International Journal of Automotive and Mechanical Engineering ISSN: 2229-8649 (Print); ISSN: 2180-1606 (Online) Volume 16, Issue 1 pp. 6281-6300 March 2019 © Universiti Malaysia Pahang, Malaysia 6281 Acoustic Study of an Air Intake System of SI Engine using 1-Dimensional Approach A. A. Dahlan 1 , M. F. Muhamad Said 1,* , Z. Abdul Latiff 1 , M. R. Mohd Perang 1 , S. A. Abu Bakar 1 and R. I. Abdul Jalal 2 1 Automotive Development Centre, School of Mechanical Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia * Email: mdfarid@utm.my Phone: +075535449; Fax: +075535811 2 Automotive Engineering Section, Universiti Kuala Lumpur, Malaysia France Institute, 43650, Bandar Baru Bangi, Selangor, Malaysia ABSTRACT Air intake system of an internal combustion engine plays main role in delivering fresh air from the environment to the engine and dampening the sound of the engine combustion process coming from the engine combustion process. In this study, a simulation was conducted to improve the existing air intake system design in terms of acoustic study to have better sound quality by modifying the resonators, air duct and airbox volume of the air intake module. This study implements the 1-dimensional simulation study using commercial software, correlate to the 1.6-liter natural aspirated engine. The objective of this study is to decrease the engine noise at snorkel of the air intake module without losing too much of pressure drop. At the end of this study, the analysis defines the geometry of air intake module with the recommended resonator for fabrication and physical testing. The simulation result shows that the modified air intake module meet the objective and fulfil the performance target. Keywords: 1-Dimensional simulation; air intake system; SI engine; engine acoustic. INTRODUCTION Noise reduction on motor vehicle in meeting passenger comfort requirement has become a major concern among automotive industries and researchers [1, 2]. As the internal combustion engine acts as the vehicle’s power source, it also creates noise which decreases passenger comfort level and contributes to noise pollution especially in a city [2, 3]. Tire, wind, exhaust and intake are considered as airborne noise in vehicle environment. Currently the focus is on having a quiet passenger cabin by reducing induction noise as the selling feature for any passenger vehicle [4, 5]. Active resonator is also studied to help in various speed and load of engine to coop with different frequencies of noise [6]. In designing a vehicle, a prediction of noise is very important to reduce the noise locally on the system. This can be done through the usage of simulation tools to achieve the optimum design in a lesser amount of time and lower cost [7, 8]. Among the commercial tools that are available in current market are AVL Boost, GT-POWER, Ricardo Wave and Lamps which are using 1-D theory for acoustical analysis [9, 10]. Air intake module (AIM) is a breathing system for the engine to provide clean air from the environment to the combustion chamber. The system must have a minimum flow