The Euro 7 proposal mandates limiting brake emissions to be not more than 7 mg/km/vehicle for particles with an aerodynamic diameter of approximately 10 µm or less. To comply, vehicle manufacturers, their supply chain, and authorities need assurance from the testing facility of their initial and ongoing capabilities to deliver valid results. Based on the requirements and maximum permissible errors allowed on the GRPE-87-40 proposal for a new UN Global Technical Regulation (GTR), this work presents some initial results applying the ISO 14253-1. ISO 22514 standards and critical elements from the VDA Guide 5, 3rd Edition. The assessment of the statistical capability of brake emissions tests for vehicle or product release, type approval, and legal requirements needs to combine the measurement system (including requirements and measurement uncertainty), the actual measurement, and the limits (in this case, from the GRPE-87-40 and the Euro 7 proposal). The appropriate quantification of the performance ratios (for the measurement system and the measurement process) uses risk-based assurance (consequences and probability of occurrence). The main methods presented in this work follow a three-step process (for measurements such as cooling air temperature, airflow, and humidity and attributes such as compliance with speed violations and kinetic energy dissipation). In general, method a) determines the requirements of the specific measurand and its associated sensors, b) estimates the measurement uncertainty using manufacturers' specifications or experimental results, and c) combines and compares the combined measurement uncertainty budget with the maximum permissible error from the GRPE-87-40. This process yields the capability metrics (performance ratios defined on ISO 22514 and VDA Guide 5, 3rd Edition). The presentation addresses examples of time-dependant variables (e.g., cooling air conditions); performance capabilities for single-sided requirements (e.g., particle mass emissions factors); fine tolerances (FT) (e.g., cooling airflow and torque near the lower limits); and estimation of uncertainty using the between-sampler method per the EN 12341 standard for particulate mass. This study limits its scope to one main design of testing systems used in a specific testing facility, limiting the ability to assess the transferability of proof of capability (to other facilities or test setups). Another limitation, which can overcome future work, relates to assessing the effects of the friction couple, brake size, and long-term stability of the test system and process. This work enables the stakeholders to understand (with data and applying industry-endorsed methods and beyond a pass/fail result) the ability of a given test setup and test facility to confidently meet the different and stringent requirements of the Euro 7 proposal, implementing the test methods from the GRPE-87-40 document. The implementation of the different tools helps a) the test system provide robust test systems, b) the test facility ensure test results remain within acceptable limits, including the measurement uncertainty of the test setup and the testing process, and c) the user of the test results proceed with manufacturing, release, and type approval.
Mr. Carlos Agudelo, Director Applications Engineering, Link Engineering Co.; Dr. Eng. Hartmut Niemann, Research Application Engineer, Link Engineering Company GmbH; Dipl.-Ing. Maximilian Hense, Test Engineer Bench Testing, Link Engineering Company GmbH; Mr. James Boatwright, Manager Technical Service, Link Engineering Co.; Dipl.-Ing. Marco Zessinger, General Manager Chief Engineer Europe, Link Engineering Company GmbH; Dr. Eng. Frederik Weis, Head of R&D, Palas GmbH