Analysis of variation of cone angle and cone distance on the development of high-performance low pollution muffler

Abstract

The use of racing or free-flow exhaust has become a trend among the public. Free-flow exhaust has been considered to increase vehicle performance. However, free-flow exhaust has a noisy sound, disturbs the environment, and causes noise pollution. Based on previous research, the HPLPM (high-performance pollution muffler) exhaust with a cone-shaped silencer can reduce exhaust noise but performs close to a free-flow exhaust. This study aims to determine the effect of cone angle variations on exhaust gas flow and pressure in the HPLPM exhaust compared to the free-flow exhaust. The computational Fluid Dynamic (CFD) method simulates the free-flow and HPLPM exhaust designs. The variations of the cone angle in this study were: 90o, 100o, and 110o. The simulation is adapted to the condition of a motor vehicle with a capacity of 150 cc. The result showed that there was an effect of cone distance on exhaust gas velocity and pressure. The variation of the cone angle of 100 and the cone distance of 30 mm has the highest average fluid velocity value of 58.030 m/s, the lowest velocity decrease compared to the free-flow exhaust of 13.5%. The variation of cone angle of 110o and cone distance of 30 mm has the highest average fluid pressure value of 20.79 MPa. The biggest pressure increase in the HPLPM exhaust variation compared to the free-flow exhaust was 152.9%.