Abstract: A system and method measures the thickness of wear liners coupled to wear substrates of industrial equipment. The system includes at least one ultrasonic transducer wear sensor device coupled intermediate the wear liner and wear substrate and a data acquisition device configured to receive thickness data from the wear sensor device. The ultrasonic transducer wear sensor device is battery powered in one embodiment and passivated in an additional embodiment and powered through an interrogation signal.

Abstract: A gas sensor includes a sensing element of a material including metal oxide and is sensitive to a target gas and to a recalibration gas different from the target gas. For recalibrating the gas sensor, a resistance of the sensing element is measured as an updated recalibration gas baseline resistance in a recalibration environment showing a recalibration gas baseline concentration.

Abstract: A method for providing static data and dynamic data of a service/display menu for a mobile device from a field device containing identification data and a total amount of static data and dynamic data. Upon query of the mobile device, dynamic data and/or static data are transmitted from the field device to the mobile device via a wireless interface. Static data required for an application for representation and/or changing of transmitted dynamic data are transmitted from the field device to the mobile device. These static data are stored in a memory in the mobile device. Further disclosed is a computer program for performing the method and an arrangement comprising a field device and a mobile device for performing the method.

Abstract: A combustible gas sensor for detecting a combustible analyte includes a first sensing element including a first conductive element in electrical connection with an electronic circuitry, a first support structure in operative connection with the first conductive element, a catalyst supported on the first support structure for catalyzing a reaction of the analyte, and a system for measuring a variable related to the reactance of the first sensing element. Changes in the measured variable over time provide an indication of an operational status of the first sensing element.

Abstract: The present invention provides an explosion-proof miniaturized combustible gas sensor, comprising: a metal casing having an accommodation space therein; a wire mesh, a vertical surface perpendicular to a side surface where the wire mesh is located and the other side surface opposite thereto being used as a transfer surface of the combustible gas; a heat insulation module embedded in the metal casing; a detection module sensitive to a combustible gas; a compensation module insensitive to a combustible gas and matching the detection module; where the detection module has a higher catalytic combustion activity than the compensation module; a sealant, where a bonding length of the sealant in the accommodation space of the metal casing is used as an effective bonding surface, and the effective bonding surface is perpendicular to the transfer surface. The present invention has the advantages of a miniaturized size, good explosion-proof property and reliable performance.

Abstract: Systems, methods, and non-transitory computer-readable media for continuously monitoring residential air quality and providing a trend based analysis regarding various air pollutants are presented herein. The system comprises an air quality monitor located in a residential house, wherein the air quality monitor is configured to measure the level of an air pollutant. The system also includes a server that is communicatively coupled to the air quality monitor, wherein the server is configured to generate a unique environmental fingerprint associated with the residential house.

Abstract: A CO detector includes a sensor configured to detect a presence of CO and generate a signal indicative of the presence of CO, and a controller in signal communication with the sensor. The controller is configured to measure a level of detected CO in response to receiving the signal generated by the sensor. The controller is further configured to detect a first trouble condition representative of an end-of-life condition of the sensor, and a second trouble condition different from the first trouble condition.

Abstract: A method of assessing overall efficiency of a selective-catalytic-reduction catalyst includes monitoring instantaneous efficiency of the catalyst. The method also includes determining the overall efficiency by summing instantaneous efficiency values weighted by a first set of coefficients if the most recent instantaneous efficiency value is above an instantaneous efficiency threshold. The method additionally includes determining the overall efficiency by summing instantaneous efficiency values weighted by a second set of coefficients if the most recent instantaneous efficiency value is equal to or below the instantaneous efficiency threshold. Furthermore, the method includes determining whether the overall efficiency has dropped below an overall efficiency threshold and reporting when the overall efficiency has dropped below the overall efficiency threshold.

