With hybrid vehicle sales forecast to exceed one million annually by 2012, the Automotive Composites Alliance (ACA, Arlington, Va.) announced on Jan. 17 the results of a benchmarking study of a prototype hybrid sedan to measure how composites can play a major role in hybrid development programs. The results generally show that in numerous hybrid vehicle applications composites can provide significant savings in mass and tooling investment, as well as advantages in parts consolidation, corrosion resistance, opportunities for model differentiation and improvements in noise, vibration and harshness (NVH).
The ACA targeted seven applications for benchmarking including hoods, fenders, deck lids, battery modules, floor pans, trunk compartments and front and rear bumper beam supports.
"We disassembled the hybrid car, weighed and measured the components and discovered a lot of opportunities for improvements,"said David Dyke, advanced engineering manager at Meridian Automotive Systems, a member company of the ACA. "We are excited about the opportunities composites provide as hybrids continue to grow in acceptance.â€
Compelling Results Hoods: ACA compared a composite hood with a steel hood from the benchmarked vehicle. The result was a 30 to 40 percent savings in mass and a 60 to 70 percent reduction in tooling investment.
Fenders: The results show a 25 to 35 percent reduction in mass and a 55 to 65 percent reduction in tooling investment. Importantly, the ACA's benchmarking shows that the fenders could be consolidated into a single composite piece from four separate metal parts. Unique styling is also possible, as is the integration of wheel lip moldings.
Deck lids: ACA's benchmarking indicates mass savings of 25 to 35 percent by consolidating four metal parts into a two-piece composite deck lid assembly. This lowers weight to help increase fuel economy and reduces tooling investment by 50 to 60 percent. Using sheet molding compound (SMC) on deck lids also allows the transmission of RF waves so that antennas for communication, navigation and audio systems can be seamlessly integrated.
Battery modules: These modules contain the battery pack, electronic controller, wiring harness and other components and often are comprised of several metal stampings. Using composites makes it possible to reduce the module to a two-piece molding with major mass and tooling investment savings. Composites also do not conduct electricity, so they provide an extra measure of safety compared to metal battery modules. They also enhance battery life because they do not corrode and allow integrated airflow cooling in the module's tunnel.
Floor pans: These are typically large structures that are constructed of numerous steel stampings welded together. ACA results indicate a mass reduction of 30 to 40 percent with tooling investment savings of up to 60 percent by using a lightweight core in a single-sandwich mold. Improvements in stiffness and sound deadening are also possible.
Trunk compartments: Using structural low-density composites in a one-piece molding can reduce mass up to 50 percent in trunk compartments. Composites can replace six to eight metal stampings in the complex geometry of the trunk at a savings of up to 70 percent in tooling investment.
Bumper beams: Composite front and rear bumper reinforcements can offer mass savings in the 30 to 40 percent range. The results also concluded that vehicle crash-worthiness can be improved if carbon fiber composites are used in crush cans.
"We think this was a valuable and worthwhile study,"said Dyke. "It validated our contention that composites technologies are right for hybrid vehicles. As fuel prices rise, so will the demand for hybrid cars, trucks and SUVs, and the ACA and its member companies are committed to providing composites solutions that will add the greatest value in hybrid vehicle applications.â€
The ACA is an industry alliance of the American Composites Manufacturers Association (ACMA). Since 1988, ACA representatives have served as the composite industry’s experts for automotive customers and the media. The ACA member network provides technical benchmarking information and industry statistics, helping member companies sell composites in the automotive and transportation markets. More information is available at ACA's website: www.autocomposites.org.