Unveiling the Flow Behavior Inside Gasoline Direct Injection Engine Cylinder Using High-Speed Time-Resolved Particle Image Velocimetry and Computational Fluid Dynamics Simulation

摘要

RICARDO-VECTIS computational fluid dynamics simulation of the in-cylinder air flow was first validated with those of the experimental results from high-speed particle image velocimetry (PIV) measurements taking cognizant of the midcylinder tumble plane. Furthermore, high-speed fuel spray measurements were carried out simultaneously with the intake-generated tumble motion at high valve lift using high-speed time-resolved PIV to chronicle the spatial and time-based development of air/fuel mixture. The effect of injection pressure(32.5 and 35.0MPa) and pressure variation across the air intake valves(150,300, and 450 mmH_2O) on the interaction process were investigated at a valve lift 10 mm where the tumble vortex was fully developed and filled the whole cylinder under steady-state conditions. The PTV results illustrated that the intake generated-tumble motion had a substantial impact on the fuel spray distortion and dispersion inside the cylinder. During the onset of the injection process, the tumble motion diverted the spray plume slightly toward the exhaust side before it followed completely the tumble vortex. The fuel spray plume required 7.2 ms, 6.2 ms, and 5.9 ms to totally follow the in-cylinder air motion for pressure differences 150, 300, and 450mmH_2O, respectively. Despite, the spray momentum was the same for the same injection pressure, the magnitude of kinetic energy was different for different cases of pressure differences and subsequently the in-cylinder motion strength.