Spray velocity vector distribution of alcohol fuels from a multi-hole injector for direct injection spark ignition engines

Fossil oil depletion and CO2 emission regulation impose significant improvement of fuel efficiency and promote the use of alternative fuels. Concerning the spark ignition (SI) engines, the alcohols represent a valid short-term solution for reducing both oil fuel demand and pollutant emission [1-3]. Further enhancements can be achieved through the direct injection (DI). In fact, DI systems allow to manage the fuel delivery with high accuracy. However, the high injection pressure and the limited time available for air-fuel mixture require a deep understanding of spray morphology and atomization for fully exploiting the capabilities of the direct injection strategy. This work aims at characterizing the effect of ethanol and n-butanol on the spray behaviour of a 6-hole nozzle for Direct Injection Spark Ignition (DISI) Engine. 2D Mie-scattering visualization and Particle Image Velocimetry (PIV) techniques have been applied for providing information about the morphology and velocity field of the spray.