Tool for the environmental assessment in the automotive context: analysis of the use stage for different typologies of LCA study

The work is developed in the context of the automotive Life Cycle Assessment (LCA) and it is aimed to represent a valid support for practitioners in the design for environment of both conventional and innovative lightweight solutions. The final target of the research is to conceive a tool able to perform the LCA of the use stage in applications to Internal Combustion Engine (ICE) turbocharged vehicles within the following typologies of study: - LCA of a specific vehicle component; - comparative LCA between a reference and an innovative lightweight alternative. The tool is constituted by a series of environmental models able to treat with the needs of the cited typologies of study and to achieve specific enhancements with respect to existing literature. The work is articulated into two main sections: simulation modelling and environmental modelling. Simulation modelling performs an in-depth calculation of weightinduced Fuel Consumption (FC) whose outcome is the Fuel Reduction Value (FRV) coefficient evaluated for a wide range of vehicle case studies. Environmental modelling refines a series of environmental models able to perform - allocation of impacts to the component (LCA of a specific vehicle component) - estimation of impact reduction achieved through light-weighting (comparative LCA) basing on the FRVs obtained by simulations. The implementation of the FRVs within the environmental models represent the added value of the research and makes the tool flexible and tailorable for any generic case study. The first part of the work defines the topic of the research, aiming to explain the relevance of the design for environment within the automotive LCA context. An introduction to the LCA methodology is provided and the importance of the use stage in the determination of the overall vehicle impact is highlighted. Chapter 2 is constituted by a State Of the Art (SOA) analysis regarding the considered typologies of LCA study; the review includes both findings from research and practices usually adopted in current LCA analyses. Literature data are collected and presented to support this section, from existing automotive LCAs to studies that deal with the determination of the mass-induced fuel consumption reduction. Current approaches are described in detail, analyzed, and critically commented, evidencing the main points of criticism they are subject to. In the light of critical analysis, theenhancements with respect to existing literature are identified and translated into specific requirements the environmental tool has to fulfill. Chapter 3 describes the stages needed in order to conceive the tool, evidencing the partition between simulation and environmental modelling. In the simulation modelling the modality for calculating the use stage FC and evaluating the Fuel Reduction Value (FRV) coefficient is established. FC is determined for different car mass-configurations and the FRV is obtained as the relationship between FC and mass; the FRV is evaluated for both the cases of Primary Mass Reduction (PMR) only and implementation of car re-design (Secondary Effects, SE). The section illustrates the main features of the use stage simulation model, the extension of the analysis in terms of both vehicle classes and driving cycles and the implementation of SEs. The environmental modelling defines structure and operation of the use stage environmental models; basic equations that quantify input/output flows between processes are defined evidencing the central role of the FRV coefficient. Chapter 4 illustrates the implementation of the use stage simulation model within the AMESim environment, including equations, logic and parameters which govern its operation. The setting of model parameters is explained in detail with the support of figures and tables in SI appendix; this phase includes also data collection, analysis and treatment performed by the Candidate. Chapter 5 reports the results of the research subdivided between simulation and environmental modelling: values of FC and FRV obtained by simulations for the various case studies (simulation modelling) and implementation of environmental models within the software GaBi6 (environmental modelling). The results are critically discussed in chapter 6. At first the values of FRV are commented by evaluating the influence of vehicle class, driving cycle and SEs. After that the existence of any correlation between the FRV and the main vehicle technical features is investigated and a criterion for implementing the coefficient within the environmental models is identified. Finally the environmental models are commented placing particular emphasis on the possibility to set up the FRV basing on technical features of the specific case study. Such a possibility represents the added value of the research with respect to existing literature and makes the environmental models a flexible and tailorable tool for application to real case studies.