The technology behind Ford’s Lightweight Concept Vehicle; prospects for Mach-II with 50% mass reduction difficult
Earlier this month, Ford unveiled its Lightweight Concept vehicle, which uses advanced materials to explore future weight-reduction solutions that could improve performance and fuel efficiency while reducing CO2 emissions. The Ford Lightweight Concept reduces the weight of a 2013 Fusion to that of a Ford Fiesta, resulting in a nearly 25% weight reduction. (Earlier post.)
The Ford vehicle is based on the first phase (Mach-I) of work of the DOE-supported Multi-Material Lightweight Vehicles project (Award DE-EE0005574) by Vehma International (an engineering and prototype division within the Cosma International operating unit of Magna) and Ford. The $20.3-million project ($10 million from DOE, $10.3 million from Vehma/Ford) has two main objectives. First, to design and build the “Mach-I” prototype vehicle maintaining donor vehicle architectural space and using commercially available or demonstrated materials and processes while delivering a 22% reduction compared to the baseline vehicle. The result of this is reflected in the Ford concept.
The second is to design a Mach-II concept vehicle—without architectural constraints—that will obtain a mass reduction of 50% compared to the 2002 Taurus baseline vehicle while still retaining the basic size attributes and customer accommodations of the vehicle.
The focus on the first phase of the project, emphasized Dr. Matt Zaluzec, Ford technical leader, Global Materials and Manufacturing Research, was the use of technologies that are targeting the use of mixed materials and that are available today. Using mixed materials to reduce weight will prove to be an important lightweighting strategy for certain vehicle segments, he noted.
I think you will see a lot of smaller cars find weight savings with advanced high strength steel. But the C/D car is where you are getting on the fence. Do you jump to all-aluminum, or do you start mixing materials? Aluminum will be very product specific; on the [new] F-150, its absolutely the right solution. A/B/C cars will find solutions with advanced high strength steel, C/D with mixed materials. In some D segment, SUVs and trucks, a lot more aluminum will creep in.—Matt Zaluzec
|DOE’s Lightweight and propulsion materials work|
|The DOE’s Vehicle Technologies Office’s Materials Technologies program focuses on two main areas: lightweight materials and propulsion materials.|
|The Lightweight materials work is focused on lowering the cost and improving the properties of lightweight materials while maintaining safety, comfort, reliability, performance, recyclability, and cost.|
|Because it takes less energy to accelerate a lighter object than a heavier one, lightweight materials offer great potential for increasing vehicle efficiency. A 10% reduction in vehicle weight can result in a 6%-8% fuel economy improvement.|
|The propulsion materials area works closely with other VTO technology areas to identify and meet requirements for materials needed to develop cost-effective, highly efficient, and environmentally friendly next-generation heavy and light duty power-trains.|
The Mach-I design demonstrated the integration of the lightweight material vehicle system into an existing OEM body shop, avoiding niche assembly/coating processes. The new MMLV components are being integrated in series-production vehicles to create full vehicles and subassemblies for testing.
Ford will test the results (FMVSS, NVH, Durability, and Corrosion) to validate that the Mach-I vehicle design is viable for OEM production.
Design of the Mach-I was completed in the first quarter of last year; the full prototype build is in process, and will be completed in the third quarter of this year. Mach-II design and CAE is underway now.
Designing the Mach-II to achieve the targeted reduction of 50% from baseline is difficult, and the team has not reached the goal of 761 kg curb weight yet, said Dave Wagner from Ford during a presentation on the Mach-II project at the DOE Annual Merit Review this week in Washington, DC. Achieving the Mach-II target will need to include reduced and eliminated comfort and convenience content such as air conditioning as well as possible loss of performance, ride and handling, and so on.
[An earlier version of this attributed Dave Wagner’s remarks to Tim Skszek from Vehma. –Ed.]
The Mach-II is a design in progress…but the real value of this to the vehicle community is how far we can get in terms of weight reduction, and wishing in place some materials and processes that are just over the edge in terms of viability right now. How light could you make vehicles?
… Our Mach II design is still 150 kilos fat right now, and we’ve done everything we can think of. Clearly we have to think of some other things and what that will likely mean is reducing customer accommodations and reducing everything except critical safety requirements. It is required that your vehicle meet federal safety standards, it is not required that it has air conditioning. It is not required that you can hear people talking in the vehicle. We are still way heavy.—Dave Wagner
Mach-I BIW. Among the components of the Mach-I design were eight high pressure aluminum die castings strategically designed to maximize stiffness and reduce part. The body castings will be anodized as pre-treatment for structural adhesive bonding and increased corrosion resistance.
|Mach-I high pressure aluminum die castings. Click to enlarge.|
Body-in-White (BIW) Modules developed included e-coated and non-e-coated assemblies; aluminum extrusions, aluminum & steel stampings; aluminum low pressure sand and high pressure die castings.
