Abstract: A gas sensor includes a structural body made up from a solid electrolyte that exhibits oxygen ion conductivity, a gas introduction port formed in the structural body, a preliminary chamber communicating with the gas introduction port and equipped with a preliminary pump electrode, a main chamber communicating with the preliminary chamber and equipped with a main pump electrode, and a measurement chamber communicating with the main chamber and equipped with a measurement electrode. In the gas sensor, at least a surface of the preliminary pump electrode is made of a material which exhibits a low activity with respect to a reaction between ammonia and oxygen.

Abstract: A gas sensor control apparatus (3) includes first current detection means for detecting a first pump current flowing between second electrodes (19, 20) in a state in which an object gas has become a prescribed gas supply state, the temperature of a sensor section (10f) has become a first target temperature, and the voltage between first electrodes (21, 22) has become a first target voltage; second current detection means for detecting a second pump current flowing between the second electrodes in a state in which the object gas has become the prescribed gas supply state, the temperature of the sensor section has become a second target temperature, and the voltage between the first electrodes has become a second target voltage; and H2O gas concentration detection means for detecting the H2O gas concentration of the object gas on the basis of the first and second pump currents.

Abstract: A nitrogen oxide sensor includes a measured gas chamber, a sensor cell, a pump cell, a voltage application circuit, a sensor output detector, a voltage control part, a concentration calculation part, a temperature estimation part, an air-fuel ratio estimation part, and a time calculation part calculating a cumulative value of time periods when the temperature of the pump cell is within a predetermined temperature region and the air-fuel ratio of the measured gas is leaner than the stoichiometric air-fuel ratio as a first cumulative time period. The concentration calculation part calculates the NOx concentration in the measured gas higher with respect to the output of the sensor cell when the first cumulative time period is relatively long compared with when the first cumulative time period is relatively short.

Abstract: A binary lambda sensor has a first electrode arranged on the exhaust gas side, a second electrode arranged contiguous to a reference air volume, and a power source arranged between the first and second electrode. A potential difference between the first and second electrodes forms a measurement signal of the sensor. In a measurement operation of the sensor, the power source is operated in a measurement operating state and provides the measurement signal. To adjust a specified oxygen concentration in the reference air volume, the power source is operated in a regeneration operating state. If a specified condition is fulfilled and the engine is operating in a coasting mode, the power source is operated in the measurement operating state, and a power source adjustment signal is determined for the regeneration operating state based on the measurement signal, for the adjustment of the specified oxygen concentration in the reference air volume.

Abstract: In a sensor control device, it is determined whether a gas sensor is activated. A concentration control is performed at an elapse timing which elapses by a first constant time from an activation timing at which the gas sensor is determined to be activated. A preliminary control is performed in at least a partial period between the elapse timing and a start timing at which a drive control is started.

Abstract: A micro-tubular solid oxide fuel cell arrangement includes two micro-tubular elements having a tubular inner electrode, covered on its outer surface with an electrolyte, the electrolyte being covered on its outer surface with a tubular outer electrode; and a connection element arranged between the micro-tubular elements for connecting one end of one micro-tubular element to one end of the other micro-tubular element, where the micro-tubular element has a first end portion with an inner cone arranged in the tubular inner electrode and a second end portion with an outer cone arranged in the tubular outer electrode, where the connection element comprises a metallic interconnector plate having a first side and an opposite second side, where the plate is provided with at least one hole; a first metallic connector on the first side and arranged around the hole and a second metallic connector on the second side and arranged around the hole.

Abstract: An electrochemical cell for applications such as electrochemical fuel cells, or electrochemical cell gas sensors used for detection of target gas species in environments containing or susceptible to presence of same. The electrochemical cell utilizes an ionic liquid as an electrolyte medium, thereby achieving a broader range of operational temperatures and conditions, relative to electrochemical cells utilizing propylene carbonate or other conventional electrolytic media.

