Study on the Effect of Intake Flow by Various Intake Port Design on Small Motorcycles Engine

Abstract

This study aims to analyze the effect of intake flow by various intake port designs on flow characteristics of small motorcycle engine cylinders by using simulation models. Geometry engine created using CAD software, then exported and analyzed using CONVERGE. The turbulence model is observed using a modified model (RNG) k-e. The pressure boundary conditions are used to determine the pressure fluid at the intake and exhaust port. The change of the intake port design based on the flow direction give effect to swirl ratio value. The helical intake port with same direction have the highest swirl ratio during intake and compression stroke. The largest increase occurred at the helical intake ports in the same direction in the middle of intake stroke by 383.33 % compared to the helical intake ports in the opposite direction. The change of the intake port based on the direction of flow do not have much effect on changes in air mass during the intake stroke. While the tangential intake port is bigger than the two helical intake ports around 3.5%. However, there was a slight change due to changes in the intake port on the accumulation of air mass during the compression stroke where in the two helical intake ports experienced a slight decrease in the incoming air mass. There is no significant effect with the change in the intake port model to this parameter especially at the beginning of the intake stroke up to 440 °CA, where the valve lift starts to be opened maximally. However, changes in turbulent kinematic viscosity occur after this point where the valve lift closes again where the highest value of increasing turbulent kinematic viscosity occurred at 585 °CA around 107.14 %, where the intake valve was almost closed. The changes of the intake port type affect the maximum value of the length scale peak where the intake port type of the helical model has a higher maximum value than the tangential type model. The highest value of increasing length scale occurred at 595 °CA around 40 %, where the intake valve was almost closed. Finally, it is concluding that the analysis carried in this work is useful in predicting the flow and in-turn optimizing combustion chamber of the engine.