Temperature influence on tire/road noise measurements: recently collected data and discussion of various issues related to standard testing procedures

Abstract

Air, road, and tire temperatures substantially affect tire/road noise emission. For measuring purposes, one would like to normalize measurements to a reference temperature by means of a reliable correction procedure. Current studies show that temperature effects remain an important source of uncertainty in tire/road noise measurements and tire testing, even after applying the correction terms provided in the various standards. This seems to be the case for the measurement methods used in OBSI, CPX, SPB, and various regulations or directives based on ECE R117. This paper examines a new dataset consisting of 7.5 million temperature measurements aimed at contributing to a better understanding of temperature effects and the ways they relate to air, road, and tire temperatures. It is assumed that tire temperatures are the most relevant for noise corrections; therefore, special studies are made for how tire temperatures relate to air and road (test surface) temperatures. A profound analysis is provided on how these relationships vary over different day times, seasons, and climatic regions. Based on this analysis, the authors provide suggestions for improvement of temperature normalization in current tire/road noise and tire testing standards. Special considerations are devoted to measurements on test tracks having ISO 10844 reference surfaces.

Empirical Study on Temperature Influence on Noise Measurements with the Statistical Pass-By Method

“…Sustainability 2022, 14, x FOR PEER REVIEW 3 of 19 quency bands in the spectrum, we investigated the frequency dependence of this parameter, as already suggested in previous studies [13,17,24]. Lastly, these analyses have all been performed for three different temperatures (air, road and estimated tyre temperature), as the literature points out the importance of the physical media in assessing temperature coefficients [23,24]. The structure of this paper is organised as follows: in Section 2, the overall research goals, research methodology, methods and selected test locations are described in more detail.…”

“…where γ t is the temperature coefficient for tyre/road noise based on vehicle class and speed, and W U is a reducing factor to account for the diluting effect of power unit noise. The standard requires the use of the air temperature, yet it is argued that the road surface and tyre temperature could also be appropriate for this correction [23,24]. Tyre temperature appears to be best suited as it is most closely related to the temperature mechanisms.…”

“…Additionally, the air temperature is more stable. In this study, both road-surface temperature and ambient air temperature were captured every 15 min to an accuracy of 0.1 • C. In addition, Equation (3) by Erik Bühmann et al [23] for estimating the tyre temperature was used to check if this could improve the statistical significance of the obtained temperature corrections.…”

“…Additionally, even though the ISO/DTS 13471-2:2021 proposes a single correction coefficient for all frequency bands in the spectrum, we investigated the frequency dependence of this parameter, as already suggested in previous studies [13,17,24]. Lastly, these analyses have all been performed for three different temperatures (air, road and estimated tyre temperature), as the literature points out the importance of the physical media in assessing temperature coefficients [23,24].…”

“…The existing research on temperature influence on road-traffic noise levels focuses mostly on CPX [13,22,23], and literature is hardly available for the SPB method. Moreover, considering the limited transferability from one method to another, this study aims to fill this gap.…”