Effect of diesel-biodiesel-ethanol blends on the spray macroscopic parameters in a common-rail diesel injection system

This work studies the viability of diesel-biodiesel-ethanol blends for compression ignition engines. Blends are prepared with a fraction of 5%, 10% and 20% of ethanol and a fraction of 10%, 20%, 30% and 40% of biodiesel in volume basis. Stability of such blends was first studied, and assessed by visually determining the phase separation 96 h after the blend was made. DB20E5, DB30E5, DB40E5, DB30E10, DB40E10 DB30E20 and DB40E20 blends maintain 0% phase separation after the test, which indicates that biodiesel acts as a surfactant and allows ternary blends being stable. For stable blends, properties (density, kinematic viscosity and surface tension) were determined. Finally, from those stable blends which properties stand within the allowed ranges by the EN-590 standard, three of them were injected in a constant volume chamber and its spray macroscopic parameters were experimentally determined. Blends with higher density show an increased spray tip penetration and those with less surface tension and kinematic viscosity show more cone angle. We conclude that DB30E10 is the blend that best air blending capacities exhibits from those with stable mixing and allowed physical properties.