Catalytic Efficiency Optimization in a Heavy-Duty Diesel Engine 2020-36-0191

Diesel engines pollutants emissions are gaining more and more attention, as the intense use of fuels derived from petroleum, especially diesel oil, is one of the protagonists of an environmental threat capable of aggravating climate change and degradation of the air quality. Since its establishment, EURO vehicle emissions regulations, recognizing the urgency of the issue, have imposed a drastic reduction in pollutant emissions. In this scenario, the selective catalytic reduction (SCR) system appears as an essential tool to meet the most recent regulations. In view of the growing dependence of this technology to meet the most current limits and the high cost of AdBlue in the Brazilian market, it is necessary to develop engineering solutions aimed at increasingly efficient and competitive products in the market. This study carried out an analysis of the influence of the positioning of the AdBlue injector and different mixing devices in order to evaluate the effects on backpressure and homogenization of the pre-SCR mixture in an after-treatment system already in production. New configurations were made idealized from the baseline. Throughout the research, two primary tubes with different layouts were tested, and after their definition, two different mixer configurations were applied. For the analysis, the NOX conversion efficiency of each set was taken into account, having as limit the amount of NH3 slip provided for in the norm, resulting in a trade-off in relation to the NOX conversion efficiency versus the NH3 generated. ETC and ESC tests cycles were carried out with the specimens in order to prove the efficiency of each set meeting the EURO V emission standards. In an ETC cycle, with the Proposal mixing pipe with 2 mixers, it was possible to achieve a 3.8% reduction in AdBlue consumption, resulting in a reduction up to 76.7% in NH3 emissions and a considerable gain in NOX conversion efficiency.