Oddball idea
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Fleet Owner
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From: Drummonds, TN USA
Oddball idea
IC engines derive power from expanding gases in their cylinders. But the gasses do not completely expand in the cylinders - they are still under expansion when released into the exhaust system.
Turbine engines are even less fuel efficient.
If it were possible to harness 100% of the force of expansion you would think that we would have something more efficient, but how could that be done?
Interesting question, isn't it?
Suppose an engine were driving a generator, and the exhaust was applied to something like an air-tool motor to drive another smaller generator so that the total HP or KW was a combination of the two...
The IC engine produces much of the power and also begins the gaseous expansion while the exhaust driven pump would scavenge the rest (up to some point).
if the output were a DC current it could be easily added together and managed after that...
Possible?
(It would need a pressure relief system and a plenum...)
I wonder how much scavenged energy could be had by using successive scavenger stages on the exhaust of an engine used specifically to initiate the fuel/air reaction?
I also wonder how effective turbos might be for this.
Turbine engines are even less fuel efficient.
If it were possible to harness 100% of the force of expansion you would think that we would have something more efficient, but how could that be done?
Interesting question, isn't it?
Suppose an engine were driving a generator, and the exhaust was applied to something like an air-tool motor to drive another smaller generator so that the total HP or KW was a combination of the two...
The IC engine produces much of the power and also begins the gaseous expansion while the exhaust driven pump would scavenge the rest (up to some point).
if the output were a DC current it could be easily added together and managed after that...
Possible?
(It would need a pressure relief system and a plenum...)
I wonder how much scavenged energy could be had by using successive scavenger stages on the exhaust of an engine used specifically to initiate the fuel/air reaction?
I also wonder how effective turbos might be for this.
Last edited by Greywolf; Oct 11, 2005 at 05:19 PM.
Elder User
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From: Mesa, Arizona
Perpetual motion machine? Electric powered motor providing its own electrical power, just needs a kick start? Very strange, now the spider in my head is awake and trying to make me think. Thanks!
"Mifflin Clay"
Joined: Jul 2005
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From: Mifflin, PA
Buy 2 small diesel engines, equip with generators. Build wood fired boiler. Heat & domestic HW from boiler. Battery bank for power. Now, equip the boiler with electric heating elements. Run the diesel exhaust thru a heat exchanger to preheat your domestic HW. While charging batterys, exhaust heat preheats water. When no one is around to fuel wood boiler, electric gen keeps batteries up and heat available. And, go the full monte - heat exchanger for waste water and air. Just a thought .......
Post Fiend
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If you could preserve the heat generated by combustion to only the molecular expansion of the inert gases you would have something, but alas you can't. Your idea has merit becuase there is residual energy left over in the exhaust stream; perhaps some TEDs (Thermo Electric Devices) could scavenge some more energy. But like I said, a good portion of the loss is to all the surface area the combustion gases touch.
Last edited by hkiefus; Oct 11, 2005 at 07:32 PM.
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Fleet Owner
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From: Drummonds, TN USA
If the primary engine was water cooled and there were several stages of scavenged gas pressure, I suppose the engine coolant could maintain some of the temperature of the gasses (And thus the expansion) through the system or in the final stage using a water jacket...
But you can't outrun the laws of Thermodynamics!
Suppose we had a four cylinder engine, and two or more of the cylinders acted like the cylinders of a steam engine, recieving the exhaust from the outlet port(s) of the internal combustion cylinder(s). That could be arranged by adding lobes to the camshaft in the right positions and routing the exhaust through a closed manifold.
It would be an engine with only one intake port, and two exhaust manifolds...
Nah - I think the back-pressure would strangle it.
But you can't outrun the laws of Thermodynamics!
Suppose we had a four cylinder engine, and two or more of the cylinders acted like the cylinders of a steam engine, recieving the exhaust from the outlet port(s) of the internal combustion cylinder(s). That could be arranged by adding lobes to the camshaft in the right positions and routing the exhaust through a closed manifold.
It would be an engine with only one intake port, and two exhaust manifolds...
Nah - I think the back-pressure would strangle it.
Last edited by Greywolf; Oct 11, 2005 at 07:44 PM.
Hotshot
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From: NW burbs of chicago
under expansion when released into the exhaust system.
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Fleet Owner
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From: Drummonds, TN USA
A turbine would probably allow a lot of the gas pressure to just flow through, unless it was at pretty high speed. A piston and cylinder would be gas-tight, so it should be more efficient I would think.
Don't know - like I said, it's an oddball idea. As in left field. As in "Orville? Wilbur? You know it ain't gonna get off the ground..."
If a lawnmower engine had its cam altered to act like a steam engine, it should be possible to make it turn by applying an air compressor hose to it. If instead of a compressor another engine had its exhaust connected to it - that should work too.
The base circles of the cam would be built up with a wire feed (so I figure) and then bench ground into another pair of lobes opposite the existing ones. Could probably run exhaust port to exhaust port, since they are pipe threaded and it doesn't matter if the recieving motor runs in reverse.
(Yeah, I've been thinking it over. Considering a cheap way to test it out)
Stranger still - the flywheel of a lawnmower engine can be used to generate voltage. It has magnets embedded in it for its ignition...
Don't know - like I said, it's an oddball idea. As in left field. As in "Orville? Wilbur? You know it ain't gonna get off the ground..."
