Background Study CONCLUSION AND RECOMMENDATION

CHAPTER I INTRODUCTION

1.1 Background Study

Engine is the most important part in one vehicle. M.F. Harrison, et. al., 2003 said, the intake manifold to an internal combustion IC engine will consist of a network of interconnecting pipes. The lengths of these pipes, and to a certain extent their diameters, must be chosen carefully as they will determine the resonant frequencies of the manifold. When the engine is run at a speed where one or more of these resonances is excited, then both the volumetric efficiency and the intake noise level maybe affected. Intake manifold or inlet manifold is the part of an engine that supplies the fuelair mixture to the cylinders. DE Winterbone et. al., 1999 in his book said, intake and exhaust manifold have a major effect on engine performance and emission of noise and pollutants. If the airfuel ratio is maintained constant the potential for energy release in the combustion process, which is manifested as the indicated mean effective pressure and ultimately the torque generated by the engine, is related to the quantity of air entering the cylinders. The majority of engines used in automobile application is naturally aspirated and operate on the four-stroke cycle, in which distinct strokes of the piston are used to induce the air and exhaust it. These strokes enable the engine to pump gas through itself and they can be significantly affected by the design of the intake and exhaust systems. DE Winterbone et. al., 1999 also said, two-stroke engines, which do not have discrete suction and exhaust strokes, rely almost entirely on the operation of the exhaust gas dynamics to purge the cylinder of combustion products and the manifolds of these engines have a dramatic effect on their performance. In order to achieve higher specific power outputs powerswept volume some engines have induction systems in which the supply pressure of the air to the engine is increased above the ambient level by some form of supercharging system. This increase the quantity of air ingested per engine cycle. Successful design of the exhaust system in turbocharged engines helps ensure that sufficient energy is available at the turbine, over the operating spectrum of the engine, to drive the compressor at a condition spectrum of the engine, to drive the compressor at a condition which will produce the required boost ratio. The requirement for lower noise and pollutant emissions levels has further increased the important of the design of the intake and exhaust manifolds. A large proportion of the total noise generated by vehicle and stationary engines is due to the pressure waves issuing from them as noise. The position of intake manifold is normally located at behind of engine block. At this time, there are so many materials that used in making the intake manifold. All of those materials are used based on the specific purpose following the usage of that vehicle which applies that type of engine. This material will also effect the output performance of intake manifold. Normally, intake manifold is created and studied by engineering field to reduce pressure wave amplitude and to act on specific component frequency. The intake manifold analyzed in this project is focus on Proton Wira 1.6 XLi model, product of ‘Perusahaan Otomobil Nasional Berhad’ PROTON. Historically, Proton Wira model started to launch on March 1993. That time, Proton Wira model is produced in three different versions which that are 1.3 GLi versions, 1.5 GLi versions and 1.6 XLi versions. Each version is available for sedan type and aeroback type. Sedan type is created to focus on family usage which providing large inner size. The aeroback type is created for multipurpose usage because of flexibility of its seat concept. This model is then expends its version by launching Limousine version which focuses on high class usage and luxurious concept. After a period of time, diesel model of Wira is introduced to fulfill the customer demands. Internal and external design level for all model is improved and in early 1996,’New Look Wira’ is launched. Emergence of new version Wira 1.8 EXi is completing the various versions among existing Wira model. Each version can be divided into 2 classes from overall of Proton Wira model version which are 1.3 GLi version and 1.5 GLi version in one class, while 1.6 XLi version and 1.8 EXi version in another class. This is because of 1.3 GLi version and 1.5 GLi version have used the same type of spare parts compared to 1.6 XLi version and 1.8 EXi version. For product of this intake manifold, 1.6 XLi version and 1.8 EXi version are using the same design. However, it is not applied in the model of 1.8 EXi DOHC Double Overhead Cam version. Overall, the intake manifold that studies in this project is intake manifold of Proton Wira 1.6 XLi version.

1.2 Problem Statement