Performance and emission analysis of sustainable rice bran-Calophyllum-CNSL biodiesel blends in a conventional diesel engine

Diesel engines are often run on blended fuels to evaluate the adaptability and alternative energy source with changing engine components. The study compares the engine performance and emission characteristics of diesel engines operating on pure diesel and biodiesel blends. Tests were carried out on a single cylinder, four stroke, water cooled direct injection diesel engine at constant speed of 1500 rpm. The 10%, 20% and 30% bio-oils by volume (B10, B20 and B30) biodiesel blends were tested at different engine loads in comparison to regular diesel without any engine modifications. The diesel engine performance was evaluated by brake power (BP), brake specific fuel consumption (BSFC), total fuel consumption (TFC) and brake thermal efficiency (BTE). Also, emissions characteristics such as carbon dioxide (CO2), nitrogen oxides (NOx) and unburned hydrocarbons (UBHC) were measured. The results revealed that all the biodiesel blends had the same braking power for all the fuels with a maximum value of 4.26KW under all loads. Because biodiesel has a reduced calorific value, performances like TFC and BSFC improved with its presence; this impact was particularly noticeable for the B30 mix. Nevertheless, the B20 blend achieved a slight increase in TFC at medium and higher loads, leading to effective fuel use. Due to better combustion aided by the oxygenated fuel characteristic, B20 outperforms the other blends, obtaining a higher BTE of 30.2% than diesel at greater loads. Higher biodiesel concentration increased the UBHC emission since it had the maximum viscosity and decreased fuel volatility. All things considered, the B20 blend offers the best balance between thermal efficiency, emission characteristics, and fuel consumption.