Abstract: An apparatus is disclosed for facilitating spoilage detection in bulk grain storage bins via dust-free or substantially dust-free air sampling. Dust particles are passively removed from sampled air without the use of barrier filters or electrostatic screens, but instead through the use of a non-linear pathway that is open at one end and closed at the other end. A system is disclosed that incorporates a coiled pathway as an air inlet element combined with a carbon dioxide or other gas detector element to provide an integrated detector module suitable for permanent installation in a dusty bulk grain storage bin environment to provide spoilage gas measurements over time. The system may communicate data to a central data storage system via cellular telephone or long range radio frequency data transmission. Alerts and alarms are generated and transmitted electronically to users via email, SMS text, automated phone messages and other means.

Abstract: A method of assessing overall efficiency of a selective-catalytic-reduction catalyst includes monitoring instantaneous efficiency of the catalyst. The method also includes determining the overall efficiency by summing instantaneous efficiency values weighted by a first set of coefficients if the most recent instantaneous efficiency value is above an instantaneous efficiency threshold. The method additionally includes determining the overall efficiency by summing instantaneous efficiency values weighted by a second set of coefficients if the most recent instantaneous efficiency value is equal to or below the instantaneous efficiency threshold. Furthermore, the method includes determining whether the overall efficiency has dropped below an overall efficiency threshold and reporting when the overall efficiency has dropped below the overall efficiency threshold.

Abstract: A method for a virtual sensor system corresponding to a target physical sensor is provided. The method may include selecting a plurality of measured parameters provided by a set of physical sensors based on operational characteristics of the virtual sensor system. The method may also include establishing a virtual sensor process model indicative of interrelationships between one or more sensing parameter and the plurality of measured parameters. Further the method may include obtaining a set of values corresponding to the plurality of measured parameters; calculating a value of the sensing parameter based upon the set of values corresponding to the plurality of measured parameters and the virtual sensor process model; and providing the value of the sensing parameter to a control system.

Abstract: A method and apparatus for gas detection uses a sensor such as an electrochemical (EC) cell and includes a feedback control loop to control a pump to establish a first predetermined gas flow rate to the EC cell. The concentration of the gas at the first predetermined flow rate is measured. If the detected concentration exceeds a predetermined Alert value at the first flow rate an Initial Warning without remedial action is generated, and, the system then changes the gas flow rate before an Alarm is indicated. An Alarm is signaled only if the system verifies the first measurement. Preferably the first flow rate is set to optimize the measurement accuracy of the EC cell being used, and the second flow rate is lower than the first. Verification of an Alarm at the first flow rate may be conducted quickly by a quick-reaction process. The controller may periodically cycle the flow rates between the first and second rates for better accuracy and faster verification times.

Abstract: A fire alarm for an installation via a housing that is flush with the ceiling, having at least one light source arranged in the housing and at least one light receiver arranged in the housing, as well as a shutter disk, which seals the housing. To prevent the spreading of stray light between the light source and the light receiver via the shutter disk, a shield, for example, is provided in the shutter disk to suppress or absorb stray light.

Abstract: A hazardous gases and wind direction sensor includes a housing having a hazardous gas sensor. The gas sensor sends an output signal to a transmitter at a predetermined frequency upon detecting a hazardous gas. Wind detection is provided by eight LEDs aligned with eight corresponding photocells disposed in the housing, where each photocell represents a topographical direction and is adapted to provide an output signal associated with a particular wind direction at a predetermined frequency. A disk is coupled to a rotatable shaft in the housing and positioned between the LEDs and photocells. The shaft is coupled to a wind direction indicator such as a windsock. The disk has a slot sized to allow light to pass from one of the LEDs to its corresponding photocell, which sends an output signal to enable a switching circuit in the transmitter. The switching circuit enables the output signal at a predetermined frequency to be transmitted to a receiver.

Abstract: A method and apparatus for gas detection uses a sensor such as an electrochemical (EC) cell and includes a feedback control loop to control a pump to establish a first predetermined gas flow rate to the EC cell. The concentration of the gas at the first predetermined flow rate is measured. If the detected concentration exceeds a predetermined Alert value at the first flow rate an Initial Warning without remedial action is generated, and, the system then changes the gas flow rate before an Alarm is indicated. An Alarm is signaled only if the system verifies the first measurement. Preferably the first flow rate is set to optimize the measurement accuracy of the EC cell being used, and the second flow rate is lower than the first. Verification of an Alarm at the first flow rate may be conducted quickly by a quick-reaction process. The controller may periodically cycle the flow rates between the first and second rates for better accuracy and faster verification times.