Abstract: A device, apparatus and method for trapping metal ions and detecting metal ion contamination in a solution provide a semiconductor device formed on a semiconductor substrate and including an N-well formed over a P-type substrate and at least a contact portion of the N-well in electrical contact with the solution. When the semiconductor device is optically illuminated, a P/N junction is formed as a result of photovoltaic phenomena. Metal ions from the solution migrate to the contact area due to the voltage created at the P/N junction. The semiconductor device includes a conductive structure with conductive features separated by a gap and therefore in an initially electrically open state. When the ions migrate to the contact area, they precipitate, at least partially bridging the gap and creating conductance through the conductive structure. The conductance may be measured to determine the amount of metal ion contamination.

Abstract: A system and method for compositional sample analysis includes a fluid sample handler having a sample pathway extending in a downstream direction from an input port to an output port, to transport a fluid sample therethrough. A sample conditioner is disposed within the sample pathway, to maintain the fluid sample within a predetermined temperature range. A fuel cell is disposed in serial fluid communication with said output port to receive the fluid sample, the fuel cell configured to use an oxidizer and the fluid sample to generate an electric potential corresponding to a concentration of a constituent of the fluid sample. A controller is communicably coupled to the fuel cell, and configured to capture and use the electric potential to calculate the concentration of the constituent.

Abstract: An SOx gas sensor includes a first solid electrolyte member composing a part of a wall of a gas reduction chamber and provided with a first gas introducing hole for introducing sample gas into the gas reduction chamber, an oxidation part for oxidizing noise gas other than the SOx gas in the sample gas, and a reduction mechanism for reducing the SOx gas in the sample gas, in the gas reduction chamber; a communication unit provided with a second gas introducing hole for introducing the sample gas into a gas measurement chamber from the gas reduction chamber; and a second solid electrolyte member composing a part of a wall of the gas measurement chamber and provided with an oxidation mechanism for oxidizing the SOx gas, and a measurement mechanism for measuring the concentration of the SOx gas, in the gas measurement chamber.

Abstract: [Objective] An object is to provide a sensor control apparatus and a sensor-control-apparatus control method which can reduce variation in startup time among a plurality of times of execution of detection processing, in consideration of variation in output characteristic among a plurality of gas sensors. [Means for Solution] In a sensor control apparatus, before drive control (S55 to S80) is started, preliminary control is executed so as to supply a constant current to a second oxygen pump cell over a constant time, to thereby control to a constant level the amount of oxygen pumped from a second measurement chamber to the outside of the second measurement chamber (S40 to 50). The preliminary control is executed under control conditions of the sensor control apparatus which are determined for each gas sensor and are associated with the amount of oxygen pumped from the second measurement chamber to the outside thereof.

Abstract: A method for detecting a proportion of at least one gas species in a measurement gas space. A sensor element is used, having an oxygen reduction pumping cell for concentration of the gas species, a pumping cell connected downstream of the oxygen reduction pumping cell having pumping electrodes, and a gas-tight chamber. A pumping electrode may be exposed to gas from the measurement gas space which has been concentrated by the oxygen reduction pumping cell. A further pumping electrode is disposed in the gas-tight chamber. At least one measuring electrode is further disposed in the gas-tight chamber. The oxygen reduction pumping cell and the pumping cell are galvanically isolated. The method includes an initialization phase, and an accumulation phase.

Abstract: A microelectrochemical sensor includes a carrier material composed of a semiconductor substrate, and includes a chemosensitive sensor element. The chemosensitive sensor element is positioned in a first partial region of the carrier material. A heating element is positioned in a region of the chemosensitive sensor element and is configured to regulate a temperature of the chemosensitive sensor element. A microelectronic unit is positioned in a second partial region of the carrier material, and is connected to the chemosensitive sensor element and the heating element via conductor tracks integrated into the carrier material. The microelectronic unit is configured to operate the heating element and the sensor element.

Abstract: A membrane electrode assembly for a gas sensor is described that includes a membrane disposed between a sensing electrode and a counter electrode. The membrane is a polymer membrane, such as an ionomer, having an ionic liquid retained therein.

Abstract: A method for measuring and/or calibrating a gas sensor for determining oxygenic gas components in gas mixtures in exhaust gases of internal combustion engines. The gas sensor has one internal pump electrode IPE, one external pump electrode APE and one decomposition electrode NOE. The measurement and/or calibration may be carried out during the ongoing operation of the gas sensor by removing the gas component and/or oxygen from one of the chambers, by introducing oxygen in a controlled manner into one of the chambers with the aid of electrochemical pumping processes. The changes caused by the introduced oxygen are measured against an additional electrode and the gas sensor may be measured and/or calibrated using the measured values.

