Evaluation of different influencing parameters on the result of brake particle emission measurements
Authors:   BMW Group, Kolbeck Katharina , Schröder Thomas ,   BMW Group, Schlichting Marco ,   BMW Group, Bacher Heinz ,   BMW Group
Published: June 2022

"Since fine dust particles in the ambient air emitted by cars, trucks and busses are identified as a health risk, emissions from combustion engines are limited by law. The increasing change from combustion to electric power train as well as the use of gasoline and diesel particulate filters lead to a focus shift to other fine dust sources like tire or brake wear. To further reduce the fine dust pollution caused by road transportation, it is planned to limit particle emissions of brake systems of passenger vehicles by law. The PMP informal working group of the UNECE is already working on a measuring cycle and a suitable test method for this purpose for several years. Hence, a draft of a test protocol was published in June 2021 and is validated in a inter-laboratory study (ILS) at different labs The proposal describes a method to test a single brake-vehicle-combination. The analysis of the market in this regard reveals an extremely large number of possible pairings. Combined with the proposed duration of a complete test-run, this leads to a very high demand of testing to determine the variety of brake emissions of existing vehicle fleets in different markets. Hence, it is crucial to understand whether there are physical correlations between different test combinations to estimate the emission levels of brake-vehicle-pairings. The aim of this study is to investigate the influence of different vehicle and brake parameters in regard of the measured particle number and mass emission. In addition, the results are analysed for physically relevant correlations. This is done using various test series in which only individual test parameters, such as the size of the brake disc or the vehicle weight, are varied. The study also tries to address the effect of different measures for noise, vibration and harshness (NVH) of the brake system on the particle number and mass emission results. The results show that plausible predictions of the emission are possible for the variation of specific test parameters. On the other hand, there are test parameters that require additional information or even a separate emission test when they are changed. Since fine dust particles in the ambient air emitted by cars, trucks and busses are identified as a health risk, emissions from combustion engines are limited by law. The increasing change from combustion to electric power train as well as the use of gasoline and diesel particulate filters lead to a focus shift to other fine dust sources like tire or brake wear. To further reduce the fine dust pollution caused by road transportation, it is planned to limit particle emissions of brake systems of passenger vehicles by law. The PMP informal working group of the UNECE is already working on a measuring cycle and a suitable test method for this purpose for several years. Hence, a draft of a test protocol was published in June 2021 and is validated in a inter-laboratory study (ILS) at different labs The proposal describes a method to test a single brake-vehicle-combination. The analysis of the market in this regard reveals an extremely large number of possible pairings. Combined with the proposed duration of a complete test-run, this leads to a very high demand of testing to determine the variety of brake emissions of existing vehicle fleets in different markets. Hence, it is crucial to understand whether there are physical correlations between different test combinations to estimate the emission levels of brake-vehicle-pairings. The aim of this study is to investigate the influence of different vehicle and brake parameters in regard of the measured particle number and mass emission. In addition, the results are analysed for physically relevant correlations. This is done using various test series in which only individual test parameters, such as the size of the brake disc or the vehicle weight, are varied. The study also tries to address the effect of different measures for noise, vibration and harshness (NVH) of the brake system on the particle number and mass emission results. The results show that plausible predictions of the emission are possible for the variation of specific test parameters. On the other hand, there are test parameters that require additional information or even a separate emission test when they are changed. "