Influence of Component Proportion on Multi-Component Surrogate Fuel Spray Characteristics under Subcooled and Superheated Conditions

Good comprehension of multi-component fuel spray behavior is essential for the improved performance of GDI engines. In this study, the spray characteristics of three distinct multi-component surrogate fuels with various proportions of n-pentane, iso-octane, and n-decane were investigated using multiple diagnostics including macroscopic imaging, planar laser Mie-scattering, and phase doppler interferometry (PDI). These surrogate fuels were used to mimic different distillation characteristics of regular unleaded gasoline with different vaporization behaviors. Test measurements show that under subcooled test conditions, the spray geometry is mainly influenced by dynamic viscosity. On the contrary, under superheated test conditions, spray geometry is controlled by the specific component of fuel which has the highest vapor pressure. A triangular methodology is created to evaluate the influence of component proportion on spray characteristics. A hierarchical model is then developed to illustrate the macroscopic behavior of multi-component fuel spray which explains well the effect of each component's proportion on the overall spray characteristics.