Abstract: An improvement in the method or technique of conditioning a gas sensor is provided through the application of Pulse Discharge Technique (PDT) in order to condition mixed-potential gas sensors. A modified planar sensor design to minimize sodium atom diffusion and platinum electrode poisoning under conditions of PDT are provided. Modification of the PDT hardware is provided without modification of the sensor design. The improvement method comprises: a) Replace a single polarity power supply with a power supply with floating positive and negative output; b) Connect one of the heater leads with the reference electrode lead and connect it to the ground.

Abstract: A gas sensor is provided in which a solid electrolyte tape of yttria doped zirconia is layered with tapes of alumina and a tape if mixed alumina-zirconia. This zirconia layer has structural modifications to increase NOx and NH3 sensitivity which the capacitance is significantly increased by creating a composite layer of platinum (Pt) plus a layer of yittrium-stabilized-zirconia (YSZ) with Pt fraction of approximately between around 10% by volume to around 25% by volume. A 100-200 ?m thick mixed tape layer of porous MgAl2O4 is provided on top of the alumina-zirconia layer. Under the alumina-zirconia tape is an exhaust gas sensing electrode which connects to a contact pad through the lead. A reference electrode, which connects to the pad through a lead, is disposed in fluid communication with a reference chamber. Proximate alumina tapes and a heater are connected to the contact pad, which is connected to corresponding leads.

Abstract: A unique solution to measure NOx emissions is achieved less expensively and with much greater sensitivity than commercially available NOx sensors. A sensor's active materials are modified and operational algorithms are used to concurrently measure single ppm levels of NOx and NH3 with response times of one second or less. A combined NOx/NH3 sensor to have much finer control of an SCR system, thereby reducing NOx emissions and ammonia slip in a closed-loop device, all at lower cost than the current state-of-the-art solutions.

Abstract: A method of treating a gas sensor with an improved pulse discharge technique is provided by adding measurements of additional parameters, modification of the data processing algorithm, and establishing new calibration procedure in the low, intermediate and high concentration ranges of NOx. Additional measurements of the charge transfer during the charging pulses of the pulse discharge technique are made, and utilizing these data in combination with discharge rates during the pauses of the pulse discharge technique allows for combined measurements of O2 and NOx, in the combustion exhaust.

Abstract: An improved pulse discharge technique is provided which continuously measures a gas sensor's impedance at elevated temperatures. The present invention is characterized in that the measured impedance values are used to control said sensor's operating temperature within a defined temperature range or to monitor said sensor's operating temperature via impedance monitoring.

Abstract: A method is provided for activating a zirconia oxygen sensor which detects the oxygen concentration of an ambient atmosphere by means of a zirconia element that has a porous electrode formed on both sides of an impervious oxygen ion conductor. An electrical current is applied as a pulsed, square wave, direct current during heat up, heat soak, and cool down of the ionic conductor that is applied to ceramic substrate, thereby causing oxygen ions to flowing through the sensor body and pumping oxygen gas through the sensor electrodes, thus improving electrode porosity distribution.

Abstract: A method of sensor conditioning is proposed for improving signal output stability and differentiation between responses to different gases such as exhaust from combustion processes. A square wave (or saw tooth) voltage pulses of opposite polarity and equivalent amplitude are applied between sensor electrodes. Pulses are separated by pauses, when charging power supply is disconnected from the sensor and sensor discharge is recorded. Useful information regarding concentration of analyzed gases can be extracted from two measurement methods.: 1. Measuring open circuit voltage decay during the pause immediately following voltage pulse. 2. Measuring the charging current during positive (negative) pulses and the discharging current during pauses following voltage pulses.