- Sustainability in the automotive industry
- Car design trends – the body
- Car design trends – the interior
- Car design trends – the chassis
- Car design trends – powertrain and electrical
- Re-imagining the in-vehicle experience
1) Connectivity
2) Health & wellness
a) Interior air quality
b) Safety features
c) Passenger comfort - Conclusions
The automotive industry is in the midst of a technological revolution characterised by the convergence of new digital technologies with the traditional car manufacture [1]. Most of the major industry players are investing in technologies to develop cars which are autonomous, connected, electric and enable shared mobility (ACES) [2] .
At present, the automotive industry is the third biggest spender on research and development, behind healthcare, and software and electronics [3] . This article discusses one aspect of this technological revolution – materials. It focuses on advances in materials to address two strategic priorities for the automotive industry: sustainability and the in-vehicle experience.
The most competitive automotive manufacturers are aware of the potential of materials engineering in achieving their key objectives. In the future, these companies are likely to use technologies from fields such as machine learning to rapidly identify candidate materials with suitable properties and accelerate materials research [4].
Sustainability in the automotive industry
Car travel currently represents about 12% of the total carbon dioxide emissions in the European Union [5]. In 2009, the European Parliament and Council adopted Regulation (EC) 43/2009, which sets out mandatory emission reduction targets for new cars.
The first target has been enforced since 2015. Further targets will apply from 2021 onwards. In April 2019, even more stringent targets for new cars and vans were introduced under Regulation (EU) 2019/631. These targets will apply from 2025 and 2030 onwards.
Research and innovation into technologies that enable these targets to be achieved will become the lifeblood of automotive manufacturers in the future. In addition, as consumers become more environmentally aware, the automotive industry is also focusing on recycling and reuse.
In order to meet emissions targets and enhance the sustainability of future vehicles, mass reduction of vehicles (lightweighting) is increasingly emerging as the top challenge facing automotive engineers. Not only do vehicles of lower mass achieve better fuel efficiency, but they also offer better acceleration, braking and handling.
Another key driver for lightweighting is the upcoming transition towards electric vehicles (EVs) [6]. Lithium-ion batteries, which are one of the most common battery types in EVs, normally weigh in excess of 200kg. Engineers are therefore seeking to reduce the mass of every vehicle component; each of which has different requirements with regards to formability, temperature, corrosion resistance and strength.
Car design trends - the body
For decades, most vehicles have been made with steel bodies due to steel’s relatively low cost, strength and malleability; however, the vehicles of the future are likely to be made from many different materials. This shift will necessitate the development of new assembly processes, particularly in relation to joining (the connection of multiple components).
New vehicles are increasingly incorporating high-strength steels, aluminium, carbon-fibre composites, magnesium, titanium, various types of plastics and even natural materials such as hemp, cotton, linen and flax.
As an example, the weight-bearing body structure of the new Audi A8 incorporates aluminium, steel, magnesium alloys and carbon fibre reinforced polymer (CFRP). The largest component in the occupant cell of the Audi A8 is an ultra-high-strength and torsionally rigid rear panel made of CFRP [7].
Carbon fibre is one of the most promising lightweight materials available for body structures. However, due to the prohibitive cost of carbon fibre, which is five to six times the cost of steel [8], and the challenges in recycling this material, its market penetration is likely to remain limited in the near future.
A report by Mckinsey suggested that three different lightweight packages are likely to emerge in the future:
- The first, which will be used for small and medium-sized cars with conventional or hybrid powertrains, will comprise mainly high-strength steel.
- The second, which will be used for premium vehicles and EVs, will include a mix of aluminium, high-strength steel and carbon fibre. The use of carbon fibre will be limited to those parts of the body that need to be very stiff or where weight reduction is particularly important, such as the roof.
- The final package of materials will mainly be used for niche luxury EVs and will be characterised by the use of a high proportion of carbon fibre [9].
Car design trends - the interior
At present, car interiors are predominantly made of plastic. Fortune Business Insights estimated that the automotive plastics market was valued at USD 38.80 Billion in 2018. This figure is projected to rise to USD 59.95 Billion by 2026 [10].
