# Sterling engine hybrid!



## EatenByLimestone (Jun 16, 2016)

http://www.khou.com/mb/features/san-antonino-man-has-engine-that-gets-100-mpg/242673922


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## begreen (Jun 16, 2016)

Cool. Looking forward to the road tests.


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## woodgeek (Jun 17, 2016)

Very sensible.  Of course we use ICE for propulsion for many reasons OTHER than its efficiency.  Notably, instant warm up, high throttle ability and great power to weight ratio.  Stirling engines are much more efficient, and from what I have heard suck at those other metrics.  But if you are going to hybridize your powertrain anyway...the door is open to other power-plants...how about fixed speed steam turbines?

If you are interested in Stirling, read about Maricopa Solar:

http://www.scientificamerican.com/article/are-engines-the-future-of-solar-power/

a bunch of talented engineers in Arizona that started with NASA derived Stirling engine drawings (imagined for the space station) and improved them tremendously.  IIRC their best engine was pretty hefty, costly and ran about 25 kW and 30% eff...

versus the 80 kW motor in my LEAF that is the size of a loaf of bread.


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## begreen (Jun 17, 2016)

woodgeek said:


> versus the 80 kW motor in my LEAF that is the size of a loaf of bread.


True, but relying on a battery bank the size of a file cabinet. 

Hope this becomes a real mainstream product. VW is talking about going seriously electric with their next gen cars. This would be a decent range extender for them.


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## Ashful (Jun 17, 2016)

woodgeek said:


> IIRC their best engine was pretty hefty, costly and ran about 25 kW and 30% eff...
> 
> versus the 80 kW motor in my LEAF that is the size of a loaf of bread.


There is no car under 350 kW that is worth driving.  ;-p


Sent from my iPhone using Tapatalk


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## begreen (Jun 17, 2016)

Ashful said:


> There is no car under 350 kW that is worth driving. ;-p


Nothing like taking a big truck on a daily, single person commute to help clean up the planet.


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## iamlucky13 (Jun 17, 2016)

The main benefit he'll see is deep hybridization, which allows you to avoid oversizing the engine and keep it running at at optimal power level. For small engines, he might get a bit more efficiency from a Stirling than from an ICE, but not huge, and the difference tends to disappear in larger engines. He'll get a couple percent more from adding thermocouples on, but at relatively high cost.

I think the best-case outcome of his work is a slight improvement on current hybrids.

There's also been a lot of interest in Stirlings for combined heat and power applications, especially for remote areas. It has seemed to be stuck as a niche market and has been for years, but I think combined heat and power is the market where they're most likely to find a breakthrough.

The NASA automotive research is actually pretty interesting. For one project they built a V-4 Stirling engine and stuck it in a family sedan (Chevy Celebrity)
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19880002196.pdf


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## peakbagger (Jun 17, 2016)

I keep an eye out for Dean Kamen to commercialize his sterling cycle engine. He claims to generate the power for his house with one and recently was in the new for another research site. He has been working on it for longer than the Segway but to date no commercial product. He claims to have no interest in producing it but is willing to license the technology. Every so often it sound like a deal is close to being signed and then it fades away. Given the demand for fuel efficiency I would expect that if its viable it would be produced but so far no news.

Sterling Energy Systems licensed the much touted (and real cool looking) DOE concentrating dish solar collector technology and sign a lot of deals to build big solar power plants but the sterling engines that were the heart of the design seemed to be a bottleneck until the declared bankruptcy. A company I worked for put in the first commercial Sterling Engine System at biodiesel factory in NJ and got real good at changing engines out as they could run any length of time before they trashed themselves until the company that supplied them went bankrupt.  Heck at one time the Chevy Vega was supposed to have a sterling engine. There was a  roll out of home energy systems in Britain a few years ago with a Sterling unit made in NZ but last thing I knew ended in failure 

As far as I know there are no long term successful long term commercial sterling applications out there, just a string of broken dreams.


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## woodgeek (Jun 17, 2016)

The problem is the 'climbing the mountain' problem for weak (small battery) EVs with a modest (low power) range extender engine, like the I3-REX.

You CAN have situations where you drain the battery and try to run on just the REX and have a real power limitation.

To overcome, you have a hefty battery, basically a REAL battery EV with a REX....and then the REX gets used so infrequently that no one cares about its efficiency...they just want to keep costs down.  So you are back with a small ICE for the REX.

Kind like teaming up solar HW with a HPWH....if you have the HPWH, then the payback on the solar is lousy, and if you have solar HW, the amount of backup you need (and all in the winter) means that HPWH looks unattractive for backup.


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## woodgeek (Jun 17, 2016)

Ashful said:


> There is no car under 350 kW that is worth driving.  ;-p
> 
> Sent from my iPhone using Tapatalk



I think my leaf would smoke your 450 hp ICE car on the 0-30.


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## brenndatomu (Jun 17, 2016)

I was doing research on Stirling engines for a project at work a couple years ago, ran across these guys 
http://cyclonepower.com/- they are doing some interesting stuff. I have been watching them for 4-5 years now, I'm kinda surprised things haven't quite taken off for them yet...


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