Combustion and Emission Characteristics of Oxygenated Alternative Fuels in Compression Ignition Engines

Abstract

Environmental pollution from petroleum products for energy generation is of grave concern nowadays. Oxygenated alternative fuels like biodiesels, alcohols, etc., have gained much popularity for internal combustion (IC) engines. Due to their inherent oxygen content, these oxygenated alternative fuels possess lower carbon-to-hydrogen (C/H) ratio for same heating value. Supporting the road map towards decarbonization of mobility, there has been a recent uptick in curiosity about the possibility of alcohols in compression ignition (CI) engines. Biodiesel contains ~10% inherent oxygen (m/m), and alcohols may contains up to 50% oxygen (m/m), affecting the CI engine's combustion, performance, and emission. An overview of CI engines fuelled with oxygenated fuels (biodiesel and alcohol blends) on combustion characteristics, engine performance, and exhaust emissions are presented in this study. Biodiesel and alcohol fuels (methanol, ethanol, and butanol) have been compared to evaluate the impact of different blend ratios, oxygen mass fraction content based on in-cylinder combustion pressure trace, heat release rate, and engine performance as brake thermal efficiency and carbon dioxide (CO2) emission. Up to 25% lowered CO2 emission was recorded for oxygenated fuel compared to diesel, with significantly lower particulate emission.