Plastics in automotive

Plastics Engineering, Sept, 1994 by Victor Wigotsky

Competition and cooperation simultaneously increase within the U.S. automotive industry. While the desire to win the consumer is fiercer than ever, the willingness of the OEMs to work together, to further the interests of the industry and society as a whole, is evident in the multiplying consortiums and cooperative ventures.

Environment-sensitive cars

The drive to develop a new generation of cleaner, more energy-efficient cars is gaining momentum. Numerous activities inside and outside the automotive industry demonstrate the growing commitment. Irvin E. Poston, manager, Polymer Composites, GM Corp., says that not only the formalized Big Three and supplier groups, such as the U.S. Council for Automotive Research (USCAR) and the Automotive Composites Consortium are involved; there is also an expanding participation of U.S. federal government laboratories and other facilities that ordinarily would not be directly identified with automotive design. Allocation of government funds, often for automotive projects under the direction of the federal laboratories, aims at dovetailing multiple developmental efforts on a cooperative basis. A Partnership for a New Generation of Vehicles (PNGV) has been organized under USCAR to coordinate industry/government projects.

Poston cites the Oak Ridge National Laboratory in Tennessee as an example. Known, of course, for nuclear research, Oak Ridge would seem like an unlikely participant. But the focus relative to the automotive industry is on large-scale saving of energy. The goal is highlighted by the U.S. Department of Energy's recent (1992) initiation of a Lightweight Materials for Transportation program. Developed through the Office of Energy Efficiency and Renewable Energy, Office of Transportation Materials, the Oak Ridge program is sponsoring R&D in industry, universities, and national laboratories. A key objective is to integrate and optimize the numerous team approaches at the cooperating facilities, including the National Aeronautics and Space Administration, the Department of Defense, the Department of Transportation, and the National Institute of Standards and Technology. Testing of appropriate models in an enhanced government-industry partnership is another basic goal.

The average weight of a passenger car has been reduced nearly 25% over the last two decades, says Geoffrey M. Wood, deputy manager, Lightweight Materials Program, Dept. of Energy Laboratory, Oak Ridge National Laboratory. Wood says that among the potential benefits of a further 25% weight reduction of the U.S. passenger car fleet, about 750,000 barrels per day of gasoline could be saved, and carbon dioxide emissions could be reduced by about 100 million tons per year. He adds that automakers estimate that existing vehicles are near optimum with the choices of materials and manufacturing methods currently employed. Therefore, a major new effort is needed to develop new processes; to create new, more cost-effective lightweight material forms; to enhance computer simulation capabilities; and to accelerate application of these gains in lighter-weight car designs.

New technology also is intended to be supportive of the federal PNGV program announced in 1993 to develop a "clean" (pollution-prevention) and "super" (energy-efficient) car with a fuel efficiency capability of 80 miles/gallon. Such a vehicle would require advances in materials concepts, aerodynamics, structural performance, and powertrain technology. The projected time-line calls for a narrowing of the technology focus by 1998; emergence of a concept vehicle by 2001; and the building of a production prototype by 2005.

One of the initial projects out of Oak Ridge, developed with the Automotive Composites Consortium, has been on adhesive bonding of composites. The goal of this industry-driven activity is to develop uniform test standards and methodologies for better prediction of the ultimate strengths of bonded joints, whether plastic-to-plastic or plastic-to-metal. Wood says that other projects, especially tied to the PNGV effort, are just starting.

Demands, demands

The automotive companies thus must deal with demands for accelerated development of materials and processes to meet anticipated objectives of mileage, emissions, and safety, and expanding requirements for recycling, all while satisfying customer desires regarding size, performance, and quality. Wood foresees polymer composites as "the longer-term future" for the projected lightweight cars, not least because of the materials' capacity to consolidate components and thus reduce tooling and assembly costs.

GM's Poston also predicts a growing role for plastics, notably polymer composites, as weight reduction, improved safety, and fuel economy continue to be targeted. The Big Three's Automotive Composites Consortium, for example, is trying to develop more economical processes for producing large, complex, composite structures. Currently involved are improvements in preforming, high-speed resin transfer molding, and robotics techniques for laying down reinforcing fibers.