A Study on Combine Effects between Swirl and Tumble Flow of Intake Port System in Cylinder Head 2000-05-0098

The variable intake systems tend to be adopted in gasoline engines for fuel economy and emission regulation. In the cases, because both swirl and tumble flows are together induced to the cylinder, in-cylinder flow pattern becomes very complicated so that we can not decide this flow as one major pattern like swirl or tumble. The purpose of this study is to find new evaluation index for in-cylinder flow characteristics instead of current swirl or tumble coefficient using a steady flow test rig on intake port systems. To this end, port flow rig tests were conducted on the DOHC head varying lift of intake valves. Finally angular flow coefficient and inclination angle were introduced as new evaluation indexes for in-cylinder angular flow characteristics.