The team used Self Piercing Rivets (SPRs) as the main jointing technology on the BIW and closures (e.g., hood and trunk lids, doors). The team used flow screws, Riv-Tac, and Huck rivets were used along with structural adhesive where SPRs could not be used in the BIW and closure joints due to single side access, insufficient gun clearance, or base material issues.￼(All joints where corrosion may form have an adhesive layer between materials to prevent galvanic corrosion and to increase stiffness/durability of the joint.)
Two types of adhesive were used: air-cured and heat-cured. Steel-to-steel weld-thru adhesive was used at B-Pillar and front rails.
The front cradle used 6063-T6 aluminum extrusions and low pressure aluminum castings with mid-welded assembly and post-machined attachments. (6063-T6 is a medium-strength aluminum allow with silicon and magnesium as major alloy components.) The front bumper featured 6063-T6 aluminum crush cans and a 6082-T6 bumper beam.
The doors features 6063-T6 extrusions; aluminum stampings; steel reinforcements; and magnesium castings.
Mach-I powertrain. The team achieved weight reductions of 20% to 48% on components on the 1.0-liter 3-cylinder engine. A cast aluminum engine block with powder metal forged billet crackable bulkhead inserts saved 48%, or 11.8 kg.
Carbon fiber components played a large role with a CF structural oil pan saving 30%; a CF front cover with mount saving 30%; and a carbon fiber plus aluminum cam carrier saving 20%. Forged aluminum connecting rods saved 40%.
On the transmission, the team achieved a weight reduction of 30% to 60% on components for the reduced torque automatic transmission. A cast magnesium case and bell housing saved 30%; and aluminum pump cover saved 55%; a cast magnesium valve body saved 35%; and a steel and aluminum clutch hub (with a friction spin weld) saved 60%.
Mach-I suspension. Prototype parts took out 30% of the suspension weight. Tall, narrow tires (155/70R19) made of new materials and constructions saved 30%. The cast aluminum or carbon fiber wheels saved 30%. (The Mach-I has no spare tire.) Aluminum brake rotors saved 35%, and hollow micro alloy steel coil springs saved 35-55%. High hardness steel stabilizer bars saved 35%.
Mach-I interior components and glazings. Carbon fiber seat designs saves ~28 kg, while a carbon fiber (or magnesium) instrument panel beam and ducts saved ~8 kg. MuCell and chemically foamed interior plastic trim saved 15% to ~40%.
A mix of lightweight glazings saved 35%. This included a laminated chemically toughened windshield, side door movable glazings, and polycarbonate rear window.Mach-II. The Mach-II design will be a “new design architecture” without architecture and integration constraint imposed by the donor vehicle and existing body shop BOP.
|The Mach-II design BIW resulted in a 144 kg reduction from the baseline (45%). Click to enlarge.|
The Mach-II BIW design makes a greater use of composites, while the closures, which rely heavily on magnesium, achieved a 47 kg reduction from baseline (51%). (The engineers are investigating joint technology for magnesium to steel/aluminum joints.)
The chassis is based mainly on aluminum extrusions and castings, and magnesium forgings. The front cradle is also being investigated as a composite structure.
|Click to enlarge.|
Mach-II powertrain. The engineers took more weight out of the powertrain, first simplifying the engine down to a 1.0-liter, 3-cylinder naturally-aspirated unit coupled with a 6 speed manual w/magnesium case. From a baseline mass of 340 kg, the Mach-II engine drops to 181 kg.
As part of the weight savings, the team developed a Multi Material Cylinder Block: a composite block body with aluminum sleeves and powdered metal bulkhead inserts.
|Multi-Material Cylinder Block. Click to enlarge.|
The team will achieve the targeted 50% reduction, Wagner said, but only through measures such as reducing and eliminating comfort and convenience features such as air conditioning, entertainment system, power seats and windows.
Further weight reduction opportunities in the chassis include reducing wheel and tire size (e.g., dropping to 15-inch), which will degrade ride and handling; reducing the bushing weight (which will degrade ride, handling and add interior vibration); and reduce the steering system weight (which will degrade responsiveness and add vibration.
Body exterior opportunities include more weight reductions in the BIW (degrading stiffness, ride, vibration and quietness); reducing or eliminating trim (degrading appearance, water ingress and quietness); and reducing mechanism weights (degrading durability and convenience).
One of the huge learnings from this is that weight saves in the primary structure do not scale to weight saves at the curb weight of the vehicle. We just can’t get there. We are reducing electric loads to get another kilo out of the battery. It’s just really difficult. We will achieve a 50% weight reduced vehicle. We will let go of all the customer requirements. This will be street legal, but that’s it. [It] is no way equivalent to the 2013 Fusion with the exception of passenger size. We are really up against it.—Dave Wagner
(DOE AMR presentations will be published on the Annual Merit Review site.)
Tim Skszek, Jeff Conklin, “Multi-Material Lightweight Vehicles,” DOE AMR 2014 Project ID #LM072
Tim Skszek, Jeff Conklin, Matt Zaluzec, David Wagner, “Multi-Material Lightweight Vehicles: Mach-II Design,” DOE AMR 2014 Project ID#LM088