Abstract: A terminal system has a mass spectrometric for inspecting of dangerous substances is installed in an inspection area, and a support system for determining whether or not a dangerous substance is present and identifying the type of the substance, based on the mass spectrometric data on the target element that has been measured by the mass spectrometric, is installed in a security service enterprise's office. Both systems are connected to each other via a communication network so that they can exchange information. Thus, the support system can send the determination result of dangerous substances and a precautions guide to the terminal system via the communication network.

Abstract: The present invention is a new sensor system with catalyst for control and one with a dummy catalyst. An apparatus and method for rapidly determining the concentration of CO, water vapor, and temperature. One of the major reasons to rapidly determine a small but sudden rise CO is for fire detection. The combination of the CO, followed by rapid relative humidity rise is a clear indication of possible fire or an appliance malfunction, blocked flu or other combustion process gone awry. If the incident is accompanied by ions or particles that would be smoke from a fire. The signal from the CO determined by numerically compensating for humidity changes. Any one or two parameters could cause an increase the sensitivity of the other in a fire detector such as combination CO, relative humidity, temperature and smoke detector. Another application for rapid CO detection is in a vehicle to protect the occupants from a catastrophic CO event.

Abstract: A sensor and method of use for detection of low levels of carbon monoxide in gas mixtures. The approach is based on the change in an electrical property (for example: resistance) that occurs when carbon monoxide is selectively absorbed by a film of copper chloride (or other metal halides). The electrical property change occurs rapidly with both increasing and decreasing CO contents, varies with the amount of CO from the gas stream, and is insensitive to the presence of hydrogen. To make a sensor using this approach, the metal halide film will deposited onto an alumina substrate with electrodes. The sensor may be maintained at the optimum temperature with a thick film platinum heater deposited onto the opposite face of the substrate. When the sensor is operating at an appropriate (and constant) temperature, the magnitude of the electrical property measured between the interdigital electrodes will provide a measure of the carbon monoxide content of the gas.

Abstract: A signal processing apparatus for detecting and displaying the properties of diesel fuel powered compression-ignition engines senses strain pulses in the fuel injection rail structure to perform a variety of testing functions. Among other capabilities, the apparatus permits the user to establish stroboscope timing, to measure engine RPM, to view the relationship between crankshaft position and injection time, and to examine the time-dependent properties of strain pulses on individual fuel injectors in order to evaluate the condition of the diesel engine.

Abstract: A handheld/portable detector for chemical vapor monitoring includes a housing and a discharge chamber that is established therein. The plasma discharge has a relatively small volume, e.g., in the micro-liter range. A first electrode and a second electrode are disposed within the discharge chamber and a discharge gap is established therebetween. A sample gas tube is in fluid communication with the discharge chamber and provides a sample gas to the discharge chamber. Also, a plasma gas tube is in fluid communication with the discharge chamber and provides a plasma gas thereto. Accordingly, the plasma gas can be used to maintain microplasma discharge between the electrodes and the sample gas can be introduced into the microplasma discharge. A spectrometer optically connected to the handheld/portable detector is used to measure the radiation emitted by the sample gas when subjected to the microplasma discharge.

Abstract: A gas detection instrument comprises a combustible gas sensor and associated circuitry, which supplies power to the sensor and measures and displays resulting sensor response. The supplied power is switched between timed pulses of electricity and steady state electricity, with the intermittent electricity being employed only when no significant change in sensor output has been detected. Alternatively, timed pulses of electricity are maintained, and predictive software algorithms are used to give readings for gas concentration during interruption of the power supply. The sensor operation enables the instrument to respond to rapid changes in gas concentration while minimizing power consumption of the sensor.

