Combustion investigation of ternary blend mixture of biodiesel/n-butanol/diesel: CI engine performance and emission control

This study aims to analyze the effects of a novel ternary blend of n-butanol and castor oil methyl ester (COME) with petro-diesel on combustion, engine performance and emission characteristics of four stroke single cylinder diesel engine and to obtain optimum blending proportion which can simultaneously reduce UHC, CO, and NOx without affecting engine performance. A quick and simple approach involving a single zone combustion model coupled with double and triple Wiebe functions has been successfully applied to analyze combustion behavior of binary and ternary fuel blends respectively. Neat diesel was used as a baseline fuel to compare combustion, performance and emission characteristics with binary and ternary fuel blends (B30, B20Bu10, B10Bu20 and B15Bu15). Apparent heat release rate (AHRR) calculated from the model is in good agreement (RMSE ≤ 1.33) with experimental values. Peak AHRR values (J/°CA) for fuel blends B30, B20Bu10, B15Bu15, B10Bu20 and neat diesel were found to be 26.1, 29.4, 32.7, 37.1, and 36.1 respectively. The ignition delay period was not affected for B30 blend however it was observed to be increased by 2.89–3.35°CA for n-butanol blended fuels. Results of B30 fuel blend showed reduction in BTE by 1–3% with increase in greenhouse gas emissions. The results of ternary fuel blend (B15Bu15) showed improvement in engine performance characteristics whereas NOx emission was reduced in the range of 20–60% compared to B30. Detrimental effect on engine performance, emission characteristics and combustion behavior was observed for B10Bu20. Therefore, B15Bu15 was considered as an optimum fuel blend.