If a lawnmower engine had its cam altered to act like a steam engine, it should be possible to make it turn by applying an air compressor hose to it. If instead of a compressor another engine had its exhaust connected to it - that should work too.
The base circles of the cam would be built up with a wire feed (so I figure) and then bench ground into another pair of lobes opposite the existing ones. Could probably run exhaust port to exhaust port, since they are pipe threaded and it doesn't matter if the recieving motor runs in reverse.
(Yeah, I've been thinking it over. Considering a cheap way to test it out)
Stranger still - the flywheel of a lawnmower engine can be used to generate voltage. It has magnets embedded in it for its ignition...
Last edited by Greywolf; Oct 12, 2005 at 09:08 AM.
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"Mifflin Clay"
Joined: Jul 2005
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From: Mifflin, PA
Originally Posted by Greywolf
A turbine would probably allow a lot of the gas pressure to just flow through, unless it was at pretty high speed. A piston and cylinder would be gas-tight, so it should be more efficient I would think.
Don't know - like I said, it's an oddball idea.
If a lawnmower engine had its cam altered to act like a steam engine, it should be possible to make it turn by applying an air compressor hose to it. If instead of a compressor another engine had its exhaust connected to it - that should work too.
The base circles of the cam would be built up with a wire feed (so I figure) and then bench ground into another pair of lobes opposite the existing ones. Could probably run exhaust port to exhaust port, since they are pipe threaded and it doesn't matter if the recieving motor runs in reverse.
(Yeah, I've been thinking it over. Considering a cheap way to test it out)
Don't know - like I said, it's an oddball idea.
If a lawnmower engine had its cam altered to act like a steam engine, it should be possible to make it turn by applying an air compressor hose to it. If instead of a compressor another engine had its exhaust connected to it - that should work too.
The base circles of the cam would be built up with a wire feed (so I figure) and then bench ground into another pair of lobes opposite the existing ones. Could probably run exhaust port to exhaust port, since they are pipe threaded and it doesn't matter if the recieving motor runs in reverse.
(Yeah, I've been thinking it over. Considering a cheap way to test it out)
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Fleet Owner
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From: Drummonds, TN USA
Its all theoretical anyway. No matter what is used, there must always be a pressure differential to make the gasses act on a movable something or other, so it can never be 100% efficient.
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Turbo chargers work on exactly this principle, no? They use the expanding exhaust gases to drive the turbine. Now, we power hounds use that energy to force more air into our cylinders, but the turbine could be turning anything - like a generator.
I wonder how much power a turbo turbine puts out. Maybe it could drive a generator that charges the batteries in a hybrid vehicle. Some of the new hybrids switch automatically from gas to electric depending on the load. This could maximize the energy wrung from the gas you used and reduce the need for outside electricity to recharge teh batteries - remember, electricty from your outlets still had to be generated somewhere, meaning burning coal or nuclear or something usually. This could reduce that.
I wonder how much power a turbo turbine puts out. Maybe it could drive a generator that charges the batteries in a hybrid vehicle. Some of the new hybrids switch automatically from gas to electric depending on the load. This could maximize the energy wrung from the gas you used and reduce the need for outside electricity to recharge teh batteries - remember, electricty from your outlets still had to be generated somewhere, meaning burning coal or nuclear or something usually. This could reduce that.
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Fleet Owner
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From: Drummonds, TN USA
I don't think I have ever heard of an actual HP rating for the turning force of an exhaust turbo. It would be interesting to know, since they obviously not only make a positive 10 to 28 PSI increase of the manifold absolute pressure, but this is being done while the intake is drawing from it...
That has to be quite a bit of power.
That has to be quite a bit of power.
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Instead of using residual pressure to power a secondary device, why not used the unburned fuels. put in a small IC inline with the exhaust to power the auxillary devices such as the alternator, power steering, and AC. This would add weight to the vehicle but you would also have less of a load on the main engine when you remove these auxillary devices.
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From: Location, Location.
here's someone doig this sort of thing. Very cool:
http://www.scania.com/products/newtr...turbocompound/
Instead of expelling ‘wasted energy’ via the exhaust pipe, more heat is extracted from the exhaust gases by a second exhaust turbine downstream from the turbocharger.
The second turbo (the turbocompound turbine) spins at 55,000 r/min. This motion is passed through turbine gears and a hydraulic coupling, then through the timing gears to the crankshaft. Stepping down the revs produces a useful boost in torque, which when reaching the flywheel adds momentum. You get this extra driving force without increasing expenditure on fuel.
http://www.scania.com/products/newtr...turbocompound/
Instead of expelling ‘wasted energy’ via the exhaust pipe, more heat is extracted from the exhaust gases by a second exhaust turbine downstream from the turbocharger.
The second turbo (the turbocompound turbine) spins at 55,000 r/min. This motion is passed through turbine gears and a hydraulic coupling, then through the timing gears to the crankshaft. Stepping down the revs produces a useful boost in torque, which when reaching the flywheel adds momentum. You get this extra driving force without increasing expenditure on fuel.
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Your assumption that the primary source of energy from a gallon of gas is from combustion. That is not correct. It includes somewhere around 30-35% of the available energy. The main energy source is the heat which we scavenge out the tail pipe and the radiator. Until we can better harness the heat energy we will continue to burn more gas energy into the air.