Design and analysis of auto-rickshaw mufflers

Abstract

In the cities and towns of India, high traffic is a big problem. Auto-rickshaw is an obvious choice for transportation in cities and towns. It can transport people and goods from any narrow street to the other street due to its small size and high steering ratio. The high steering ratio of auto-rickshaws makes it a better choice to move in high traffic hours. However, the noise radiation from such auto-rickshaws is not only the concern for other people on the roads or nearby houses, but also for the driver and passengers sitting because of the open passenger cabin which is partially covered with metal sheets and canvas. Therefore, the auto-rickshaws running on single cylinder engines need to have very efficient mufflers for the attenuation of unmuffled exhaust SPL. The automotive engines run on different crankshaft speeds and engine loads. Therefore, the muffler used in an auto-rickshaw need to have wideband insertion loss (IL) spectrum with good attenuation at low frequencies. In this study, three old auto-rickshaw mufflers were taken from the scrap market. At first, these mufflers were cut to see the internal structure, then the measurement of dimensions were taken. After that, plane wave analysis and 3-D FEM analysis were carried out. The modification in one of the silencers were made to achieve the better attenuation characteristics in the low frequency region. Also, back pressure is calculated for all three mufflers, it should be too high. Keywords: Auto-rickshaw mufflers, plane wave analysis, 3-D FEM, Insertion Loss