Application of Rotational Transformation of Flow to Improve Engine Air Induction System

Pre-rotation of the flow upstream of a curved duct by means of a set of vanes reduces flow separation and attenuates the cross-stream velocity gradients. Comparative tests of air flow in the intake manifold of an internal combustion engine with and without pre-swirl indicate that insertion of the vanes results in a smoother velocity waveform and an increase in the rate of flow. This increases the engine power for the same displacement. The uniformity of flow also reduces flow deviation among the cylinders, thereby, reducing the unburned hydrocarbons in the exhaust.