Abstract: A gas sensor including a gas sensor element that extends in an axial direction and has a detection section at a front-end side thereof, and an electrode pad at a rear-end side thereof; a connection terminal that is electrically connected to the electrode pad; and an insulated separator that extends along the axial direction and has an inserting hole into which the connection terminal is inserted. An element side section is arranged within the inserting hole and is connected the electrode pad, and an external circuit side section extends further to the outside in a diametrical direction than an outer surface of the separator through one or more first bending sections from the element side section.

Abstract: A gas sensor comprises a substrate layer; a pair of interdigitated metal electrodes, said electrodes include upper surfaces, the electrodes selected from the group consisting of Pt, Pd, Au, Ir, Ag, Ru, Rh, In, Os, and their alloys. A first layer of solid electrolyte staying in between electrode fingers and partially on said upper surfaces of said electrodes, said first layer selected from NASICON, LISICON, KSICON and ??-Alumina. A second layer of metal carbonate(s) as an auxiliary electrolyte engaging said upper surfaces of the electrodes and the first solid electrolyte. The metal carbonates selected from the group consisting of the following ions Na+, K+, Li+, Ag+, H+, Pb2+, Sr2+, Ba2+, and any combination thereof.

Abstract: In a sensor control device, it is determined whether a gas sensor is activated. A concentration control is performed at an elapse timing which elapses by a first constant time from an activation timing at which the gas sensor is determined to be activated. A preliminary control is performed in at least a partial period between the elapse timing and a start timing at which a drive control is started.

Abstract: A method of making a sub-miniature “micro-chip” oxygen sensor is provided where multiple sensor elements are applied to a dielectric ceramic substrate consisting of a heater pattern, followed by a dielectric layer. Intermeshing electrodes are then applied either over the heater pattern/dielectric layers or on the opposite side of the substrate. The space between the intermeshing electrodes is filled with an n-type or p-type high temperature semiconductor which is covered by a porous protection layer. After singulation (dicing), the sensor element is assembled having conductors applied to the contact pads on the element and is packaged in an assembly for introduction to the exhaust stream of a combustion process. A large step-wise change in the resistance of the element takes place as a result of changes in oxygen content in the exhaust whereby one can determine if the exhaust is rich or lean for use in an engine management or combustion management systems for emissions control.

Abstract: Method and apparatus for measurement of the oxygen partial pressure or the oxygen content in a measurement gas in at least one measurement cycle using a solid electrolyte cell having at least one oxygen-conducting solid electrolyte, and having at least one reference electrode as well as at least one measurement electrode, wherein the at least one measurement electrode is in communication with the measurement gas and the at least one reference electrode is in communication with a reference gas or reference volume separated from the measurement gas, wherein a current is imposed via the electrodes on the solid electrolyte cell for pump operation and a measurement voltage (UM) is tapped at the electrodes.

Abstract: The sniffing leak detector comprises a sniffing probe, a suction device and gas detector. An operator-activated switch initiates the beginning of a measuring operation. The switch starts a time measurement, wherein an alarm signal is generated by a signal transmitter at the end of a predetermined measuring period. The sniffing leak detector allows for an operator guidance from measuring point (MP) to measuring point, wherein the measuring period is predetermined and an adherence to the measuring period is monitored.

Abstract: A gas sensor includes a gas sensor element. The gas sensor element includes a first detection chamber; a first oxygen pumping cell including a first solid electrolyte body and a pair of first electrodes; a second detection chamber; a second oxygen pumping cell including a second solid electrolyte body and a pair of second electrodes; and an oxygen-concentration sensing cell including a third solid electrolyte body and a pair of third electrodes. A sensing electrode of the third electrodes is disposed downstream beyond a first inner electrode of the first electrodes relative to a gas flow direction. A cross-sectional area of a space of the first detection chamber which faces the first inner electrode falls within a range from 0.03 mm2 to 0.22 mm2.

