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Life Cycle Design of Air Intake Manifolds February 1999

This life cycle design project was a collaborative effort between the Center for Sustainable Systems (formerly National Pollution Prevention Center) at the University of Michigan, a cross functional team at Ford, and the National Risk Management Research Laboratory of the U.S. Environmental Protection Agency. The project team applied the life cycle design methodology to the design analysis of three alternative air intake manifolds: a sand cast aluminum, brazed aluminum tubular, and nylon composite. The design analysis included a life cycle inventory analysis, environmental regulatory/policy analysis, life cycle cost analysis and a product/process performance analysis. These analyses highlighted significant tradeoffs among alternatives.

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 manifold contribution to the vehicle fuel consumption dominated the total life cycle energy consumption. 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. Red mud generated during alumina production accounted for 70% of the total life cycle solid waste for the brazed tubular manifold while the nylon component of auto shredder residue was responsible for 53% of the total waste for the nylon composite manifold.

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 which were about $10 greater than the two aluminum manifold designs. The use phase gasoline costs to the customer over the lifetime of the vehicle, however, for the composite and the aluminum brazed tubular manifolds were about $6 and $5 cheaper, respectively, compared to the cast aluminum manifold. End-of-life management credits of $4.10 for the cast aluminum manifold and $2.30 for the brazed aluminum tubular manifold would accrue to Ford under automobile take back legislation. In addition, 20 performance requirements were used to evaluate each design alternative.

This report was submitted in partial fulfillment of Cooperative Agreement number CR822998-01-0 by the National Pollution Prevention Center at the University of Michigan under the sponsorship of the U.S. Environmental Protection Agency. This work covers a period from November 1, 1994 to May 31, 1997 and work was completed June 1, 1997.


Ken Stone

Office of Research & Development | National Risk Management Research Laboratory

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