Measurements of the Three Components of the velocity in the Intake Ports of an I. C. Engine

The three components of the velocity were measured by laser Doppler velocimetry at 35 locations in each of the six intake ports of a single-cylinder I.C. engine motored at 600, 900, and 1200 rpm. The intake ports were designed to impart both swirl and roll to the air. Pressure was also measured at the intake and exhaust. The detailed information is valuable mostly for computations of engine flows and for the assessment of multidimensional models. However the following trends were observed. The intake velocity is affected by resonant pressure waves. The flows in the six ports tend to be similar. The three components of the ensemble-averaged velocity generally have uniform profiles across the port area, whereas the fluctuation intensities are higher at the top of the port. All velocities tend to be higher at the beginning and end of intake. Averaged over the port area and intake time, the ensemble-averaged radial and axial velocity components are about 5 times the mean piston speed, the tangential component is about 10 times, and the fluctuation intensities are between 2 and 3.4 times.