Simulation Study of Combustion Characteristics of DieselEthanol-Palm Oil Methyl Ester Blends in Diesel Engine
Keywords:palm oil methyl ester, combustion characteristic, heat release rate, ignition
Diesel-ethanol-palm methyl ester (PME) blends are believed to be able to improve the combustion characteristics since diesel, ethanol, and PME have different fuel characteristics. This paper is aimed to study the combustion characteristics of pure diesel and diesel-ethanol-PME blends with different compositions through simulation works and to estimate the best fuel composition that can be used in real engine applications. A simulation work was conducted using seven different diesel-ethanolPME blends for a combustion based on a compression ignition Yanmar TF90 engine parameter by using a CONVERGE CFD software. Seven diesel-ethanol-PME blends (10 vol% to 40 vol%) PME were mixed in ethanol together with 50 vol% diesel fuel operated at 1600 RPM. High PME percentage increased the heat release rate (HRR). However, due to non-uniform chemical energy release from the reaction, the blends of 25 vol% PME with 25 vol% ethanol blends released the highest HRR. A high percentage of ethanol reduced the temperature and increased the heat release. From the cumulative heat release, ignition delay occurred for blends that had more than 15 vol% ethanol. In conclusion, blending ethanol and PME in diesel increased the combustion heat release rate to have better engine efficiency. However, the blend that contained more than 35 vol% ethanol was not suitable to be used in direct injection compressed ignition engine without any modification since the temperature and HRR of the blends is very low.