Although the use of plastics in ‘under the bonnet’ and exterior applications is on the rise, the car interior currently represents the main use of automotive plastics and is likely to continue to do so in the future. Due to their durability, aesthetic appeal, low density and chemical resistance, polymer combinations are used in wide-ranging applications including seats, door panels, upholstery and instrument panels.
Whilst it is likely that plastics will continue to be an important component of the material strategy for the car of the future, many manufacturers are increasingly striving to incorporate natural fibres into their materials strategy.
As an example, the door panelling and instrument panel cover of the BMW i3 is made from Kenaf, a fast-growing plant combined with fibres of polypropylene (PP) covered with a wafer-thin black PP decorative film that is laminated onto the surface. The resulting natural fibre-reinforced plastic (NFP) is said to have achieved a weight reduction of about 30-45%, and it is claimed to have advantages in crash events since NFPs do not splinter but rather break without sharp edges [11].
The BMW i3 also incorporates other natural fibres elsewhere in the car interior. For example, the seat covers are made from 40% pure new wool – a fabric renowned for its breathability [12].
In recent years car seats have become a focus for lightweighting of car interiors. The driver’s seat is one of the heaviest parts of a vehicle’s interior due to the fact that it must be ergonomic, adjustable and should protect the driver in the event of an accident.
Faurecia, one of the largest suppliers of seating to the automotive industry, recently entered into a partnership with FAW Foundry to develop seating structures constructed from magnesium alloys. These are anticipated to lead to a 25% reduction in weight by comparison with traditional steel seating structures.
Multi-material systems are also being investigated by a number of manufacturers [13]. By way of example, Adient, another automotive seating manufacturer, has revealed a seating concept using die-cast magnesium seat structures with glass-fibre reinforced plastic front seat backrests [14]. Numerous manufacturers are developing multi-material seating systems incorporating CFRP.
CFRP is also increasingly prevalent in other car interior applications including panels, boot lids and instrument dashboards. The most significant advantages of CFRP for use in car interiors is its high strength-to-weight ratio, ability to be worked into complex shapes, and corrosion resistance.
Car design trends - the chassis
The chassis is the main supporting structure of a motor vehicle. Traditionally, steel has been used for the vehicle chassis. However, a number of cars have been unveiled that use a combination of an aluminium chassis with a separate body shell (often aluminium or CFRP) in order to minimise the overall mass of the structure.
An example of a car using this type of body architecture is the Chevrolet Corvette C7 Stingray [15]. Alternative strategies to lightweight the chassis include mixed-material combinations such as CFRP/aluminium. The Mercedes-Benz SLR McLaren was an example of such a design [16]. Magnesium alloys have also been proposed as potential chassis materials [17].
Car design trends - powertrain and electrical
The development of battery materials and the requirements for increased EV ranges is one of the most significant challenges for automotive manufacturers. Whilst lithium-ion batteries are one of the most prevalent types of EV batteries today, there will likely be a shift towards other types of battery in the future, including solid-state batteries.
Battery manufacturers will also face the challenge of either eliminating some of the rare-earth metals, such as neodymium, currently present in batteries, or developing processes to recycle these materials. Cautious use of rare-earth metals is required due to their high-cost and the risk of over-dependence on supplies from China [18].
Analysts believe that the mass of lithium, nickel and cobalt required to manufacture sufficient batteries to meet projected EV demand, may exceed mining capacity unless there is a significant investment in this area [19].
