Automotive: Lightweighting Central to Mass Reduction
By Rachel Duran
Automotive manufacturers are hard at work meeting fuel economy mandates set for 2025, looking to reduce the mass weight of vehicles in any manner possible. Under the Corporate Average Fuel Economy (CAFE) regulations, light vehicles are expected to achieve 54.5 miles per gallon by 2025, essentially doubling fuel economy.
One way the industry aims to meet the mandates is by incorporating lightweight materials that already exist to build mixed-material cars, where the materials enable each other.
Major materials used in auto manufacturing include steel (60 percent of a car), aluminum and composites; and smaller volumes of materials such as titanium and magnesium. The three major materials represent opportunities to lower the weight of cars; and all come with pros and cons. A challenge in producing mixed-material cars is that the three major material industries naturally have organizations dedicated to promoting their specific material as the solution to reducing the mass weight in automobiles. “From an engineering standpoint, while those alternatives are likely to exist in the marketplace, the optimum solution for many vehicles will be a multimaterials solution, says Doug Richman, vice president of engineering and technology, Kaiser Aluminum. “A mixed-material environment will emerge as perhaps the largest single sector in the automotive design space for the next 15 years.”
Kaiser Aluminum makes extruded aluminum products, with the majority of the growth in the auto industry in sheet-rolled products converted by companies into hoods, fenders, doors, trunk lids, roof panels and so forth. Aluminum has traditionally been used in engine blocks and transmission cases. Richman says the expansion of aluminum materials will extend to the body structures of automobiles. “We recognize that for car companies to meet their needs in terms of mass reduction they will need technologies that efficiently, effectively and reliably merge the different materials,” Richman says. “We are a player so we believe supporting a multimaterial organization brings value to the industry that we depend on.”
The organization Richman speaks of is the Coalition for Automotive Lightweighting Materials (CALM). Until two years ago, the three main material industries lacked an initiative to band together and focus on the best use of materials, whatever they may be. CALM’s members focus on developing mixed-material solutions because they are believed to be optimal in the lightweightingof vehicles to achieve fuel economy goals.
“Our mission is that we are material independent, we support the auto industry,” says Dr. Jay Baron, president and CEO, Center for the Automotive Research (CAR), which is a nonprofit organization based in Ann Arbor, Mich. CAR’s leadership formed CALM, which is guided by a steering committee consisting of CAR, the Aluminum in Transportation Group of the Aluminum Association Inc., and the American Chemistry Council Inc. At this time, CALM’s membership is dominated by aluminum and composites industry members; steel fabricators participate, but not the steel companies themselves.
Baron notes that the steel industry has been a bit more defiant in collaborating than the aluminum and composites industries. High strength steels have an important role in the vehicle especially to ensure safety; however, the steel industry comes from the perspective that there isn’t really a need to transfer the supply chain from steel to aluminum. “Clearly aluminum and composites are the up and comers, and will do so to some extent at the expense of steel,” Baron says.
With a multimaterial vehicle come challenges because up until now the body structure has been all steel, all aluminum or all plastic, Richman says. “We have to deal with joining dissimilar metals, or composites, which will also find their way on to the body structures. So for now we are entering an area where the engineers have to work around multiple materials in a given structure. It brings up design issues and how to compensate for them.”
Richman says the usage rate of aluminum in automobiles have risen 7 pounds each year for 35 years. The average car in the United States has 343 pounds of aluminum, and it is estimated that the increased usage per vehicle in North America will increase 10 pounds per year for the next five or six years.
By working together, CALM’s members have found there are a number of applications in a car when one material will enable another material. An example is the sophisticated adhesives produced by the composite companies. “When you use these new materials you don’t need to use resistant spot welding, which is the standard technology,” Baron says. “You get into sophisticated technologies where you are using joining technology, more rivets and more adhesives. The adhesives are enabling technologies that allow you to bond a composite to aluminum or even aluminum to steel.”
At this time, the auto industry supply chain is primarily metals oriented, making it more challenging to implement composites. “The supply chain is not as mature; there is not enough experience and not as many chemical engineers as mechanical engineers,” Baron notes. “Composites offer a wonderful opportunity. They tend to be a little more expensive than aluminum. We see that it is growing but lags behind the two others [steel and aluminum].”
However, the use of composites in automobiles is on the rise. In 1960, the average amount of plastics used in vehicle manufacturing was 20 pounds; it was 194 pounds in 1990; it was 286 pounds in 2000; and is 377 pounds today, which is 10 percent of a car’s total weight, says Gina Oliver, senior director, the automotive group in the plastics division of the American Chemistry Council Inc. The 14 members of the automotive team produce the resins used to manufacture composite parts.
“Plastics typically make up 50 percent of the volume of light vehicles, which accounts for less than 10 percent of the vehicle weight, which is more fuel efficient and results in fewer greenhouse gas emissions,” Oliver says. “We think sharing solutions will enable manufacturers to successfully achieve future fuel economy goals.”
Oliver points out that 96 percent of all manufactured goods are directly touched by the chemical industry, which includes the automotive industry. Manufacturers in 45 states are using more than 5.7 billion pounds of plastic annually to create auto parts and components. The use of composites in the near future will be concentrated in mixed-material vehicles. Future uses include more applications used in the body, such as carbon fiber. BMW currently produces a carbon fiber car, the i3, on an aluminum chassis.
“We need to make sure we are bringing new and plausible lightweight solutions for components and parts to the auto industry to assist in lightweighting vehicles because striving for CAFE is the most important thing for manufacturers,” Oliver adds.
The Best You can Do
Baron says CALM opens doors for member companies, connecting them to design engineers at auto companies. “With a coalition of this type you can command a broader audience at the auto companies or even large Tier I companies. You can reach the right people to get the answers to what the barriers are so they can go back to their technical centers with what they need to work on.”
The members of CALM are working on co-development projects, focusing on topics such as a lightweight door, specifically looking to identify challenges, document best practices and develop the business case including cost and production solutions — regardless of the materials used, developing the lightest mixture of materials as cost effectively as possible.
It is also hoped that the collaborative efforts will attract the attention of federal agencies. “Working as a team, we can go to some of the federal agencies, such as DoE, and demonstrate that we want to work on this as a team, bringing our expertise together. We like to call this advancing the technology.”
Adds Richman: “To our perspective that is what CALM is about — to facilitate from the supply side the technologies necessary to be successful in a multimaterial vehicle environment.”
How will lightweighting move the auto industry forward? “We know a 10 percent reduction in the mass of a vehicle achieves a 6.5 percent improvement in fuel economy,” Richman points out. To meet the CAFE requirements by 2025, an average number of 400 pounds or 10 percent needs to come out of a vehicle.
“Some of the reduction comes from using the new materials, some from downsizing the engine,” Baron says. “As your car gets lighter, your shocks can be lighter, your gas tank can be smaller, and your horse power can effectively be reduced. By 2025 you will see more aggressive use of composites that will get additional weight out of the vehicle, probably another 5 percent. It does come at some cost — weight reduction is not free. There is a big dispute as to what the cost really is.”
For example, NIST and the EPA estimate that it will cost 43 cents a pound to get the weight down. “I think it costs more than that,” Baron says. “I think they have grossly understated the costs. I think it is upwards of $1.50 to $2 a pound.”
Richman summarizes the lightweighting approach, saying: “It will take the best we all can do to get the whole fleet to where we want it by 2025.”
For complete details about the organizations featured in this article, visit:
Illustration by Paul at Free Digital Photos.net