Concept Based Evaluation and Development of Close-Coupled DOC through Model in Loop Simulation Supported by Experimental Investigations on 3L Light & Medium Duty BS - VI Diesel Engine 2022-01-0561

The implementation of stringent BSVI norms from April 2020 has greatly revolutionized the automobile industry. With the plan for implementation of more stringent BSVI OBD-II norms from April 2023, in place, meeting legislative limits, particularly with CI engines, will be a challenge. The major challenge is the reduction in nitrogen oxides (NO_x) which necessitates a selective catalytic reduction (SCR), together with effective calibration, to maintain the conversion efficiencies at the highest possible levels. The conversion efficiency is majorly dictated by temperature and exhaust mass flow. Hence, optimization of thermal management modes are very important. This is achieved by a close-coupled diesel oxidation catalyst (DOC). This paper describes the stepwise effectiveness of model based development for model in the loop simulation on virtual test bed (VTB), along with, experimental testing that goes hand in hand for development of a close-coupled DOC for a light & medium duty (LMD) engine. The close-coupled DOC is positioned nearer to the engine, resulting in higher temperatures, in comparison with a conventional DOC. This facilitates in improving the exhaust gas temperatures into the DOC, thereby contributing in improving the thermal management as well as in diesel particulate filter (DPF) regeneration. With higher exhaust flow temperatures, thermal management mode utilization would reduce, thereby improving the fuel efficiency. In addition, properly optimized platinum group metals (PGM) loading on DOC accelerates NO₂ conversion which facilitates faster selective catalytic reduction reactions to overcome NO_x emissions.