Study of Induction Tumble by Particle Tracking Velocimetry in a 4-Valve Engine 912376
The angular momentum of a tumble vortex occurring inside a 4-valve spark ignition engine was measured by particle tracking velocimetry, PTV. A cylindrical glass liner was designed for a single cylinder motored engine. Light-scattering particles and a laser light sheet, directed through the axis of the cylinder, were used to observe the simultaneous flow field. Three different intake port designs were used in this study. The in-cylinder tumbling motions were measured and the tumble ratios were calculated. The intake configurations were also visualized and measured with PTV in a steady flow rig, at a fixed valve lift. In addition, the results were compared with measurements from a conventional steady flow rig which measures the angular momentum flux with a torque-meter, and with laser doppler measurements, LDV, in a motored engine.
All four techniques indicated clearly the qualitative difference between the ability of the intake ports to produce an in-cylinder tumbling motion. Quantitative numbers of angular momentum could be drawn from the PTV-results in the motored engine and from the conventional flow rig, while the LDV-measurements gave significant information about turbulence characteristics.