Abstract
The noise emitted by tyres contributes significantly to the drive-by-noise of vehicles. For passenger cars tyre/road-noise exceeds the propulsion and the aerodynamic noise between 60 km/h and 100 km/h. As a significant reduction of the overall noise level can only be achieved by muffling the strongest sound source, the importance of the tyre-pavement noise for meeting future noise legislation criteria becomes evident.
Within the framework of the EC-research project TINO (Tire-Noise-Emission) the Department of
Automotive Engineering of Darmstadt University of Technology developed a trailer with which the acoustical behaviour of tyre-pavement combinations can be examined under variation of the parameters slip angle, camber, torque, speed and wheel load, independently of each other. A hydraulic system allows to apply braking and driving torque to the tested wheel. The driver of the towing vehicle operates the whole system.
This trailer allows to examine the acoustical behaviour of a wide range of tyre and rim dimensions under the influence of the above mentioned parameters on the same tool without changing the measurement conditions. As a mobile tool it is possible to take measurements on all pavements which are accessible with a passenger car.
Measurements were conducted by the Darmstadt University of Technology, Automotive Engineering Department, on characterised test-tracks. To examine the influence of tread, structure and rubber compound of the tyre, a set of tyres was used which differed from each other only in one of these parameters. During measurements trailer speed, tyre revolutions, slip angle, torque, wheel load and tyre temperature were registered.
This paper deals with the influence of some of the parameters affecting tyre/road-noise, their ranking order and the range of variation of the sound pressure level regarding these parameters.