Concerning the sound emission of electric vehicles there are two main challenges: On the one hand, the exterior noise is on a very low noise level and approaching electric vehicles might not be recognized in city traffic. On the other hand, compared to internal combustion engines, electric drives develop a considerably high torque from the standstill which might increases tire road noise of about 10 dB in the near-field. Since combustion engine noise gets eliminated, tire road noise will not be masked anymore during acceleration but instead occurs as a disturbing, dominant acoustic source. The paper describes first an inner drum test rig which allows the reproducible measurement of tire road noise on real road surfaces at driving and braking torque. Then, test results of special tires with different rubber compounds and pattern designs are presented. The influence of pattern stiffness and tire torque on tire road noise generation is analysed. Additional the inner drum test results were validated by pass-by measurements on different road surfaces. Finally, the effects and mechanisms of the noise phenomena are discussed and tire pattern design concepts for low noise emission under driving torque are derived.
展开▼
