Multidimensional Intake Flow Modeling of a Four-Stroke Engine with Comparisons to Flow Velocity Measurements

Intake flow for a four-stroke experimental gasoline engine is modeled considering moving valves and realistic port geometries. The numerical model is based on the KIVA-3 code and computed flow velocities are compared with LDV measurements. Computations start prior to intake valve opening and the pressure boundaries are specified at both the intake and exhaust pipe cross sections. Numerical results show that the in-cylinder flow pattern is well simulated in the symmetric plane passing through the cylinder axis. The computed and measured cylinder pressure and flow velocities agree reasonably well during the intake process. At top-dead-center, computations show a rotating flow pattern exists in the squish region corresponding to an area with relatively high turbulent kinetic energy. Results of intake flow modeling also show the evolution of in-cylinder averaged turbulent kinetic energy is different if the intake charging process is not modeled.