Experimental Evaluation and Reduction of Timing Gear-Induced Rattle Noise in a High-Powered Agricultural Tractor

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. Further data analysis concluded that the source of noise was from the front cover of the engine. With the introduction of proper design and acoustic material at the front cover and timing geartrain, this issue was rectified.