Abstract: A method of operating an electrochemical gas sensor includes: a) exposing, for a first predetermined duration, the electrochemical gas sensor to an atmosphere containing a target gas while the gas reaction capability of the electrode assembly is substantially reduced from a working level, such that target gas is collected within the housing; b) increasing the gas reaction capability of the electrode assembly to a level at which it consumes collected target gas and thereby outputs a signal to the sensing circuit, including an initial transient decay signal; c) monitoring the transient decay signal; and d) analysing the rate of decay of the transient decay signal to determine whether the performance of at least one component of the electrochemical gas sensor is within acceptable limits. An apparatus for operating an electrochemical gas sensor, adapted for connection to an electrochemical gas sensor via a sensing circuit for control thereof, can carry out the disclosed method(s).

Abstract: A method for detecting a proportion of at least one gas species in a measurement gas space. A sensor element is used, having an oxygen reduction pumping cell for concentration of the gas species, a pumping cell connected downstream of the oxygen reduction pumping cell having pumping electrodes, and a gas-tight chamber. A pumping electrode may be exposed to gas from the measurement gas space which has been concentrated by the oxygen reduction pumping cell. A further pumping electrode is disposed in the gas-tight chamber. At least one measuring electrode is further disposed in the gas-tight chamber. The oxygen reduction pumping cell and the pumping cell are galvanically isolated. The method includes an initialization phase, and an accumulation phase.

Abstract: A gas probe, in particular a lambda probe for the analysis of exhaust gases from a mobile internal combustion engine, includes at least one protective device, at least partly surrounding a sensitive sensor element of the gas probe, which comes into contact with a gas. The at least one protective device includes a gas contact face which at least partly has a hygroscopic surface.

Abstract: Lightweight, portable oxygen concentrators that operate using an ultra rapid, sub one second, adsorption cycle based on advanced molecular sieve materials are disclosed. The amount of sieve material utilized is a fraction of that used in conventional portable devices. This dramatically reduces the volume, weight, and cost of the device. Innovations in valve configuration, moisture control, case and battery design, and replaceable sieve module are described. Patients with breathing disorders and others requiring medical oxygen are provided with a long lasting, low cost alternative to existing portable oxygen supply devices.

Abstract: A degradation detector of an exhaust gas sensor is disclosed. The detector comprises a first heater resistance estimator (16) for estimating a resistance of a heater that heats the exhaust gas sensor, based on a device resistance of the exhaust gas sensor; a heater resistance calculator (17) for calculating a resistance of the heater, based on a heater current of the heater; and a degradation determiner (18) for determining whether the exhaust gas sensor is degraded, by comparing the estimated resistance of the heater and the calculated resistance of the heater.

Abstract: A method is disclosed for operating an electrochemical gas sensor with a measuring electrode pair and a pumping electrode pair. The method includes obtaining a measurement of the interfering species at a location spatially adjacent to a measuring electrode of the measuring electrode pair; and adjusting one or more of an operation or an output processing of the electrochemical gas sensor based on the measurement of the interfering species. In this manner, the measurement of the interfering species may be used to adjust the removal rates of the interfering species and/or to adjust an offset of an analyte measurement to compensate for the presence of the interfering species.

Abstract: A method and an article of an electrically conductive ceramic interconnect bonded to a compatible ceramic housing for an oxygen partial pressure sensor system. The interconnect includes a LaxSryAlzMn1?zO3 (LSAM) having a stoichiometry enabling good electrical conductivity at high temperatures and the LSAM also bonded to a yttria stabilized zirconia forming a stable and durable seal.

Abstract: In a sensor element for a solid electrolyte gas sensor, comprising a gas-tight pumping chamber, a heater, a first pumping electrode arranged in the pumping chamber, and an at least second pumping electrode, an autonomous pumping cell is arranged as a gas inflow restrictor instead of a diffusion barrier. The autonomous pumping cell comprises an outer and an inner autonomous pumping electrode which are contacted or short-circuited from outside by means of a trimmable resistor.

Abstract: A method for manufacturing a gas sensor element (300), which includes a plate-like second solid electrolyte member (109), a fourth electrode (110) formed on the second solid electrolyte member (109), and a protection layer (111) including a reinforcement member (112) having an insertion hole (112a), and a porous electrode protection member (113a) provided in the insertion hole (112) and adapted to protect the fourth electrode (110) from becoming poisoned.

