Elucidating complex design and management tradeoffs through life cycle design: air intake manifold demonstration project

摘要

The life cycle design (LCD) framework for enhancing design analysis and decision making is demonstrated through a collaborative effort between the University of Michigan, a cross functional team at Ford, and the US Environmental Protection Agency. The LCD framework was used to evaluate three air intake manifold designs: a sand cast aluminum, brazed aluminum tubular, and nylon composite. Life cycle inventory, life cycle cost and product/process performance analyses highlighted significant tradeoffs among alternative manifolds, with respect to system design requirements. The life cycle inventory indicated that the sand-cast aluminum manifold consumed the most life cycle energy (1798 MJ) compared to the tubular brazed aluminum (1131 MJ) and nylon composite (928 MJ) manifolds. The cast aluminum manifold generated the least life cycle solid waste of 218 kg per manifold, whereas the brazed aluminum tubular and nylon composite manifolds generated comparable quantities of 418 kg and 391 kg, respectively. Material production accounted for 70% of the total life cycle solid waste for the brazed tubular manifold, while auto shredder residue was responsible for half the total waste for the nylon composite design. The life cycle cost analysis estimated Ford manufacturing costs, customer gasoline costs, and end-of-life management costs. The nylon composite manifold had the highest estimated manufacturing costs but the least use phase gasoline costs. Significant end-of-life management revenues from aluminum recycling would accrue to Ford under automobile take back legislation. A total of 20 performance requirements were used to evaluate each design alternative.