Investigation of performance and emissions of lower blends of algae biodiesel on variable compression ratio diesel engine

The large increase in vehicular population and depletion of world reserves of petroleum, resulted in increase in demand of petrol and diesel. In developing countries lot of foreign exchange is spent on petroleum products. Biodiesel is one of the alternatives which can be successfully used to reduce the consumption of petroleum fuels. This research investigates the performance and emissions of lower blends of algae biodiesel (ALB), B05, B07, B10 and B20 in comparison to conventional diesel fuel. The preparation of these blends involved the utilization of a suitable transesterification process. Properties of all blends were assessed according to established standards. Performance of the engine and emission analyses were conducted using a single-cylinder, water-cooled diesel engine, considering two distinct compression ratios (CR) of 16:1 and 18:1. Performance parameters, including torque, brake power (BP), brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE), were thoroughly evaluated. Simultaneously, emission parameters, namely hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO2), and nitrogen oxide (NOx) emissions, were analysed. These results were then compared with the performance and emissions of traditional diesel fuel. The findings revealed that torque and BP variations were minimal compared to conventional diesel fuel for both CR 16:1 and CR 18:1. Additionally, at a CR of 18:1, BP and BTE exhibited slight improvements for the B05, B07, and B10 blends in contrast to diesel fuel. Furthermore, BSFC remained nearly consistent across all lower blends. HC and CO emissions demonstrated a considerable reduction for the B05 and B07 blends compared to diesel fuel, while B10 and B20 blends displayed similar trends, particularly at both CR. It was observed that NOx in exhaust emissions increased as the percentage of algae in the blend was increased. The study suggested that lower blends of algae biodiesel can offer comparable performance to conventional diesel fuel with slight improvements in BP and BTE at higher CR. Moreover, the B05 and B07 blends exhibit significant reductions in HC and CO emissions, making them environmentally favourable options and meets existing emission norms.