Filter regeneration curve

The DOC provided several functions for the urea SCR and filter system oxidation of HC and CO to meet tailpipe emissions, exotherm generation during cold start and filter regeneration, and NO oxidation for improved, durable SCR performance. Typical curves for HC and CO oxidation for an aged Pt DCXT are shown in Fig. 21.5... 

Of the two curves in Figure 5 one was attained with catalytic filters one was attained by regenerating a CB-330 covered catalytic filter and the other by regenerating a BS covered catalytic filter. In spite of the change of carbon material the combustion features do not vary significantly. In both cases the carbon material starts to bum at about 500 K and the complete regeneration is achieved at about 800 K. In addition, the regeneration rate curves show a dominant peak at about 660 K in the case of CB-330 and at about 690 K in the case of BS. 

In Figure 4, the influence of regeneration on the performance of the system is shown. The difference between the curves is not significant. This implies that there is no plugging of the filter by the copper collected on the filter within the experimental time. On the other hand, it is clear that the copper that is built up... 

The expected performance curves for LNT and Urea SCR versus fuel penalty are shown in Fig. 21.2 for the LD FTP-75. The NOx conversions were optimistic projections for the best formulations available in 2003 without any type of cold start strategy. It was assumed that the NOx catalyst is located downstream of a DOC, and similar engine out conditions were used for each technology. A penalty of 3 % was included for all systems to account for the increased backpressure and periodic regeneration of a soot filter. An equivalent fuel penalty for use of urea... 

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