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In urban driving conditions, the steering vibration plays a major role for a customer, spending a significant amount of time behind the steering wheel. Considering the urban drive at Indian roads, 1000~1600rpm band becomes primary area of concern. In this paper, study has been conducted to define the target areas as well as its achievement in reference to given driving pattern on a front wheel powered passenger car for steering vibration. During the concept stage of vehicle development, a target characteristic of steering wheel vibration was defined based on the competitor model benchmarking and prior development experience. A correlated CAE model was prepared to evaluate the modification prior to prototype building and verification. Vibration level in all 3 degrees of freedom at the steering wheel location was measured in the initial vehicle prototypes and target areas of improvement are identified.

Inside cabin of a passenger car, low frequency booming noise still presents a major hurdle for NVH engineers to fine tune a vehicle. Low frequency booming noise is presently taken care with addition of mass damper and large reinforcements. These conventional countermeasures add weight to the vehicle as well as increase the overall production cost. The study presented in this paper proposes a countermeasure model that not only reduces the booming noise but also avoids any weight and cost addition. It has been focused for low frequency booming noise around 30 ∼ 40 Hz. Within the range mentioned, one of the major reasons for booming noise in hatchback models is the bending resonance of backdoor. By modifying the mode of the backdoor in such a manner that it cancels the effect of bending on the vehicle acoustic cavity, improvement can be achieved in terms of sound pressure level at the driver’s right ear location (DREL).