Abstract: Disclosed herein is a composition for use in a NOx electrode comprising: Tb(1-x)Ln(x)E(1-y)Q(y1)X(y2)Z(y3)O3 wherein Ln is a lanthanoid or a combination of lanthanoids, E is a metal selected from chromium, iron, and a combination thereof, Q is an element selected from magnesium, calcium, strontium, and a combination thereof, X is an element selected from boron, lead, phosphorus, germanium, and a combination thereof, Z is an element selected from barium, silicon, aluminum, and a combination thereof, x is from 0 to about 0.5, y is from about 0.05 to about 0.8, and y1, y2, y3 are independently from 0 to about 0.8, with the proviso that y=y1+y2+y3, and y2+y3 is greater than 0. Also disclosed are a method of making it, electrodes and sensors comprising it, and a method of detecting NOx.

Abstract: A reformer system comprising a hydrocarbon reformer; a fuel supply system; an air supply system; a hydrogen sensor disposed in a reformate exhaust stream from the reformer; and a reformer controller for receiving input from the hydrogen sensor and setting the flow values for fuel and air to provide a desired O/C ratio in the reformate stream. A protocol of varying fueling rates is run in which a calibration relating hydrogen sensor values to O/C ratio is generated and is programmed into the controller. From this calibration, a fueling rate is selected which provides an O/C ratio within a predetermined range. The reformer system is especially useful for regeneration of a nitrogen oxides trap in a diesel exhaust system. The calibration protocol may be run during engine operation and can adjust the fueling rate when different diesel fuel mixtures are presented.

Abstract: Exhaust gas sensors and methods for measuring concentrations of NOx and ammonia and temperatures of the sensors are provided. In one exemplary embodiment, an exhaust gas sensor utilizes one zirconia layer and a plurality of alumina layers therein for generating signals indicative of concentrations of NOx and ammonia, and having an impedance indicative of a temperature of the exhaust gas sensor.

Abstract: In a fuel cell system, a reformer supplies reformate to a fuel cell stack. A portion of the reformate flow is diverted for analysis by a hydrocarbon analysis system. Residual hydrocarbons in the reformate may damage the anodes of the fuel cell stack. Although incompletely-reformed reformate may include a variety of hydrocarbon compounds, the invention simply measures methane as an indicator of the overall performance level of the reformer. A currently preferred embodiment includes a catalytic combustion methane sensor. Combustion air and reformate are delivered in a fixed ratio to the sensor via positive displacement pumps. The system can provide alarm means or optionally a shut-off means to protect a fuel cell stack from elevated levels of hydrocarbons in the reformate stream.

Abstract: Disclosed herein are NOx sensors and methods of using the same. In one embodiment, a method for sensing NOx comprises: contacting a first NOx electrode with the gas, contacting a second NOx electrode with the gas, determining a NO2 emf between the first NOX electrode and a first reference electrode, determining a NOx emf between the second NOx electrode and a second reference electrode, and determining a NO2 concentration and a NO concentration using the NO2 emf and the NOx emf. The first electrode can be at a first temperature of greater than or equal to about 700° C., and the second electrode can be at a second temperature of about 500° C. to about 650° C.

Abstract: In a planar oxygen sensor having a pump cell, a reference cell, a sensor chamber and a heating device, a ground plane electrode is provided and includes a sensing portion having a first sense lead and a second sense lead and a measuring portion having a first measuring lead and a second measuring lead, wherein the first measuring lead and the second measuring lead have increased surface area relative to said sensing portion such that the resistance between the first measuring lead and the second measuring lead is reduced and wherein the first measuring lead is disposed so as to be communicated with the first sense lead and the second measuring lead is disposed so as to be communicated with the second sense lead.

Abstract: A compact ceramic fuel property sensor comprises a plurality of laminated ceramic layers. The heater, temperature sensor, and capacitance measurement electrodes are embedded between the layers. The capacitance electrodes include interdigitated electrodes and fuel traps for containing a sample of liquid fuel disposed between the interdigitated electrodes. The dimensions of the fuel traps are selected so that the fuel traps remain filled with liquid after said sensor has been bathed in fuel. A method for monolithically preparing the sensors provides a reduced cost method and a sensor that can survive indefinitely in liquid fuel.

