Influence of the Injector Configuration on the Spray Evaporation Characteristics under Superheated Conditions

In spark ignition direct injection (SIDI) engines, the injector configuration plays an important role on influencing the spray atomization and evaporation. In order to optimize the injector configuration to generate a better fuel spray, the further study to understand the effect of injector configuration is needed. In this study, the influence of the hole length to diameter ratio (L/D) on the fuel spray evaporation is investigated in a constant volume chamber under various operating conditions. The laser induced exciplex fluorescence (LIEF) technique is utilized to capture the vapor fluorescence signal of fuel spray. The fuel sprays with the fuel temperature ranging from 45°C to 85°C and ambient pressure ranging from 20kPa to 100kPa are investigated to study the influences of superheated degree (SD) on the spray evaporation. The experimental results indicate that with a higher fuel temperature and lower ambient pressure, the superheated degree is higher, and hence the vapor concentration of fuel spray is increased due to the higher evaporation rate. In addition, the evaporation rate of fuel spray increases with higher L/D under the flash-boiling conditions.