Spray development and droplet characteristics of high temperature single-hole gasoline spray

As increasing fuel injection pressure in GDI (Gasoline Direct Injection) engines has been used for improving atomization quality, raising fuel temperature is also receiving more and more attention as another promising method to improve mixing quality and combustion process. In order to understand atomization process with increased fuel temperatures, spray development and droplet characteristics of high fuel temperature spray were investigated by using back-illumination imaging technique and Phase Doppler Particle Analyzer (PDPA) with fuel temperature up to 376 °C as supercritical state. Results show that sprays dispersed more widely and became more transparent with increasing fuel temperature. Spray penetrations had some reduction and spray cone angle had obvious increase with increased fuel temperature not more than critical temperature. While droplet arithmetic mean diameter (D10) and Sauter Mean Diameter (SMD) was reduced from about 10 μm to 1.5 μm and from 30 μm to 3 μm as fuel temperature rise from 25 °C to 261 °C, high temperature more than 261 °C resulted in droplets became too small to be measured by the PDPA instrument.