J. Aminuddin, Wihantoro, Bilalodin, Sunardi, and N. Rauf

The exhaust is an important spare part of the car for reducing noise and emission. The Noise is an unexpected sound from the roar of the engine that caused a hearing problem. The emission is originated from the combustion of an engine that causes air pollution. In this study, we enhance an exhaust performance for decreasing noise and emission by optimizing of the muffler part. Through the conjugate gradient method, we estimate an ideal dimension of the muffler part for circulating thermal energy at around 26 kcal/mole for 13.39 seconds in the closed system. From the results of the conjugate gradient estimation, we develop the muffler plus a reheater with 58 and 14 cm of length and diameter, respectively. Furthermore, the muffler's performance is evaluated by doing a measurement of both noise and emission. The measurements are conducted by comparing the muffler without and with re-heater. From the measurement process of sound intensity level, we seek that the noise is decreased by approximately 3.79 and 3.00 % in the lower and faster rotation of the engine, respectively. Besides, the test result shows that utilizing re-heater can reduce of CO, CO2, and HC of 0.35, 14.6, and 76.29 % compare to the muffler without re-heater. The results indicate that the muffler with re-heater designed in this study is effective in reducing noise and emission from the roar and combustion of the engine, respectively