so as to be exposed to a measured gas, and a reference gas side electrode provided on another surface of the solid electrolytic substrate so as to be exposed to a reference gas. The measured gas side electrode is covered by a porous electrode protecting layer. A limit current density of the electrode protecting layer is in a range from 0.04 mA/mm2 to 0.15 mA/mm2 on a unit area of the reference gas side electrode.

Abstract: A method of treating a gas sensor comprising: disposing the gas sensor in a basic agent solution comprising a basic agent selected from the group consisting of Group IA of the Periodic Table of Elements, Group IIA of the Periodic Table of Elements, and combinations comprising at least one of the foregoing metals, wherein the gas sensor comprises an electrolyte disposed between and in ionic communication with a first electrode and a second electrode; disposing the gas sensor in an acidic agent solution; wetting at least a portion of a porous protective layer of the gas sensor with an alkaline-carbonate solution; and heating the gas sensor.

Abstract: Intended for application on ducts through which flow a fluid at a high temperature, and particularly at a high pressure, comprising two bodies (4) and (8) which axially screw onto each other, one body (4) provided with a threaded neck (5) for attachment to the orifice of duct wall (3), which body (4) houses within it sensor element (2) of the probe which is thus placed inside the duct, with second body (8) screwed onto first body (4) and exerting on sensor element (2) the pressure required to secure it in its housing, with second body (8) further provided with an axial orifice through which passes a metallic tube (9) open to the exterior and which is provided with a metallic washer (10), soldered to said tube (9), which is separated from second body (8) by an electrically insulating washer (12).

Abstract: A potentiometric sensor for nitrogen oxide (NOX) measurement based on yttria-stabilized zirconia with a zeolite-modified electrode is presented. A potentiometric sensor of the present invention comprises a tube having an interior and an exterior. A cap member comprising yttria-stabilized zirconia closes one end of the tube. The cap member has an interior surface exposed to the interior of the tube where a first electrode is disposed. The first electrode is then covered with a zeolite layer. A second electrode is disposed on the exterior of the cap member.

Abstract: A sensor is described for measuring the concentration of a gas component in a gas mixture, particularly a lambda probe for measuring the oxygen concentration in the exhaust gas of an internal combustion engine, having a solid electrolyte and having two electrodes separated by the solid electrolyte, of which an outer electrode is exposed to the gas mixture and an inner electrode is situated in a cavity separated from the gas mixture by a diffusion barrier. To achieve a broadband measuring of the air ratio &lgr; and a simplified construction compared to a known lambda broadband probe having a pump cell and a Nernst cell, the sensor is operated according to predefined criteria, alternately as lean operation probe according to the limiting current principle and as transition probe having a pumped reference.

Abstract: One embodiment of a method of fabricating a sensor element for an exhaust gas sensing device, comprises disposing an electrolyte in ionic communication with a sensing electrode and a reference electrode to form the sensor element. The sensing electrode comprises an activator comprising silica and an oxide of an element. The element is selected from the group consisting of alkaline earth elements, rare earth elements, and combinations comprising at least one of the foregoing elements.

Abstract: A gas-detecting element comprising an oxygen-ion-conductive solid electrolyte substrate, a sensing electrode fixed onto said solid electrolyte substrate and active with a detection object gas and oxygen, and a reference electrode fixed onto said solid electrolyte substrate and active with at least oxygen, for detecting potential difference between the sensing electrode and the reference electrode to determine the concentration of the detection object gas, the sensing electrode and/or the reference electrode being covered by an electrode-coating layer made of an oxygen-ion-conductive solid electrolyte, and the electrode-coating layer having a portion bonded to the solid electrolyte substrate directly or via an electrode underlayer made of an oxygen-ion-conductive solid electrolyte.

Abstract: A multi-layer gas sensor element is described which comprises a solid electrolytic member, a substrate, and a porous member, wherein each of the substrate and the porous member has a thickness larger than that of the solid electrolytic member with respect to a lamination direction; the substrate and the porous member face each other and sandwich the solid electrolytic member; a ceramic component constituting the substrate in the highest volume percent is the same as the ceramic component constituting the porous member in the highest volume percent thereof; and the volume percent (R2) of the ceramic component contained in the porous member is 80% or more the volume percent (R1) of the ceramic component contained in the substrate.

Abstract: A sensor comprises: a pump cell comprising an inner pump electrode, an outer pump electrode, a pump cell electrolyte layer interposed between the inner pump electrode and the outer pump electrode and a cell isolation layer disposed on the inner pump electrode on a side opposite the pump cell electrolyte, wherein the outer electrode is in fluid communication with a reducing gas. A reference cell is in operable communication with the pump cell, the reference cell comprising an outer reference electrode and an inner reference electrode, and a reference cell electrolyte interposed between the outer reference electrode and the inner reference electrode.

