Dual-monolith converters containing Pd-only catalysts followed by Pt/Rh three-way catalysts (TWCs) provide effective emission solutions for NLEV and Tier IIa close-coupled dual-bank V-8 applications due to optimal hydrocarbon and NOx light-off, transient NOx control, and balance of precious metal (PGM) usage. Dual-catalyst [Pd +Pt/Rh] systems on a 5.3L V-8 LEV light truck vehicle were characterized as a function of PGM loading, catalyst technology, and substrate cell density.NLEV hydrocarbon emission control of the 6500 lb vehicle was optimal using dual 1.2L converters with each containing front ceria-free Pd catalysts coupled with rear Pt/Rh TWCs. Advanced non-air prototype calibrations coupled with reduced catalyst washcoat mass on 600cpsi/4mil substrate resulted in minimal Pd usage of ∼0.02 toz/vehicle due to achieving catalyst inlet temperatures of 350-400°C in <10 sec on both banks of the V-8 engine. The lower mass Pd washcoat contribution was ∼10-15 mg/mi NMHC due to improved light-off performance.The more stringent Tier IIa NOx emission levels required larger converter volumes, higher Pd content, increased oxygen-storage capacity, and higher cell density 600cpsi/3mil substrates. Larger dual close-coupled 1.67L converters with front ceria-containing Pd catalysts substantially improved NOx performance during transient A/F excursions. The front Pd ceria-containing technology improved NOx by ∼20mg/mi compared to the ceria-free technology, but the ceria-free technology had ∼10mg/mi better NMHC control. The higher cell density 600cpsi/3mil substrate resulted in 10-15mg/mi lower NOx emissions.


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    Titel :

    Palladium and Platinum/Rhodium Dual-Catalyst NLEV and Tier IIa Close-Coupled Emission Solutions


    Weitere Titelangaben:

    Sae Technical Papers


    Beteiligte:
    Bortun, A. (Autor:in) / Robota, H. J. (Autor:in) / Nunan, J. G. (Autor:in) / Richmond, R. P. (Autor:in) / Williamson, W. B. (Autor:in)

    Kongress:

    SAE 2001 World Congress ; 2001



    Erscheinungsdatum :

    05.03.2001




    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch




    Palladium and Platinum/Rhodium Dual-Catalyst NLEV and Tier lla Close-Coupled Emission Solutions

    Williamson, W. B. / Richmond, R. P. / Nunan, J. G. et al. | British Library Conference Proceedings | 2001


    Palladium and Platinum/Rhodium dual-catalyst NLEV and Tier IIa close-coupled emission solutions

    Willimanson,W.B. / Richmond,R.P. / Nunan,J.G. et al. | Kraftfahrwesen | 2001


    Palladium and Platinum/Rhodium Dual-Catalyst Emission Solutions for Close-Coupled or Underfloor Applications

    Williamson, W. B. / Ball, D. J. / Linden, D. G. et al. | British Library Conference Proceedings | 2000


    Palladium and Platinum/Rhodium Dual-Catalyst Emission Solutions for Close-Coupled or Underfloor Applications

    Linden, D. G. / Ball, D. J. / Robota, H. J. et al. | SAE Technical Papers | 2000