Abstract
The reduction of greenhouse gas (GHG) emissions over the entire life cycle of vehicles has become part of the strategic objectives in automotive industry. In this regard, the design of future body parts should be carried out based on information of life cycle GHG emissions. The substitution of steel towards lightweight materials is a major trend, with the industry undergoing a fundamental shift towards the introduction of electric vehicles (EV). The present research aims to support the conceptual design of body parts with a combined perspective on mechanical performance and life cycle GHG emissions. Particular attention is paid to the fact that the GHG impact of EV in the use phase depends on vehicle-specific factors that may not be specified at the conceptual design stage of components, such as the market-specific electricity mix used for vehicle charging. A methodology is proposed that combines a simplified numerical design of concept alternatives and an analytic approach estimating life cycle GHG emissions. It is applied to a case study in body part design based on a set of principal geometries and load cases, a range of materials (aluminum, glass and carbon fiber reinforced plastics (GFRP, CFRP) as substitution to a steel reference) and different use stage scenarios of EV. A new engineering chart was developed, which helps design engineers to compare life cycle GHG emissions of lightweight material concepts to the reference. For body shells, the replacement of the steel reference with aluminum or GFRP shows reduced lifecycle GHG emissions for most use phase scenarios. This holds as well for structural parts being designed on torsional stiffness. For structural parts designed on tension/compression or bending stiffness CFRP designs show lowest lifecycle GHG emissions. In all cases, a high share of renewable electricity mix and a short lifetime pose the steel reference in favor. It is argued that a further elaboration of the approach could substantially increase transparency between design choices and life cycle GHG emissions.
Highlights
The design of future vehicle generations and their constituting parts is driven by major transitions, e.g., electrification of drivetrains, prolonged lifetime driving distances or adapted driving profiles in Mobility-as-a-Service (MaaS) business models [1]
Particular attention is paid to the fact that the greenhouse gas (GHG) impact of electric vehicles (EV) in the use phase depends on vehicle-specific factors that may not be specified at the conceptual design stage of components, such as the market-specific electricity mix used for vehicle charging
Politic and industrial discussion, the mitigation of negative environmental impacts, especially considering climate change and the reduction of greenhouse gas emissions (GHG), have been identified as prevalent global challenge. This is acknowledged by automotive original equipment manufacturers (OEM), e.g., Volkswagen, stating that new vehicle generations must contribute to a reduction of life cycle environmental impacts [2]
Summary
The design of future vehicle generations and their constituting parts is driven by major transitions, e.g., electrification of drivetrains, prolonged lifetime driving distances or adapted driving profiles in Mobility-as-a-Service (MaaS) business models [1]. Politic and industrial discussion, the mitigation of negative environmental impacts, especially considering climate change and the reduction of greenhouse gas emissions (GHG), have been identified as prevalent global challenge This is acknowledged by automotive original equipment manufacturers (OEM), e.g., Volkswagen, stating that new vehicle generations must contribute to a reduction of life cycle environmental impacts [2]. Lightweight design approaches leveraging material substitution became a major innovation strategy for vehicle body parts. The conceptual design stage of body parts is subject to unknown parameters regarding its respective life cycle, that needs to be reflected in environmental assessment [9,10]. An analytical method should be developed that links the conceptual design of lightweight body parts with LCA-based assessments of potential GHG impacts.
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