Abstract: A gas sensor is created comprising an electrochemical cell having a solid electrolyte layer disposed between an exhaust gas electrode and a reference electrode. A resistor is disposed in electrical communication with a heater and the reference electrode. The resistor can be disposed on a side of the gas sensor; on a side of the gas sensor such that the resistor is electrically connected through a via hole; over at least a portion of at least two sides of the gas sensor; or disposed in a void extending at least from the heater to the pump electrode, such that the void extends to at least a surface of the gas sensor, extends to at least partially through the gas sensor, or extends completely through the gas sensor. A method for using this gas sensor comprises applying a voltage to the heater within the gas sensor. A current is directed through the resistor to the reference electrode to pump oxygen into the reference electrode.

Abstract: Disclosed herein is a gas sensor and a method of making a gas sensor comprising disposing a reference electrode on an inner surface of an electrolyte; sputtering a sensing electrode on an outer surface of the electrolyte; sputtering a zirconia layer on a side of the sensing electrode opposite the electrolyte, wherein the zirconia layer has a thickness of about 20 nanometers to about 1 micrometer, and disposing a protective layer on a side of the zirconia layer opposite the sensing electrode.

Abstract: A measured gas side electrode is provided on one surface of a solid electrolytic substrate so as to be exposed to a measured gas. A reference gas side electrode is provided on an opposite surface of the solid electrolytic substrate so as to be exposed to a reference gas stored in a reference gas chamber. A water-vapor absorbing member is provided in the reference gas chamber.

Abstract: A gas sensor comprises a cylindrical metallic housing, a sensor element having at a front end thereof a sensing portion and disposed axially in the housing with the sensing portion protruded from a front end of the housing, a sensor terminal fitted to a rear end of the sensor element to produce a signal output from the sensing portion, a first protective cover attached to a front end portion of the housing to cover the sensing portion and a second protective cover attached to a rear end portion of the housing to cover the sensor terminal. The first and second protective covers includes attachment portions attached around the front and rear end portions of the housing, respectively. At least one of the attachment portions of the first and second protective covers has a lower hardness than a remaining portion of the protective cover.

Abstract: Disclosed herein is a method for producing a gas sensor, comprising disposing a reference electrode on a side of an electrolyte, disposing a measuring electrode on a side of the electrolyte opposite the reference electrode, disposing a first protective coating on a side of the measuring electrode opposite the electrolyte, treating the sensor with an aqueous salt solution comprising chloride and carbonate salts comprising elements selected from the group consisting of Group IA and IIA elements of the Periodic Table to form a treated sensor comprising the chloride and the carbonate salt mixture, drying the treated sensor, and disposing a second protective coating on a side of the first protective coating opposite the measuring electrode.

Abstract: An oxygen sensor is disposed downstream from a catalyst for purifying exhaust gas from an internal combustion engine and which can suppress an influence of unburnt hydrocarbon on an output voltage. After forming a platinum thin film on the outer periphery of a zirconia ceramic body, only a detection electrode of the ceramic body is dipped in a silver nitrate aqueous solution of 0.1 mol/l, and the silver nitrate is pyrolyzed through a heat treatment. Subsequently, a platinum reference electrode is formed on the inner periphery of the ceramic body. To protect the silver-doped detection electrode, a protective layer is formed on the surface of the detection electrode. By the exposure to combustion gas and through aging, a detection element is formed, and set into a metal case together with a cylindrical heater, to complete an oxygen sensor to be disposed downstream from a CNG engine catalyst.

Abstract: The present invention provides a gas sensor element and its production method, in which poisons are trapped in a porous protective layer to prevent them from reaching a measured gas side electrode, thereby making it possible to maintain a stable sensor output over a long period of time.

Abstract: A solid electrolyte layer or body capable of being co-fired with an insulating ceramic substrate or body to be used as a gas sensor laminate. The gas sensor laminate is preferably composed of an alumina substrate (1) and an oxygen-ion conductive solid electrolyte layer (6) bonded to the alumina substrate (1) by firing. The oxygen-ion conductive solid electrolyte layer or body is formed from partially or wholly stabilized zirconia, which layer contains alumina in an amount of 10% to 80% by weight, particularly 30% to 75% by weight. In this manner, another ceramic layer; particularly, a ceramic layer (7) of alumina can further be bonded to the oxygen-ion conductive solid electrolyte layer. The relative density of the ceramic layer can be 60% to 99.5%, preferably 80% to 99.5%.