Abstract: A procedure to calculate the Lambda value with a wideband Lambda sensor of an internal combustion engine of a motor vehicle is thereby characterized, in that from the measured pumping electricity and the sensitivities of the wideband Lambda sensor as well as the gas concentration ratios, in the lean operation an oxygen concentration and in the rich operation an oxygen deficit are determined and from these respectively a conclusion is drawn about the Lambda value using the Pischinger Formula.

Abstract: A sensor supervision system for periodically providing a test to accesses the status of a gas detection sensor, such as a carbon monoxide (CO) sensor, is provided. To access the status of the CO sensor, a processor provides a voltage to the sensor supervision system, such that a voltage is applied to CO sensor, charging the CO sensor. The status of the CO sensor is accessed by determining the change in the voltage charge of the CO sensor between two sampling time points. If the first sample voltage is substantially equal to the second sample voltage, i.e., a substantially constant voltage, the carbon monoxide sensor fails the test. However, if there is an change is the voltage change between the first and second sampled time points, the CO sensor passes the test.

Abstract: The present invention generally relates to carbon dioxide (CO2) sensors. In one embodiment, the present invention relates to a carbon dioxide (CO2) sensor that incorporates lithium phosphate (Li3PO4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li2CO3) and barium carbonate (BaCO3). In another embodiment, the present invention relates to a carbon dioxide (CO2) sensor has a reduced sensitivity to humidity due to a sensing electrode with a layered structure of lithium carbonate and barium carbonate. In still another embodiment, the present invention relates to a method of producing carbon dioxide (CO2) sensors having lithium phosphate (Li3PO4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li2CO3) and barium carbonate (BaCO3).

Abstract: A gas sensor includes a substrate and a pair of interdigitated metal electrodes selected from the group consisting of Pt, Pd, Au, Ir, Ag, Ru, Rh, In, and Os. The electrodes each include an upper surface. A first solid electrolyte resides between the interdigitated electrodes and partially engages the upper surfaces of the electrodes. The first solid electrolyte is selected from the group consisting of NASICON, LISICON, KSICON, and ??-Alumina (beta prime-prime alumina in which when prepared as an electrolyte is complexed with a mobile ion selected from the group consisting of Na+, K+, Li+, Ag+, H+, Pb2+, Sr2+ or Ba2+). A second electrolyte partially engages the upper surfaces of the electrodes and engages the first solid electrolyte in at least one point. The second electrolyte is selected from the group of compounds consisting of Na+, K+, Li+, Ag+, H+, Pb2+, Sr2+ or Ba2+ ions or combinations thereof.

Abstract: A limiting current type oxygen sensor having a gas diffusion mechanism comprising a gas diffusion bore and an internal space communicating with the gas diffusion bore for supplying a diffusion-rate-determined gas. The gas diffusion mechanism may be configured such that an oxygen concentration gradient within the internal space satisfies the expression: 1/Ilim=(1/4 FDCo2){(l/S)+(lin/Sin)} based on the Faraday constant (F); a diffusion coefficient (D); an oxygen concentration (Co2); a bore area (S) of the gas diffusion bore; a bore length (l) in the axial direction of the gas diffusion bore; a distance (lin) in the internal space between the first electrode and the inner surface opposed thereto; an effective cross section (Sin) of the internal space; and an output current value (Ilim). This makes it possible to accurately sense and measure the oxygen concentration, even at low oxygen concentrations, and achieve easy producibility and cost reducibility.

Abstract: The gas sensor control apparatus develops a first voltage based on a first reference voltage at a negative terminal of a gas sensor device through a resistor and a second voltage based on a second reference voltage at a positive terminal of the gas sensor device. A controller samples through the resistor a sensor current, as created upon the development of the first and second voltage for measuring the concentration of gas. When the impedance of the gas sensor device is measured, the controller alternates the first voltage across the first reference voltage. The value (i.e., a zero-point) of the voltage applied to the gas sensor device when the sensor current is zero (i.e., 0 mA) depends upon the first and second reference voltages. The zero-point is corrected by regulating the second reference voltage to match an applying voltage characteristic to the gas sensor device correctly.

