Coconut oil biodiesel as an emulsifier in diesel-ethanol blends for diesel engines

Coconut methyl ester (CME) or coconut oil biodiesel was chosen as the emulsifier for the diesel-ethanol blends. This study involved the stability testing and determination of physical and emission properties of the diesel-CME-ethanol blends in various proportions of the components at different temperatures. The stability testing results showed that blends with greater than 5% CME and using ethanol with 100% purity were stable at all observation temperatures. Using the 99.5% pure ethanol, the blends with 2-5% CME content and ethanol content greater than 10% were not stable at temperatures below 25°C. The fuel properties of the blends were found to be within the range of the diesel fuel standard and having values not much in different with commercially available diesel except the flashpoint. Moreover, the addition of ethanol into the blends slightly lowered some of the fuel properties value such as heating value and viscosity. The diesel-CME-ethanol blends at of 90% diesel, 5% CME and 5% ethanol 85% diesel, 10% CME and 5% ethanol 80% diesel, 15% CME and 5% ethanol and 80% diesel, 10% CME and 10% ethanol for 100% and 99.5% ethanol purity had very close properties to commercially available diesel and exhibited acceptable properties values to the standard properties of high-speed diesel fuel. Engine operation at low speed especially at idle-no load and using a bigger size engine will lead to a minimum ignition delay and result in the lower fuel rate consumption. The emission testing results with the new-blended fuels showed a reduction in CO2 and smoke opacity and increasing of CO compared to commercially available diesel. The blends could deliver an efficient combustion and could run efficiently since production of the CO2 gases is higher than that of CO. Addition of coconut oil biodiesel as emulsifier for the diesel-ethanol blends produced a more stable blend and exhibited fuel characteristics that are close to diesel fuel