Effect of EGR and Ethanol additive on Performance and Emission Characteristics of Diesel Engine Fuelled with Rubber Seed Biodiesel Blends

Alcohols are being considered as an alternative to traditional fuels for compression ignition engines due to their oxygen content and biomass origin. While alcohols have lower cetane numbers, making them more suitable for premixed combustion, they are also a promising option for reducing exhaust emissions in internal combustion engines through methods like exhaust gas recirculation. In this study, we investigate and improve the performance of a single-cylinder, four-stroke diesel engine by introducing ethanol into the intake port during the intake stroke. The main fuels used were diesel and rubber seed biodiesel, which were injected directly into the combustion chamber. The results showed that increasing the amount of ethanol combined with rubber seed biodiesel and his EGR by 10% improved brake thermal efficiency and reduced NOX emissions. The timing and duration of ethanol injection are optimized for dual fuel operation. The highest brake thermal efficiency for a 20% ethanol energy contribution was 34% for diesel, 31.16% for B20 with EGR, and 31.15% for B20 without EGR at full load. In addition, NOX emissions were reduced by 25.44% and 26.08%, respectively, for B10 with EGR and B20 with EGR at maximum thermal efficiency. However, increasing the ethanol energy fraction increased HC, CO2, and smoke emissions for all loads of B10 with EGR and B20 with EGR, respectively. In addition, peak pressure and maximum pressure rise rates increased for B10 with EGR and B20 with EGR, while ethanol injection resulted in a shorter combustion duration and higher heat release rate.