Developments in environmental issues and European regulations require that the design of automotive products is based on a "global and systemic environmental assessments” of technical solutions. LCA (Life Cycle Assessment) is the only truly recognized approach for measuring the environmental performance of systems, by identifying the critical steps and the most polluting activities throughout their life cycle. The LCA results enable then taking action or developing strategies to reduce environmental impacts from the design phase, providing feedback on the evaluated technical solutions. To do this, LCA must be truly integrated and operated in “real time” in the design process. This condition is the only way to "guarantee" a "real and effective" consideration of the environmental performance of new products in design decisions. Since a significant part of these decisions belong to the design team, their involvement in the environmental assessment is essential to have a maximum space for eco-innovative design. LCA in its standard and marketable form is too complex to be directly integrated into the design process. Several difficulties arise regarding mainly the tool appropriation by the design team and its integration into the design process. We have developed and tested during this thesis, with the automotive supplier Faurecia a new methodology to operationalize the LCA in the design phase. It stands on three principles. The first principle deals with standardization of assumptions and the scope of the LCA modeling for a product in the same company. The second principle is returning the environmental profile of a product without going through the LCA modeling, through a fictional approach by "functions of impact". The third principle is to simplify the interpretation of LCA results by the design team, by reducing the number of criteria to consider and facilitate their understanding by creating an environmental system of reference per range of product.
