The direct usage of vegetable oils for diesel engine fuel is possible by blending vegetable oils with conventional diesel fuels in a suitable ratio. Bio ethanol is considered a biodegradable bio fuel which acts as an oxygenate, accelerating the complete fuel combustion [9,12]. However, an obstacle for ethanol–diesel blends is the immiscibility from the low solubility of ethanol in diesel [13,14]. Therefore, a surfactant is introduced to enhance the miscibility of a blend of vegetable oil, ethanol, and diesel by forming a micro emulsion. In addition to the miscibility, the ethanol and surfactants are expected to reduce the kinematic viscosity of the blend.