- Density: 7.01 g/cm³ at 20 °C
- Elastic modulus: 41.4 GPa at 20 °
- Hardness, Brinell: 265 [-] at 20 °C
- Poisson’s ratio: 0.28 [-] at 20 °
- Tensile strength: 182 MPa at 20 °C
- Density: 0.54 g/cm³ at 20 °C
- Elastic modulus: 4.91 GPa at 20 °C
- Hardness, Brinell: 5 [-] at 20 °C
- Poisson’s ratio: 0.36 [-] at 20 °C
- Tensile strength: 15 MPa at 20 °C
- Density: 8.89 g/cm³ at 20 °C
- Elastic modulus: 207 GPa at 20 °C
- Hardness, Brinell: 700 [-] at 20 °C
- Poisson’s ratio: 0.31 [-] at 20 °C
- Tensile strength: 449 MPa at 20 °C
- Density: 8.9 g/cm³ at 20 °C
- Elastic modulus: 209 GPa at 20 °C
- Hardness, Brinell: 700 [-] at 20 °C
- Poisson’s ratio: 0.31 [-] at 20 °C
- Tensile strength: 207 MPa at 20 °C
Re-imagining the in-vehicle experience
It is predicted that as vehicles become increasingly autonomous, the in-vehicle experience will become one of the main factors that distinguishes manufacturers.
1) Connectivity
Connectivity is an increasingly important feature of modern vehicles and autonomy will enable occupants to interact more freely with the outside world whilst travelling. Although many of the advances in this area relate to software, the development and use of materials such as plastics that can shield electronic assistance systems from electromagnetic interference is of growing interest to automotive manufacturers [20].
2) Health and wellness
Consumers are increasingly interested in health and wellbeing products. Many automotive manufacturers are alert to this trend and are innovating through materials engineering to offer wellness features in their vehicles.
In February 2020, Grand View Research, Inc. estimated that the global corporate wellness market size would reach USD 97.4 billion by 2027, expanding at a compound annual growth rate of 6.9%. A few examples of such technologies are discussed below:
a) Interior air quality
Many of the materials that are commonly used in car interiors are potentially able to emit volatile organic compounds (VOCs) over time, reducing the air quality inside the vehicle and, in some instances, impacting the health of the occupant.
As an example, the VOC acetaldehyde has been reported to cause symptoms including nausea, headaches and aggravated respiratory conditions [21].
Automotive manufacturers are increasingly monitoring and striving to reduce interior VOC emissions over the lifetime of their vehicles.
b) Safety features
Most automotive manufacturers are investigating applications of smart materials to enhance driver safety. As an example, in 2017 Nissan unveiled a prototype vehicle in which a smart coating that can detect whether the driver is dehydrated was applied to the steering wheel and front seats. The sweat-sensing technology called SOAK changes colour if perspiration is high in salt, indicating dehydration [22].
A study conducted by scientists at Loughborough University found that dehydrated drivers made twice as many mistakes as those who were properly hydrated and were as error-prone as drivers who have consumed the legal limit of alcohol [23].
c) Passenger comfort
Over the course of their lifetime, on average, UK drivers spend almost four years driving. The comfort of vehicle occupants is, therefore, very important [24]. BMW is investing in adaptive materials that could be used to generate transformable surfaces tailored to human comfort.
Vehicles with higher degrees of autonomy are set to transform travel, and it is plausible that the vehicle interior of the future will be a modular space that can be adapted in accordance with user requirements.
One promising technology that was recently developed by BMW in collaboration with the Self-Assembly Laboratory at the Massachusetts Institute of Technology is liquid printed pneumatics. It combines liquid printing of silicone and soft robotics to create objects that are able to change shape and stiffness almost instantaneously [25].
Conclusions
In summary, the automotive industry is on the verge of an unprecedented transformation characterised by autonomous driving, electrification and an ever-increasing demand for personalised products that enhance the wellbeing of occupants.
Advances and innovation in materials engineering will be key to the adaptability and success of automotive manufacturers in this competitive and evolving landscape.
*This article is the work of the guest author shown above. The guest author is solely responsible for the accuracy and the legality of their content. The content of the article and the views expressed therein are solely those of this author and do not reflect the views of Matmatch or of any present or past employers, academic institutions, professional societies, or organizations the author is currently or was previously affiliated with.
References:
[1] Mckinsey, ‘Mckinsey Centre for Future Mobility, Race 2050 – A vision for the European Automotive Industry’ (January 2019), Accessed 22 August 2019.