Abstract: The invention provides a catalyst deterioration detecting system that is capable of detecting the degree of deterioration of each catalyst in a catalyst converter which includes two or more catalysts in series. The catalyst deterioration detecting system of an internal-combustion engine according to the invention is provided with a upstream catalyst located on an upstream side of an exhaust system of the internal-combustion engine and a downstream catalyst located on a downstream side of the exhaust system. The device comprises an oxygen density detector which is disposed downstream of the downstream catalyst and a deterioration detector for detecting a deterioration degree of the upstream catalyst based on the output of the oxygen density detector. According to an aspect of the invention, the deterioration detector detects deterioration degree of the downstream catalyst based on the previously detected deterioration degree of the upstream catalyst.

Abstract: A gas detection sensor system including active and reference elements (Rsense, Rref) are arranged in a modified bridge circuit (12, 14, 22, 24) which allows power (Vbat) to be supplied seperately to the active and reference element (Rsense, Rref). A digal processor (30) monitors the resistances of the elements (Rsense, Rref) to control a pulse-width modulator supplying power to the elements, thereby maintaining nearly constant temperatures in the sensor elements (Rsense, Rref) and to translate the decrease in power needed to maintain constant temperature on the catalytic element into an output proportional to the concentration of combutible gas in air. The system periodically measures the resistance of the elements (Rref, Rsense) and enables dual operating modes of catalytic-bead detector. One active or reference element (Rsense, Rref) can alternately measure low concentrations of combustible gases up to the lower explosive limit (LEL) or measure high concentrations, up to 100% by volume.

Abstract: A device for switching a connection according to the state of an apparatus to be monitored, especially a safety switch, includes an actuator having first signaling device preferably be fixed on the apparatus to be monitored. The actuator can be brought into contact with an actuator receiver having a second signaling device and can be detachably held to prevent it from being withdrawn. A signal transfer can be carried out in a contactless manner between the first and the second signaling devices. The actuator and the actuator receiver are engaged in an interlocking manner when touching. The first and second signaling devices are arranged such that signal transfer between the actuator and the actuator receiver is only possible in the position in which they are engaged in an interlocking manner.

Abstract: A network for detecting a substance includes at least two detectors that are capable of transmitting a signal, and a remote station capable of receiving the signal. The detectors are adapted to detect a substance and transmit data that indicates the presence of that substance to the remote receiving station.

Abstract: The current invention provides a wireless monitoring system. The system has one or more monitoring devices. Each device can transmit data and receive messages from an output center or alarm system. The output center can also transmit and receive messages. Both the output center and each device preferably have a transceiver that enables both the transmission and receipt of messages. No remote terminal units hardwiring is required for the system to function. The system is truly a wireless gas monitoring system. The system may use low earth orbit satellite technology, or licensed radio frequencies or any other means to wirelessly transmit and receive messages.

Abstract: Various pH sensor apparatus, and methods of providing such apparatus, include using a hydrogen ion (H+) sensitive element formed of a corrosion-resistant metal, such as titanium or zirconium. The pH sensitive element makes use of a discontinuous metal oxide layer, e.g., titanium dioxide, formed on a surface of the metal hydrogen ion (H+) sensitive element (e.g., titanium wire core element). Preferably, the discontinuous metal oxide layer is formed by thermal treatment in the presence of an oxygen containing media. The pH sensor apparatus may be used with any of a range of standard reference electrodes for providing the pH measurement. Further, a pH sensor apparatus can be used as a reference electrode with a hydrogen sensing electrode, e.g., a fine gold wire, for measuring dissolved hydrogen (H2) concentrations.

Abstract: A method and apparatus for protecting workers from casualty due to a combustible gas. A portable combustible gas detector is disclosed which is particularly suitable for portable use. The detector generally comprises a circuit, housed in the same chamber as the sensor, for controlling the operation of the gas detector; and operation software for operating the detector through the circuit. The circuit of the detector is encased in armor to protect the circuit from electromagnetic wave disturbance.

