Auto Heavyweights Meet to Discuss Best Way to Make Lightweight Vehicles
Senior Editor James D. Sawyer
In the past when talk turned to materials at the annual Management Briefing Seminar (MBS) put on by the Center for Automotive Research (CAR; Ann Arbor, MI) it invariably came down to a discussion of steel versus aluminum. This year was different. It was not that the two materials didn’t have supporters waving their banners as they have in the past. The difference was that the people who make the decisions about what materials will go into automaking have come to a consensus that the future will be a multi-material one as automakers scramble to meet increasingly stringent and fast approaching fuel economy and emission standards.
Thus it was rather symbolic that the first annual Altair Enlighten Award was won by a component that uses no metal at all. It went to BASF for a thermoplastic composite front seat pan for GM’s Opel brand. Presented by Altair Engineering in conjunction with CAR, the award is the automotive industry’s first award program created specifically to acknowledge innovations in vehicle lightweighting. The BASF entry was one of 10 nominees. The award’s judging committee, chaired by Jay Baron, President and CEO of CAR and director of CAR’s Coalition for Automotive Lightweighting Materials (CALM), was comprised of experts from the global auto community.
One only need look at the massive capital investment in manufacturing facilities by automakers and their suppliers to understand why a mix of materials is desirable. The cost of sweeping factories clean of existing machinery and filling them with new machines to handle new materials and technology is prohibitive. It is thus more prudent to use materials that can be handled with little or no change in machinery if weight goals can be met by using them.
Speaking at a conference session titled “Featherweight Competitions: The Path to a Lightweight Car,” Mike Regiec, GM’s Manufacturing Chief, Body Manufacturing Engineering, explained a four-step decision tree GM works through in making decisions about materials:
1. Is the vehicle the right size for its purpose, target market and customer?
2. Do the parts have the right topology?
3. Are the materials the right ones in terms of reliability, durability, occupant safety, fit and finish, machinability, manufacturability and a host of other requirements?
4. Does the vehicle have the right design details and are those details “managed by the gram?”
Application of these “efficient fundamentals reduces mass and cost and results in ‘Foundation Efficiency’,” according to Regiec. More advanced materials are turned to only when these conditions can not be met, he said.
As an example of a vehicle that did require more advanced materials in greater quantity, the structure of a 2014 Corvette was on display. Highly aluminum intensive, the body also sports other composites and some steel. The move away from steel helps the ’Vette maintain its performance capabilities while increasing its fuel efficiency at the same time.
The cause of aluminum was championed by the all-aluminum body in white of the new Land Rover Sport and Jaguar Land Rover’s Mark White, chief engineer, Body Complete Business Unit, Product Development.
Land Rover has a 65-year history of making vehicles using aluminum. The body panels of the very first production Land Rovers were aluminum, not because of a need to lightweight (although less mass was a benefit), but because aluminum was easier to come by in England in the wake of World War II. (Most of it was left over from the aircraft industry.) When it came time—1970—to develop a four-door model that was more suited to road use it was a no-brainer to continue with aluminum for the most of the body panels. The hood and tailgate were done in steel because it was too difficult to stamp the desired contours in aluminum. (Like its predecessor, the body structure was steel.) Jaguar, too, has a background with aluminum, having used an all-aluminum body on the XJ model since 2004.
Jaguar Land Rover (JLR) “wants to use as much of our existing capital equipment and facilities as possible,” said Mark White, echoing many other manufacturing executives. The fact that JLR has had a head start with aluminum doesn’t hurt. Having the infrastructure and the experience has paid off with the new Land Rover Sport. Overall weight savings, White said, has resulted in a vehicle that weighs 400 kg less than its predecessor and delivers 10% better fuel economy. The vehicle is also 25% stiffer. In addition, the use of rivets for joining some areas of the body that had been welded before also conserves water.
Even though he had no idea when he signed on to present MBS that his company’s seat pan would win an award, Dr. Martin Jung, BASF Senior vice president of structural materials, was prepared to talk about the development of the innovation created for Opel. Most seat pans are made from a number of stamped steel components that are welded together. They have stiff cost and time-to-manufacture standards to meet and they must also comply with safety regulations to protect occupants in a crash.
BASF surmounted the challenges using two special Ultramid Polyamide (PA6) injection molding grades for the Opel Astra OPC seat pan. The weight of the piece was reduced from the 1.5 kg it would have weighed in metal to 0.8 kg (45%) and is cost neutral.
Plus, noted Jung, the manufacture of the seat pan “has a cycle time of only about 70 seconds.”
Craig Parsons, President, Automotive, The NanoSteel Co., educated attendees about what is arguably the country’s least-known steel company. That’s because NanoSteel does not make steel. It serves as a de facto R&D arm for the steel industry, creating proprietary nanostructured steel material designs for use in the automotive, oil & gas, mining and power industries. The company has achieved what it terms a breakthrough in the development of nanostructured sheet steel with exceptional strength and ductility.
Parsons also revealed the results of a lightweighting study conducted by EDAG, Inc., an independent engineering firm, demonstrating the potential for the company’s Advanced High Strength Steel (AHSS) to enable a 30% reduction of weight in the body-in-white (BIW) structure of a 2011 Honda Accord sedan.
EDAG used the same architecture of the existing BIW design optimized for weight savings by material substitution. The results showed a 30% (100 kg/220 lb) weight reduction in BIW vs. the baseline 2011 Honda Accord.
Parsons said the optimized BIW even showed a 10.5% (27 kg/60 lb) weight reduction over a NHTSA Light Weight Vehicle design.