Sensors (Aug 2011)

Determination of the NOx Loading of an Automotive Lean NOx Trap by Directly Monitoring the Electrical Properties of the Catalyst Material Itself

  • Ralf Moos,
  • Gerhard Fischerauer,
  • Andrea Geupel,
  • Sebastian Reiß,
  • Peter Fremerey

DOI
https://doi.org/10.3390/s110908261
Journal volume & issue
Vol. 11, no. 9
pp. 8261 – 8280

Abstract

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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.

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