Not just for the sake of regulations but for the need to make vehicles more fuel-efficient and safer, automakers are racing against time.
Lightweighting is a concept whose time has come. This was more than evident at the 17th Auto Shanghai trade show that took place in April this year with most of the leading vehicle and automotive component manufacturers putting on display products and technologies that will help make cars, in particular, lighter in weight and more fuel-efficient. One such was ElringKlinger that presented products in the full range of drive technologies. Alongside its extensive portfolio of gaskets and seals, the company has been focusing heavily on products that are not restricted to a specific type of drive system. They include lightweight plastic components as well as solutions tailored to the requirements of battery and fuel cell technologies.
“Lightweight engineering plays a pivotal role in the latest generation of vehicles, as downweighting translates into lower fuel consumption and a reduction in harmful emissions. In electric cars, too, lightweight construction is seen as a game-changer. After all, the lighter a vehicle is, the longer its battery will last,” said Michael Stecher, General Manager, ElringKlinger Automotive Components (India). The company’s cockpit cross-car beams combine the benefits of high-end functionality and low weight. Carrying the dashboard, steering column, heating and ventilation modules, airbags, glove compartment, centre console, and other features, they ensure that all components are securely connected to the vehicle body. Engineered with the help of hybrid technology, the lightweight parts are produced at various sites within the ElringKlinger Group, including the company’s plant in Suzhou, near Shanghai.
So what is the latest scenario on lightweighting? It certainly is positive and moving in the right direction. For instance, Ford cut 700 pounds from its biggest seller, the F-150 pickup, by changing to an aluminum body. “The global automotive industry is leaving no molecule untouched as it searches for new and different ways to wring weight from its vehicles in the quest to reduce carbon emissions and boost fuel economy. Stricter emissions and fuel economy standards in the US and many other parts of the world have automotive makers not only using more aluminum but sampling other potential materials, such as magnesium, high-strength steels, carbon fiber, compressed wood and even soy. For every 10 pounds they can squeeze out of their machines, it means about 10 to 15 pounds less of carbon dioxide spewed into the atmosphere each year,” reports Jeff Bennett in the Wall Street Journal.
The problem though is with size. Over the past 10 years, cars have gained in size and therefore in weight. It’s time to reverse the order. A compact car is now almost as big as what a midsize car was 10 years ago. There is also more content in a vehicle, whether it is for safety or entertainment. That adds weight! Steel continues to reign as the top material. About 60 per cent of the average vehicle is still built out of steel. In the race for lightweighting though, steel makers are now trying to keep in step with the changing times by producing lighter grades of steel and instituting different heating and cooling techniques that can cut the pounds without weakening the metal. But the latest rage is aluminum, which has all the advantages of steel but is generally 40 per cent lighter. The one drawback: It’s about double the price of steel.
Automotive makers are now experimenting with turning body parts, door panels, hoods and roofs into aluminum. Ford Motor Co. took the lead when two years ago it switched the body of the F-150 pickup truck to aluminum. Such initiatives have spurred deeper research and tests. For example, Sapa, an aluminum specialist based in Norway, has a research and development centre near Detroit where it makes and tests parts for Ford, Tesla Motors Inc. and other car makers. “The Sapa centre makes its parts using the so-called extrusion method which pushes aluminum through moulds to make a part,” Bennett reports. A study by the Center for Automotive Research in Ann Arbor, USA, has concluded that if automakers really want to reduce weight in vehicles, they will increasingly need to turn to fiber-reinforced plastic composites to achieve their aims.
The study surveyed exactly what materials went into 44 different 2015 model year cars, then asked what materials automakers would turn to if they need to cut 5 per cent, 10 per cent and finally 15 per cent of the weight out of key parts. The report found that highest priority for lightweighting are the hood and fenders (both closures) followed by front doors, the deck lid, the engine cradle, A and B pillars, and the truck frame. The A and B pillars are highly dependent on crash requirements and are reportedly an area of the vehicle where some of the most advanced lightweighting technology is seen. The greater the mass reduction target, the more plastic composites are set to come into play.
The data also shows that while 90 per cent of existing closures are made from steel, as little as a 5 per cent lightweighting objective in a vehicle will likely result in an 85 per cent transition from steel to aluminum. Additional efforts to lightweight the vehicle beyond 5 per cent will begin to introduce magnesium and composites, with slightly greater growth in composites. Composites growth was found to be dependent on aggressive vehicle lightweighting at 10 per cent and 15 per cent. The material trend to aggressively lightweight the car body (body-in-white) is more complicated than closure panels according to the report. Aluminum has the most significant opportunity, growing by about 70 per cent from current use if vehicles are to become 15 per cent lighter but composite use is also anticipated to grow significantly with the 10 per cent and 15 per cent levels of lightweighting.
