Engineering Materials
BMW Engine Powered by Aluminum Piston

BMW will use a new Federal-Mogul aluminum piston (right) for the triple-turbo, 93kW/liter engine (left) in its M550d xDrive sedan. The piston is design to satisfy the high heat and strength requirements of new diesel engines. (Source: Federal-Mogul)
BMW will use a new Federal-Mogul aluminum piston (right) for the triple-turbo, 93kW/liter engine (left) in its M550d xDrive sedan. The piston is design to satisfy the high heat
and strength requirements of new diesel engines.
(Source: Federal-Mogul)

Return to Article

View Comments: Newest First|Oldest First|Threaded View
<<  <  Page 2/2
Charles Murray
User Rank
Re: Is aluminum strong enough?
Charles Murray   7/13/2012 6:08:21 PM
Nice story, Ann. Do you know if these pistons use cast iron cylinder liners? Going way back to the old Chevrolet Vega (does anyone remember the Vega?), engineers have tried to use aluminum. When the Vega's engine had problems, engine builders started employing the cast iron liners. In the '90s, engineers got rid of the cast iron liners and started using hypereutectic aluminum alloys for the blocks and various coatings for the inside of the cylinder, but I don't know how that came out. Are they still using the liners?

Ann R. Thryft
User Rank
Re: Is aluminum strong enough?
Ann R. Thryft   7/13/2012 12:45:57 PM
Dave, thanks for the feedback on the re-melting process. I agree, it doesn't sound intuitively obvious as a manufacturing process. Regarding the alloy, I'd like to know, too: no details on this product were given. On the company's website appears this general statement about their aluminum pistons. but whether it applies to the new diesel piston is not clear: "We offer aluminum diesel pistons made of Federal-Mogul's exclusive, high-strength B3 alloy (2006) for high-end light-vehicle diesel applications, giving a 10 percent higher fatigue resistance at 440º C to absorb extreme loads in performance engines."

Dave Palmer
User Rank
Re: Is aluminum strong enough?
Dave Palmer   7/13/2012 12:19:58 PM
Ann, do you know what kind of aluminum Federal Mogul is using for this application? I assume it is an aluminum-silicon alloy.  Do you know if it is hypereutectic, eutectic, or hypoeutectic? (This is metallurgy-speak for more than 12% silicon, about 12% silicon, or less than 12% silicon).

The DuraBowl re-melting process is interesting, and, like many good ideas, seems obvious in retrospect.  Doing failure analysis of aluminum pistons, I've often observed that areas which melted (in service!) are much harder and have a much finer microstructure than the surrounding area.  But I'm not sure that it would have occurred to me to exploit this as a manufacturing process.

Friction stir processing is another way to achieve improved properties in the piston bowl area.  I'm not sure whether anyone is doing this commercially yet, but there is a lot of interest in it.  At last year's Materials Science and Technology conference, Dr. Saumyadeep Jana gave a presentation on friction stir processing of cast aluminum alloys; during the Q&A session, it was clear that just about everyone in the audience (including myself!) had pistons on their mind.  I strongly suspect we'll be seeing friction stir processed pistons in the next couple years.  This would be a good topic for an article.

Ann R. Thryft
User Rank
Re: Is aluminum strong enough?
Ann R. Thryft   7/13/2012 11:50:37 AM
The aluminum industry has been working on high-strength versions, including alloys such as aluminum-lithium, for some time now. For example, it's the major metal in aircraft, where it's mostly replaced steel (see my upcoming July feature article on aircraft materials). We've also covered a brake rotor prototype made of an aluminum composite:
Aluminum rotors aren't new, but this one is managing to keep up with the increasing heat requirements of today's smaller, hotter engines, not a small feat. There are some under-hood applications of plastics, including carbon composites, such as this one I wrote about
but AFAIK, not yet in car engines.

User Rank
Is aluminum strong enough?
richnass   7/13/2012 10:49:48 AM
I'm a little surprised that they found that aluminum is strong enough for this application. And very pleased, asuming it can work well over time. Is plastic next?

<<  <  Page 2/2
Partner Zone
More Blogs from Engineering Materials
Dow Chemical and several other companies have launched a program in Omaha, Neb. to divert about 36 tons of plastics from landfills in its first phase, and convert it into energy used for cement production.
BASF is partnering with Hyundai on a high-performance concept car that showcases both eco-friendly, sustainable materials and materials to enable lighter weight cars.
A make-your-own Star Wars Sith Lightsaber hilt is heftier and better-looking than most others out there, according to its maker, Sean Charlesworth. You can 3D print it from free source files, and there's even a hardware kit available -- not free -- so you can build one just in time for Halloween.
Some next-generation bio-based materials are superior in performance to their petro-based counterparts, but also face some commercial challenges. This is especially true of certain biopolymers, adhesives, coatings, and advanced materials.
Cars and other vehicles, as well as electronics and medical devices, continue to lead the use cases for the new plastics products we've been seeing, as engineers design products for tougher environments.
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Oct 10 - 14, Embedded System Design Techniques™: Getting Started Developing Professional Embedded Software
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6 |  7 | 8 | 9 | 10

Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Course September 27-29:
Sponsored by 3M
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Technology Marketplace

Copyright © 2016 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service