Performance and combustion analysis of diesel-biodiesel-ethanol blends in a compression ignition engine at constant speed

Abstract

The increasing demand for cleaner and sustainable energy sources has led to growing interest in biodiesel and alcohol-based fuel blends as alternatives to conventional diesel in Compression Ignition (CI) engines. In the present study, the performance and combustion behaviour of diesel, biodiesel and ethanol blends were experimentally investigated using a single-cylinder, four-stroke, water-cooled CI engine operated at a constant speed of 1400 rpm. Biodiesel produced from Amoora rohituka and Calophyllum inophyllum oils were blended with ethanol in different proportions and tested under varying load conditions. Engine performance was evaluated in terms of brake horse power (BHP), brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE). The results showed that the addition of ethanol influenced the combustion characteristics of both diesel and biodiesel blends due to its oxygenated nature. Certain blends exhibited improved brake thermal efficiency while maintaining brake power comparable to neat diesel. A marginal increase in BSFC was observed with higher ethanol content, which can be attributed to the lower calorific value of ethanol. Overall, the findings indicates that appropriately formulated diesel-biodiesel-ethanol blends can enhance combustion performance and serve as a viable alternative fuel for CI engines without any engine modifications.