Study of Intake Ports Design for Ultra Low Cost (ULC) Gasoline Engine Using STAR-CD 2012-01-0407
In this study, different designs of intake ports for two-stroke Ultra Low Cost Gasoline Direct Injection Engine (ULC-GE) has been analyzed to conclude on best design using steady state analysis in STAR-CD. The four types of intake ports design with two cylinders, each having fourteen ports, have been studied. The basic differences in designs are horizontal inlet entry (perpendicular to cylinder axis) and vertical inlet entry (in-line with cylinder axis) having rotation of flow clockwise and anticlockwise. Each type is further differentiated in eight cases with varying distances between axis of two-cylinder as 85mm, 88mm, 91 mm, 94 mm, 97 mm, 100 mm, 105 mm and 112 mm. These designs are analyzed for four different pressure drops as 10 mbar, 50 mbar, 100 mbar and 150 mbar. The initial study for all four types of intake ports, with 85 mm distance between axis of two-cylinder has been carried out and it is found that at all the port entries, static pressure is almost homogeneously distributed for vertical entry designs as compared to horizontal entry designs. Hence, this homogeneous distribution of pressure leads to higher permeability and mass flow rate for vertical intake entry designs. From the further study of intake ports designs of vertical entry for different cylinder distances, it is concluded that, intake port design with vertical entry, and distance between axis of two-cylinders 94 mm with anticlockwise rotation of flow is having minimum deviation in permeability for all the pressure drop conditions than any other design. This design corresponds to the minimum gap between perimeters of cylinders, which is comparable to intake pipe width. The direction of rotation of flow inside the cylinder due to port orientation in clockwise and anticlockwise direction has less effect on permeability.