Flow analysis of intake port geometry of spark ignition engine using simulation

Abstract

The activity presented in this paper is focused on the relationship between mass flow rate and the intake port geometry in the cylinder head. Mass flow rate in this study refers to the amount of air-fuel mixture passing through the intake port per second (g/s). The mass flow in the intake port was studied with the help of the Ansys Workbench simulation. The intake port in the cylinder head is symmetrical. Thus, only half part is used for the simulation. During the simulation, the pressure of the air-fuel mixture applied to the intake port remained constant and the valve was held fixed ranging between 4 mm to 10 mm, as is typically done in superflow bench test. Then, the mass flow rate is recorded corresponding to the valve lifts. The simulation tests were carried out by using a HP workstation computer at Automotive Development Centre (ADC), Universiti Teknologi Malaysia. In this study, several modifications were made to the intake port geometry. Simulation is carried out using all intake ports. It was found that each intake port has its own mass flow rate value. One of the best intake ports in this study has an improvement of mass flow rate up to 7.1% at 8mm valve lift. The mass flow rate increase if air flow has a better attachment to the surface. Theoretically, the perfect intake port is completely straight. The straight and large diameter intake port is more suitable for high valve lifts.