The Effect of Induced Swirl Pattern on TDC Flow Field in a HSDI Diesel Engine

The present work studies the effect of cylinder swirl patterns along the cylinder axis obtained during early compression, on bowl flow velocities and generated turbulent kinetic energy at TDC. In-cylinder velocity field is simulated during induction and compression strokes using multidimensional fluid dynamics theory. The operating speed for the simulation is fixed at 900 rpm, which is typical of idling speeds. For a fixed averaged cylinder swirl ratio, axial stratification of swirl with higher magnitude located near the piston surface at early compression (55° BTDC) results in high magnitude of swirl and turbulent kinetic energy inside the piston bowl near compression TDC.