AN APPROACH TO CFD AIR FLOW SIMULATION IN THE IC ENGINE INTAKE MANIFOLD Stjepan L. GALAMBOŠ, Nebojša M. NIKOLIĆ, Dragan A. RUŽIĆ, Jovan Ž. DORIĆ Department of Mechanization and Design Engineering, Faculty of Technical Sciences, University of Novi Sad, Novi Sad, Serbia Corresponding author; E-mail: galambos@uns.ac.rs The subject of this paper is modeling of an intake manifold of a four-stroke IC engine using contemporary software tools. Virtual 3D CAD model of an intake manifold was designed based on a real intake manifold of a four- stroke IC engine. Based on the CAD model a 3D CFD model of the intake manifold was created. The modeling has been done with the purpose of simulation of the air flow inside the intake manifold in order to monitor values of the internal pressure during several seconds of the engine operation in three different operating points. Also, an experiment was conducted, which included measurements of intake manifold pressure in the same engine operating points in the course of a time interval of approximately the same duration. The results of both the simulation and the experimental measurements have been shown in the paper proving that the created model was good enough for the intended purpose. Key words: intake manifold pressure, IC engine, CFD simulation, air flow, Star CCM+ 1. Introduction For more than 150 years people have been trying to make a system which would transform various forms of energy to mechanical energy as effectively as possible, and thus decrease physically demanding efforts imposed on humans. Starting with the steam engine whose efficiency was on a very low level, people have in time created systems which increase efficiency to a much higher level. The appearance of the IC engine represents the beginning of a new era of converting chemical energy of fuels to mechanical power. The major division of IC engines in spark-ignition and compression- ignition IC engines was established at the beginning of the 20 th century and has remained almost the same today. For spark-ignition engines, the mixture is ignited with the help of an energy source coming from the outside, which produces a spark sufficient for ignition of the mixture, as well as its further combustion. With compression-ignition engine, the process is similar, but due to the chemical nature of the fuel and higher pressure inside the cylinder of the engine, the ignition of the mixture occurs without the need for an external source of energy, the purpose of which is to generate the initial spark [1]. The IC engines represent generators of mechanical energy which still have a relatively low level of efficiency, in spite of the great influence of modern technology. The research in IC engines mostly relies on finding new, innovative solutions for the construction, thermodynamic processes and technology which would lead to an increase in the working efficiency [2], [3].