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Currently, noise pollution has become one of the major environmental concerns. To address this, new noise standards and regulations are being introduced and mandate the tractor OEM’s (Original Equipment Manufacturer) to meet the defined noise levels. Fan noise from the cooling fan is one of the key contributors to the overall vehicle noise. Hence, the reduction of fan noise at the source is a very important and critical task. Even though fan noise is broadband in nature its aerodynamic noise sources are most dominant at the higher harmonics of the blade pass frequency (BPF). The aerodynamic noise of a fan can be varied by changing the fan geometry viz., blade profile, fan width and diameter, number of blades, and ring on its periphery. A cooling fan is an important component of the cooling system which ensures adequate airflow for radiator cooling and avoids engine overheating with uniform heat dissipation.

The vibration and acoustic behaviour of the internal combustion engine is a highly complex one, consisting of many components that are subject to loads that vary greatly in magnitude and which operate at a wide range of speeds. The interaction of these components and the excitation of resonant modes of vibration is a major problem for the powertrain engineer when optimising the noise and vibration characteristics of the engine. This paper summarises a study that has been undertaken to assess and optimise the dynamic behaviour of a current production diesel engine with the objective of reducing radiated noise from the engine. The dynamic behaviour of the diesel engine has been assessed using simulation tools. The dynamic analysis will predict the forces and displacements at each of the nodes of the model by forced response analysis. Predicted results and experimentally measured values were found to be in close agreement.

The automotive market has seen a steady increase in customer demands for quiet and more comfortable tractors. High noise at Operator Ear Level (OEL) of tractor is the major cause of fatigue to the operator. With growing competition, and upcoming legislative requirement there is ominous need for the agricultural tractor manufacturers to control noise levels. The objective of this study is noise reduction on agricultural tractor by stiffening sheet metal components. The design and analysis plays a major role for determining the root cause for the problem. Once the problem and its root cause were well defined, the solution for addressing the problem would be made clear. The engine excitation frequency and Sheet metal Components such as fender and platform natural frequency were coming closer and are leading to resonance.

This paper deals with the techniques of reducing noise in agricultural tractors. Noise reduction in agricultural tractors is an emerging concern and apart from meeting the noise norms it helps in increasing the productivity of farmers. Noise is also a factor affecting the health of the farmers. Two major European regulatory requirements are driver ear noise level and passer by noise level. Of the two regulatory requirement, driver ear noise is critical, since the limit is 86 dB (A) compared to 89 dB (A) of passer by noise limit which is measured at 7.5 meters from tractor. Various strategies for noise reduction are discussed in this paper including reduction at source level and passive solutions. Passive solutions are used where the timeline for development is short. Various passive solutions like acoustic foam design are discussed. Finally with the combination of active and passive solutions, driver ear noise target was met successfully.