A Study on the Reduction of Road-induced Noise Level through Improving Suspension Transfer Characteristics by Using Suspension Rig

Recently, the trend of the automobile industry has been rapidly shifting from conventional internal combustion engine vehicles to green vehicle as like electric, hydrogen fuel cell and hybrid vehicles. Customers are no longer able to hear engine combustion noise at low speeds of the vehicle, and the road noise that is masked by the noise is becoming the dominant interior noise. In the era of the electric car, the biggest issue in automotive NVH is the reduction of road-induced noise. Generally, the time given to vehicle development is about one year from the design is finalized and the proto-car is manufactured. During this time, however, it is not enough to review and improve the suspension and car body that contribute to road noise performance. This study introduces the evaluation method of the suspension rig which can obtain the basic performance of the road-induced noise before proto-car production and how it can be applied to vehicle development. By analyzing the transfer characteristics of the suspension system excluding the vehicle body using the suspension rig and changing the suspension bushing insulation characteristics, it is possible to obtain the target performance of the road noise in early stage.