h a l f b a k e r yIt's as much a hovercraft as a pancake is a waffle.
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Basically this idea would be more production cost friendly, and perhaps more efficient.
As I see it, today's turbos work by doing two things: First, exhaustflow is changed into rotational energy that drives a hydrobearing shaft 2) That shaft drives another fan or compressor that both compresses
the air and despenses it to the intake at the appropriate rpm's.
How about turning the exhaustflow into ac current? All you would have to do is connect a spinning magnet to the exhaust-ended fan. As rpm's increased, more current would be created, driving more amps to another spinning magnet which would either work an air compressor (or a fan blade) to effectively force more air into the engine intake.
I am basically suggesting that the driveshaft and gearing necessary to connect the exhaust rotor to the intake rotor be done away with. Instead of having all that added rotational and planar weight, you would simply have the rotational weight of the magnets, the ultra low friction in an ac (brush) generator, along with the negligable resistance of the wires.
I would be willing to admit that the rotational inertias of my turbo and the traditional turbo might (i don't know) be about the same, but with mine the exhaust rotor doesn't have to be anywhere near the intake rotor. You can use wires as long as you want to put an exhaust rotor where more efficient exhaust flow would be, and the air intake compressor closer to where maximum intake airflow would be. There would be no set driveshaft orientation. It would be the same turbo boost (possibly more), just with more flexibility.
I think your basic electrical motors would be cheap and up for the challenge (just like your alternator, just smaller), and would stand up to the heat of pressure and exhaust. It would definetely be cheaper than hydropacked bearings and the titanium (idk) driveshaft along with all the little hardware and gearing garbage. This idea would perhaps more efficiently transfer the same pwer traditional turbos are creating in a cheaper and more flexible way.
More ideas...
I would think that with this idea you could also have the turbo in the lower rpm's. You would just have to convert the dc (battery) into ac (a very inefficient and panistaking task, but it can be done). The ac would be routed directly to the intake fan for turbo whenever you wanted it.
P.S. this is my first ever post, so I would appreciate your kindness. This idea may have been used before, however I have not found it anywhere. Please don't post any rude comments!
Turbodyne Technologies
http://www.turbodyne.com/
Developer of electricly-assisted turbos. (Courtesy of [bthomps]) [phoenix, Oct 04 2004]
E-Ram electric supercharger
http://www.electric...r-com/Autoframe.htm
Courtesy of [senatorjam]. [phoenix, Oct 04 2004]
Caterpillar's ETC Turbocharger
http://www.orau.gov...ession8/Hopmann.pdf
tech briefing on electric assist turbo for diesel engines [friggin_jeenyus, Oct 04 2004]
Boman Power
http://www.bowmanpo...bo_alternators.html
turbo Alternator [quickerest, May 09 2008]
Controlled Power Technologies
http://www.greencar...ontrolled-powe.html
Turbo Alternator Production Models [quickerest, May 09 2008]
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Welcome to the HB, chuck, but don't expect TOO much kindness ... anyway, I see a pretty good half-baked idea. Perhapse augment an alternator for racing applications, and whatnot ... I understand that you'd have to increase the output to spin something latger than just an RC car motor, but I have very little experience in that area ... very nice first idea [+] |
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In order to achieve boost, a turbocharger uses the exhaust flow from the engine to spin a turbine, which in turn spins a compressor turbine on the intake side. The turbine in the turbocharger spins at speeds up to 150,000 rotations per minute (RPM) -- that's about 30 times faster than most car engines can go. And since it is hooked up to the exhaust, the temperatures in the turbine are also very high. In order to handle speeds of up to 150,000 RPM, the turbine shaft has to be supported very carefully. Most bearings would explode at speeds like this, so most turbochargers use a fluid bearing. This type of bearing supports the shaft on a thin layer of oil that is constantly pumped around the shaft. This serves two purposes: It cools the shaft and some of the other turbocharger parts; and it allows the shaft to spin without much friction. If one were to replace the shaft assembly with a magnetic generator unit to power the compressor side of the turbocharger electrically, one would create several significant problems. The power requirement to drive the compressor side of the turbocharger is around 18-25Kw (24 - 34 Hp) in a shaft turbine. The electrical requirement for a motor that could produce the required power output to spin the compressor side turbine to 150,000 RPM would be enormous, as would be the motor required to do so. Most common (read cheap) electrical motors can barely spin up to 9-10,000 RPM reliably and produce a negligible amount of horsepower and torque (the twisting force required to spin something). Most of them would also self destruct long before the required RPM was reached. A motor that could do the job would be prohibitively expensive, very large, very heavy, and require an enormous power input. This nullifys the original benefit of the turbocharger, a 10-40 percent power increase with a negligible weight gain on the order of 20 to 30 lbs. The motor and generator system weight would be 8-10 times an order of magnitude as heavy and would cost in the 10's of thousands of dollars. |
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It was a good idea, just a little early in the technology curve. As electric motors become more efficient they produce more power for less weight and cost. As motors become more refined in the future this could become a viable idea, but the prospect is still beyond the horizon. |
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Note that by tapping the exhaust, you're only stealing power from one part of your engine and moving it somewhere else. |
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Among other issues, wouldn't a magnet in the exhaust rapidly reach the Curie temperature and demagnetize? |
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I suggested an idea very simalar in an anno I made to "turbo generator hybrid"... |
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[phonenix] - One of the benefits includes that the engine only experiences excess backpressure as long as is needed to recharge the battery via the turbine. At other times the wastegate would remain open. |
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[evangelon] - many RC car motors can reach speeds in excess of 20,000 RPM, they don't cost much money either. I would think that a well-developed motor paired with an ideal compressor design would provide the desired results without the need for extremely high RPMs. |
