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The improvement of spray atomization and penetration characteristics of GDI multi-hole injector sprays is a major component of the engine combustion developments, in order to achieve the fuel economy and emissions standards. Significant R&D efforts are directed towards optimization of the nozzle designs, in order to achieve optimum multi-objective spray characteristics. The Volume-of-Fluid Large-Eddy-Simulation (VOF-LES) of the injector internal flow and spray break-up processes offers a computational capability to aid development of a fundamental knowledge of the liquid jet breakup process. It is a unique simulation method capable of simultaneous analysis of the injector nozzle internal flow and the near-field jet breakup process. Hence it provides a powerful toll to investigate the influence of nozzle design parameters on the spray geometric and atomization features and, consequently, reduces reliance on hardware trial-and-tests for multi-objective spray optimizations.

The spray plume geometry and fuel atomization characteristics of the gasoline direct-injection (GDI) multi-hole injectors are of paramount importance with respect to the GDI engine homogenous-charge combustion and emission characteristics. A major component of the GDI combustion system development is the optimization of the spray-targeting and mixture preparation. Significant R&D efforts are directed towards optimization of the nozzle design and the manufacturing process in order to achieve optimum multi-plume spray characteristics. The Volume-of-Fluid Large-Eddy Simulation (VOF-LES) of the injector internal flow and near-field primary atomization has been receiving attention as a tool to enable analysis of the influence of nozzle design on the key spray parameters and reduce reliance on hardware trial-and-tests for multi-objective spray optimizations.