A Transient Water Analog of a Dual-Intake-Valve Engine for Intake Flow Visualization and Full-Field Velocity Measurements

It has been recognized that the fluid motion during the engine induction process has a significant effect on combustion in terms of efficiency and emissions. To understand the intake process, a transient water analog visualization engine has been developed. This model, which simulates a single cylinder engine, has a transparent dual-intake-valve cylinder head and a transparent cylinder and is used to study the in-cylinder and port flows both qualitatively and quantitatively during the induction process. A special illumination coding procedure and recording technique along with an image analysis method were also developed to obtain full-field cycle-resolved velocity information from the visualization images. Results obtained for this engine indicated that the flow field during the induction stroke is totally dominated by the generation of two jet flows which produce several vertical motions on different planes along the engine cylinder. In most cases the vortices diameters were less than the cylinder radius.