Evaluation of CRDi Engine Fueled With Binary and Ternary Blends of Biodiesel, Butanol, and Diesel

An automotive-type four-cylinder turbocharged common rail direct injection (CRDi) engine has been considered to utilize a higher proportion of biodiesel beyond 20% while effectively addressing the NO_x–soot engine performance trade-off with biodiesel, butanol, and petro-diesel fuel blends. Mixed feedstock obtained from Sterculia foetida oil and used palm oil in equal proportions to prepare biodiesel, and three binary and three ternary blends, prepared in different proportions, have been considered. Fuels were prepared with butanol blended with biodiesel and petro-diesel in different proportions. Investigations were carried out at various speed and load conditions similar to idling, urban, and highway drive conditions by varying the main injection timing and boost pressure, keeping other parameters at optimized values. The speed test conditions are chosen from a modified Indian driving cycle to simulate real driving conditions. The results obtained with different blends are compared against engine operation with neat petro-diesel operation. The engine is incorporated with a variable geometry turbine for increasing intake air and an open electronic control unit (ECU) for setting the operating parameters. For facilitating split injections, a dwell period (time between start of pilot and start of main injection) of 27° crank angle (CA) [i.e., with pilot injection timing (PIT) at 28 deg before top dead center (bTDC) and main injection timing (MIT) at 1 deg bTDC], pilot injection quantity (PIQ) of 11%, and fuel injection pressure (FIP) of 61.4 MPa are recommended for the speed and load conditions under consideration and the given engine configuration. Among the tested ternary blends, B20Bu10D70 and B30Bu10D60 showed improvement in NO_x and smoke emissions, with low-temperature combustion-like conditions observed. The use of renewable fuels will effectively address UNO's sustainable development goals.