Automotive engineering consultancy Drive System Design (DSD) and global chemical company Solvay SA have teamed up to improve efficiency and reduce the weight of automotive transmissions through the increased use of structural plastics.
Through the new partnership, the companies say they aim to make the large-scale use of plastic composites in transmissions a viable solution for future vehicles. Substituting plastic materials for conventional metal castings produces an immediate weight savings. The companies say it also has the potential to improve efficiency due to the greater inherent damping provided by polymeric materials.
This means, once the new lightweight transmissions come to market, they can help vehicle manufacturers meet increasingly strict fuel efficiency and emissions standards.
Potential exists for shafts, casings and hydraulic cylinders to be made from plastic, reinforced where appropriate. Full implementation could produce savings of up to 45 percent in terms of the casing weight for a typical passenger car transmission although with an NVH ‘skin’ included this reduces to 25 percent, but allows a reduction in transmission losses of up to 0.5 percent per gear mesh, the companies say.
However, this is still five to 10 years in the future.
There remain a number of challenges to be overcome before this happens, according to Shaun Mepham, DSD president, North America. “New and unfamiliar materials bring pitfalls for the unwary because of the subtleties of the mechanical properties, which can change by up to 50 percent over the operating temperature range due to non-linear behavior,” he says.
DSD and Solvay are in discussions with vehicle manufacturers to determine the areas within transmission and driveline systems that offer the best potential for material substitution in the future.
Currently, the technology is in the development phase to optimize the most suitable materials and processes in a “near production ready” state. DSD and Solvay anticipate a five to ten year timescale before the first applications come to market. Once proven in niche applications such as premium EVs, and processing costs have been reduced by expanding the volumes, they say it could become a mainstream technology for passenger car transmissions.
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