DefinePK

Abstract

This study is to analyze the exhaust backpressure of older and new exhaust piping design and silencer or muffler position after modification of the exhaust system of a 4-stroke marine diesel generator which operates at Marine Generator Workshop, Ungku Omar Polytechnic, Malaysia. The purpose of the exhaust system modification is to collect the exhaust gases produced inside combustion chamber of the engine cylinders and discharge them as quickly and silently as possible to atmosphere. Generally the better a silencer or muffler is at attenuating sound the more backpressure is generated. In a reactive silencer where good attenuation is achieved, the exhaust gases are forced to pass through numerous geometry changes of exhaust system and a fair amount of backpressure may be generated, which reduces the power output of the engine slightly. However, too much backpressure generated may led the power losses, weakening the engine performance and increased the fuel consumption. Henceforth, the study is aims to find the relationship between the exhaust backpressure levels occurred in exhaust flow design as well as silencer position and yet propose the best design to ensure the optimization of engine performance. The actual dimensions of the exhaust system is used to perform the computational fluid dynamic (CFD) simulation and analysis. The performance of an exhaust system is based on velocity and exhaust backpressure. Investigation in CFD was performed on four parameters comprises manifold temperature, manifold pressure, exhaust piping system temperature and atmosphere pressure. Results of CFD simulation was showed in the form of pressure and velocity contours and streamline. This study found the modification of exhaust piping design of the 4-stroke marine diesel generator increased the backpressure up to 94.7%.