Experimental Investigation on the Effect of Ignition Enhancers in the Blends of Sapota Biodiesel/Diesel Blends on a CRDi Engine

The enthusiasm for biofuels as feasible alternatives for use in diesel engines has significantly expanded on account of their spotless consuming nature in addition to fossil fuel independence. The present study utilizes two oxygenates, dimethyl carbonate (DMC) and n-butanol (n-B), derived from non-food-based lignocellulosic biomass in a blended form with transesterified oil extracted from waste sapota seeds to power a modern one-cylinder common rail direct injection (CRDi) diesel engine for any improvement in combustion, performance, and emission characteristics. Three test fuels, viz., B40%, B40% + DMC10%, and B40% + n-B10%, were prepared by splash blending, and the results were correlated with baseline diesel fuel. The experimental results indicate that accrual of oxygenates to sapota oil methyl ester has improved the combustion characteristics in comparison to diesel and B40% + n-B10%: the peak heat release rate (HRR) for B40% + DMC10% was 4.89 and 5.14% higher, respectively. The brake thermal efficiency (BTE) of an engine fueled with a B40% + DMC10% blend was better than that fueled with B40% + n-B10% but lower than that fueled with baseline diesel. The oxides of nitrogen (NOx) emission were higher side when the engine was fueled with both oxygenated blends compared to diesel: B40% + DMC10% exhibits 6 and 2% higher values than diesel and B40% + n-B10%, respectively, at peak load conditions. Smoke opacity experienced a sharp reduction when fueled with a B40% + n-B10% blend; there was about 11.76, 19.60, and 23.52% reduction when fueled with diesel, B40%, and B40% + DMC%, respectively. Carbon monoxide for B40% + DMC10% was the lowest compared to diesel, B40%, and B40% + n-B10%, and there were about 21.59, 86.85, and 34.74% reduction in emissions, respectively. Hydrocarbon emission for B40% + DMC10% was the lowest compared to diesel, B40%, and B40% + n-B10%, and there were about 8.62, 27.58, and 17.24% reduction in emissions. Reformulation of diesel with DMC, n-butanol, and sapota oil methyl ester renders a chance to decrease emissions and use renewable fuel in diesel engines.