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Globally the customers are demanding more powerful yet silent vehicles to enhance their daily commuting and goods transportation needs. The current trend in the design is to enhance the engine power without major change in the physical configurations of the engine systems. Increasing the power and torque of the powertrain will have an undesirable and adverse effect on NVH levels. In this research work, a light weight rear wheel drive vehicle was investigated from torsional vibration perspective. The vehicle is powered by a two cylinder engine with turbo charger. The power and torque of the vehicle was increased approximately two times with the help of turbocharger which resulted in increasing the powertrain torsional vibration. This increased vibration was further amplified through inevitable driveline resonances which causes severe vibration at the passenger seat location and steering. Also, the noise levels are above the comfortable zone.

NVH is becoming one of the major factor for customer selection of vehicle along with parameters like fuel economy and drivability. One of the major NVH challenges is to have a vehicle with aggressive drivability and at the same time with acceptable noise and vibration levels. This paper focuses on the compact utility vehicle where the howling noise is occurring at higher rpm of the engine. The vehicle is powered by three cylinder turbocharged diesel engine. The noise levels were higher above 2500 rpm due to the presence of structural resonance. Operational deflection shapes (ODS) and Transfer path analysis (TPA) analysis was done on entire vehicle and powertrain to find out the major reason for howling noise at higher engine rpm. It is observed that the major contribution for noise at higher rpm is due to modal coupling between powertrain, half shaft and vehicle sub frame.