A colleague returned from a trip to Europe and announced that according to an engineer at one well-known vehicle manufacturer, the future structural basis of vehicles would be something you could pick up at a local plumbing supply store: PVC pipe. After all, it’s strong, lightweight...
While that may not occur anytime soon, what is the likelihood of a car’s hood being made out of recycled soda bottles (PET)? Better than you might imagine. Hyundai Motor Co. and GE Plastics collaborated on a vehicle that was unveiled at the 77th Geneva International Motor Show (March 2007), that uses approximately 900 PET bottles as the feedstock for the material, Xenoy iQ, that is used to produce various body panels on the demonstration crossover SUV named the QarmaQ (pronounced “Car-mac”). The goal of this execution was to develop what is, in the words of Dr. Kwon Moon-Shik, Hyundai’s vice president of advanced technology, “a safer, more environmentally responsible car.”
And, no, there is no PVC pipe under the plastic skin.
According to Derek Buckmaster, Global Market Director, Body Panels & Glazing, GE Plastics Automotive (he’s based in the Netherlands) Hyundai was working with GE Plastics on some 30 separate projects and a decision was made to bring them together in a single vehicle.There were three primary areas of interest in developing the crossover, that was designed at Hyundai Motor Europe’s Design and Technical Center in Russelsheim, Germany:
There are two aspects of the exterior design that are clearly out of the norm. First there is the relationship of the glazing to the body work. A preponderant proportion of the vehicle skin is clearly glass, although it is not glass being used. Rather, Lexan polycarbonate is used for the glazing all around. Polycarbonate is not yet approved for use in the windscreen by the National Highway Traffic Safety Administration (NHTSA); side and rear glass deployment is acceptable (per FMVSS 205). In the case of the QarmaQ, there is the Exatec 900 system used to provide an abrasion-resistant and weatherable surface on the glazing (Exatec the company is a 50:50 joint venture between GE Plastics and Bayer). Another notable capability is that of molding the seals and fastenings right into the windows so they are more seamless than would be the case with glass. In addition, the panoramic roof is also made with Lexan. There is UV-blocking technology in the resin that helps minimize heat into the vehicle.
Also, the sunroof has an antenna that is molded into the material. The work to develop the “Fractal Antenna Design” in the Exatec 900vt material was done by Exatec and FICOSA Advanced Antenna Systems Business Unit (www.ficosa.com). Essentially, the antenna is “printed” in the material and then molded over in the second step of 2K injection molding. The antenna is capable of handling multi-bands. Because it is integrated into the polycarbonate panel, there are no external attachments (e.g., masts) required. Although the vehicle has a high belt line, the use of glazing down into the door provides a sense of openness. While some people have apparently questioned whether the doors could pass impact tests, Buckmaster says that GE and Hyundai engineers are confident that they could be engineered to meet the requirements. There are windows integrated into the larger panels that can be opened. The use of the plastic material instead of glass is said to provide a weight savings of some 50%.
The other big difference on the exterior is the integration of the front fascia and front fenders: there’s no cut line between them. According to Buckmaster, Xenoy resin has been used for front (and rear) fascias for years, that it effectively created the market for plastic fascias (he notes, however, that many of these applications have moved to polypropylene due to cost considerations). What they’ve done is taken Xenoy iQ material and implemented the high modulus ductile (HMD) technology GE Plastics has developed. This uses a nano material filler. The result is a material that provides a low coefficient of thermal expansion and high modulus, or stiffness. Not only can they mold the large fenders, but the number of brackets and supports that one might think would be necessary to support such are large component is minimized due to the stiffness. What’s more, the material has a coefficient of thermal expansion (CTE) of 4.0, less than the CTE of 5.0 that some automakers have been asking for. This means that the gap and flush issues that thermoplastic materials have been up against are essentially solved.
The hood is a high-performance thermoplastic composite (HPPC) that has been developed by the joint venture company Azdel, which combines capabilities of GE and PPG. There were several goals associated with this development. One was to have a material that is on-line paintable. This material can handle the thermal and chemical requirements of e-coat, according to Buckmaster. Another is to be light, while meeting the European pedestrian safety requirements, the head-impact test, in particular. This meets that requirement, as well. The hood for the QarmaQ was produced in what Buckmaster describes as “almost production-scale tooling,” aluminum compression-molded tooling. The final challenge to overcome is molding parts that have a Class A surface out of the tool.
Overall, the front end of the vehicle has an energy-absorbing structure. They’re calling it the “Elastic Front” safety system. It combines the properties of the exterior materials as well as an energy-absorbing structure beneath the skin that means that the structure should meet the pedestrian safety regulations without the need to deploy some additional mechanical devices (e.g., an airbag for the pedestrian).
In the back, there is the liftgate that is said to weigh half—10.4 kg—of what an equivalent steel/glass/rubber assembly would. It was engineered with Carbotech of Salzburg, Austria. It is based on a carbon fiber frame with thin structural channels to support the polycarbonate backlight. Because of the light weight of both the frame and the polycarbonate, the gas struts, the lift mechanism and electric motor are all lighter spec as a result.
Inside the car there are also some interesting design/material deployments. For example, instead of having comparatively nondescript HVAC vents in the instrument panel, there is a translucent plastic, Lexan Visualfx, that is back lighted. Lexan EXL resin, a ductile material, is used for the IP top and carrier. There is a seamless surface for the airbag door as laser scribing is used to perforate the door area. The steering wheel is also made with Lexan EXL. There is no magnesium steering wheel ring. Rather, the lightweight steering wheel is molded in two halves, welded, then wrapped with leather. The seat backs and center console have a deep white gloss finish that could become unsightly due to dust and dirt, so an electrostatic dissipative material, a weatherable resin, Geloy XTW, is used to mold the parts.
There is an array of other technologies that Hyundai and GE Plastics are working on that are integrated into the QarmaQ, ranging from silicone elastomer seat inserts that have been treated so that they have a leather-like feel to silica tires made with NXT silane. While not all of the technologies that are demonstrated will necessarily find application in production vehicles, Hyundai has announced that some of them will be deployed in vehicles produced between 2008-20014. As for the PVC pipe chassis...