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: Disclosed herein are methods of sensing NH3 in a gas and sensors therefore. In one embodiment, a method of sensing NH3 in a gas comprises: contacting a NOx electrode with the gas, and determining if a NOx emf between the NOx electrode and a reference electrode is greater than a selected emf. If the NOx emf is greater than the selected emf, a NH3 emf between an NH3 electrode and the reference electrode is determined. If the NOx emf is not greater than the selected emf, a NH3 emf between the NH3 electrode and the NOx electrode is determined.

Abstract: A temperature sensor includes a membrane supported by a substrate and a circuit having elements for a substrate electrical resistance indicative of the temperature of a substrate and a membrane electrical resistance indicative of the temperature of a membrane. The substrate resistance and the membrane resistance are arranged in a bridge configuration to facilitate measurement of a differential voltage responsive to temperature change. The resulting temperature signal includes a first varying portion and a second varying portion. A controller receives a temperature signal from sensor, eliminates the second varying portion and generates a temperature value based on the based on the first varying portion. In this manner, the sensor provides an improved, fast response to changes in the surrounding temperature.

Abstract: One embodiment of an ammonia gas sensor includes: a reference electrode, an ammonia selective sensing electrode and an electrolyte disposed therebetween. The sensing electrode comprises the reaction product of a main material selected from the group consisting of vanadium, tungsten, molybdenum, vanadium oxides, tungsten oxides, molybdenum oxides, and combinations comprising at least one of the foregoing main materials, and an electrically conducting material selected from the group consisting of electrically conductive metals, electrically conductive metal oxides, and combinations comprising at least one of the foregoing.

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 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: In one embodiment, a method for forming the sensor comprises: disposing capacitance electrodes and a heater on green layers; disposing the layers such that the capacitance electrodes are disposed between adjacent green layers and the heater is disposed on a side of a green layer opposite one of the capacitance electrodes; disposing a gap insert in physical contact with the capacitance electrodes, wherein the gap insert has a higher sintering temperature than the green layers; sintering the green layers; and removing the gap insert.

Abstract: In one embodiment, a method for forming the sensor comprises: disposing capacitance electrodes and a heater on green layers; disposing the layers such that the capacitance electrodes are disposed between adjacent green layers and the heater is disposed on a side of a green layer opposite one of the capacitance electrodes; disposing a gap insert in physical contact with the capacitance electrodes, wherein the gap insert has a higher sintering temperature than the green layers; sintering the green layers; and removing the gap insert.

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: A gas sensor comprises a first electrode and a reference electrode with an electrolyte disposed therebetween, wherein the first electrode and said reference electrode are in ionic conmmunication, wherein the reference electrode has a surface on a side of the reference electrode opposite the electrolyte and the surface has a surface area. The gas sensor also comprises a reference gas channel in fluid communication with the reference electrode, wherein at least a portion of the surface of the reference electrode physically contacts at least a portion of the reference gas channel, and wherein the portion of the reference electrode in physical contact with the reference gas channel is less than about 90% of the surface area.

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 compact ceramic fuel property sensor comprises a plurality of laminated ceramic layers. The heater, temperature sensor, and capacitance measurement electrodes are embedded between the layers. The capacitance electrodes include interdigitated electrodes and fuel traps for containing a sample of liquid fuel disposed between the interdigitated electrodes. The dimensions of the fuel traps are selected so that the fuel traps remain filled with liquid after said sensor has been bathed in fuel. A method for monolithically preparing the sensors provides a reduced cost method and a sensor that can survive indefinitely in liquid fuel.

Abstract: A sensor includes a substrate consisting essentially of a non-conductive material, a first electrode, and a second electrode disposed on a first surface of the substrate, wherein the first electrode includes a first major portion traversing a length of the substrate and a finger extending from the major portion, wherein the second electrode includes a second major portion traversing the length of the substrate and a finger extending from the second major portion, wherein the first electrode finger extends toward the second electrode major portion and the second electrode finger extends toward the first electrode major portion and is substantially parallel to the first finger, and a third electrode connected to a ground, wherein the third electrode is interposed between and about the first and second electrodes.