In this work, airborne brake wear particulate matter (PM) emissions from a brake system were investigated by time-resolved and temperature-dependent measurement using a dynamometer. The measurement was performed for representative friction materials, 3 low-steel (LS) and 4 non-steel (NS), which are currently in worldwide use. The PM emission factor was found to be varied as large as by one order of magnitude depending on the composition of friction materials(pads). The airborne particle mass emissions from the LS materials ranged from 1.88 to 3.14 mg/km/vehicle, while the emissions from the NS ranged from 0.3 to 2.34 mg/km/vehicle, which is, in general, smaller than the LS. The time-resolved data imply that particle emissions in the extra-high-speed region of the WLTC cycle, where friction occurs at high temperature (T_disk > 150 °C), is much higher than in the low-speed region, and determines the total PM mass emission factor. It was found that the friction materials containing metals such as Cu and Sn (LS-2/-3 and NS-4/-5) exhibited a lower PM emission factor. This result suggests that copper and tin, which forms an effective lubricating tribolayer in the interface between the pad and disk at high temperature, remarkably reduces PM emissions. It has been also found that the surface roughness of worn brake pads is positively proportional to PM emissions according to surface topography analysis, which is consistent with composition effect. These findings suggest that tribological engineering to provide sliding frictional behavior at elevated temperature is crucial to reducing PM emissions.

在这项工作中，使用测功机通过时间分辨和温度相关的测量研究了来自制动系统的机载制动器磨损颗粒物（PM）排放。对代表性的摩擦材料（3种低钢（LS）和4种非钢（NS））进行了测量，这些材料目前已在全球范围内使用。发现PM排放因子的变化幅度最大为一个数量级，具体取决于摩擦材料（摩擦片）的组成。LS材料的空气传播颗粒物排放量在1.88至3.14 mg / km /车辆的范围内，而NS的排放量在0.3至2.34 mg / km /车辆的范围内，通常小于LS。时间分辨数据表明，在WLTC循环的超高速区域中，在高温下会发生摩擦（T_盘 > 150°C），比低速区域要高得多，并决定了总PM质量排放因子。已经发现，包含金属如Cu和Sn（LS-2 / -3和NS-4 / -5）的摩擦材料表现出较低的PM排放因子。该结果表明，铜和锡在高温下在垫和盘之间的界面中形成有效的润滑摩擦层，从而显着降低了PM排放。还已经发现，根据表面形貌分析，磨损的制动衬块的表面粗糙度与PM排放成正比，这与组成效应一致。这些发现表明，在高温下提供滑动摩擦性能的摩擦学工程对减少PM排放至关重要。