Effects of Intake Port Geometry on Large Scale In-Cylinder Flows 980484
A set of experiments has been performed which were aimed at quantifying the effects of specific intake port geometry changes on large-scale in-cylinder motions. Using a modular engine with replaceable intake port blocks, 3 different intake ports were used and results obtained at 3 crank angles: BDC, 90° before TDC of compression, and at TDC of compression. For each port, in-cylinder flows were quantified using a pulsed laser and high-speed imager. The resulting images were analyzed using a particle-tracking scheme.
The results of the experiments indicate that there are significant differences among the flows produced by the ports, particularly at BDC. Nearer TDC, the differences among the flows diminish, but some differences in velocity and vorticity scale and distribution remain.
Tumble ratios are shown, using a variety of tumble ratio calculation methods. In general, the methods give similar results showing moderate change in tumble from BDC to 90° BTDC, then a significant decrease to TDC.