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Maybe you could recharge the battery during cruise, and keep the turbine unloaded during hard acceleration to further enhance power gains. (Extra power produced without extra drag - at least for a little while.) |
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By all means, the system as a whole would weigh much more than a conventional turbocharger system, and would be a total kick in the nuts to the KISS concept, but hey it's half-baked. |
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One other factor to be considered is that in converting energy from one type to another (ie kinetic to electrical), there is an inherrent loss of efficiency, at least until someone works out how to make superconducting magnets and wire generally available to people poorer than Mr Gates. Then it needs to be converted back to kinetic energy again, losing still more efficiency. |
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Perhaps if the second stage did not utilize rotational means to accelerate the air, along the lines of the way ion drive engines in space probes work, then this might possibly be a more efficient system. Although in this case, the turbine first stage could be replaced by a more powerful alternator on the engine |
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Well, if one day technology becomes efficient enough, this design could actually do away with the alternator. That's a different idea, a turbo alternator. |
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Would there be a way to using the mechanical side of an EMP without creating too much backpressure? Is there a way of producing the EMP effect with rotational motion instead of a linear motion? If this could be done, you would have enough "AC" power to create a usable amount of compressing power. This would probably be more on the lines of a turbo alternator however. |
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I think some problems with an exhaust-electric system would include: |
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high mass of magnets creating high intertia, probably comparable to existing direct mechanical linked exhaust and compressor wheels. |
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heat from exhaust roasting the magnets and alternator, through conduction through housings etc. so elaborate cooling would be required.. perhaps even more sophisticated than the oil lubing and cooling systems in existing direct mechanical linked systems. |
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decreases in transmission efficiency from exhaust wheel to compressor wheel. (electro-magnetic losses. inefficient control circuitry.) |
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decreased thermal efficiency of the engine. the heat transmitted between the exhaust wheel and the compressor wheel in a direct mechanical link essentially feeds waste heat energy from exhaust gases back into the engine as increased volumetric efficiency (with the aid of an intercooler usually). removing this heat transmission will result in reduced thermal efficiency of the engine. (energy in fuel converted into rotational energy) |
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more components. added complexity. |
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though some advantages could be: |
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unused generated energy can be stored and used on demand (ie. will provide full compression, when alternator is still "spooling"). thus overall thermal efficiency is increased. though still may not match that of direct mechanical link. this would essentially be an "anti-lag" system, and could double as a secondary "battery charger". |
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all pros and cons aside, some serious development could raise this as a contender. |
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i say drop the piston engine, just use a turbine which maintains a constant speed which provides power - to either charge batteries or drive car and car drives from batteries/turboelectrics. |
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Then consider posting an actual idea of what you suggest rather than posting it as an anno in a completely un-related idea. |
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I think you misunderstand how turbos work. There is no gearing or additional hardware between the turbine and the compressor; they are on the same shaft supported by the same bearings. You wouldn't really save any of the cost or complexity of a turbo system, but you might increase its efficiency and maybe the motor's responsiveness. |
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To whom are you addressing that to, [raspberry]? |
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To the author of the idea. Was there maybe a correction that I didn't see earlier? |
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I doubt it. It looks as though the author hasn't been here in years. |
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“How about turning the exhaust flow into ac current? All you would have to do is connect a spinning magnet to the exhaust-ended fan. As rpm's increased, more current would be created, driving more amps to another spinning magnet which would either work an air compressor (or a fan blade) to effectively force more air into the engine intake.” |
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Great idea especially for on demand power. Bowman power (linked to the left) produced a turbo alternator capable of 400000 rpm without issue. They are able to produce 3.8kw per low end turbo alternator and with twin turbo that would be plenty to not only remove all the pulleys on the engine releasing power but also to power an electric centrifugal supercharger. Your only remaining problem is power storage and the current market of flex vehicles have that portion fixed. So it’s a great idea. The turbo alternator was first tested by the department of defense in the early 90’s. The other company who is producing smaller turbo alternator units is Controlled Power Technologies also linked to the left. |
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You might want to make your "turbocharger" in 2 separate parts: an electricity producing impeller end which acts as a generator(/alternator), and an electrically driven compressor end... maybe with a clutch or gearbox in the middle for continuous use. |
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As long as you are making power with your exhaust side you don't have to drive a centrifugal pump on the intake side, you could run a lysholm screw compressor at a lower speed (though requiring more torque) and make the same boost. This will at least avoid a crazy motor that has to run at 20,000 rpm. |
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