Steam engine (from exhaust heat)

[iHero]

Has anyone built a small steam engine that could be run from the heat of a car's exhaust manifold? The steam engine/turbine would be used to power a generator/alternator.

[Tourigjm]

arent steam engines typically... massive

and the energy requirements to keep even a small amount of water would be quite high. It also wouldnt work right away. you would have to boil off the water first, and this wouldn't work in cold weather.

I'm kinda ranting but i think its probably more problems than its worth.

[azraelswrd]

Mercedes and a few others have been working on ways to recapture the heat as reusable energy. Stirling engines were an early favorite but they have their own issues.

[Vince-HX]

what kind of issues with the Sterling engines?

I've been researching them recently and they seem like a great way to reclaim a bit of heat energy.

YouTube - Free Energy - Solar Powered Sterling Engine

I would love to make a big version of this one and stick it on my roof. Plenty of sunshine round here

[woohoo207]

Stirling engines have been making some headway lately, mostly being used in solar energy and for marine propulsion/secondary electricty. The main problems are the size to power ratio, potential temperature difference, pistion seals, and engine controls, specifically engine pressure control. The working solar commercial models that I have seen have used molten sodium-- but more practically for automotive use the working fluid would be helium. Plain air could also be used, like the original stirling, but there have been problems with the lubricants oxygenizing and causing explosions. Nasa acutally did some automotive testing with stirling engine for main propulsion in the late 70's and early 80's in a chevette.

[FastPlastic]

I think this is something that is definitely worth looking in to. Especially if you could pull enough power out of it to replace the alternator.

If you use steam would you have to have the boiler inspected?

[azraelswrd]

I doubt it can replace the alternator but I can see it replacing an A/C or even for some kind of regenerative charging system for hybrids. Love that prototype in the video -- but I know when people hear "hydrogen" they automatically think of Hindenburg-like images of immolation and fiery coffins of doom.

...guess they didn't know about fuel cells or metal hydride release systems.

[bbjsw10]

That demonstrator is cool even to just play with make an rc boat out of it.

[iHero]

Originally Posted by azraelswrd

I doubt it can replace the alternator but I can see it replacing an A/C or even for some kind of regenerative charging system for hybrids. Love that prototype in the video -- but I know when people hear "hydrogen" they automatically think of Hindenburg-like images of immolation and fiery coffins of doom.

...guess they didn't know about fuel cells or metal hydride release systems.

So along with these from azrael:
driving style
aerodynamics
tires
weight reduction
engine maintenance

I think we should add steam to the list for a small inexpensive method to reclaim some of our energy. Even in cold whether it should work -- provided you use a shroud to keep some of the air out of the engine compartment. Add a solar reflector to the game -- and POW -- we are getting H-O-T.

We should keep thinking small, inexpensive mods -- because once things get to elaborate they don't make sense from a financial perspective.

[iHero]

Looks like BMW is building a gas / steam hybrid.

BMW Developing a Steam/Gas Hybrid Engine : TreeHugger