Waste Heat from Exhaust

[Sideblinder]

I know that old radial aircraft engines used to use a power recovery exhaust turbine. It was a turbine, powered by the exhaust gasses, but the shaft actually went through reduction gearing to the crank shaft. If I remember correctly they were supposed to increase power to weight by 8%. I'll dig out my books and find it. I know nothing like this is used in modern aircraft, only regular turbochargers.

[Sideblinder]

Woop, found some info. They are more properly known as power recovery turbines. The 18 cylinder Wright_R-3350 used 3 of them (one on each cylinder row exhust) them to increase power by 20ish%. Unfortunately: "This is not without cost, however, for those devices are also nicknamed "Parts Recovery Turbines" (and worse) and were another source of failures."

They also use fluid couplings (like an auto transmission) to transfer energy to the crank.

[jamesqf]

The turbo in the exhaust thing is being researched, for instance here: Put A Tiger In Your Exhaust

As for the turbo-compounding of aircraft engines, the amusing part is that the engineers eventually figured out that the turbine was more efficient if they removed the piston engine altogether - and so the turboprop was born :-)

[ConnClark]

Originally Posted by jamesqf

The turbo in the exhaust thing is being researched, for instance here: Put A Tiger In Your Exhaust

As for the turbo-compounding of aircraft engines, the amusing part is that the engineers eventually figured out that the turbine was more efficient if they removed the piston engine altogether - and so the turboprop was born :-)

Actually the Napier nomad was more efficient than a turbo prop. The turbo prop has the advantage of using less refined hence cheaper fuel. It also has the advantage of less complexity and less wear and tear due to lack of recipricating motion. A turbo prop is more economical but not more fuel efficient.

[TES111]

Originally Posted by MazdaMatt

I like the idea of using the exhaust gas for a half-turbo to belt-drive an alternator. Sounds like ther eisn't much complication compared to the other ideas. Using exhaust HEAT to run some heat-engine to turn the alt would be the next step in my opinion, but that is a factor more difficult than the previous idea. using a turbo or heat engine to run a generator to produce HHO to produce more power/efficiency... that's getting a little silly, no?

Silly...? Why? They do produce gas and it does explode (don't ask).

Its not silly when people put nitrous oxide into their engine to produce power.

I want to run hho to reduce the amount of gasoline I burn not get HP gains.

[MazdaMatt]

no, no, no... i don't htink it is silly to use HHO to reduce gasoline consumption. I think it is silly to use exhaust heat to run a motor, to run a generator, to hydrolize water to put HHO into the engine. Too many steps. Too many devices. too complicated.

Simply going from a half-turbo to the alternator and AC would be a great, simple, reliable addition.

[TES111]

Roger that. Just think that if you could scavenge the heat as well as the flow you could increase the efficiency even more. Otherwise the heat is just wasted money.

[TES111]

My point with the heat exchange is that if you use a glass or insulated resivoir (cool) then inject heated (via the manifold) distilled water onto metal you get an instant explosion. Do not try this as it will happen and you will be badly burned.

So assuming that you could have a pre heater then inject the pre heated water on to hot metal you would get a violent reaction for nothing that you arent already paying for. We are already creating (from what I have read) 1000 degrees of heat (at the manifold) that would be effective at powering a steam turbine / alternator (front side of the turbo). A combined unit. Not two seperate units.

A normal turbo with a distilled water front steam turbine and the exhaust side powered by the exhaust flow. You would have a double drive on scavenged energy. Instead of air induction you have steam induction on a closed circut that will allow the steam to condense in the tank before it hits the hot rear side and then be pre heated by the exhaust side for a quicker flash reaction when it re circ's to the hot side of the manifold. Because as someone already has pointed out in this thread that exhaust is inconsistent the steam cold compensate for the other and visa versa when the engine is @ cruise.

Also today I was thinking about the drive shaft. Magnets and copper on something that already spins. Another generator of electricity for HHO production. It seems that there are alot of waste energy areas in an ICE loop that could be used to power HHO production for ICE engines.

Wish I could change the title of the thread to waste energy instead of waste heat.

[TES111]

[QUOTE=Andyman;64359]From what I've been reading about turbo compounding, the power from the exhaust turbine is about 10% of the engine's power. To use this with an alternator, I think you would have to add an electric motor to help power the wheels. The battery wouldn't be able to absorb the amount of power coming from the alternator connected to the exhaust turbine.QUOTE]

The idea is to use the energy to power an HHO generator to give some gas relief (gas ex but for your car)

[metromizer]

Originally Posted by bikin' Ed

Yes, I've thought of using a rear mount turbo to power an alternator. ... My plan, though still in the thinking stage, is to find a salvage yard turbo, plumb it into the exhaust, machine a collar to mate it to my alternator shaft, extend the wiring, and replace the engine acc. drive belt.

You would likely need to build some sort of gear or multi-belt reduction drive to slow the output shaft. The picture below is the inverse, that is, the compressor side of a junk yard turbo being belt driven as an accesory (through a home-built speed increasing drive) and used to supercharge the intake tract of an engine.