Quiet Road Traffic Reducing tyre-road-noise by optimising car tyres, wheelarches and roads

摘要

Traffic noise on roads where vehicles travel at high speeds is produced by the interaction of tyres and the roadway. Significant reductions in the noise made are only possible if the measures carried out focus on the source, i.e. the tyres and the roadway. With this aim in mind, 15 partners from the tyre, vehicle and road construction industries and at universities conceived the “Quiet road traffic – reduced tyre-roadway noise” project. The project was coordinated by the Federal Highway Research Institute (Bundesanstalt für Stra?enwesen – BASt) and funded by the Ministries of Education and Research and Transport, Building and Housing. The aim of the project was to draw up proposals to reduce tyre-roadway noise by 3 dB(A) within the 3 ? years which the project was due to run; the project was completed in the summer of 2004. Continental AG worked on the part of the project entitled “ Optimisation of passenger car tyres”. Whilst optimisation has previously related only to the tyre noise of vehicles travelling on a roadway standardised in accordance with ISO 10844, this investigation included several common roadway surfaces which form part of the roadway network in Germany. The first series of tests on the BASt test grounds in Sperenberg consisted in taking readings of the noise produced by tyres with different profiles, carcasses and rubber mixtures when travelling over a concrete surface course, an asphalt concrete, a mastic asphalt, a porous Twinlay (OPA) and over the Contidrom of the ISO test track. The results of these initial tests showed that optimising the noise characteristics of car tyres is a multi-faceted and in some cases inherently conflicting task. From the findings gained, pre-production “quiet” test tyres were manufactured for a second series of tests which were supposed to be quieter than a set of “reference” tyres also used in the test, both on the well-known surface courses and on the “optimised” surface courses. The level of noise was reduced by 1-1.5 dB(A), depending on the roadway surface. At the same time, in the part of the project dealing with road construction, roadway surfaces with optimised noise characteristics were laid as test sections on a federal road, the B56 near Düren. A mastic asphalt was created which was 2 dB(A) quieter than a reference mastics surface. A new construction method was also tested, namely a porous concrete; it approached reduction levels achieved by porous asphalt by producing a noise level 4 dB(A) lower than conventional dense surface courses. Another sub-project, on which will be reported here dealt with retreaded tyres. This sub-project was carried out by the BASt. At the same time, Volkswagen and the BASt also carried out another sub-project, in which the rear wheel-arches of a test vehicle (VW Passat) were cladded and the inside of the wheel arches lined with noise-absorbing material. This produced a reduction of approx. 1-1.5 dB(A) in noise, depending on the roadway surface and the tyre used.