Diesel engines have the potential to significantly increase vehicle fuel economy and decrease CO2 emissions; however, efficient removal of NO(x) and particulate matter from the engine exhaust is required to meet stringent emission standards. A conventional diesel aftertreatment system consists of a Diesel Oxidation Catalyst (DOC), a urea based Selective Catalyst Reduction (SCR) catalyst and a diesel particulate filter (DPF), and is widely used to meet the most recent NO(x) and PM emission standards for medium and heavy-duty sport utility and truck vehicles. The increasingly stringent emission targets have recently pushed this system layout towards an increase in size of the components and consequently higher system cost. An emerging technology developed recently involves placing the SCR catalyst onto the conventional wall-flow filter. This technology enables reduced aftertreatment system volume and mass when compared to the conventional SCR system architecture. This technology also offers the potential of cost saving and packaging flexibility. In this work, the potential of the Cu/Zeolite-based SCR/DPF technology for meeting future emission standards was evaluated on a heavy-duty diesel engine operating on an engine dynamometer. In addition, a laboratory fixed-bed flow reactor system was used to determine the NH3 storage characteristics and the SCR performance as a function of soot loading and aging. Laboratory reactor results indicate that NH3 storage capacity decreases approximately 30 % on a degreened catalyst as a function of soot loading, but shows no significant decrease on an aged catalyst. The greatest impact is observed at 200 deg C on a degreened catalyst at soot loadings below 1.0 g/L. Additionally, there is only marginal impact of 2.5 g/L soot loading on the SCR performance below 400 deg C with about 10 to15% lower conversion at 200 deg C and about 5% lower conversion at 300 to 400 deg C. While the volume of a 2-way SCR/DPF cannot replace an equivalent volume of a flow through SCR substrate, it can greatly reduce the total volume of the complete system (i.e., SCR + Filter). It is currently estimated that the flow through volume can be reduced by 40% to 55% when used in combination with a reduced washcoat loaded 10.4L 2-way SCR/DPF. This is beneficial in reducing the complete vehicle exhaust aftertreatment architecture packaging volume. The elimination of PGM (i.e., Pt) on the DPF reduces the risk of NH3 oxidation to NO(x) if NH3 slip is to occur, and the added volume can help to improve high temperature DPF regeneration NO(x) conversion efficiency. The main risk to removing PGM from the DPF is excess HC slip during the DPF regeneration and cold start events.


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    Titel :

    The development of advanced 2-Way SCR/DPF systems to meet future heavy-duty diesel emissions


    Weitere Titelangaben:

    Die Entwicklung eines fortschrittlichen 2-Wege SCR/DPF Systems zur Erfüllung zukünftiger Heavy-Duty Diesel-Emissionsgrenzwerte


    Beteiligte:
    Tan, Julian (Autor:in) / Schmieg, Steven J. (Autor:in) / Solbrig, Charles (Autor:in) / Martino, Paolo Di (Autor:in)


    Erscheinungsdatum :

    2010


    Format / Umfang :

    23 Seiten, 14 Bilder, 5 Tabellen, 8 Quellen


    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Datenträger


    Sprache :

    Englisch




    The Development of Advanced 2-Way SCR/DPF Systems to Meet Future Heavy-Duty Diesel Emissions

    Solbrig, Charles / Tan, Julian / Schmieg, Steven J. | SAE Technical Papers | 2011


    The development of advanced 2-way SCR/DPF systems to meet future heavy-duty diesel emissions

    Tan,J. / Solbring,C. / Schmieg,S.J. et al. | Kraftfahrwesen | 2011


    The development of advanced 2 way SCR/DPF systems to meet future heavy duty Diesel emissions

    Tan,J. / Schmieg,J. / Solbrig,C. et al. | Kraftfahrwesen | 2010


    2011-01-1140 The Development of Advanced 2-Way SCR/DPF Systems to Meet Future Heavy-Duty Diesel Emissions

    Tan, J. / Solbrig, C. / Schmieg, S.J. et al. | British Library Conference Proceedings | 2011


    Advanced in-line pump for medium-duty diesel engines to meet future emissions regulations

    Itoh,S. / Sasaki,S. / Arai,K. et al. | Kraftfahrwesen | 1991