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Comfort is a key factor in the automobile industry. Vehicles are designed to provide optimum comfort levels to passengers and drivers. The agricultural industry is a vital sector and requires long hours of operation for which comfort levels are a priority. To achieve these comfort levels Noise, Vibration, and Harshness (NVH) engineering is done, which includes computer-aided and prototype testing to troubleshoot problems and provide necessary solutions. This research work is based on the final stage of tractor development, during which an abnormal rattle noise was observed. This paper presents the airborne and structure-borne NVH study on a tractor by measuring sound pressure and vibration levels at vehicle and engine levels. A preliminary inspection of the tractor indicated the presence of abnormal noise during operation. For a detailed study, the engine was removed from the vehicle and mounted on a testbench to conduct a series of tests.

Noise & Vibration refinement of automotive vehicles is becoming important parameter due to its influence on environmental aspect and comfort perceived by occupants. NVH parameters are driving factors in current vehicle design strategy. Drivers comfort is extremely important, and driver’s expectations from commercial and heavy-duty trucks are as good as refined passenger cars. Other trends in commercial vehicle segment such as engine downsizing, weight, cost reduction and meeting stringent emission norms have influenced vehicle design dynamics. These parameters are critical and often contribute to vehicle NVH issues. Considering these new trends in commercial vehicle segment, it becomes challenging for an NVH engineer to provide optimized solutions. NVH issues could be related to the various subsystems such as driveline, axle, transmission steering wheel etc. in the vehicle and its resonant frequencies.

NVH is very important topic in development of a vehicle. Legislative requirements for driver ear level, the comparison to competitor vehicles in terms of noise and vibration as well as sound quality set very challenging targets. High noise at Driver Ear Level (DEL) and tactile vibrations of tractor is the major cause of exhaustion to the operator. With growing competition there is need for the tractor manufacturers to control noise and vibration levels. Recognizing the corrective measures to reduce the noise and vibration has a greater impact in increasing the efficiency of the product and operator comfort. Objective of this paper is to control vehicle level noise and vibrations using vehicle level structure modifications. It includes airborne and structure borne NVH study on a tractor by measuring sound pressure and vibration levels at vehicle level. Single cylinder engine was mounted on light weight structure to meet the power and torque requirements in the tractor.