SI-Engine Design Concept for Reducing Cyclic Variations

Fluid-dynamic principle for obtaining relatively stable combustion is found by performing cycle-resolved computations of turbulent flows in engines. Cycle-resolved computations are performed by using the implicit large eddy simulation (ILES) code, which we have proposed earlier. Calculations over continuous cycles show us the existence of “silent domain” in the engine cylinder, having weak cyclic-variations of flow. Time-dependent velocities averaged over six cycles, mean velocities, are also small in the silent domain. Moreover, we examine further on why cyclic variations of flow is weaker in the silent domain. This brings us a way for controlling cyclic variations for several engines.