There are ongoing efforts by the automobile industry to reduce unsprung mass of the vehicle and brake wear emissions. An option to attempt to reduce these emissions is the application of alternative rotor materials and/or coatings. However, these may give rise to other problems and need to be assessed in a holistic approach. The research will develop an LCA model to quantify the emissions and environmental impact of disc brakes across their full life cycle, from cradle to grave. The objective of this research is to assess LCA as viable approach for this application, as well as analysing the suitability of alternative brake rotor materials. Life Cycle Assessment (LCA) is a methodology for assessing and quantifying the environmental impacts of a product through the whole life cycle. The LCA will be applied on four chosen brake rotors in accordance with ISO 14040. The selected rotors are a hard ceramic coated Grey Cast Iron (GCI), an Aluminium Metal Matrix Composite (MMC), a Polymer Electrolyte Oxidation (PEO) coated Aluminium rotor and the current GCI for baseline comparison. This paper focuses on developing the LCA model and testing its application on the GCI rotor. LCA has four distinct stages: goal and scope, life cycle inventory analysis, life cycle impact assessment and Interpretation. The Methodological choices are defined within the goal and scope. The functional unit will be the decelerating of a vehicle over its specified lifetime, with the case study of medium sized, commercial vehicles with urban driving cycles. The emissions and impacts will be allocated according to the mass of the products and by-products throughout the life cycle. Excel is used as the software package to produce an original model, which can be forwards compatible with testing new brake rotor materials and adjusting for new legislation. Developing a model this way instead of using already available software models allows for flexibility and transparency of the study. This paper is focussed on documenting the results from the development of the LCA model and the tested application on the current GCI rotor. Within the research project, future work will be done applying this model to the three alternative rotors as well as a Life Cycle Cost (LLC) analysis, which will be documented at a later date. The main limitation of this study is data availability when gathering inventory for each brake rotor. The emissions released are dependent on the frictional interface between the brake pad and the rotor. Therefore, both the brake pad and rotor must be included within the system boundary, when considering a fair comparison. However, due to the pad constituents being highly confidential and complex, data availability is difficult for this section of the study. To overcome this, the model will be created including the pads, to make it forwards compatible for them to be analysed in the future. However, a partial case study might be required for this research, with focus on the disc, using a simplified pad life cycle. There has been significant research into alternative brake rotor materials and potential coating to overcome the drawbacks of the current GCI. However, research investigation the whole life span of these new rotors and their costs is limited. This study allows for the full analysis of environmental impacts rather than just the performance improvement and wear and corrosion reduction. LCA has many past applications but is very limited with brake research. The few studies that do exist focus more on other aspects of LCA such as the validity of omitting identical parts in a comparative LCA study or the viability of refurbishing a coated rotor during its lifetime (Olofsson et al., 2021). In summary, this paper investigates the viability of LCA as a technique to quantify and assess the environmental impact and emissions released during the life cycle of brake rotors. This is done through the development of an original self-developed Excel model. Sensitivity analysis of results to manufacture data and durability assumptions has been conducted. References: OLOFSSON, U., LYU, Y., ÅSTRÖM, A. H., WAHLSTRÖM, J., DIZDAR, S., NOGUEIRA, A. P. G. & GIALANELLA, S. 2021. Laser cladding treatment for refurbishing disc brake rotors: environmental and tribological analysis. Tribology letters, 69, 1-11.
Mr. Matthew Currie, PhD Researcher, University of Leeds; Prof. David Barton, Professor, University of Leeds; Dr. Yue Huang, Associate Professor, University of Leeds; Dr. Peter Brooks, Associate Professor, University of Leeds