Production, characterization, engine performance and emission characteristics of Croton megalocarpus and Ceiba pentandra complementary blends in a single-cylinder diesel engine

Compounding energy demand and environmental issues necessitate suitable alternative or partial replacement of fossil fuels. Among the possible sources, biodiesel from non-edible vegetable oil sources is more economically feasible and possesses characteristics close to those of petroleum diesel. Two potential non-edible biodiesel feedstocks "Croton megalocarpus" and "Ceiba pentandra" were used for biodiesel production through esterification and transesterification process on a laboratory scale. Biodiesel characterization, engine performance and emission characteristics were investigated in an unmodified direct injection, naturally aspirated, single-cylinder diesel engine. 20% (v/v) of each of C. megalocarpus (CM), C. pentandra (CP) and their combined blends (CMB20, CPB20, CMB15CPB05, CMB10CPB10, and CMB05CPB15) were tested under varying engine speeds ranging from 1000 rpm to 2400 rpm at full load conditions. CMB20 and CPB20 reduced the brake power (BP) by 2.63% and 3.70%, brake thermal efficiency (BTE) by 5.97% and 3.72%, carbon monoxide (CO) emission by 1.09% and 2.39%, hydrocarbon (HC) emission by 1.48% and 4.62% and smoke emission by 12.35% and 17.13%, respectively compared to petroleum diesel. On the other hand, CMB20 and CPB20 increased the brake specific fuel consumption (BSFC) by 9.74% and 7.63%, NO_X emission by 13.19% and 15.45%, respectively. A mixture of 10% of both biodiesels with diesels (CMB10CPB10) provides better performance and emission characteristics. CMB10CPB10 reduced BP, BTE, CO, HC and smoke by 0.53%, 0.50%, 5.21%, 8.38% and 20.71%, respectively and increased BSFC and NO_X by 3.90% and 18.66%, respectively compared to conventional diesel. A combined blend of CM and CP could be a sustainable substitute for fossil diesel in the context of performance and emission.