Meeting the upcoming NOx emissions standards is a major challenge for the lean-burn engines, thus requiring a highly efficient exhaust gas aftertreatment. Currently, the Selective Catalytic Reduction (SCR) appears to be the most promising technology, especially when operated with two kinds of reductants: ammonia (generally derived from urea) and ethanol. In order to reach high conversion levels while avoiding the overinjection of the reductant, a very accurate model-based control assisted with at least one NOx sensor is required.This study focuses on the sensitivity of NOx sensors to the main nitrogenous species encountered: ammonia, isocyanic acid (HNCO) and hydrogen cyanide (HCN). The cross-sensitivity to ammonia is the only one to be already described in literature and already used in the urea-SCR control systems to limit the risks of ammonia-slip. However, HNCO can also be found downstream of a catalyst during urea-SCR if the urea delivery or the catalyst are deficient. With an ethanol-SCR system, the very dangerous HCN might be found if the selectivity of the catalyst deteriorates. Both species were found to interfere with the NOx sensor signal: the observation of the these cross-sensitivities was stated on an engine test-bench while additional characterizations were performed on a synthetic gas bench. Meanwhile, nitrous oxide, ethanol or aldehydes appeared not to bias the sensor signal.The obtained results suggest that the identified cross-sensitivities may be used to detect the presence of HNCO for urea-SCR or HCN for ethanol-SCR instead of or in addition to ammonia, due to different interference factors. These particularities are intended to help diagnose some failures of the SCR aftertreatment system.


    Zugriff

    Zugriff prüfen

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    About Cross-Sensitivities of NOx Sensors in SCR Operation


    Weitere Titelangaben:

    Sae Technical Papers


    Beteiligte:
    Frobert, Arnaud (Autor:in) / Jeudy, Eric (Autor:in) / Raux, Stephane (Autor:in) / Creff, Yann (Autor:in)

    Kongress:

    SAE 2013 World Congress & Exhibition ; 2013



    Erscheinungsdatum :

    08.04.2013




    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch




    About Cross-Sensitivities of NOx Sensors in SCR Operation

    Frobert, A. / Raux, S. / Creff, Y. et al. | British Library Conference Proceedings | 2013


    About cross-sensitivity of NOx sensors in SCR operation

    Frobert,A. / Raux,S. / Creff,Y. et al. | Kraftfahrwesen | 2013


    Analysis of Wood Cross-Tie Price Sensitivities

    Gauntt, J. C. / Zarembski, A. M. / American Railway Engineering and Maintenance of Way Association | British Library Conference Proceedings | 2000


    Design Sensitivities

    Sóbester, András / Forrester, Alexander I J | Wiley | 2014


    NEP Mission Sensitivities

    J. H. Gilland | NTIS | 1991