Abstract: A bifunctional total NOx and O2 sensor assembly with an internal reference for high temperature sensing. Two electrochemical total NOx(NO+NO2) measuring systems and method were coupled with a metal/metal oxide internal oxygen reference to detect O2 and NOx simultaneously in a combustion environment using a single sensor. A Pd/PdO-containing reference chamber was sealed within a stabilized zirconia superstructure by a high pressure/temperature bonding method. An amperometric and potentiometric NOx sensor assembly was built on the outside of the Pd/PdO chamber. Pt-loaded zeolite Y was used to obtain total NOx capacity and also to cover the Pt electrodes for detecting oxygen in the presence of NOx.

Abstract: A method for preparing a thin ceramic material with a continuous controlled surface porosity gradient is disclosed as well as its use for producing electrochemical cells that conduct by oxide ions. The thin ceramic material is characterized by a continuous variation in porosity from 0% to about 80% of small thicknesses.

Abstract: In a sensor diagnosis process, a controller for controlling an NOx gas sensor performs processing of changing the oxygen partial pressure in a second measurement chamber by changing the oxygen partial pressure in a first measurement chamber (S190), processing of detecting a current flowing through a second pump cell before the change of the oxygen partial pressure (S180), and processing of detecting a current flowing through the second pump cell after the change of the oxygen partial pressure (S230). Furthermore, the controller performs processing of judging whether or not the ratio between the current values detected by the respective current detecting unit falls within an allowable range, judging that the second pump cell 113 is in a normal state if the ratio between the current values falls within the allowable range, and judging that the second pump cell 113 is in a deteriorated state if the ratio between the current values is out of the allowable range (S240 and S250).

Abstract: A single cell oxygen sensor apparatus and method are disclosed. An yttrium-based stabilized layer having electrical terminals connected to the yttrium-based stabilized layer can be provided on a substrate, wherein the yttrium-based stabilized layer is excitable by a constant current applied to the electrical terminals. A plurality of electrodes are located on a side of the yttrium-based stabilized layer and a plurality of heater elements located on said substrate opposite said yttrium-based stabilized layer. The heater elements can maintain the yttrium-based stabilized layer at a particular temperature. A cavity is formed and located between the yttrium-based stabilized layer and the heater elements. The partial pressure of oxygen can be measured by comparing the partial pressure of oxygen within the cavity with respect to the partial pressure of oxygen in the atmosphere external to the single cell oxygen sensor apparatus.

Abstract: [Objective] An object is to provide a sensor control apparatus and a sensor-control-apparatus control method which can reduce variation in startup time among a plurality of times of execution of detection processing, in consideration of variation in output characteristic among a plurality of gas sensors. [Means for Solution] In a sensor control apparatus, before drive control (S55 to S80) is started, preliminary control is executed so as to supply a constant current to a second oxygen pump cell over a constant time, to thereby control to a constant level the amount of oxygen pumped from a second measurement chamber to the outside of the second measurement chamber (S40 to 50). The preliminary control is executed under control conditions of the sensor control apparatus which are determined for each gas sensor and are associated with the amount of oxygen pumped from the second measurement chamber to the outside thereof.

Abstract: A sensor element is provided for determining a physical property of a measuring gas, especially of the concentration of at least one gas component in the measuring gas, which has at least one ceramic layer, a diffusion barrier adjoining the at least one ceramic layer and at least one electrode that is exposed to the measuring gas diffusing through the diffusion barrier. In order to reduce the production variations with respect to the static pressure dependence and the limiting current of the diffusion barrier), the proportions of silicon in the diffusion barrier and in the at least one ceramic layer are approximately equal and differ by not more than 1 wt. %.

Abstract: An electrochemical gas sensor, a method for making the sensor and methods for the detection of a gaseous species. The electrochemical gas sensor is a solid-state gas sensor that includes a solid polymer electrolyte. A working electrode is separated from a counter electrode by the solid polymer electrolyte. The sensor can include a multilaminate structure for improved detection properties, where electrode microbands are disposed within the solid polymer electrolyte.

