A comprehensive experimental investigation of green diesel as a fuel for CI engines

Many possibilities have been explored so far for replacing petro-diesel with biodiesel and hybrid fuel, but none of these bio-fuels could completely substitute the petro-diesel with or without modification in the CI engine. In this perspective, renewable diesel or green diesel has been gaining popularity due to its higher cetane index and calorific value than that of petro-diesel, biodiesel, and hybrid fuel. This study investigates the production of green diesel from waste cooking oil (WCO) by hydro-processing and TBP distillation. The fuel properties of the green diesel thus produced were estimated using ASTM/EN standards and thereafter green diesel (G100) and its blends (G10, G20, G30 & G50) were used as fuel in a CI engine to analyze the effect on engine combustion, performance and emission characteristics. The results obtained were compared with petro-diesel, optimized biodiesel blend B30 and hybrid fuel (HB-1) to explore its efficacy under same experimental test rig and operating conditions. Over the entire loading conditions, green diesel blends showed higher BTE with lower BSEC. The emissions of CO, UHC and smoke opacity reduced, but a slight increase in NOX level was observed. The shorter ignition delay and higher cetane index of green diesel generated peaks of CP, HRR and ROPR near TDC as compared to the other tested fuels.