GM awarded DOE money to research Shape Memory Alloy heat engines

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General Motors has been awarded $2.7 million by the Department of Energy to create a working prototype engine using Shape Memory Alloys (SMA). The idea is for the prototype to use SMA tech to capture heat energy from engine exhaust gasses via an electric generator and transfer that energy to recharge batteries for hybrids or electric vehicles.

SMA tech can also theoretically power electronic devices like power seats and windows in a standard gas- or diesel-powered car, perhaps even replacing the power-sapping alternator. The GM press release, which is pasted after the jump, doesn't go into much depth explaining how memory alloys work, but the basic principle is easy to understand.

"When you heat up a stretched SMA wire, it shrinks back to its pre-stretched length, and when it cools back down it becomes less stiff and can revert to the original shape" said Jan Aase, director of GM's Vehicle Development Research Laboratory. "A loop of this wire could be used to drive an electric generator to charge a battery."

While $2.7 million isn't a lot of coin in the realm of GM finances (the General seemed to shed about $2.7 million every ten minutes pre-bankruptcy) the grant was significant in that it was the only monies awarded by the DoE given to an automaker. GM is working with partners from outside the auto industry to make the concept a reality, a practice that the General says is imperative to get breakthroughs like this to market. No timetable was given as to when GM's SMA concept would see the light of day.

[Source: GM]
Click to expand...

I think it would be very good for GM if they could get something like this up and running. Sure, first versions might be a little shaky, but I think it's a development that could become pretty important in the future. Taking the alternator out is certainly something I could see benefiting the industry. And if GM could be the ones to get this thing up and running, it would probably give them a much needed boost to their reputation.
 
I wonder how that would work in States like Nevada,some parts of California, Arizona,and Texas? But that is an interesting concept. I wonder if it could be of some universal use though.
 
I'm guessing that it'll get hot enough that it could be in Death Valley and still run good. Wondering if it's even like a Stirling, where all it needs is a heat difference.
 
Interesting that the diagram appears to be based on a Corvette sketch. Otherwise, its pretty nifty technology that would be totally awesome when paired with Voltec technology. Probably.
 
Interesting... much like the BMW steamcharger... only less cumbersome... still... one wonders how much heat you can actually pull out of the exhaust after the catalytic converter?
 
Indeed...I'd put it ON the cat converter.

Still, I have to wonder...why use this expensive technology when the Stirling-cycle heat engine is readily available? Put it right on the exhaust manifold, it'll run for a long time if designed heftily enough.
 
They might be able to run something like a Carnot cycle too...

By guess is that they're specifically looking for something that doesn't have a working fluid and all those pistons and things to deal with. I haven't read any engineering notes on the thing, but I wonder just how efficient this thing would be compared to something using fluids.

Also, I think it'd be cool if they could fine tune it to run off the coolant. The temperature difference might not be as high, but it would certainly help because the cooling system wouldn't have to be as significant and then you have even less power going to keeping the engine cool.
 
Heh...

The Carnot isn't a specific sort of engine, it just describes how a fluid-type engine works. Steam engines are basically Carnot-type engines...as well, a heat pump, like an air conditioner, classifies as a carnot-type device, only reversed.

anyway, it'll be interesting to see how this memory material stuff works, and how efficient it really is.
 
Now, building it in and around the cat or exhaust manifold... yes, that might work...

I'd like to see durability testing on it, though... how many cycles before metal fatigue wears the coil out... and how much it'll cost to replace.
 
Does anybody know how this thing works? I understand how the SMA works and how an SMA heat engine would work using crank shafts, but I'm not able to see how they're making a heat engine out of it that wraps around the exhaust like in the picture.

I think it's pretty interesting so yeah. Can anybody explain this a bit more?
 
You move a magnet through a coil and it causes electrical current to flow through the coil... through the same mechanism that electrical current flowing through a coil will create a magnetic field... this is the process behind all electrical generation systems.

The shape memory alloy changes length and moves through a coil, causing current to flow. The question is how many expansion/shrinking cycles can the SMA perform before wearing out... and how many cycles are needed to produce a useable amount of power.
 

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