Acoustic Noise Synthesis For Muffler System Design And Simulation

Mufflers are typically used to reduce the automotive exhaust noise, which is one of the major contributors of noise pollution in an urban environment.In addition, mufflers are also used to reduce the noise generated in HVAC ducts and cabin conditioning noise in aircraft.This paper describes an Acoustic Noise Synthesis (ANS) technique used for design of a virtual muffler based on Insertion Loss (IL) approach and additionally provides an audio simulation of its sound output.In this ANS technique, first the transfer function of the given muffler system is evaluated using the four pole parameters, source strength, source acoustic and termination acoustic impedances.Then the impulse response of the predicted transfer function is convolved with source signal to obtain the acoustic noise output of the muffler system in frequency domain.In order to verify this technique, the simulated output sound from virtual muffler is compared with experimentally measured sound for two types of systems namely a straight pipe and a simple expansion chamber.The results shows that the proposed ANS procedure gives reliable simulation of the acoustical noise generated by the real muffler system.The proposed ANS procedure can be applied to any complex system.The ANS procedure will have applications in studies related to virtual muffler design, sound quality and noise control studies of muffler system before actual fabrication of the muffler system.