Numerical Assessment of OME₃ Combustion and Emission Reduction Under Oxy-Fuel Conditions in a CI Engine

The use of renewable synthetic fuels is a suitable alternative for combustion-based systems. Their implementation can reduce pollutant emissions such as soot, CO and CO${}_2$, but NO${}_{\mathrm{x}}$ remains difficult to abate. The objective of this study is to evaluate the combination of Oxymethylene Ether-3 (OME${}_3$) with the oxy-fuel concept, hence operating without N${}_2$ and minimizing nitrogen oxides formation. For this purpose, advanced numerical simulations were used to investigate the effects of this strategy on combustion thermodynamics, efficiencies, and exhaust products. This model was adapted for the OME${}_3$ use, obtaining a reduction in soot production due to the fuel characteristics, but an increment of NO${}_{\mathrm{x}}$ emission. To overcome this issue, the oxy-fuel concept was implemented to remove N${}_2$ from the combustion process. The numerical analysis provides insights into combustion performance to enhance the comprehension of the factors responsible for emission reductions. Preliminary results have shown the feasibility to eliminate NO${}_{\mathrm{x}}$ while maintaining a near-zero soot production. Further evaluations pointed out a reduction of 90% and 30% of CO and HC, respectively, with a slight improvement (1%) of the combustion efficiency (98%) and Gross Indicated Efficiency (GIE) (36%). Overall, the present study demonstrates the feasibility of the concept and highlights its potential for further optimization and experimental validation.