1. Why cars are getting lighter
particles - where science matters
  • Why lightweighting? Striking the balance between safe, comfortable cars and fuel efficiency

    By Sue Casement, 3M Storyteller

    A woman examines car doors on an assembly line

    • Changing times mean changing needs. There once was a time when people actually drove cars without GPS, side air bags or seat warmers.

      Now, that’s a rarity. We’ve come to expect a lot of creature comforts when we go from point A to point B.

      Those features – powerful engines, increased safety, roominess, better climate control and less road noise – usually add weight to our vehicles. We also want better gas mileage. And governments are taking measures to ensure good air quality by enacting regulations to limit emissions. That’s a big challenge for the transportation industry – continually increasing efficiency while keeping our cars, trucks and planes safe and comfy.

      Transportation manufacturers are keying in on solutions: making engines more efficient, implementing electrification, optimizing aerodynamics of vehicle bodies and lowering the weight of components in all our modes of transportation.

    • Bar graph showing expected growth of the middle class from 3.2b in 2016 to 5.2b in 2028
      Source: Brookings.edu

      Why are lighter vehicles so important?

      The need for lower emissions and more efficient vehicles is driven largely by megatrends – sustained forces that impact economies and societies around the globe. Some trends that concern governments in relation to transportation and emissions include urbanization, growing economies and the regulation of air quality.

      Urbanization is affecting every region in the world, but developing countries will see the biggest impact. More and more people are living in cities, and this trend is only expected to increase. According to UN.org, about 55 percent of people currently live in an urban area. The trend toward urbanization is expected to continue well into the future. There will most likely be more cities, and we’re expecting to see more megacities – urban areas with more than 10 million people. There are currently 31 megacities in the world. More than 38 million people call Tokyo, Japan, home. Delhi, India, claims a population of upwards of 26 million, and 24 million citizens live in Shanghai, China. By the year 2030, 10 additional cities are projected to join the list of megacities.

      Many people are moving to cities for better access to jobs and education. And as economies grow, so does the middle class. In the 19th century, the industrial revolution caused great growth of the middle class in Western Europe and in the U.S. This trend is happening today in emerging economies, especially in Asia. According to Brookings.edu, the global middle class is currently about 3.2 billion people, and it will most likely grow to 4.2 billion people by 2022. And middle-class families often travel more as they achieve more wealth – whether by air or land – and a significant goal for many is to acquire their own car.

    • Graphic illustrating global greenhouse gas emissions by economic sector

      Climate risk

      As more people gather in urban centers, and as more of them drive cars, there is a bigger push by governments to offset the impacts that come with those changes. One overriding concern is air quality and managing climate risk, with a primary focus on reducing the amount of greenhouse gas emissions.

      According to the Environmental Protection Agency, the transportation sector is responsible for 27 percent of greenhouse gas emissions in the U.S. and about 14 percent globally. Many governments are passing legislation to offset climate risk by reducing emissions and greenhouse gases, especially carbon dioxide, or CO2 – which causes 63 percent of global warming issues. The Paris Agreement is an international agreement reached in 2015 to address the threat of global climate change. Countries agreed to set their own targets for reducing carbon emissions.

      Nine global governments – Brazil, Canada, China, the European Union, India, Japan, Mexico, South Korea and the United States – have set or plan to set emission standards for vehicles. This represents about 80 percent of vehicles currently being sold around the world.

      The European Union set a target to reduce carbon dioxide emissions across all sectors, including transportation, from 1990 to 2020 by 20 percent and by 40 percent by 2030.

      The U.S. had been pushing to make passenger vehicles more fuel efficient for decades, largely to reduce dependence on oil imports. The U.S. corporate average fuel economy – or CAFE – standards were originally enacted in 1975. Congress updated the U.S. fuel economy regulations in 2007.

      And some countries are planning to shoot for zero emissions on new cars. More than a dozen countries and several U.S. states have set targets for selling electric cars. Norway, viewed as a leader in this area, aspires to sell only zero-emissions passenger cars by 2025 and India hopes to sell only electric cars by the year 2030.

      One answer to making cars more energy efficient is to make them lighter weight. Accelerating a light vehicle takes less energy than accelerating a heavy one, so lightweight materials are a clear solution. According to the U.S. Department of Energy Vehicle Technology Office, a 10 percent reduction in vehicle weight can result in a 6 to 8 percent improvement in fuel economy. Whether cars are powered by gas or electricity, or any other energy source, there will be a need for efficiency and lightweight materials.

    Red car in motion
    How 3M™ Glass Bubbles save plastic weight

    • How will we get there?

      How will transportation manufacturers do it? How will they balance creating low-emission, fuel-efficient lightweight vehicles with the increasing expectations of consumers for a safe, comfortable and affordable vehicle? By finding new ways to create them.

      Part of the answer is leveraging new technology and using different materials in the body structure. Engineers are constantly searching for the best properties like strength, stiffness, and ease of molding, while taking into consideration cost, safety and ease of manufacturing. They have been limiting their use of high-strength steel, reserving it for parts like bumpers and reinforcing beams. Original equipment manufacturers – or OEMs – use lighter-weight materials like aluminum, steel alloys, plastics and carbon fiber throughout the vehicle.

    • Congested street in Mumbai, India

      One way to cut weight and make car parts lighter is using high-strength glass bubbles for some car components. As early as the 1980s, car makers have been adding glass bubbles to molded composites to decrease their weight. The technology continues to evolve and manufacturers continue to find new ways to use a wide variety of bubbles in different components. They are used throughout the car, from the steering wheel to engine covers.

      Another solution to saving weight is through coatings and films. Some car designs include a high ratio of glass, especially those with sunroofs. Films allow for thinner glass – meaning less weight – by making the glass stronger and shatter resistant. Films on glass and other areas of the exterior can also reflect heat, so you are more comfortable while driving, and you don’t need to rely on a heavy-duty air conditioner to keep you cool.

      Vehicle manufacturers also build in efficiency by packing more power into less space. Components with higher friction and less slippage are more efficient and can transmit higher torque loads. The secret? Diamonds. By embedding diamonds that bite into surfaces, engineers can build vehicles with lightweight and compact friction shims in parts of the car like the crankshaft and camshaft.

      You may wonder if lightweight vehicles are as safe as older, heavier versions. With advances in both construction technology and in driver-assist features, it’s increasingly possible for cars to be light and safe. Many composites, like materials made with high-strength glass bubbles, or materials bonded with super durable manufacturer-approved tapes, can help lighten vehicles while maintaining physical integrity. Advanced safety features are already available and include the first steps in using the technology behind self-driving vehicles. Drivers can get some help from their cars with lane-drift detection and collision-avoidance braking.

    What’s next?

    As automakers move into the future, they are thinking about how to meet increased demand from consumers for features like connectivity, personalization and amenities like under-floor storage and panoramic sunroofs. At the same time, automobiles need to be safe, lightweight and reasonably priced. Even as we move toward vehicles that are fully electric, autonomous and even solar-powered, the need for efficiency and lighter-weight materials will still be a major driver for the transportation industry.