制动磨损颗粒物的生成特性:基于定工况的研究

Brake wear emission has become a significant source of vehicle emission. To understand the generation process of brake wear particles, a brake disc-pad assembly of a passenger car is tested on the brake dynamometer. The results show that the emission peak of large-size particles（ LPs, Da > 2.5 μm） shows a stable relationship with pressure application, with the generation of large particles closely related to mechanical wear. The maximum generation time offset between small-size particles （SPs, Da < 2.5 μm） and LPs can reach 6 seconds, which stems from the temperature rise during the braking process. Previous braking processes significantly affect the wear state of brake pads, thereby causing variation in emission. For SPs, peak concentration drops from 5×10⁵ to about 1 000 #/cm³ during continuous braking, due to the organic component consumption in brake pads and the friction layer’s protective effect. For large particles, emission decreases by 55% under the same conditions, linked to the experienced high pressure and temperature braking processes, which reduce the real contact area between friction surfaces. Based on these findings, potential vehicle brake emission control technologies are also discussed in this study.