Abstract: A system for monitoring carbon monoxide in an environment which includes an apparatus emitting carbon monoxide, such as an internal combustion engine. A carbon monoxide sensor measures a concentration of carbon monoxide in the environment and provides an electrical signal to a processor that is representative of the measured concentration of carbon monoxide. The processor determines the concentration of carbon monoxide corresponding to the electrical signal, provides an output signal at or above predetermined carbon monoxide concentration thresholds, calculates an estimated carboxyhemoglobin level for the operator corresponding to the carbon monoxide concentrations calculated over time, and provides an output signal at or above predetermined carboxyhemoglobin thresholds. The signals are then received by one or more devices which provide textual, visual, and/or audible warnings indicating that environmental concentrations of carbon monoxide have caused a predetermined warning threshold to be met or exceeded.

Abstract: A low power local alarm indicating system for interconnectable detectors enables a viewer to, after the fact, determine which detector or detectors had previously gone into a local alarm. An alarm latch, such as a bistable multi-vibrator circuit, is set each time the respective detector goes into a local alarm. Subsequently, if the detector's test switch is activated, a local alarm visual indicator is provided. In a disclosed embodiment, the indication is provided by blinking a light emitting diode on the detector, for a predetermined interval. Where multiple detectors are interconnected, each detector that goes into alarm not only sets its local alarm latch and emits a local alarm, it also generates an interconnect alarm signal to the remaining interconnected detectors. The interconnected detectors go into alarm at least for as long as the interconnect signal is present.

Abstract: A gas detector-alarm comprises a hot-wire gas sensor 1 having an actuating power control 7 that supplies pulsed actuating power with a cycle T0 when the concentration of gas detected by the hot-wire gas sensor is lower than a first reference level, with a cycle T1 that is shorter than said cycle T0 at least once when the concentration of gas exceeds a second reference level, and with a cycle T0 again after an alarm has been triggered.

Abstract: The current invention discloses a wireless monitoring system. The system has one or more monitoring devices. Each device can transmit data and receive messages from an output center or alarm system. The output center can also transmit and receive messages. Both the output center and each device preferably have a transceiver that enables both the transmission and receipt of messages. No remote terminal units or hardwiring is required for the system to function. The system is truly a wireless gas monitoring system. The system may use low earth orbit satellite technology, or licensed radio frequencies or any other means to wirelessly transmit and receive messages.

Abstract: An alarm system for portable chemical monitors comprising a housing configured for attachment to the portable chemical monitor having a twist lock mechanical connector capable of connecting to the portable chemical monitor, at least three pins mounted within the housing that are capable of inserting into the portable chemical monitor, a circuit board electrically connected to the pins and capable of receiving electrical signals from the chemical monitor, and a ceramic disk supported within the housing having an indicator means for generating vibrational movement that provides a audible sound. A method for monitoring for the presence of chemical agents is disclosed.

Abstract: The invention includes systems and methods which allow reactivation of supported noble metal catalysts. The method involves heating the catalyst in the presence of a gaseous hydrocarbon in the absence of oxidizing agents. Systems of the invention provide for in situ reactivation of catalytic material.

Abstract: A gas detector is disclosed which includes a CO sensor and a processor. The CO sensor senses an environmental CO concentration and provides a variable electrical output in response. The processor receives digitized samples of the sensor's electrical output and computes, with each measurement sample, a COHb level of a hypothetical person exposed to the CO concentration sensed. The computation involves determining an equilibrium COHb level for each measurement sample, which is compared with a previously computed COHb level associated with previously measured samples. The previously computed COHb level is updated based on the comparison. When the computed COHb level is above a predetermined danger threshold, the processor preferably causes an audible and visual alarm to be activated to alert any persons present. The gas detector can further include a CH.sub.4 sensor coupled to the processor for independently sensing CH.sub.4 levels such that an alarm is activated when the CH.sub.

Abstract: A chemical sensor couples a material that changes temperature in response to a chemical condition with an oscillator. The oscillator is coupled to the material to detect the change in temperature in the material so that the frequency of the oscillator changes in correspondence with the change in temperature as an indication of the chemical condition.

