A study on the effects of tyre to vehicle acoustical comfort in passenger car cabin

Car cabin interior vehicle acoustical comfort is one of the factors which attract the buyers to purchase the vehicle in order to have comfort sound and minimum noise in passenger car cabin. Basically the amount of discomfort depends to magnitude, frequency, direction and also the duration of exposed vibration in the cabin. The comfort of the driving influences driving performance. Generally the vibration is caused by two main sources: engine transmission and interaction between tyre and road surface. In this study the effects of tyre to vehicle acoustical comfort were investigated. A vehicle acoustical comfort index (VACI) was used to evaluate the effect of tyre to vehicle acoustical comfort. By substituting the sound quality (loudness, sharpness, roughness, and fluctuation strength) which were influenced by the vibration due to interaction between tyre and road surface, both of the VACI values (stationary and moving) can be obtained, and the difference between both values can be considered as the effect of the tyre. The sound quality study has focused on the estimation of the noise quality changes through the trends pattern based on the generated sound quality which relates to engine speeds. From the results, the amounts of sound quality changes with the increase of the engine speeds, except for both of fluctuation strength and sharpness parameters. The results of the study provide one method to predict the amounts of the VACI values caused by the effect of the tyre and the interaction between tyre and road surface.