Light

“The focus is on making lightweight cheaper”

Ever since the birth of the automobile industry, weight has been a major issue. Light vehicles simply use less fuel. And batteries have a longer range in a lightweight electric vehicle than in a heavy one.

In spite of this knowledge, cars have unfortunately tended to get heavier. The focus has been on safety, comfort and driving performance. It is only over the last 10-15 years, as environmental awareness has become more widespread, that properties have become more balanced in favour of energy-efficient designs.

The improved efficiency of drivetrains is not only used to increase engine power as before, but also to lower fuel consumption and emissions. The car’s structure has not only been made stronger but also lighter by using high-strength steel in the structural components and aluminium or polymers, for example, in the door, bonnet and boot.

Composite - the latest trend

The latest trend is to use composite materials such as carbon-fibre reinforced plastic in both structural and exterior details.

“By designing structures so that the new material’s properties are fully exploited, as well as integrating multiple functions, its properties are optimized further. Simply replacing the materials in existing structures is not the whole solution,” says Claus Katt, department manager Design engineering at Semcon in Germany.

The lightweight materials already exist. They are used in exclusive sports cars, but are still too expensive to put into mass-produced cars.

Bringing lightweight technologies closer to mass-production cars was the aim of the EU-funded research project, Superlight Car (SLC), in which Semcon participated. Semcon is also one of the key players in the Swedish research project “Sånätt”, which has 40% weight reduction as a goal.

Involved in Volkswagen 1-litre project, XL1

For example, Semcon engineers were involved in the Volkswagen 1-litre project, XL1, which aimed to build a car that used less than one litre per 100 kilometres. It consisted almost entirely of carbon-fibre reinforced plastic used in Formula One cars. The XL1 weighs only 795 kg and is virtually ready to be launched.

Carbon-fibre reinforced plastic (CFRP), is a material attracting considerable interest in the automotive industry right now. “The advantages of the material, apart from its low weight, are high strength, high resistance to corrosion and the possibilities of increasing functionality,” says Katt.

CFRP is a so-called anisotrope, which has different physical properties in different directions. “Depending on the choice of fibre direction and the production method, you can achieve almost any feature you want,” Katt says, continuing:

“There is no doubt that lightweight materials like aluminium, magnesium manganese (MnE21) and carbon-fibre-reinforced plastics will gradually begin to be used in mass-production cars. Just look at the new BMW i3. The challenge now is to find ways to make lightweight solutions cheaper.”

MnE21, in particular, is a material that many have high hopes for. “The material is a good compromise in terms of weight, durability and environmental-friendliness. MnE21 is 100% recyclable and may well be the future lightweight alternative to reinforced plastics,” Katt says.

With MnE21, production and assembly processes can be simplified, thereby reducing carbon emissions during production, reducing costs at the same time. A bonnet structure made out of MnE21, for example, could compete in terms of cost with an aluminium structure. Also, the weight reductions are considerable. The use of MnE21 in some car components could reduce weight by over 36 kg in a typical car.

Many car manufacturers have a goal of reducing overall vehicle weight by 30-40%.

“The challenge in the future is to find the optimal balance of different materials, use the right materials in the right place and also include environmentally-friendly production, recycling and costs in the calculation,” Katt says. Semcon also participated in concept development in the research project SEVS (Safe, efficient vehicle solutions) at Chalmers University in Göteborg, studying what transport systems might look like by 2030. Here, the lightweight concept is an important part of the vision of a sustainable society.

The need for lightweight solutions unites many different industries. The automotive industry has come a long way, but Semcon has also worked on lightweight solutions in the train, aviation, and marine industries.

“Our experience in lightweight solutions, in combination with the knowledge we obtain through our commitment to research, allows us to assist customers with lightweight projects, regardless of the industry,” Katt say

There is a major focus in the automotive industry to reduce the weight of cars, trucks, buses and other vehicles. For the light vehicles (cars etc) it is mostly an emission and range issue, for the heavy vehicle it is a combination of increasing pay load by reducing vehicle weight as well as to reduce emissions. A lighter bus chassis can take more passengers within the same axis load specification.

Future light weight challenges lies in selecting the best solutions from a range of materials to keep the vehicle performance and improve range, emissions and load carrying. AND keep or reduce the cost level.

Semcon has very good knowledge in a number of present materials;