Abstract: A CO concentration monitoring device operating under the control of a processor periodically checks the CO sensor to insure its ongoing integrity and to issue a distinctive audio signal to a user if sensor integrity has become suspect. The periodic integrity check procedure places a predetermined DC voltage across the sensor. Then, the voltage source is removed leaving the sensor charged as a capacitor such that reading the voltage remaining across the sensor, reading the temperature of the sensor and comparing a temperature adjusted representation of the voltage appearing across the sensor to at least one predetermined representation of a voltage representing a threshold at which sensor integrity becomes suspect. If this condition is determined, a sensor condition alert signal responsive is issued to drive a horn in a distinctive audio sequence (e.g., three 10 millisecond duration pulses spaced at about 500 millisecond intervals).

Abstract: A gas leak and cut-off device is provided including a gas-powered hot water heater having a cylindrical configuration with a circular top face, a circular bottom face, and a cylindrical periphery formed therebetween. The bottom face has a plurality of stanchions coupled thereto and extending downwardly for engaging a recipient surface. A gas input pipe is provided having a first end connected to a gas supply and a second end connected to the periphery of the hot water heater for supplying gas thereto to heat water. A plurality of monitors are each mounted in spaced relationship on the recipient surface with the outboard ends in line with the periphery of the water heater. Each monitor is adapted for generating an activation signal only during the detection of fluid.

Abstract: An electrochemical gas sensor is provided, the use of which permits quantitative measurement of volatile gas contaminants in an atmosphere being monitored, generally at ambient temperatures below 100.degree. C. The sensor is constructed of a sensor electrode and a reference electrode on a separator in such a manner as to be exposed to the atmosphere which is sensed for gaseous contaminants. In an alternative embodiment, the sensors can be covered with a selective filter which will selectively allow only small molecule toxic gases to pass for sensing by the sensor electrode while excluding larger interfering gas molecules. In another alternative embodiment, a multiple layer electrochemical gas sensor detects the presence of volatile gas contaminants in a sample gas as well as humidity, temperature, and/or pressure of the gas sample.

Abstract: A gas detector is disclosed which includes a CO sensor and a processor. The CO sensor senses an environmental CO concentration and provides a variable electrical output in response. The processor receives digitized samples of the sensor's electrical output and computes, with each measurement sample, a COHb level of a hypothetical person exposed to the CO concentration sensed. The computation involves determining an equilibrium COHb level for each measurement sample, which is compared with a previously computed COHb level associated with previously measured samples. The previously computed COHb level is updated based on the comparison. When the computed COHb level is above a predetermined danger threshold, the processor preferably causes an audible and visual alarm to be activated to alert any persons present. The gas detector can further include a CH.sub.4 sensor coupled to the processor for independently sensing CH.sub.4 levels such that an alarm is activated when the CH.sub.

Abstract: A gas detection and alarm system and a method thereof for monitoring a predetermined dose of carbon monoxide and other gases in the atmosphere which can be harmful to humans, having a gas detection/alarm device comprising a detection circuit which detects a predetermined dose of a gas such as carbon monoxide, an indication circuit which visually and audibly indicates the dose detection to the user based on the detection circuit, a microprocessor for digitally operating the detection circuit and the indication circuit, a power conversion circuit which converts AC power to DC power without using any transformers and which supplies the converted constant power to the detection circuit, indication circuit and microprocessor, and a housing which compactly houses the detection circuit, indication circuit, power conversion circuit and microprocessor.

Abstract: A ceramic sensor comprising a thin film of Cu.sub.x Mn.sub.3-x O.sub.4 is provided that quantitatively measures the partial pressure of CO and hydrocarbon gases in a flowing system. The sensor is specific to both CO and hydrocarbon gases and is negligibly affected by the presence of the common automobile exhaust vapors NO and H.sub.2 O, within the operational temperature range from about 250.degree. to 450.degree. C. The CO/hydrocarbon sensor of the invention has other applications, such as monitoring CO and hydrocarbon levels in laboratories, mines, and industrial smoke stacks, and may be used in environments up to about 700.degree. C.

