An Approach to Minimization of Drive Train Noise Through Redesign of Engine Mounts

Abstract

Drive train noise is more annoying for passenger. For a V-hull base mine protected 4WD defence-vehicle, metallic noise was observed from drive train. To resolve this kind of NVH problem of complicated vehicle like defence required commending knowledge base and experience or say know-how. The critical constraint of subject vehicle was fixed position of engine or engine mounts and transfer case. This causes higher slope equivalent angle of first drive shaft with respect to the installation standard. Noise issue observed as consequence of aforesaid issue which has impact installation parameters of torsional, inertia and secondary coupling excitation frequencies. In this context, a structured methodology has been followed in present work for finding root causes and optimizing the design to come out with optimum solution. Engine mounts have major influence to finalize first drive line slope angle. Hence, re-designing and verification have been done for engine mounts considering its major design parameters and criteria (e.g. shape factors, shore hardness, static deflection and isolation efficiency). At the same time, effects of those changes have been verified theoretically and practically on vehicle. Pass by noise, cabin inside noise, isolation efficiency of front and rear mounts and vehicle floor vibration level were measured. The objective of the exercise is to find out a solution for minimization of drive-train noise.