[2] Jaguar Land Rover, ‘Future-type Concept – Jaguar’s Vision for 2040 and Beyond’, Accessed 30 July 2019.
[3] Barry Jaruzelski, Robert Chwalik and Brad Goehle, ‘What the Top Innovators Get Right, Strategy+Business, Tech & Innovation’ (Strategy Business, Winter 2018, Issue 93), Accessed 19 August 2019.
[4] Greg Satell, ‘Materials Science May be the Most Important Technology of the Next Decade. Here’s Why’, (Inc.com, 1 December 2018), Accessed 10 April 2020.
[5] European Commission, ‘Reducing CO2 Emissions From Passenger Cars – before 2020’, Accessed 10 April 2020.
[6] Michael Pooler, ‘How to Lightweight a Car – In Charts’ (Financial Times, 4 June 2019), Accessed 11 April 2020.
[7] Christoph Lungwitz, ‘TechDay Body Structure – Audi A8’, Accessed 12 April 2020
[8] Mckinsey, ’Lightweight, Heavy Impact’ (Advanced Industries, February 2012), Accessed 11 April 2020.
[9] Ibid.
[10] Fortune Business Insights ‘Automotive Plastics Market Size, Share & Industry Analysis, By Type (Polypropylene, Polyurethane, Polyamide, Polyvinylchloride, Acrylonitrile Butadiene Styrene, Polycarbonate, Polyethylene, and Others), By Application (Interior, Exterior, and Under Bonnet), and Regional Forecast, 2019-2026’ (Chemicals & Materials, January 2020), Accessed 12 April 2020.
[11] John Pellettieri, ‘Kenaf – Natural Fibre for Lightweighting’ (Lightweighting World, 19 March 2019), Accessed on 9 April 2020.
[12] BMW, ‘Sustainability is the Answer That Calls Everything Into Question’, Accessed on 10 April 2020.
[13] Colin Pawsey, ‘Lightweight Automotive Seating Structures – Concepts and Challenges’, Accessed on 12 April 2020.
[14] Adient, ‘Adient Unveils Lightweight Solutions for Seat Structures’ (16 January 2018), Accessed on 16 January 2018.
[15] European Aluminium Association, ‘Applications – Car Body – Body Structures’ (2013), Accessed on 11 April 2020.
[16] Ibid.
[17] Office of Scientific and Technical Information (OSTI), Department of Energy, ‘Demonstration Project for a Multi-Material Lightweight Prototype Vehicle as Part of the Clean Energy Dialogue with Canada (29 December 2015), Accessed on 12 April 2020.
[18] Commercial Fleet, ‘Future Powertrains: Intense Hunt for the Ideal Powertrain Solution’ (17 December 2018), Accessed on 12 April 2020.
[19] Linklaters, ‘Powering the Future: Sourcing Raw Materials for Electric Vehicle Batteries’ (Insights, 1 July 2019), Accessed on 8 April 2020.
[20] Naveen Arul, ‘Future Materials To Enable Automotive Industry Move Towards Megatrends’ (Auto Tech Review, 11 February 2019), Accessed on 4 April 2020.
[21] Emissions Analytics ‘The Self-Poisoning Car’, Accessed on 12 April 2020.
[22] Telegraph Reporters ‘Nissan’s Car Which Can Tell When You’re Thirsty After Experts Found Dehydration ‘As Bad As Drink-Driving’’ (Telegraph News, 29 September 2017), Accessed on 4 April 2020.
[23] Adam Withnall, ‘Driving While Dehydrated Can Be Just As Dangerous As Drink Driving, Study Suggests’ (Independent, 19 April 2015), Accessed on 4 April 2020.
[24] Webuyanycar,com, ‘Drive of a Lifetime’, Accessed on 12 April 2020.
[25] Kat Sprague, ‘Soon You May Be Able To Change Your Car’s Interior at the Touch of a Button’ (CNBC Business News, 11 June 2018), Accessed on 5 April 2020.