More importantly, lightweighting has also been initiated to achieve the Corporate Average Fuel Efficiency (CAFE) standards, which will be implemented in India from 2017 and again in 2022. This will require OEMs to meet the target of 130 g/km in 2017 and 113 g/km in 2022 based on the average weights of 1,037 kg and 1,045 kg, respectively. Unlike in Europe or the US, the Indian automotive industry is predominantly made up of small cars. In India customer preference is also moving towards sedans and SUVs. This may shift the average weight from 1,037 kg to 1,145 kg.
In other developments, General Motors has been integrating lightweight materials and innovative manufacturing techniques into its new passenger cars and trucks. This includes introducing new assembly materials with aluminum alloy a priority on the list. The same basic material used to make commercial aircraft is the new material of choice for most automakers as the metal is lightweight, easy to work with, durable, and more corrosion-resistant than low-carbon steel. As per a report, special techniques were created by GM’s engineering team that allows materials with different melting points to be bonded together. The automaker is able to combine a lightweight aluminum skin (for example, a hood or trunk lid) with a sturdy steel frame, which allows each material to complement the other’s strengths while reducing overall weight.
Recently, the US-based NanoSteel, a leader in nano-structured steel materials, produced and delivered in the market a new class of advanced high strength steels (AHSS). The company claims that the steel will increase performance and meet the OEMs’ demands for materials that would enhance safety and fuel economy. NanoSteel has supplied its first AHSS to General Motors for initial testing. According to the company, the AHSS is designed to provide automakers with a new standard in material performance and accelerate vehicle lightweighting initiatives focused on affordably meeting rising global fuel economy regulations.
NanoSteel’s commercially produced automotive sheet steel overcomes the historical trade-off between strength and formability by delivering exceptional levels of both properties at the same time (approximately 1,200 MPa tensile strength and 50 per cent elongation). The high strength allows designers to create parts utilising thinner gauge material (less weight) while the high elongation allows manufacturers to produce the newly designed parts without expensive processing techniques, employee retraining or additional capital costs.
Hyundai Motors in its 6th generation Elantra, launched in India recently, uses AHSS for lightweight. “The latest Elantra is made with 53 per cent of AHSS, 32 per cent more than in the previous model. AHSS components are used to increase stiffness of chassis and protect passengers effectively in case of collision. Also the chassis structure is developed to give stability and actual mileage improvement during high-speed driving. The AHSS, manufactured by Hyundai Steel, has higher yield and tensile strength than traditional automotive-grade steel,” Rakesh Srivatsava, Senior Vice President and Division Head, Hyundai Motors India Ltd, has stated in a published report.
The fact that lightweighting of vehicles is being taken very seriously is evident from the steps taken by some of the leading automakers and component manufacturers. Tata Steel, along with Indian Institute of Technology Madras, has set up an Advanced Materials Research Centre to develop products for green energy and for lightweight technologies using carbon-based materials. One area of focus for weight reduction in vehicles is the primary sealing system used around door and trunk openings. 3M took on the challenge and found a new way to attach the seal to the flange. The tape system eliminates weight in three ways: It removes metal from the extrusion, allows for the reduction of flange size around the body opening, and enables the use of lower gauge steel or aluminum body panels.
Pune-based Bright AutoPlast has taken a number of new technology initiatives designed to produce lightweight parts. Informs CEO Gagandeep Singh of Bright AutoPlast, “What we think can be easily done to save on weight would be the door structures in the interior, trunk, tail gate, floor parts, front end, fuel system, degauss tank, engine covers, engine housing cover, and others. Normally weight reduction achieved is in the range of 20-30 per cent in comparison to the conventional metal parts. Weight savings of less than 15 per cent usually does not make business sense. The opportunity will be that we will become system suppliers and not just a part supplier. This will be enabled through our JV called BAPL Rototech, which is a joint venture with Italy-based Rototech.” Some of the other companies taking giant strides in this area include Lanxess India which, with its plastic-metal hybrid technology, is facilitating intelligent construction with outstanding component properties and Henkel, manufacturer of adhesives.
Lightweight engineering play a pivotal role in the latest generation of vehicles.”
- Michael Stecher,
ElringKlinger Automotive Components India.
Weight savings of less than 15 per cent usually does not make business sense.”