Abstract
Visualization of the flow and mixing of gas induced into the cylinder through each of the two intake ports of the spark ignition engine has been carried out during intake and compression strokes on horizontal and vertical sections of the engine cylinder by using a high speed video camera and image processor. In order to observe the flow and mixing process of gas from each port, particles were alternately mixed with air flowing through the each of intake ports. Velocity vectors on the sections were measured by means of particle tracking velocimetry. Velocity fields were calculated by interpolation using the measured velocities on each section of the cylinder. Flow behavior and mixing of the gas induced from each intake port were made clear in various crank angles during intake and compression strokes.