Abstract: A method for pumping a sealed internal reference chamber of a solid electrolyte oxygen sensor, having an internal electrode and an external electrode, during a dynamically controlled, null balancing, calibration process, the method including: initializing a set of pumping current pulse parameters controlling pulse ON time, post pulse relaxation time and pulse magnitude; applying a pulsed pumping current based on the set of pulse parameters to the internal and external electrodes, wherein the application of current transitions the chamber from a substantially evacuated state to a substantially null or balanced oxygen partial pressure state with respect to an applied external calibration gaseous environment; periodically comparing the Nernst voltage of the sensor to a predetermined limit to determine whether the chamber is at a null or balanced state; comparing an elapsed time from the application of the pulsed pumping current to a third predetermined time limit to determine if the sensor has failed, and progre

Abstract: To provide a malfunction diagnosing method and apparatus capable of reliably determining a malfunction even where the malfunction occurs in a common wire connecting a gas sensor and a control circuit for driving it. In a gas concentration measurement unit 1 having a sensor control circuit 50 which is connected to a sensor element 10 including an oxygen pump cell 14 and an oxygen concentration detection cell 24 and controls and drives this sensor element 10, a variation state of a terminal voltage at one connecting point (specifically, a Vs+ terminal) other than connecting points between electrodes facing a measurement chamber of each cell 14 and 24 and a common wire 24 is detected by a malfunction detection circuit 53 and an arithmetic processor 54. Based on this variation state of the terminal voltage, diagnosis of malfunction in the common wire 42 is executed. When the common wire 42 is broken, the terminal voltage at the Vs+ terminal varies with oscillations.

Abstract: Apparatus and methods for measuring NOx concentrations are disclosed. One method includes the steps of providing a gas stream having a NO concentration and a NO2 concentration, wherein a sum of the NO concentration and the NO2 concentration is a total NOx concentration; contacting the gas stream with a first zirconium oxide based oxygen sensor at a first temperature to achieve a first NO:NO2 equilibrium at the first temperature; contacting the gas stream with a second zirconium oxide based oxygen sensor at a second temperature to achieve a second NO:NO2 equilibrium at the second temperature; and determining the total NOx concentration by measuring a response of the first zirconium oxide based oxygen sensor to achieve the first NO:NO2 equilibrium and a response of the second zirconium oxide based oxygen sensor to achieve the second NO:NO2 equilibrium. The second temperature is different than the first temperature.

Abstract: In a procedure to recognize the gas composition of a gas mixture, which consists of at least two gases of preferably different diffusion properties, delivered to a wideband lambda sensor, especially a gas mixture of an exhaust gas of an internal combustion engine of a motor vehicle, whereby the lambda sensor has a pumping cell with at least one gas measurement chamber, provision is made for the recognition of the gas composition of the gas mixture to result by means of modulation of the gas in the gas measurement chamber. Preferably the air number in the gas measurement chamber of the pumping cell is periodically altered, whereby the sensitivity of the lambda sensor to the gases, of which there are at least two, likewise periodically changes.

Abstract: Disclosed is a gas sensor for controlling a concentration of oxygen and/or measuring NOx by allowing a current to flow through an ion-conductive member for conducting oxygen ion, by the aid of a current supply circuit, wherein the current, which is outputted from the current supply circuit, has a pulse waveform (current signal) having a constant crest value, and the current supply circuit comprises a rectangular wave-generating circuit for controlling a frequency of the current signal on the basis of an electromotive force generated in the ion-conductive member to which the current signal is supplied. Accordingly, it is possible to highly accurately measure the predetermined gas component while scarcely being affected by the electric noise or the like.

Abstract: A low cost room temperature electrochemical gas sensor with humidity compensation for sensing CO, alcohol vapors and other toxic analyte gases has a solid protonic conductive membrane with a low bulk ionic resistance. A sensing electrode and a counter electrode, optionally a counter electrode and a reference electrode, which are separated by the membrane, can be made of mixed protonic-electronic conductors, or can be made of a thin electrically conducting film such as platinum. A reservoir of water maintain the solid protonic conductive membrane at constant 100 percent relative humidity to compensate for ambient humidity changes. Embodiments of the inventive sensor also include an electrochemical analyte gas pump to transport the analyte gas away from the counter electrode side of the sensor.