An Experimental Study on the Solubility of a Diesel-Ethanol Blend and on the Performance of a Diesel Engine Fueled with Diesel-Biodiesel - Ethanol Blends

The phase stability of DE and DBE blends at different component concentrations, as well as the effects of using DBE blends including ethanol of various proportions on a CI engine performance are experimentally investigated. The engine was operated with DBE blends having 5, 10, 15 and 20% ethanol with fixed 10% biodiesel on a volume basis, to solve the phase separation problem, as well as on diesel fuel alone at constant load and at engine speed ranges from 800 to 1600 rpm for each run. The experimental results of the phase stability revealed that the DE blends is not stable and separated after 2, 5, 24 and 80 hours, for 20%, 15%, 10% and 5% ethanol concentration, respectively. Whereas for DBE blends the separation time is longer than of the first system and reached 1, 3 and 9 days for 20%, 15%, 10% ethanol concentration, respectively. The blend of DBE5 was of the best stability with very little separation. The experimental results of the engine performance indicated that the equivalence air-fuel ratio and the brake specific fuel consumption for the fuel blends are higher than that of diesel fuel and increases with the increase of the ethanol concentration in the blends. The brake power for the fuel blend of 5% ethanol concentration is close to that of diesel fuel and decreases with higher concentrations. The brake thermal efficiency was increased with fuel blends of 5 and 10% ethanol concentration and decreases with a higher ethanol proportion in the blends. In conclusion, among the different fuel blends, the blends containing 5 and 10% ethanol concentration are the most suited for CI engines due to its acceptable engine performance and to the fuels solubility.