材料製造時の環境負荷発生を考慮した自動車のライフサイクル環境負荷に及ぼす部品軽量化効果の定量的評価

抄録

Automobile transportation is one of the predominant sources of air pollution, producing CO₂, NO_x, and SO_x. The weight reduction of automobiles is essential for reducing the environmental burden during their life cycle. High-tension steel, aluminum alloy and resin are candidates for such purpose. However, substituting aluminum for steel is not always beneficial with respect to reducing the burden on the environment, because the energy consumption during aluminum production is considerably greater than that for steel. A generalized equation has been derived to describe the relationship between the driving distance, weight reduction, materials production route, and change in environmental performance. In particular, the effect of the difference of electricity source for aluminum smelting on life cycle CO₂, NO_x, and SO_x, by substituting aluminum for steel in automobile parts, is discussed. The reduction of CO₂ emission can be expected for all cases, if 50% of mass reduction is made. On the other hand, aluminum produced by the uncontrolled coal fire power is not capable of reducing NO_x emission. It is also suggested that a reduction of SO_x emission can only be obtained when using very clean aluminum.