As the risk of air pollution increases around the world, regulations on automobile emissions are being tightened. In particular, fine particles emitted from automobiles are classified as carcinogens, and it is planned to regulate fine particles emitted from non-exhaust part such as brakes and tires as well as automobile exhaust pipes. Accordingly, brake manufacturers urgently need to develop technology to respond to fine dust emission regulations. Currently, the UNECE PMP Working Group requires that the evaluation of fine dust emitted by the brakes be carried out through the brake dynamo system. However, in the development stage of brake friction materials, it is difficult to analyze the wear amount and fine dust emission characteristics during the formulation process of materials through the dynamo system, in terms of product development efficiency such as time and economy. In this study, we would like to propose a material test scheme that can measure fine dust generated by the brake system in the development stage of brake friction materials, and a brake fine dust emission prediction method based on numerical analysis. A fine particle collection and measurement system was installed on the Pin on Disk friction tester. The wear particles generated during the friction test were suspended in the air and the fine particles were collected on the mixed air flow at a certain speed to measure the number and mass of particles. Disc-shaped brake friction materials and fin-shaped brake disc materials were manufactured, and the amount of wear and fine particle emissions between the friction material and the disc material were measured according to the change of each factor in consideration of environmental factors during real braking process, such as contact pressure, friction speed, and friction temperature. Formulating was performed to approximate the amount of wear and fine particle emissions due to changes in environmental conditions, and apply the formulation to finite element analysis. Braking analysis was performed through the finite element analysis program ABAQUS, and the fine particle emission characteristics according to the formulated environmental factors were applied through a user material subroutine supported by the analysis program. Through this process, a technique that can easily measure fine particle emissions of the brake in the material compounding process was derived, and the fine particle emission characteristics that generated in the product state could be predicted through the linkage with the braking analysis.
Dr. Younki Ko, Principal Researcher, Korea Automotive Technology Institute; Dr. Pyoungchan Lee, Senior Researcher, Korea Automotive Technology Institute; Ms. Boae Jang, Research Engineer, Korea Automotive Technology Institute; Mr. Shin Woncheol, Senior Research Engineer, Myunghwa Co.,Ltd.; Dr. Jungjoo Lee, Principal Research Engineer, Sangsin Brake Co., Ltd.