Statistical Assessment and Temperature Study from the Interlaboratory Application of the WLTP–Brake Cycle

Atmosphere

Sebastian Gramstat¹  Guido Perricone²  Jaroslaw Grochowicz³  Marcel Mathissen⁴  Matt Robere⁵  Simone Ansaloni⁶  Agusti Sin⁶  Theodoros Grigoratos⁷  Alejandro Hortet⁸  Ravi Vedula⁸  Carlos Agudelo⁸  Marco Zessinger⁹  Andreas Paulus^1,10 

[1] Audi AG, 85045 Ingolstadt, Germany;Brembo S.p.A., 24040 Stezzano (BG), Italy;Ford-Werke GmbH, Henry-Ford-Straße 1, 50735 Köln, Germany;Ford-Werke GmbH, Süsterfeldstraße 200, 52072 Aachen, Germany;General Motors Company, Novi, MI 48377, USA;ITT Friction Technologies, Via Crocetta 11/c, 12032 Barge (CN), Italy;Joint Research Centre (JRC), European Commission, Via E Fermi 2749, 21027 Ispra, Italy;Link Engineering Co., 43855 Plymouth Oaks Blvd., Plymouth, MI 48170, USA;Link Europe GmbH, Am Fleckenberg 10, 65549 Limburg an der Lahn, Germany;TMD Friction Services GmbH, Schlebuscher Str. 99, 51381 Leverkusen, Germany;

关键词: interlaboratory study;    non-exhaust emissions;    brake emissions;    WLTP–brake cycle;    statistical analysis;    temperature measurement;   

DOI  :  10.3390/atmos11121309

来源: DOAJ

【 摘 要 】

The relative contribution of brake emissions to traffic-induced ambient Particulate Matter (PM) concentrations has increased over the last decade. Nowadays, vehicles’ brakes are recognised as an important source of non-exhaust emissions. Up to now, no standardised method for measuring brake particle emissions exists. For that reason, the Particle Measurement Programme (PMP) group has been working on the development of a commonly accepted method for sampling and measuring brake particle emissions. The applied braking cycle is an integral part of the overall methodology. In this article, we present the results of an interlaboratory study exploring the capacity of existing dynamometer setups to accurately execute the novel Worldwide Harmonised Light-Duty Vehicles Test Procedure (WLTP)–brake cycle. The measurements took place at eight locations in Europe and the United States. Having several dynamometers available enabled the coordination and execution of the intended exercise, to determine the sources of variability and provide recommendations for the correct application of the WLTP–brake cycle on the dyno. A systematic testing schedule was applied, followed by a thorough statistical analysis of the essential parameters according to the ISO 5725 standards series. The application of different control programmes influenced the correct replication of the cycle. Speed control turned out to be more accurate and precise than deceleration control. A crucial output of this interlaboratory study was the quantification of standard deviations for repeatability (between repeats), sample effect (between tests), laboratory effect (between facilities), and total reproducibility. Three critical aspects of the statistical analysis were: (i) The use of methods for heterogeneous materials; (ii) robust algorithms to reduce the artificial increase in variability from values with significant deviation from the normal distribution; and (iii) the reliance on the graphical representation of results for ease of understanding. Even if the study of brake emissions remained out of the scope of the current exercise, useful conclusions are drawn from the analysis of the temperature profile of the WLTP–brake cycle. Urban braking events are generally correlated to lower disc temperature. Other parameters affecting the brake temperature profile include the correct application of soak times, the temperature measurement method, the proper conditioning of incoming cooling air and the adjustment of the cooling airspeed.

【 授权许可】

Unknown