Modification of Reactive Muffler in Farm Tractor to Reduce Noise Level Using Finite Element Method

다국어 초록 (Multilingual Abstract)

Purpose The improvement in transmission loss (TL) in the target frequency band is the primary goal of exhaust muffl er design. The non-refl ective boundary conditions are simulated, and the transmission loss is calculated using the fi nite element method.
Methods By modifying structural elements such as the expansion diameter, expansion length, open area ratio, and baffl e plate, the reactive muffl er used in the farm tractor was given an improved TL using the fi nite element method (FEM).
Improved muffl ers’ noise emission was tested and compared to that of an existing reactive-type muffl er. The tests were conducted in accordance with ISO 7216 and ISO 5131, the worldwide requirements for product noise emissions while considering diff erent types of exhaust systems, location of the sound level meter, engine speed, and operating gear. The collected data was examined using a factorial test that was based on a fully randomized design.
Results The modifi ed muffl er-2’s TL in the frequency range of 0–2000 Hz increased on average by 22.75 dB in comparison to the existing reactive-type muffl er. According to the outcomes of a completely randomized design, the primary infl uences of engine speed, gear position, and exhaust type on the noise produced by tractors were found to be signifi cant at a 5% level of signifi cance. Modifi ed muffl er-2 decreased tractor sound pressure level for a range of 2.26–3.03 dBA in all treatments.
Conclusions Structural modifi cation in reactive muffl er based on FEM helped in improving transmission loss which results in the reduced sound pressure level of the tractor.