Korean automaker Renault Samsung Motors is exploring various means of vehicle lightweighting as it faces up to impending tougher emission and fuel economy standards from 2020 onwards. Describing recent work at the car company, Cheoi-hwi Lee, Chief of the firms Organic Materials Section at its R&D Division, says the task is particularly challenging given vehicles have tended to add weight in recent years along with the introduction of new equipment such as climatic, sound and passive safety systems, and the trend towards larger vehicle sizes for added comfort. “But what we need is a 400 kg decrease vehicle in weight to achieve a 40-g reduction in emissions.”
|Among the lightweighting infinitives being implemented at Renault Samsung Motors are a glass fiber-reinforced SMC spare tire housing weighing in at 5.7 kg used in its SM6 (Talisman) model.|
Excess emissions over and above 97 g/km will be taxed at KRW10,000 ($9.20) per gram per vehicle produced from 2o20. Off-cycle credits such as using HFC-134a as a refrigerant, idle stop/start, high efficiency external lamps, solar cell panels, and active aerodynamics do, however, apply.
Despite being head of organic materials, Lee says at present aluminum is the most affordable material out there, whereas while magnesium, a material also under consideration, is very light, it is not affordable. One resin-related area that Renault Samsung is working on is a carbon fiber-reinforced epoxy composite for a vehicle trunk lid as part of a government project that kicked off in 2014. The development targets are a curing time of sub-2 minutes, heat resistance of 180°C-plus to endure the E-coat painting process, and a part cost of KRW13,000 ($12)/kg including processing. The final part will weigh 5.6 kg if development succeeds, which is 60% lighter than a steel trunk lid.
Renault Samsung’s Lee believes that multi-material solutions combining steel, magnesium, aluminum and composites may become the best solution for weight reduction and cost competitiveness. “This means joining technologies will also be important, such as adhesive technologies for CFRP.”