Primary manufacturing, engine production and on-the-road CO2: how can the automotive industry best contribute to environmental sustainability

Legislation in the automotive industry currently focusses on tailpipe CO2 emissions, with no consideration for the CO2 footprint of the materials used in the manufacture of vehicles. This has led OEMs to adopt lower density materials, to contribute to weight reduction and fuel economy, in the expectation that the weight reduction will provide a net CO2 benefit to society. This paper will present the results of a full assessment of the energy and CO2 impact during the manufacture of diesel and petrol engine blocks. The research is based on inputs from over 100 world experts from across the automotive supply chain, including raw material mining and smelting companies, alloy recyclers, iron and aluminium foundries, OEM engineers, independent manufacturing specialists, design consultants, heat treaters and impregnators. Despite current perceived wisdom, the use of lower density materials frequently results in net energy and CO2 penalties, when considering the complete life cycle of manufacture and use. For the 1.6 litre engine block investigated in this study, more than 200,000 km of on-the-road driving is required to compensate for the up-front energy consumption and CO2 emissions associated with the production of aluminium engine blocks. The paper also comments on other environmental impacts from the iron and aluminium manufacturing routes. These results provide new insights for OEM decision-makers, and a new perspective for legislators to define regulations that truly contribute to the environment and to society.