Breaking the NOx-soot trade-off in compression ignition engines at mid-load with high-percentage n-Pentanol blends through charge cooling and oxygenation

The quest for sustainable and environmentally friendly fuel alternatives has significantly increased interest in exploring higher alcohols, particularly n-pentanol, as a promising oxygenated biofuel option for internal combustion engines. This study meticulously analyzed the combustion, performance and emission characteristics of a 60% n-pentanol/40% n-dodecane blend, designated P60D40 , and n-dodecane, D100, utilizing computational fluid dynamics simulations. Here, n-dodecane was used as a surrogate for diesel fuel. The analysis was conducted under a variety of engine operation control parameters to ensure a thorough understanding of their behaviors. The results showed that under identical operating conditions, the indicated thermal efficiency of the P60D40 blend was 47.94%, which is higher than the 44.32% for D100. Furthermore, the equivalent indicated specific fuel consumption for the P60D40 blend was 169.89 g/kWh, in contrast to the 183.77 g/kWh of D100. This represents a 7.55% reduction in fuel consumption, highlighting the efficiency benefits of using n-pentanol as a fuel component. In addition to the performance improvements, the study also found significant reductions in harmful emissions. Specifically, emissions of soot, nitrogen oxides and carbon dioxide were reduced by 91.46%, 86.18% and 12.91%, respectively, compared to D100. The utilization of a 60% n-pentanol blend demonstrates considerable potential, as it not only meets the selected Euro VI reference limits of 0.4 g/kWh and 0.01 g/kWh for NO x and soot, respectively, but also offers excellent performance characteristics. Moreover, it shows the capability to effectively address the common trade-off between NO x and soot emissions, particularly under mid-load operating conditions.