{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,14]],"date-time":"2025-10-14T22:53:29Z","timestamp":1760482409105,"version":"build-2065373602"},"reference-count":45,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2011,8,25]],"date-time":"2011-08-25T00:00:00Z","timestamp":1314230400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Recently, it has been shown that the degree of loading of several types of automotive exhaust aftertreatment devices can be directly monitored in situ and in a contactless way by a microwave-based method. The goal of this study was to clarify whether this method can also be applied to NOx storage and reduction catalysts (lean NOx traps) in order to obtain further knowledge about the reactions occurring in the catalyst and to compare the results with those obtained by wirebound NOx loading sensors. It is shown that both methods are able to detect the different catalyst loading states. However, the sensitivity of the microwave-based method turned out to be small compared to that previously observed for other exhaust aftertreatment devices. This may limit the practical applicability of the microwave-based NOx loading detection in lean NOx traps.<\/jats:p>","DOI":"10.3390\/s110908261","type":"journal-article","created":{"date-parts":[[2011,8,30]],"date-time":"2011-08-30T06:04:23Z","timestamp":1314684263000},"page":"8261-8280","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":33,"title":["Determination of the NOx Loading of an Automotive Lean NOx Trap by Directly Monitoring the Electrical Properties of the Catalyst Material Itself"],"prefix":"10.3390","volume":"11","author":[{"given":"Peter","family":"Fremerey","sequence":"first","affiliation":[{"name":"Bayreuth Engine Research Center (BERC), Universit\u00e4t Bayreuth, 95440 Bayreuth, Germany"}]},{"given":"Sebastian","family":"Rei\u00df","sequence":"additional","affiliation":[{"name":"Bayreuth Engine Research Center (BERC), Universit\u00e4t Bayreuth, 95440 Bayreuth, Germany"}]},{"given":"Andrea","family":"Geupel","sequence":"additional","affiliation":[{"name":"Bayreuth Engine Research Center (BERC), Universit\u00e4t Bayreuth, 95440 Bayreuth, Germany"}]},{"given":"Gerhard","family":"Fischerauer","sequence":"additional","affiliation":[{"name":"Bayreuth Engine Research Center (BERC), Universit\u00e4t Bayreuth, 95440 Bayreuth, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6960-9805","authenticated-orcid":false,"given":"Ralf","family":"Moos","sequence":"additional","affiliation":[{"name":"Bayreuth Engine Research Center (BERC), Universit\u00e4t Bayreuth, 95440 Bayreuth, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2011,8,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2291","DOI":"10.1016\/j.ssi.2006.05.051","article-title":"Engines and exhaust after treatment systems for future automotive applications","volume":"177","author":"Alkemade","year":"2006","journal-title":"Solid State Ionics"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1023\/B:TOCA.0000024348.34477.4c","article-title":"Urea-SCR in automotive applications","volume":"28","author":"Gabrielsson","year":"2004","journal-title":"Topics in Catalysis"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1023\/B:TOCA.0000024344.91688.e4","article-title":"NOx storage-reduction catalysts for gasoline engines","volume":"28","author":"Takeuchi","year":"2004","journal-title":"Topics Catal"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"419","DOI":"10.1016\/S0920-5861(02)00384-X","article-title":"Automotive catalytic converters: current status and some perspectives","volume":"77","author":"Fornasiero","year":"2003","journal-title":"Catal. 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