Abstract: Method and apparatus for the detecting hazardous conditions including the hazardous leakage of carbon dioxide gases by detecting spontaneously a plurality of the conditions which are encoded with a different response for each condition; for the detection of hazardous conditions associated with combustion or potential combustion, the detection is of a plurality of gaseous conditions having different chemical and thermal characteristics and the presence of each such condition is indicated; when the detection is of the leakage of fuel gases, a plurality of catalytic units is used, each having a platinum wire extending to a junction with a comparator and bridged by a detector provided with bridge balance and threshold adjustment; periodic heat cleansing is by a multi-terminal bistable oscillator; smoky carbon particles are detected by an ionization chamber connected to alarm circuitry.

Abstract: A system and method for using a gas detecting device that conducts electricity increasingly for increasing concentration of a gas being detected. The temperature of a gas sensor element is regulated to first burn-off impurities on the surface thereof, and then to cool down the gas sensor element to a temperature at or above which the gas catalyzes. During catalyzation, the sensor element conducts and electrically signals a microprocessor concentration data, which microprocessor controls a three color LED so as to emit a color pattern indicative of the concentration level of the gas. A sum of previously measured concentration levels is taken to gauge exposure to the gas over a period of time. The gas detection system includes a self-calibration routine that can be run prior to normal use by successive exposure to varying concentrations of gas to determine the sensor element-specific reaction.

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 ceramic sensor (12) comprising a thin film (14) of Cu.sub.1=x Mn.sub.2-x O.sub.4-y is provided that quantitatively measures the partial pressure of CO gas in a flowing system (22). The sensor is specific to CO gas and is negligibly affected by the presence of the common automobile exhaust vapors NO, H.sub.2 O, and CH.sub.4, within the operational temperature range from about 250.degree. to 450.degree. C. The CO sensor of the invention has other applications, such as monitoring CO levels in laboratories, mines, and industrial smoke stacks, and may be used in environments up to about 700.degree. C.

Abstract: An on-board monitoring system for an automotive emission catalyst has (i) a test chamber remote from the automobile's engine exhaust gas stream; (ii) apparatus for supplying the chamber with sampled exhaust gases sequestered from the stream; (iii) a single hydrocarbon sensor exposed to the exhaust gas in the chamber to render a signal responsive to the concentration of hydrocarbon in the chamber; and (iv) apparatus for comparing the sensed signal with a reference signal, and, if a predetermined difference is exceeded, the catalyst is indicated as faulty. Apparatus (ii) has a supply channel interconnected between the chamber and the gas stream upstream of the catalytic converter, a supply channel independently interconnected between the chamber and the gas stream downstream of the catalytic converter, and valve apparatus for permitting flow-through of no more than one channel to the chamber at any one moment, preferably cycled at a certain frequency.

Abstract: A temperature limited catalytic gas detector includes a catalytic gas sensor in one branch of a Wheatstone bridge network. A power supply is connected through a voltage controlled regulator to the bridge network. An instrumentation amplifier measures electrical imbalances across the bridge network. A display is connected to the output of the instrumentation amplifier. The detector also includes a comparator which compares the output of the instrumentation amplifier with a predetermined limit signal and produces an output when the output of the instrumentation amplifier exceeds the limit voyage. The regulator is responsive to the output of the comparator to thereby reduce the power supply to the bridge network. The limit signal is equivalent to the output of the instrumentation amplifier when the gas sensor is at a particular high temperature. The arrangement prevents the gas sensor from operating at excessive operation temperatures.

Abstract: Chemical microsensors are fabricated by applying dithiolene transition metal complexes as thin films to chemiresistor devices using the Langmuir-Blodgett technique. The thin films interact with ambient gases and change electrical conductivity upon exposure to a particular gas or vapor. The film material determines the chemical sensitivity and selectivity. The degree of current change depends on the particular gas or vapor and its concentration. These compounds are different in structure and electrical conductive response to gas or vapors than previous materials used for chemical microsensors. This invention is particularly suited for hydrazine detection.