Vehicle Fuel Economy – Innovative Materials and Processes That Lighten the Load
Previously reserved exclusively for expensive sports cars and Formula 1 vehicles to increase speed, vehicle lightweighting has become a key focus area for automotive OEMs for all vehicle makes and models. This concept involves using alternative materials to traditional steel, such as carbon fiber, aluminum and plastic to reduce a vehicle’s weight to improve speed and fuel economy. Driven by increasingly stringent CAFE emissions standards and government-mandated fuel economy regulations, automotive OEMs are looking to new materials and manufacturing processes to reduce vehicle weight and improve fuel economy. In addition, lightweight materials are a solution to offset increasing vehicle weights due to the addition of improved safety functions, electric equipment and the heavy batteries required for electric vehicles. According to one estimate, the automotive lightweight materials market will reach $157.7 billion by 2027, up from $89.1 billion in 2019, registering a CAGR of 7.4%.
Battery electric vehicles (BEVs) represent the largest market for lightweight vehicle materials, as the battery accounts for approximately 70% of the vehicle’s weight. This will be a key driver for lightweight materials market, as many automotive OEMs are planning to expand their range of electric vehicles in the coming decade. The power train is the top focus area for efforts to reduce weight, with the chassis coming in second and vehicle interiors a growing target. Automotive OEMs are focusing R&D efforts on using mixed materials optimized for different parts of the vehicle, and innovative manufacturing processes to develop novel parts that are more optimized for function.
Reducing vehicle weight by 10% can lead to a 6%-8% improvement in fuel economy for internal combustion engine (ICE) vehicles. Lightweighting can improve the range of electric vehicles, allowing for smaller batteries, thus reducing the cost of the most expensive aspect of EVs. When the primary structure of a vehicle becomes lighter, secondary parts, such as suspension and brakes, can be smaller, creating a ripple effect of weight reduction. As automakers continue to integrate safety functions and electronic equipment for vehicle connectivity, vehicles are becoming heavier and lightweighting is becoming important to meet stringent fuel emissions standards.
Automotive OEMs and suppliers are developing multi-material solutions that involve a mix of aluminum, carbon-fiber composites, advanced high strength steel and magnesium optimized to meet performance, strength and safety requirements for different parts of the vehicle. Some are also exploring natural materials as alternatives. Currently, the most common solution is a combination of advanced high strength steel and carbon fiber reinforced plastics.
High strength steel has become a popular alternative to traditional, carbon-based steel. This steel is stronger, allowing for a thinner gauge that can achieve weight savings of 20%-25% at a low cost. Aluminum is also being used as a substitute for traditional steel, as seen in the all-aluminum 2014 Ford F-150. Although aluminum is much lighter than high-strength steel, it is weaker and more expensive. Magnesium is more expensive than aluminum and high strength steel but offers up to 60% weight savings. Magnesium has a few technical challenges, such as its intrinsic brittleness and tendency to cause corrosion when interacting with other metals.
Carbon fiber is one of the promising materials for lightweighting, but cost, cycle times and additional workforce training are limiting factors. In addition, joining composites and metals has proven a challenge for engineers.
Porsche launched the new 718 Cayman GT4 Clubsport in July 2019, which is now the first car in series production to feature body parts made of natural-fiber composite materials. Fraunhofer WKI researchers developed natural fiber-reinforced plastics that offer lower environmental impact and cost than carbon fibers. The vehicle has been in use on the racetrack since 2015, but extensive testing has proven the materials fit for higher-volume production.
New manufacturing processes, such as digital manufacturing, 3D printing and innovative joining methods, are providing efficiency gains, allow for more flexible development of new parts and meet the evolving demands of electric vehicle platforms. Innovations in joining dissimilar materials is key to lightweighting initiatives and multi-material designs while continuing to meet safety and operating standards.
Digital manufacturing involves the computer simulation, 3D visualization, analytics and collaborative tools to develop new parts and define accompanying manufacturing processes. Enabled by the flexibility of 3D printing, digital manufacturing allows automakers and suppliers to design smaller, lighter weight and optimized parts that are not under the design constraints of traditional manufacturing processes.
In the past year, automotive OEMs have been very active in this sector through partnerships and acquisitions. In September 2019, Toyota entered a partnership with 3D Systems, making the latter their ‘Additive Manufacturing Provider of Choice’, to bring to market manufacturing solutions, including 3D printing machines, materials and software. In March 2018, Ford led a $65 million funding round in Desktop Metal, a provider of a metal and continuous fiber 3D printers that can fit on a desktop.
So far this year, BMW made its third investment in Xometry, 3D printing company and Tier 1 supplier to BMW, and a first investment in Elise, a developer of generative engineering software to automate product development. BMW has also previously invested in Carbon, a leading developer of 3D printers that has high profile partners Proterra, Ford and Automobili Lamborghini. In March 2019, Porsche made its second investment in Markforged, an industrial-scale 3D printer developer. In addition, General Motors has partnered with Autodesk to apply generative design technology (a type of digital manufacturing) to develop innovative automotive parts.
Some innovators are rethinking vehicle design, developing new vehicles from the ground up to optimize for weight and fuel efficiency. Gazelle Tech, a French startup founded in 2014, have developed a self-supporting, modular body design made completely of composite materials. The company is also pioneering a new industrial model based on micro-factories that can build vehicles geographically closer to consumers. Gazelle recently raised $1.2 million in Series A funding and receive product development support from ESI Group.
Incremental improvements can be made through multi-material design and optimization, but automotive OEMs are also looking for new materials and processes that can provide massive gains. Although auto OEMs are focusing their own R&D efforts in this area, there is space for startups with materials and manufacturing process expertise to develop innovative solutions. Competition will be based on lightweighting potential, material cost, availability of raw materials, how easily the material can be fit into part shapes and precise dimensions and ability to perform under extreme conditions and adhere to rigid safety standards.