NVH Refinement on the Agriculture Tractor using Coupled Test and Simulation Approach

The Indian farmers choice of agriculture tractor brand is driven by the ease of operation and fuel efficiency. However, the customer preference for operator comfort is driving many tractor OEMs for improvement in noise and vibration at the operator location. Also, the compliance to CMVR regulation for noise at operator ear location and vibration at driver touch point location are mandatory for all the tractors in India. NVH refinement development of the tractor plays a critical role in achieving the regulated noise level and improved tactile vibration In presented work, Noise Source Identification (NSI) is carried out to identify and rank airborne and structure borne noise sources at tractor level through elimination method followed by engine level testing in hemi anechoic chamber to identify the major noise radiating components by using noise and vibration measurement, sound intensity mapping tools. The outcome of NSI has revealed silencer, timing gear cover and oil sump to be highest ranked sources in descending order. The silencer design using FEM/BEM tools is carried out which had yielded noise reduction up to 3 dB at Full load. Also, operational deflection shape of complete chassis system is carried out to identify the structural weakness. Improvement in engine primary balancing and structural changes has yielded up to 60% reduction in driver touch point vibration.