Abstract: The oxygen sensor of the present invention has excellent durability capable of effectively preventing contamination with lead or the like for a detection electrode even in low temperature exhaust gases, and having stable response over a long period of time. The contamination preventive layer provided in the sensor device comprises composite powders having coarse powders covered therearound with fine powders, and hollows not filled with fine powders are scattered in gaps among the composite powders. Both the coarse and fine powders comprise ceramic powders. Further, it is particularly preferred that the ceramic powders are powders of a titania powder having a peak at 1 &mgr;m or less and a composite ceramic powder containing alumina such as spinel having a peak at 10 &mgr;m or more.

Abstract: An electrochemical sensor element, in particular for determining the oxygen level in gas mixtures, includes at least one measuring electrode exposed to a measured gas, at least one reference electrode exposed to a reference gas, at least one heating device, and one reference gas channel, through which the reference gas can be supplied to the reference electrode. The reference electrode is connected to the reference gas via a volume provided with pores. The volume is formed in a layer between the reference gas channel and the reference electrode.

Abstract: An oxygen sensor element is provided which may be used in an oxygen sensor designed to measure the concentration of oxygen contained in exhaust gasses of an automotive internal combustion engine. The gas sensor element includes a solid electrolyte body, a target gas electrode, a reference gas electrode, and a catalytic layer formed over the target gas electrode. The catalytic layer is made of heat resisting ceramic grains which hold thereon catalytic metal grains whose average grain size is 0.3 to 2.0 &mgr;m, a weight of catalytic metal grains per unit area of the catalytic layer, as defined by projecting the target gas electrode on a plane, is 10 to 200 &mgr;g/cm2. This facilitates the reaction of exhaust gasses such as H2, NOx, and HC with O2 over the target gas electrode, thus resulting in improved accuracy of a sensor output over a wide temperature range.

Abstract: A nonfragile ad quickly activatable structure of a gas sensor element which may be built in a gas sensor employed in an air-fuel ratio control system for automotive vehicles for measuring the concentration of gas such O2, NOx, or CO. The gas sensor element is made of a lamination of a measurement gas electrode, a reference gas electrode, and a heater. The heater works to elevate the temperature of the gas sensor element up to a given value required to bring the gas sensor element into an activated condition. The heater includes a heater substrate, a heating element, and power supply leads. A minimum distance X between an edge of the heater substrate and an edge of the heating element meets a relation of 0.1 mm≦X≦0.6 mm, thereby minimizing a thermal expansion difference between the heater element and the heater substrate to avoid cracks in a portion of the heater substrate near the heater element.

Abstract: One embodiment of a method for producing a gas sensor, comprises: disposing said gas sensor in a basic agent solution comprising a basic agent comprises a hydroxide of a metal selected from the group consisting of Group IA of the Periodic Table of Elements; Group IIA of the Periodic Table of Elements, and combinations comprising at least one of the foregoing basic agents, wherein said gas sensor comprises an electrolyte disposed between and in ionic communication with a first electrode and a second electrode; and disposing said gas sensor in an acidic agent solution.

Abstract: A permeable protective coating for a single-ship hydrogen sensor. A hydrogen-permeable coating is applied to a semiconductor wafer containing hydrogen sensor dies, prior to dicing of the wafer. The permeable coating is preferably an organic spin-on polymer, and the hydrogen sensors preferably include hydrogen-sensing elements composed of a palladium nickel alloy.

Abstract: A second protective layer is a ceramic porous protective layer comprising coarse particles and fine particles structurally arranged in such a manner that interparticle cavities formed between the coarse particles are filled with the fine particles. At least either of the coarse particles and the fine particles contain at least one selected from the group consisting of &ggr;-Al2O3, &thgr;-Al2O3, &dgr;-Al2O3 and solid solution having the same crystal structure as those of &ggr;-Al2O3, &thgr;-Al2O3, &dgr;-Al2O3.

Abstract: The poison resistant sensor comprises a sensing electrode (4) having a first and second side; a reference electrode (7) having a first and second side; an electrolyte (1) disposed between and in intimate contact with the first side of the sensing electrode and the first side of the reference electrode; a first side of a protective layer (3) disposed adjacent to the second side of the sensing electrode; and a protective coating (17), comprising alpha alumina and gamma alumina, disposed in physical contact with the second side of the protective layer.

Abstract: A fuel cell gas sensor for detecting gases such as Hydrogen (H2) and Carbon Monoxide (CO) comprises a main body (10) in which are mounted a protection membrane (11), a working electrode (12), electrolyte (13), a counter electrode (14), a protection membrane (15) and respective contacts (16). A catalyst disk (17a) or a very low impedance fuel cell (17b) in placed between the counter electrode (14) and the protection membrane (15). The membrane (15) slows down the flux of gases onto the counter electrode (14). The catalyst disk (17a) eliminates chemically while the fuel cell (17b) eliminates electrochemically the gases to be detected that permeate through the protection membrane (15). This arrangement makes it possible to detect the gases in places where the gases to be detected are able to reach both the working electrode (12) and the counter electrode (14).

