ASSET Series B (2005) 4 (1): 107-114 ASSET An International Journal ISSN 1595 – 9694©UNAAB 2003 107 SILENCER NOISE MINIMIZATION USING LINEAR PROGRAMMING TECHNIQUE B. O. BOLAJI (1) AND M.I.A. ONIPEDE (2) (1) Department of Mechanical Engineering, University of Agriculture, P.M.B. 2240, Abeokuta, Nigeria. E-mail: bobbolaji2007@yahoo.com (1) Department of Mechanical Engineering, Federal Polytechnic, P.M.B. 5351, Ado-Ekiti, Nigeria ABSTRACT This paper presents the process involved in the optimization of vehicle silencer in order to minimize the noise level of the exhaust gases. Various performance parameters of vehicle silencer were optimized using linear programming technique. The results obtained from the optimization process formed the parameters used for the construction of the new silencer. The optimized silencer was tested on selected motor cars and the results obtained revealed that, to the large extent, it is effective in minimizing the car exhaust noise level. An average noise level of 23.3 dB (experimental) was obtained using the optimized silencer as against 40.4 dB, obtained with the unmodified car silencer. The experimental value is however slightly higher than 21.2 dB which is the theoretical value obtained from optimization process. The average percentage of noise reduction is found to be 43.3 % and the process efficiency also is 89.1 %. Keywords: Noise, linear programming, optimization, silencer, vehicle. INTRODUCTION Technological advancement is an important desirable and necessary ingredient for economic and social growth. It has made it possible for a large number of persons to enjoy the goods of life. The introduction and the use of inappropriate technologies often destroy the productive potential of ecosystems. The expansion of technology has been at the expense of other forms of life (Bolaji, 2005). Noise by its own nature, is propagated from a source in all directions in form of sound energy which may be heard or not by the human ear whose perception of sound is limited to frequencies of about 16 – 20,000 Hz (Olufemi, 2003). Generally the subjective loudness of the measured sound is compared to a standard sound with frequency of 1000 Hz. In most cases the intensity of noise is measured in decibel (dB), which is the ratio of two sound pressures in which one has been chosen as reference. Whenever mechanical power is generated or transmitted, a fraction of this power is converted into sound power and radiated into the air. Since most of the vehicles on roads are mechanically operated they produce sound and when the sound produced is above certain level, it becomes unwanted, unpleasant to ears and causes discomfort to people (Ajueyitsi and Bolaji, 2003).