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The diesel oxidation catalyst (DOC) is one of the major components of a diesel after treatment system. Earlier, DOCs were majorly used to oxidise un-burnt HC and CO from the exhaust gas to keep these pollutants within legislation limits. As legislative norms evolved towards becoming more stringent, the technology and chemistry of after-treatment catalysts have also advanced simultaneously. For Diesel Engines to meet BSVI emission norm, the DOC has a vital role to play. Apart from oxidizing un-burnt THC and CO, now it has to perform additional functions of converting NOx to NO2 to achieve desired NO2/NOx ratio for better DeNOx in the SCR and also give efficient exotherm across it when the cat burner fuel is injected during DPF Regeneration with minimal HC slip. In this paper, two DOCs having different PGM loadings and volumes are evaluated for their exothermal efficiencies and corresponding THC slips.

An efficient after treatment technique is driven by the need to maintain strict emission norms for heavy-duty and medium-duty ground vehicles. SCR being an advanced active emission technology system for diesel engine, is one of the most cost-effective and fuel-efficient technologies available for complying with the stringent NOx emission legislations. The design of the SCR system involves catalyst selection, complex controller development like urea dosing strategy and the interaction between engine setup and after treatment system. For this purpose, the SCR model must be computationally efficient to evaluate the complete efficiency along with to take care for the NH3 slip also. The SCR model was prepared with respect to SCR inlet temperature and ratio of NOx and ammonia to study the behavior of NOx conversion efficiency keeping consideration of NH3 slip also required for optimizing the calibration.