A lighter design for a more sustainable car?

In the first blog post of our Sustainable Alternatives Series, we talked about how efficient tire management can reduce cars’ carbon footprint. In this chapter we talk about how and why car manufacturers use a lighter design to decrease the weight of their cars. 

Fuel and energy prices are soaring. A sustainable mobility strategy and a sensible use of resources are a must for any company. Hence, there is a lot to be said for sustainable cars and the methods to build them.

 

The energy saving potential of lightweight cars

Driving less and more consciously and opting for fuel-efficient cars. These are two things that help reduce the energy consumption of cars and make fleets more sustainable. But the biggest energy saving potential for cars lies elsewhere. Namely in the way cars are built.

Light structures and alternative materials are becoming increasingly popular among car manufacturers. Why? The lighter the car and the smaller the engine/battery, the less energy is needed to drive. Seems logical enough, right? True, but to a certain extent.. 

Indeed, the effect of efficient construction on the actual energy balance of cars is not without its rebuttals. Heavier cars, for instance, can recover more energy through recuperation while driving.

Yet car manufacturers do strike home when it comes to sustainability. In fact, by reducing the weight of their cars, they are not only pursuing a lower energy consumption, but two other objectives as well. These objectives are:

• Saving valuable resources and materials;
• Lowering the environmental impact of their cars.

 

How manufacturers make their cars lighter

Car manufacturers are generally able to achieve their sustainable goals and make their cars lighter by combining three things in their construction processes.  

 

1. They get rid of the unnecessary

If you want to travel more efficiently, you have to pack less. Of course, that’s easier said than done, especially when you translate that concept to the process of building a car.

Reducing the amount of parts in a car is not an easy task, especially when keeping in mind that  engineers strive to create the most efficient car design right from the start. Moreover, most cars would have to be hundreds of kilos lighter to significantly reduce energy consumption, without sacrificing safety, stability and comfort as well. It’s a very difficult puzzle to solve, with seemingly multiple possible pieces to do so. 

Therefore, a lot of manufacturers just try to shave off parts wherever they can. They look at the interior, the tires, electronic parts, etc. and remove all unnecessary elements from their cars to make them lighter and more sustainable. Every gram counts. 

 

2. They use new and sustainable materials

When the automotive industry looks at new materials to build sustainable cars, the materials have to meet certain criteria: 

• They must be able to withstand the comparison with traditional materials such as steel.
• They must have desirable properties, such as a relatively low weight or low cost.
• They must be of sustainable origin.

Examples of durable materials that have been used for many years already, are magnesium, carbon and aluminium. But new materials are emerging all the time. Below, we discuss some materials that manufacturers have started using in more recent years.

 

Polymers

Thermoplastic and thermosetting materials - such as polymers - are great robust alternatives for metal parts. Examples include glass-, metal-, or ceramic-filled polymers and liquid silicone rubber (LSR). All of these are lighter and cheaper compared to metal and have a higher durability. 

 

Fibre composites

Car parts made of fibre composites last up to 25 years or more than a million kilometres, Conventional car parts and bodywork, by contrast, are designed to last "only" 200,000 kilometres.

 

Secondary aluminium and steel

The introduction of new materials does not mean that traditional materials will disappear completely. The BMW Group, for example, has ambitious to transform its production according to the principles of the circular economy and aims to use more and more secondary (disassembled) materials, such as secondary aluminium and steel. Using such secondary materials is a lot less environmentally damaging and CO2-intensive than extracting and producing new (primary) materials.

 

Other (unlikely) alternatives

Another element of the BMW Group’s sustainable approach, is the fact that it also looks at materials that seem unlikely at first glance. This even includes vegan and sustainable alternatives that can significantly reduce CO2 emissions while avoiding animal materials. 

Examples of such materials include: 

• Recycled household waste,
• Wood and plant fibres,
• Mirum™, an alternative to fabric made from a bio-based and petroleum-free plant material,*
• Deserttex™, an alternative to leather made from cactus powder and a bio-based mix of polyurethane*

 

3. They leave room for ideas 

One final way car manufacturers are trying to save materials is by rethinking the design of essential car parts. Does the axle really need to be that wide? Could the frame be a few centimetres smaller here and there? 

New and stronger materials allow some elements to be designed more efficiently, without sacrificing stability. It is a matter of re-evaluating the status quo and using fewer materials where possible. 

 

Want to know more about sustainable cars and mobility? 

Hopefully you learned more about sustainable alternatives in the automotive industry. We hope we were able to spark your interest. 

Would you like to know more about innovative car models and how to save energy as well as costs with a sustainable fleet? Then don't hesitate to contact us. We are happy to show you the possibilities. 

In our next blog post on 'sustainable alternatives', we will tell you more about eco-friendly car interiors with the help of car technology expert Faurecia. Stay tuned!