17th July 2017 by Richard Yen
There’s just two weeks until the winners of the 2017 Altair Enlighten Award are due to be revealed at the CAR Management Briefing Seminars. Before that though, we’ll be finishing off our look back at last year’s nominees. Today it’s the turn of BMW who entered the 2016 7 Series into the award’s full vehicle category.
Back in 2013, BMW released the revolutionary i3, a mass produced electric vehicle that made extensive use of carbon fiber reinforced plastics (CFRP) materials to keep the weight as low as possible to maximize the car’s range. This was an incredible achievement that required a huge investment in CFRP technologies and manufacturing processes. In its nomination for the 7 Series, BMW noted that the whole development process of the i3 allowed the company to transfer knowledge and technology to its other models. As a result, one of the most significant weight saving design choices for the 7 Series involved the material where multiple CRFP technologies were used.
Firstly, the vehicle features an innovative coreless roof frame which was produced through CFRP resin transfer molding. Then the vehicle’s B pillars were produced using a CFRP-Steel hybrid which allowed the design team to reinforce the structures in very specific areas. Furthermore, CF sheet molding compound and CFRP wet compression molding were used throughout the production of the carbon core body.
However, CRFP technologies were not the only factor that attributed to the weight savings achieved. For example, the side member is one die-cast aluminum peace that replaces 18 single parts that were used for the same purpose in the vehicle’s predecessor. In addition, the implementation of an at-source insulation concept and the use of super absorbers significantly improved interior acoustics coupled with a reduction in weight as well as a reduction of un-sprung masses through a focus on lightweight design for the suspension, brakes and wheels. All of this was backed up by an extensive use of design optimization technologies to maximize performance of the components and systems while reducing material use. In total, the BMW 7 Series is 286 lbs (130 kg) lighter than its predecessor.
BMW’s nomination is extremely impressive and took the runner up place for the 2016 award in a close run battle for first prize. CFRP materials have the potential to save weight for vehicle manufacturers but, outside of sports vehicles, the technology had not seen significant use in high volume vehicles. BMW’s commitment and investment in composite technologies for its ‘i’ platform has proved the material can enhance development programs of far more mainstream vehicles with BMW now reaping the benefits of learning picked up along the way.