Why no foil bearing turbos yet?
Why no foil bearing turbos yet?
(OP)
As I understand, foil bearings are not a terribly new technology. Supposedly when used in conjunction with modern high temperature coatings, the technology is quite effective.
Google "Nasa foil bearing turbo" and you will see that they claim the technology works and has good potential. Supposedly they've been able to match conventional bearing turbo performance, using air as the lubricant in foil bearing units.
My question is, why aren't these being widely used yet? Why aren't they commercially available? Is it purely a matter of economics, or is there an engineering concern that prevents them from being adopted?
Evidently Garrett has been behind much of the research into foil bearings to be used in turbochargers, but they're actively pushing their ball bearing, ceramic turbine units instead. Anyone know why?
Thanks
Google "Nasa foil bearing turbo" and you will see that they claim the technology works and has good potential. Supposedly they've been able to match conventional bearing turbo performance, using air as the lubricant in foil bearing units.
My question is, why aren't these being widely used yet? Why aren't they commercially available? Is it purely a matter of economics, or is there an engineering concern that prevents them from being adopted?
Evidently Garrett has been behind much of the research into foil bearings to be used in turbochargers, but they're actively pushing their ball bearing, ceramic turbine units instead. Anyone know why?
Thanks





RE: Why no foil bearing turbos yet?
A few weeks back, I spoke with a Garrett rep at the SEMA show in Vegas. He said that most of the development work he knew about going on at Garrett was focused on VNT and EGR coolers.
RE: Why no foil bearing turbos yet?
RE: Why no foil bearing turbos yet?
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RE: Why no foil bearing turbos yet?
I guaran- damn- tee that the NASA test rig was not assembled in a working factory.
Would you risk a couple billion dollars on that data?
Mike Halloran
Pembroke Pines, FL, USA
RE: Why no foil bearing turbos yet?
RE: Why no foil bearing turbos yet?
Mike Halloran
Pembroke Pines, FL, USA
RE: Why no foil bearing turbos yet?
Therefore I amend my previous statement as follows:
Prototypes don't tell you squat about real world durability.
Mike Halloran
Pembroke Pines, FL, USA
RE: Why no foil bearing turbos yet?
Besides the manufacturer can design it and make it and sell it just so Joe Public can abuse it and wreck it!
RE: Why no foil bearing turbos yet?
And, for what its worth, the technology could potentially change other applications besides just turbos.
RE: Why no foil bearing turbos yet?
I should imagine there are also cracking problems in the exhaust upstream of the turbo as support while accommodating thermal expansion in the longer pipe will be a problem.
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RE: Why no foil bearing turbos yet?
Because new technology is out there it does not necessarily follow manufacturers will adopt it.
The concept of financial inertia plays a large part in these considerations.
They may not be prepared to have their technology based on that of another source which they would need to pay licencing fees to obtain which adds to their cost base.
The more satisfactorily the current technology fills the need of the marketplace the less likely this is to happen.
Turbo builders such as Garrett would certainly be aware of the foil bearing but since they most likely already have their manufacturing equipment set up to build conventional bearing turbos they would be unlikely to change unless some clear advantage could be proven.
They would also have their own patents and methods in place so it is also unlikely they would move away from these.
Pete.
RE: Why no foil bearing turbos yet?
RE: Why no foil bearing turbos yet?
So which OEMs make their own turbos?
RE: Why no foil bearing turbos yet?
(Heck PPAP could cost millions for some components.)
RE: Why no foil bearing turbos yet?
If something still does a good job why change for the sake of it.
RE: Why no foil bearing turbos yet?
I love air bearings. I've made a motor driven compressor for primary charge air supply to a PEM FC at high altitude, and it was a joy to test (no messy oil based lube system).
But understand that only aerospace programs can possible justify the current cost. Remember that the highly engineered damping component of compliant foil bearings is absolutely critical in a high speed turbomachine that typically traverses two rigid body critical speeds. And this assumes a "sub-critical" machine, that is, operation below the first bending critical.
Don't take my word for it. Call the folks at MITI and get a ROM quote on a bearing development program and recurring production cost.
Dick
RE: Why no foil bearing turbos yet?
I just re-read the string more carefully. Mike Halloran hit the nail on the head. I won't bore you with the many examples I have that support his claim, as I'm sure that you all have your own set of horror stories. I just happen to have some that involve high volume production turbocharger bearing systems, including the wonderful, aerospace proven, compliant foil air bearing.
Name withheld so that my ex-Garrett compatriates won't hunt me down and shoot me.