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Pulsed-potential method for NOx detection using standard zirconia-based lambda sensors

Title data

Fischer, Sabine ; Pohle, Roland ; Guth, Ulrich ; Farber, Boris ; Fleischer, Maximilian ; Moos, Ralf:
Pulsed-potential method for NOx detection using standard zirconia-based lambda sensors.
2011
Event: Sensor 2011 , 07.-09.06.2011 , Nürnberg, Deutschland.
(Conference item: Conference , Other Presentation type)
DOI: https://doi.org/10.5162/sensor11/d3.4

Official URL: Volltext

Abstract in another language

A measurement technique is presented to increase the differentiation between single exhaust gas components using a pulsed-potential method. After applying a pulsed charging voltage (2.5 V) for a defined duration (100 ms) to a standard thimble-type zirconia-based potentiometric lambda probe, the self-discharge voltage of the sensor is recorded for a defined time duration (10 s) and repeated using a voltage with opposite sign. This pulse sequence with electrode polarizations of opposite signs is used permanently and the discharge curves are measured continuously. The effect of different gas components NO, NH3, H2, ethanol, and a mixture of hydrocarbons in a range of 5 ppm to 150 ppm (HC to 240 ppm) in N2 base gas is evaluated. The sensor is operated at approximately 590 °C. Already in the lower ppm-range, the self-discharge characteristic after polarization shows a strong dependency on the NO concentration for both signs. Also an individual discharge characteristic for all investigated gases can be distinguished. This leads to the conclusion, that several gas species can be measured. The differences U(cgas)–U(0 ppm) for each gas component and concentration are calculated to investigate the cross-sensitivities. The characteristic semi-logarithmic curves are analysed for a defined evaluation time after voltage pulses for positive and negative direction. After polarization with positive voltages, the response to NO is most prominent compared to other gases, whereas ethanol shows a larger slope after negative polarization. Nevertheless, a gas component can be specified by the characteristic appearance of the curves after positive and negative polarization. In summary, this pulsed-potential method is capable to enable NO sensing in exhaust gas with improved selectivity using standard lambda probes.

Further data

Item Type: Conference item (Other)
Refereed: Yes
Institutions of the University: Faculties > Faculty of Engineering Science
Faculties > Faculty of Engineering Science > Chair Functional Materials > Chair Functional Materials - Univ.-Prof. Dr.-Ing. Ralf Moos
Faculties
Faculties > Faculty of Engineering Science > Chair Functional Materials
Profile Fields > Advanced Fields > Advanced Materials
Research Institutions > Research Centres > Bayreuth Center for Material Science and Engineering - BayMAT
Profile Fields
Profile Fields > Advanced Fields
Research Institutions
Research Institutions > Research Centres
Result of work at the UBT: Yes
DDC Subjects: 600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited: 30 Mar 2015 13:02
Last Modified: 13 Apr 2016 06:43
URI: https://eref.uni-bayreuth.de/id/eprint/9450