Abstract
Over the years, there has been increasing interest from multiple stakeholders on characterizing particle emissions from foundation brakes. Multiple projects have used different brake configurations (full corner, chassis dynamometer, and tribometers), different test methods (performance and duty cycles), and different brake emissions measurement methods (sampling, particle size range, and quantification techniques). These variations produce different and sometimes conflicting results. Here, we have used inertia dynamometer to quantify, in a systematic manner, the effects of how the brake particulate emissions are affected by test setup, test procedure and type of friction material. The results are expressed in the form of particle emission number, mass concentration, and size distribution. The test program includes assessment of two brake formulations (NAO and low-met); two emission measurement setups (isokinetic in outlet duct, and open sampling near the brake); and six test procedures (modified ISO 26867 friction behaviour; modified SAE J2707-B block wear Los Angeles City Traffic/LACT/USCT; Frankfurt City Traffic; NEDC duty cycle; and WLTP duty cycle based on the exhaust emissions schedule). The test factors aim to support the industry in moving forward with a standardized test method to characterize brake emissions using brake inertia dynamometer testing. Furthermore, based on our main findings, the paper outlines areas deserving further investigation and testing.