Life cycle assessment of automotive lightweighting through polymers under US boundary conditions
In the transportation sector, reducing vehicle weight is a cornerstone strategy to improve the fuel economy and energy efficiency of road vehicles. This study investigated the environmental implications of lightweighting two automotive parts (Ford Taurus front end bolster, Chevrolet Trailblazer/GMC Envoy assist step) using glass-fiber reinforced polymers (GFRP) instead of steel alloys.
The cradle-to-grave life cycle assessments (LCAs) for these studies consider a total service life of 150,000 miles for two applications: a 46 % lighter GFRP bolster on the 2010 Ford Taurus that replaced the 2008 steel and GFRP bolster, and a 51 % lighter GFRP running board for the 2007 Chevrolet Trailblazer/GMC Envoy that replaced the previous steel running board including its polymer fasteners. The life cycle stages in these critically reviewed and ISO-compliant LCA studies include the production of upstream materials and energy, product manufacturing, use, and the end-of-life treatment for all materials throughout the life cycle.
Results and discussion
The results show that the lighter GFRP products performed better than the steel products for global warming potential and primary energy demand for both case studies. In addition, the GFRP bolster performed better for acidification potential. The savings of fuel combustion and production during the use stage of a vehicle far outweigh the environmental impacts of manufacturing or end-of-life. An even greater benefit would be possible if the total weight reduction in the vehicle would be high enough to allow for the reduction of engine displacement or an elongation of gear ratio while maintaining constant vehicle dynamics. These so-called secondary measures allow the fuel savings per unit of mass to be more than doubled and are able to offset the slightly higher acidification potential of the GFRP running board which occurs when only the mass-induced fuel savings are considered.
The lightweight GFRP components are shown to outperform their steel counterparts over the full life cycle mainly due to the reduced fuel consumption of the vehicle in the use phase. To harvest the benefits of light weighting to their full extent, it is recommended that the sum of all mass reductions in the design process be monitored and, whenever feasible, invested into fuel economy by adapting the drive train while maintaining constant vehicle performance rather than leveraging the weight reduction to improve vehicle dynamics.
KeywordsAutomotive Design for environment Fuel economy Glass-fiber reinforced polymers Life cycle assessment Lightweighting
- ACC (2012a) Life Cycle Assessment of Polymers in an Automotive Bolster. American Chemistry Council. Available online at http://plastics.americanchemistry.com/Education-Resources/Publications/Life-Cycle-Assessment-of-Polymers-in-an-Automotive-Bolster.pdf
- ACC (2012b) Life Cycle Assessment of Polymers in an Automotive Assist Step. American Chemistry Council. Available online at http://plastics.americanchemistry.com/Education-Resources/Publications/Life-Cycle-Assessment-of-Polymers-in-an-Automotive-Assist-Step.pdf
- Alcoa (2012) Comparative Life Cycle Assessment of Aluminum and Steel Truck Wheels. Alcoa, Inc. http://www.alcoawheels.com/alcoawheels/north_america/en/pdf/Alcoa_Comparative_LCA_of_Truck_Wheels_with_CR_statement.pdf. Accessed Nov 13, 2012
- Bare JC, Norris GA, Pennington DW, McKone T (2003) TRACI - The Tool for the reduction and assessment of chemical and other environmental impacts. J Ind Ecol 6(3–4):49–78Google Scholar
- EIA (2012) Annual Energy Review 2011. U.S. Energy Information Administration. http://www.eia.gov/totalenergy/data/annual/pdf/aer.pdf. Accessed Nov 13, 2012
- EPA/NHTSA (2012) 2017 and Later Model Year Light-Duty Vehicle Greenhouse Gas Emissions and Corporate Average Fuel Economy Standards. Federal Register (17) 199. http://www.nhtsa.gov/staticfiles/rulemaking/pdf/cafe/2017-25_CAFE_Final_Rule.pdf. Accessed Nov 13, 2012
- IPCC (2007) Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (AR4). Cambridge University Press, Cambridge, United KingdomGoogle Scholar
- ISO (2006a) ISO 14040:2006 - Environmental management – Life cycle assessment – Principles and framework. International Organization for Standardization, Geneva, SwitzerlandGoogle Scholar
- ISO (2006b) ISO 14044:2006 - Environmental management – Life cycle assessment – Requirements and guidelines. International Organization for Standardization, Geneva, SwitzerlandGoogle Scholar
- Lovins AB, Datta EK, Bustnes OE, Koomey JG, Glasgow NJ (2005) Winning The Oil Endgame – Innovations for Profits, Jobs and Security. Rocky Mountain Institute. http://www.rmi.org/cms/Download.aspx?id=6663&file=WinningOilEngame.pdf&title=Winning+the+Oil+Endgame. Accessed Nov 13, 2012
- NASA (2012) Earth’s Moon: Facts & Figures. http://solarsystem.nasa.gov/planets/profile.cfm?Display=Facts&Object=Moon. Last updated December 13, 2012. Accessed on February 5, 2013
- Schlegel C, Hoesl A, Diel S (2009) Detailed Loss Modeling of Vehicle Gearboxes. Proceedings of the 7th Modelica Conference, Como, Italy, Sep. 20–22, 2009. Available at http://www.ep.liu.se/ecp/043/048/ecp09430059.pdf
- SuperLIGHT-CAR (2009) Final press release. SuperLIGHT-CAR research project. http://www.superlightcar.com/public/docs/SuperLIGHT-Car_final_press_release.doc. Accessed Nov 13, 2012
- ThyssenKrupp (2003) NSB® NewSteelBody—For A Lighter Automotive Future. ThyssenKrupp Steel Europe. www.thyssenkrupp-steel-europe.com/tiny/Ji1/download.pdf. Accessed Nov 13, 2012
- Transportation Research Group (2006) Tires and Passenger Vehicle Fuel Economy. Special Report 286, Washington DC. http://onlinepubs.trb.org/onlinepubs/sr/sr286.pdf
- U.S. Department of Transportation (2006) National Highway Traffic Safety Administration (NHTSA), Vehicle Survivability and Travel Mileage Schedules. Available at http://www-nrd.nhtsa.dot.gov/Pubs/809952.pdf
- Volkswagen (2011) Vision becomes reality – Volkswagen’s “Formula XL1”. Press release. https://www.volkswagen-media-services.com/medias_publish/ms/content/en/pressemitteilungen/2011/01/25/to_the_point__world.standard.gid-oeffentlichkeit.html. Accessed Nov 13, 2012
- worldsteel (2011) Life cycle assessment methodology report. World Steel Association. ISBN 978-2-930069-66-1Google Scholar