Aluminum replaced steel in the inner door beam on the ultralight door (pictured here) developed by Magna International Inc. The use of aluminum reduced the weight in the part by two kilograms.Courtesy of Magna International
Battery-powered vehicles may eventually deliver a knockout blow to the internal-combustion engine, but auto makers and suppliers are developing counterpunches that will extend the life of the more than century-old technology that put the world on wheels.
The internal-combustion engine (ICE) is getting help from a tactic that seems simple on the surface, but is complex in practice – putting vehicles on a diet.
Materials that are lighter than steel, but were once too costly to replace steel for major applications in vehicles, are becoming more common. The use of aluminum, magnesium and carbon fibre is expected to grow to represent as much as 40 per cent of the body structure and closures in a vehicle by 2030, compared with 14 per cent currently.
Regulations that will require auto makers to reduce their carbon emissions (burning less gasoline means a reduction in emissions) are one key reason behind the trend.
The use of lighter metals is more than a temporary trend designed to stretch out the life of internal-combustion engines. Internal-combustion engines are by far the dominant method of propulsion on the road and are expected to continue to dominate well into the next decade, so auto makers need to find ways to make them more efficient as the rules on emissions become more stringent.
Reducing the weight of vehicles equipped with internal-combustion engines helps cut emissions while car companies work on making battery-electric vehicles (BEVs) more affordable and making them available in more market segments.
"The regulatory pressure to improve fuel economy is expected to accelerate the evolutionary rate of the introduction of lightweight materials into the vehicles," says a study by the Center for Automotive Research, an industry think-tank located in Ann Arbor, Mich.
Cutting weight helps improve the efficiency of internal-combustion engines, but will also be useful in battery-powered vehicles because the range of BEVs can be extended if they're lighter, says Evan Hirsh, a PricewaterhouseCoopers auto industry consultant.
"If you lighten the load, it helps both [technologies]," Mr. Hirsh says. "It helps more on internal-combustion engines because you're really pushing up against two barriers – you've got more metal and weight in the ICE, so it's more important there."
It will take a combination of improvements to internal-combustion engines and the growth of battery-electric vehicles to meet the new fuel economy and emissions regulations, says Tim Skszek, senior manager of government partnerships for Magna International Inc.
Auto makers are tapping Magna and other Canadian parts makers such as Linamar Corp. and Martinrea International Inc. to find ways to trim weight, and the parts companies are spending hundreds of millions of dollars developing components or systems that are both lighter and stronger than steel.
"We know without even having a discussion that if we can make something lighter, it probably means less material, which means we can be more competitive on pricing," says Rob Wildeboer, executive chairman of Toronto-based parts supplier Martinrea International Inc. "Our customers will listen to that every day of the week."
Linamar officially opened a North Carolina plant last week with joint-venture partner Georg Fischer Ltd., that will make magnesium cross car beams beginning in 2020.
One of Magna's innovations is the ultralight door module, which makes greater use of aluminum than existing vehicle doors.
The beam inside the door that prevents a vehicle piercing the door in a T-bone collision is made of aluminum instead of steel. Switching that piece alone provides a two-kilogram saving on each door, Mr. Skszek says as he displays the concept at Magna's U.S. headquarters in Troy, Mich.
The replacement of traditional steel by aluminum and other materials cuts the total weight of the door by 15.5 kilograms and the entire weight of the car by about 60 kilograms if an auto maker chooses Magna to supply all four doors.
"We really like the combination of a high-strength structure – equivalent in performance to a steel structure and also being 42 per cent lighter than the current model," he says.
When Magna began the project in December, 2015, it examined various materials and combinations of materials as a way of cutting the weight in a car door. It studied carbon fibre, cast aluminum parts and a combination of stamped aluminum with a cast structural aluminum part.
The cost to replace steel was lowest when using the combination of aluminum stampings and the cast structural part. It was $2.59 (U.S.) a pound more than steel, which is considered a fair tradeoff.
The other advantage for auto makers is that Magna can assemble and supply the entire door, Mr. Skszek adds.
For car companies, that "really minimizes their labour, which is high cost and it also minimizes the square footage in their assembly plant or their trim plant," he says.
When Fiat Chrysler Automobiles NV replaced the Town & Country minivan with the Pacifica, it substituted aluminum and high-strength steel for traditional steel in several body components, including sliding doors and rear liftgates.
The Pacifica weighs 113 kilograms less than the vehicle it replaced. That improves fuel economy to 12.4 litres/100 km in city driving and 8.4 litres/100 km on the highway from 14.1 and 9.5 litres, respectively, on Town & Country models.
Mr. Wildeboer says the material used in vehicles doesn't matter to Martinrea, which has grown as a metal stamper and supplier of fluid systems.
The company makes a traditional steel-cross member that weighs 18.7 kilograms. A solid aluminum version weighs 15.4 kilograms and a hollow aluminum version checks in at 12.4 kilograms.
"On a pure electric vehicle or a hybrid, you're got battery trays and a bunch of things that you would not put in a pure ICE vehicle. We know how to do that type of stuff as well."
Hybrid vehicles need gas lines and fluid systems, "so we're pretty agnostic," he says.
Mr. Hirsh cautions that the takeover of the roads by BEVs is far from imminent, pointing to the high costs of batteries. He forecasts that by 2027, just 3.8 per cent of new vehicles sold in the U.S. market will be battery-electric, up from a fraction now.
"If you do all the math and you line up how much somebody has to pay for an internal-combustion engine versus a battery-electric vehicle, [the BEV] just costs more," he says.