Comprehensive assessment of gasoline spray robustness for different plume arrangements

Optimizing fuel injection spray is essential to comply with stringent future emission regulations for hybrid vehicles and internal combustion engine vehicles, and the spray characteristics and geometry must be robust for various engine operating conditions. This study presents experimental and numerical assessments of spray for lateral-mounted gasoline direct injection (GDI) sprays with different plume arrangements to analyze collapse characteristics, which can significantly deteriorate the geometry and characteristics of fuel sprays. Novel spray characterization methods are applied to analyze complex spray collapse behaviors using LED-based diffusive back-illuminated extinction imaging (DBIEI) and 3D computed tomographic (CT) image reconstruction. High-fidelity computational fluid dynamics (CFD) simulations are performed to analyze the detailed spray characteristics besides experimental characterization. Detailed plume dynamics of common triangle-pattern spray are evaluated and compared to a plume pattern with a more open arrangement. The results show that the triangular pattern, with plumes enclosed by other plumes, undergoes significant spray collapse behavior under various conditions. The inversed-T pattern, the opened pattern where plumes are arranged not to have a closed volume, has robustness against collapse due to an open layout, which prevents an imbalance of the local pressure field that may cause collapse. The approach applied in this study to mitigate spray collapse was verified to be effective and can be referenced in spray design to ensure the robustness of GDI sprays.