Effect of small proportion of butanol additive on the performance, emission, and combustion of Australian native first- and second-generation biodiesel in a diesel engine

This paper aims to investigate the effect of the addition of 5% alcohol (butanol) with biodiesel-diesel blends on the performance, emissions, and combustion of a naturally aspirated four stroke multi-cylinder diesel engine at different engine speeds (1200 to 2400 rpm) under full load conditions. Three types of local Australian biodiesel, namely macadamia biodiesel (MB), rice bran biodiesel (RB), and waste cooking oil biodiesel (WCB), were used for this study, and the data was compared with results for conventional diesel fuel (B0). Performance results showed that the addition of butanol with diesel-biodiesel blends slightly lowers the engine efficiency. The emission study revealed that the addition of butanol additive with diesel-biodiesel blends lowers the exhaust gas temperature (EGT), carbon monoxide (CO), nitrogen oxide (NOx), and particulate matter (PM) emissions whereas it increases hydrocarbon (HC) emissions compared to B0. The combustion results indicated that in-cylinder pressure (CP) for additive added fuel is higher (0.45–1.49%), while heat release rate (HRR) was lower (2.60–9.10%) than for B0. Also, additive added fuel lowers the ignition delay (ID) by 23–30% than for B0. Finally, it can be recommended that the addition of 5% butanol with Australian biodiesel-diesel blends can significantly lower the NOx and PM emissions.