Small high pressure water pump?
 

I have thought for a while that you could get some copper brake pipe, wrap it right around the exhaust manifold, then insulate the whole lot with loads of heat wrap to keep all the heat in! The copper pipe could be wrapped around many times, pressing right up against the manifold.

Then, if you had a high pressure water pump which, when not working, doesn't let water flow backwards, you could pump water slowly down the pipe, with high pressure steam coming out of the other side.

The steam could then go into a small steam engine (just the piston part of it), or maybe a modified model car / plane engine or something, which could be connected to a small alternator.

This could generate electricity to run the lights, ECU, and so on.

Any thoughts on this? I know that people using the alternator-off mod get good rises in total FE.

I'm pretty sure one of the Euro car makers has done something along these lines, using residual exhaust heat to run an alternator and maybe even an AC compressor..

BMW?

Stirling engines have fascinated me in the past and they can be made to produce mechanical output on as little as the warmth of your palm.. These are known as low delta-t (for low temp differential) stirling engines and are especially designed for very low friction.

https://www.youtube.com/watch?v=GbwbxGtHKxU

I'm hoping to do something like that, thermosiphon driven dynamo for making HHO.

BMW is the company that's working on the steam technology. IIRC they were actually using it to contribute power to the drivetrain.

I like the OP's idea of using exhaust heat to generate electricity. I think it may be possible to do more simply and pleasantly than a steam engine; there are other ways to convert heat into electricity. Also, the heat will probably have to be taken behind the cat, not in front of it; I'm pretty sure the cat depends on that heat to operate properly, doesn't it?

You wanna know what I think is stupid as regards regulations which might be an obstacle to such things getting into mass production....

You can have a 45 PSI pressure cooker on the kitchen stove...
You can have 30-200 psi refrigeration and air con systems with hydrocarbon refrigerants.
You can have a 200 PSI fuel pump in your tank, and 50 PSI injector rails on your motor...
You can have a 125PSI air compressor and tank system...
You can have high PSI propane tanks on your BBQ, CNG tanks in your vehicle (Installation might have to be certified) etc etc.....

But a steam boiler system, anything over 15 PSI has to be inspected and certificated annually, have a licensed operator and get torn down for annual inspection....

Probably all because back in 1890 or so, some yahoo blew away a party of schoolkids on a hayride with a badly serviced traction engine... or something...

Yes hot steam is baaad mmmkay, but 15 psi??? can't do crap with that... probably wanna have a closed system with boiling nitroglycerine at 1000 PSI instead to stay legal.


Edit: Oh yes, I was thinking about a closed system a few months back. It seemed to me that oversizing the airconditioning compressor a little and replumbing the system a bit, might give you a system that could drive the crankshaft when not required for A/C use. Basically you'd be using the compressor as a motor driven by refrigerant expansion from coolant or exhaust heat.

The ultimate evolution of such a system might be to have the motor propane powered, with a rotax type double sided vane pump providing additional power by expansion of the propane running through the block as coolant. It's fuel heat, and heat recovery in one handy dandy package. I'd have started working on it, but haven't seen that propane is a viable mass market fuel. The renewable sources of propane still have to prove themselves viable.

One idea I had was to take e.g. 100 litres of water, and extract exhaust heat into the water, maybe using a block of insulated conductive metal as a heat pipe. Then even short journeys would allow you to heat up this water. If you had some kind of heat exchange system, you could then park, plug in a heat exchanger to the house, and use it to heat the house :)

Also, my car doesn't have a cat anyway :D so I will would extract the heat from the manifold and downpipe itself. Having no cat does mean I try to avoid enrichment more, as there is no cat to 'burn' the enriched mixture on WOT.


Regarding those regulations - from a safety point of view, a thin piece of copper pipe would mean you only have a tiny amount of steam at any one time, so even if the system ruptured, it wouldn't really matter. From a legal point of view, I am in NZ, so hopefully we won't have that particular law!

I like the idea of using the air con pump as a motor too! Would that be possible? I know they can consume 1-2 bhp easily, so that could be a good addition to engine power if you were crusing at 50mph or so.

It's BMW, they claim 15% improvement in mileage. I think it's running all of the acessories off the heat. No fan belts whatsoever.

Interesting points and a good topic since we loose 2/3 the energy in heat.

Use the engine for primary power through the drivetrain, but also as a boiler for power to drive everything else. Boiler should be immediately behind the cat, where temps are highest.

Generate electricity and drive everything using the electricity.
The air conditioning would be a mini heat pump, reversible of course.

Engine coolant would be the first stage of heating with steam stage behind cat. Could also be used to generate electricity for a hybrid.

The pathway to the car of the future will have to include steps like this during the transition period.

Simply keeping the coolant in an insulated jug would dramatically reduce warm up time.

regards
gary

Roadwarrior, a boiler is a very different beast than a compressed air tank. When water is boiled under pressure it boils at a higher temperature than when under regular atmospheric pressure. When a boiler ruptures and the pressure is released in can cause the rest of the water in the boiler to instantly boil, the result is something far far different than if a 125psi air tank fails.

I see what you're saying, but then kitchen pressure cookers would be the same thing at 45 psi, and propane and CNG will also flash boil and make an instant fuel-air bomb... just saying that with improvement in materials over the last 100 years there should be some revision of steam boiler rules so they can be screwed around with by alternate energy folks.... mind you that's a bit much to expect when you can still get a ticket up here for not having white stripes on the forks and rear mudguard of your bicycle, for black out safety in case those naughty nazis catapult launch a Feisler Storch off a U-boat and manage to leaflet bomb us and drop a hand grenade or two.