First aluminum panels, now magnesium liftgate as car designers embrace fuel economy
Fiat Chrysler Automobiles NV is turning to magnesium as the latest trick in the auto industry’s design tool kit to reduce the weight of vehicles and boost fuel economy in the face of rising emissions standards.
The Italian-U.S. auto maker is embracing the lightweight metal as a replacement for heavier steel in the rear liftgate of its 2017 Pacifica minivan, which arrives at U.S. dealers later this year. Magnesium is 75% lighter than steel and 33% lighter than aluminum, according to trade group the International Magnesium Association.
Magnesium brings something significant to auto designers: the ease at which it can be molded with thick and thin areas on the same part. It opens the door to cutting waste and allows designers to do more shaping. In the Pacifica’s case, pockets were molded into the liftgate so taillights could be an integral part.
“The cool thing about magnesium is that you can use it in more parts of a vehicle architecture to reduce weight without compromising safety and performance,” said Joe Petrillo, director of North American sales for a unit of Wanfeng Auto Holding Group, which builds the Pacifica’s liftgate.
Chrysler’s new Pacifica minivan hits dealer lots later this year with a list of features aimed at boosting fuel economy, including an optional battery pack, that lets the vehicle drive for 30 miles in electric mode before the gasoline-engine kicks in.
The vehicle debuts as buyers are flocking to pickups, a move undercutting some of the average fuel economy gains achieved in the last decade. With much tougher emissions standards looming for 2025, many auto makers are introducing electrified vehicles or using lighter, more-expensive materials, such as aluminum.
Ford Motor Co. ’s current F-150 pickup uses aluminum body panels to save up to 700 pounds over earlier, steel-bodied versions, and General Motors Co. is expected to employ aluminum in future versions of its trucks and sport-utility vehicles.
Magnesium is a costly alternative. A kilogram of the metal costs auto makers roughly $3.75, while the same amount of aluminum costs $1.54. Steel costs between 40 cents and 98 cents per kilogram, depending on the grade, according to industry data.
But Mr. Petrillo said magnesium can have a “compounding” effect on weight-savings across a vehicle. A lighter lift gate can lead to smaller brackets or even a smaller motor to open the door. Take enough weight out of a vehicle and an auto maker might be able to reduce the size of the engine, too.
Fiat Chrysler’s fastest-selling products are hefty Jeep SUVs and Ram pickup trucks, placing near the bottom of industry ratings for real-world fuel economy and emissions performance, according to the EPA. Some analysts have questioned whether the company has adequate plans to address the problem. Sergio Marchionne, the company’s chief executive, has said the industry may not meet 2025 standards, particularly with gasoline prices so low.
The Pacifica’s lift gate indicates the company isn’t throwing in the towel.
“When we started to look at designing a new minivan we already knew we had to find ways to cut the weight,” said Pacifica lead engineer Jessica LaFond. Magnesium, which is heated and poured into a cast mold, gave designers flexibility to style a more attractive back end. And they were able to reduce the need for additional parts, such as brackets, while adding inset taillights and a slightly larger back window. Ms. LaFond said the auto maker is studying whether to expand the use of magnesium in other Fiat Chrysler models.
Lighter materials that are often more expensive are becoming more common in car designs. Since 2009, the percentage of aluminum as a component of vehicle weight has shot up 17% to 379 pounds a vehicle, or nearly 10% of the total.
Carbon-fiber composites also are showing up in some vehicles, but auto makers are reluctant to commit to the expensive material. BASF AG’s new carbon fiber oil pan is 40% lighter than steel or aluminum versions, for instance, but the company is still looking for a buyer.
Chrysler’s Pacifica, which has aluminum sliding doors, could be a pioneer when it comes to wider use of magnesium. Used on cars since 1920, the average light vehicle has about 10 pounds worth of the material in its composition, that number is poised to triple by 2025, according to a forecast by Ducker Worldwide, a Troy, Mich., consulting and research firm.
“Magnesium has always been an interesting product for engineers since it provides a lot of weight savings but still provides strength,” said Abey Abraham, a project director at Ducker Worldwide. The average light vehicle has about 10 pounds worth of the material in parts such as instrument panels and seat frames, and its use is poised to triple by 2025, it estimates.
“As the new emissions guidelines get closer, magnesium is starting to appear in more vehicles and in bigger parts,” Ms. Abraham said. Ford Motor Co.’s Lincoln MKT luxury crossover was the last vehicle to use magnesium for the lift gate, but its volumes were slight compared with expected demand for the Pacifica.
Auto suppliers are preparing for wider use of the metal. Ramzi Hermiz, chief executive of Ohio-based parts maker Shiloh Industries Inc., said his company is looking to expand magnesium parts production by doubling the size of a factory in Poland once devoted exclusively to steel. A similar move is being made in Tennessee.
“We saw [magnesium] first begin to grow with the European auto makers,” Mr. Hermiz said. “In this time of big vehicles in the U.S. we are getting more calls about how we can make this component or that component out of magnesium, aluminum or some combination.”
Source: shiloh.com
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