Abstract: A solid state electrochemical cell (10a) for measuring the concentration of a component of a gas mixture (12) includes first semiconductor electrode (14) and second semiconductor electrode (16) formed from first and second semiconductor materials, respectively. The materials are selected so as to undergo a change in resistivity upon contacting a gas component, such as CO or NO. An electrolyte (18) is provided in contact with the first and second semiconductor electrodes. A reference cell can be included in contact with the electrolyte. Preferably, a voltage response of the first semiconductor electrode is opposite in slope direction to that of the second semiconductor electrode to produce a voltage response equal to the sum of the absolute values of the control system uses measured pollutant concentrations to direct adjustment of engine combustion conditions.

Abstract: A sensor is described for measuring the concentration of a gas component in a gas mixture, particularly a lambda probe for measuring the oxygen concentration in the exhaust gas of an internal combustion engine, having a solid electrolyte and having two electrodes separated by the solid electrolyte, of which an outer electrode is exposed to the gas mixture and an inner electrode is situated in a cavity separated from the gas mixture by a diffusion barrier. To achieve a broadband measuring of the air ratio &lgr; and a simplified construction compared to a known lambda broadband probe having a pump cell and a Nernst cell, the sensor is operated according to predefined criteria, alternately as lean operation probe according to the limiting current principle and as transition probe having a pumped reference.

Abstract: A gas sensor, comprising an oxygen pump cell with a first pump electrode and a second pump electrode disposed on opposite sides of a first solid electrolyte layer and a second pump electrode. The sensor also comprises an emf cell with an emf electrode and a reference gas electrode disposed on opposite sides of a second solid electrolyte layer. The emf electrode is disposed in fluid communication to the second pump electrode. A via hole is disposed through the first solid electrolyte layer, such that the first pump electrode is in fluid communication with the second pump electrode. A protective insulating layer, having a passage for gas to be sensed, is disposed in contact with the first pump electrode. A first insulating layer, having a conduit, is disposed in contact with the emf electrode. A second insulating layer, having an air channel, is disposed in contact with the reference gas electrode. A heater is disposed in thermal communication with the emf cell.

Abstract: A gas sensor is disclosed comprising an oxygen pump cell having at least one exterior pump electrode and at least one interior pump electrode disposed on opposite sides of a first solid electrolyte layer. An emf cell having a first and second emf electrodes and first and second reference gas electrodes are disposed on opposite sides of a second solid electrolyte layer. At least one insulating layer is in contact with the first and second emf electrodes. At least one via hole is disposed through the first solid electrolyte layer. At least one air channel is disposed through at least one insulating layer. An air vent is disposed in at least one insulating layer in contact with the first and second reference gas electrodes. A heater is disposed in thermal communication with the sensor. And at least five electrical leads are in electrical communication with said sensor. A method of using a gas sensor is also disclosed.

Abstract: A method of adjusting an output of a gas sensor element is provided. The gas sensor element includes a lamination of a solid electrolyte body, a target gas-exposed electrode, a reference gas-exposed electrode, and a diffused resistance layer in which a target gas to be measured diffuses. The target gas-exposed electrode is disposed on a first surface of the solid electrolyte body exposed to the target gas. The reference gas-exposed electrode is disposed on a second surface of the solid electrolyte body exposed to a reference gas. The diffused resistance layer is disposed on the first surface of the solid electrolyte body. The target gas-exposed electrode and the reference gas-exposed electrode produce a sensor output. The adjustment of the sensor output is achieved by decreasing a diffusion length of the target gas in the diffused resistance layer as a function of a quantity of the sensor output to be adjusted by, for example, removing a portion of the diffused resistance layer.

Abstract: An exhaust gas sensor element has an electrolyte body, an inner electrode disposed on an inner surface of the electrolyte body, an outer electrode disposed on an outer surface of the electrolyte body, and a ground isolating coating disposed over the outer electrode. The ground isolating coating is typically alumina and extends from an active end of the electrolyte body toward an opposing end of the electrolyte body. The invention also includes a method for constructing a gas sensor element, the steps of which comprise forming an electrolyte body having an inner surface and an outer surface, applying an electrode ink to the inner surface to form an inner electrode and to the outer surface to form an outer electrode, and depositing a combination poison resistant/ground isolating coating, which is typically alumina, over the outer surface such that the combination coating extends from an active end of the electrolyte body toward an opposing end of the electrolyte body.