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To improve overall customer experience, it is imperative to minimize the noise levels inside agricultural equipment cab. Up-front prediction of acoustic performance in product development is critical to implement the noise control strategies optimally. This paper discusses the methodology used for virtual modeling of a cab on agricultural equipment for prediction of interior noise. The Statistical Energy Analysis (SEA) approach is suitable to predict high frequency interior noise and sound quality parameters such as articulation index and loudness. The cab SEA model is developed using a commercial software. The structural and acoustic excitations are measured through physical testing in various operating conditions. The interior noise levels predicted by the virtual model are compared with the operator ear noise levels measured in the test unit. The resultant SPL spectrum from SEA correlates well with the test.

Engine is one of the major sources of noise in off-highway vehicles. Muffler plays an important role in attenuating the noise emitted by engines. Mufflers are designed to provide maximum noise attenuation without significantly affecting the back pressure. Inlet and outlet arrangements of muffler are proposed based on engine exhaust system and engine compartment design. Multi-inlet and/or multi-outlet mufflers are used based on the needs. This paper details the procedure used for evaluation of transmission loss of a muffler on off-highway vehicle which has two-radial inlets and one axial outlet. 3D simulation is used to obtain the transmission loss parameters. To validate the models, virtual analysis is carried out in two steps. In the first step, one inlet is open to source while the other is blocked and termination at the outlet is anechoic. In the second step, the open and closed inlets are swapped.