I'm not the only one to have thought of this, but as yet no real work has been done. How about a hybrid car powered with a Stirling Engine? (Not spelled Sterling, btw.)
The Stirling is more efficient than the internal combustion or diesel engine, and it's also a lot quieter. Sounds great, but it's not good for cars because it can't rev up quickly and it takes about 5 minutes to get the engine hot enough to run well. We want our cars to start the minute we put the key in.
A hybrid design (with enough batteries for 10-20 miles) solves this. You can get all the acceleration you need from the electric motors, and you can start driving right away, while heating up the Stirling "boiler". Then it kicks in to provide the power to run the car for the long haul. If you know the trip is short, no need to fire up the Stirling until the battery gets low.
The Stirling can burn anything. Gasoline, kerosene, diesel, vegetable oil, hydrogen, even wood! Yes, you could, in theory, be stuck by the side of the road out of gas, then go out with an axe to chop trees and refuel your car.
Well, almost. You want high-temperature burning for the best efficiency, and this would pollute and probably dirty your nice clean boiler. Right now the engines are expensive to machine but I suspect that could change.
This occurred to me as well, but there are very good reasons why automotive Stirling engines are still a fair way off. They are significantly larger than internal combustion engines for the same output because the working fluid is separate both from the combustion gas and from the atmosphere. They require huge radiators and lots of air blowing through the radiators to get the kinds of efficiencies they boast. People like roomy cars, not cars that devote half their space to the engine and its associated bits. Large, efficient radiators (not to mention regnerators and other sorts of heat-exchange doohickeys that would be used on automotive Stirling engines) also tend to be expensive, not to mention heavy.
Ultimately, there is no particular reason to believe that, even given large amounts of development work (time, money), a Stirling-powered hybrid would be any more efficient or even cleaner or quieter than even current hybrids or even a plain old Honda Civic. Plus, hybrid diesels are on the horizon, which will give an additional 30% efficiency boost on top of the already impressive numbers from current hybrids, while being cleaner than current gasoline engines. The hybrid design eliminates most complaints about diesel engines at least as well as it eliminates (some) complaints about Stirling engines.
Keep in mind that the Prius also isn't your grandpa's Otto cycle. It uses a Miller cycle engine, which allows it to run on beer. Err, actually, it gets rid of the need for a throttle plate by using intake valve timing to control load on the engine, thus eliminating losses due to sucking a vaccuum. Unfortunately, this has a drawback on regular cars - no low end torque. This is why the Mazda MX6 that used a Miller cycle engine was supercharged, which kind of gets rid of some of the efficiency advantages. A hybrid like the Prius (and now the Ford Escape) can bypass this problem altogether. Sound familiar?
IMHO, the engine that the hybrid design, especially series hybrids, fits the best with is the turbine engine. Turbines like to run at constant speed; their acceleration characteristics are even worse than Stirling engines. They are the most compact engines for a given output, at least for higher output (>50 hp or so), and their ability to scale down to even smaller outputs and higher power densities is improving evey day due to the use of microturbines in industrial applications. They have the same "run on any fuel" characteristic as external combustion engines such as the Stirling engine, though diesels actually also have this characteristic.
In conclusion, don't be so quick to throw out internal combustion! Otto and his cousins have a lot of years left in them, and I expect we'll be driving around in internal combustion-powered cars right up until flywheel-powered electric cars put them out of business. That is, assuming the energy policy people get their act together and either get out of the way or quit kowtowing to the eco-nazis who are preventing us from using one of the greenest electricity sources of all: nuclear power. If not, well, I guess we'll be driving around with good ol' Otto well into the next century.
BTW, boilers are steam engine parts. The part of the Stirling engine that you're talking about is the combustion chamber, and there is no particular reason it needs time to heat up. Even steam engines can be made to come to temperature quite quickly.
Nuclear Power!- Green?
Nuclear Power - Greenest - I think not...
When assessing the costs ($, environmental & opportunity etc.) you need to look at the full lifecycle, and at everything that is affected by it.
In the case of nuclear power - the people who keep insisting we look at it consistently omit the massive decommissioning costs (which far outwiegh the initial commissioning costs). We also need to look at the human costs, which thus far are consistently covered up and avoided (how many americans have factor V leiden mutation?, how many children have lukaemia? how many people have lost their jobs and their reputations for asking these questions?).
Not to mention the increased chances of some terrorist getting hold of some weapons grade plutonium...
The reason they keep pushing for it is probably because they own stock in the construction companies (eg Haliburton) that would win the contracts...
Why make power when it's already there? We should be harnessing the solar, wind and wave power that is there already. Cars could easily run on biomass, eg. Wood alcohol (renewable and truly clean).
We could also massively reduce our energy needs without compromising our modern lifestyle. The average house could reduce it's power consumption to a fifth if we just switched to energy saving technologies and were properly insulated.
Nuclear power= Very Green
Your argument is petty, nuclear power is the cleanest we have at the moment. There is less radioactive poisoning in the cooling water that is released into the environment then there is in a pint of beer! If you want to bring in arguments about ecological impacts then lets talk fossil fueled power plants, more specifically, coal. Coal plants generate in excess of 40 million tons of mercury and 13.6 times the radioactive fallout of a nuclear plant.
simply put, there is no substance that can fuel a candle hot enough to nuclear power-nothing!
Dont be too happy about
Dont be too happy about nuclear power. The waste problem is unresolved, the bomb proliferation problem seems to press america into a new war, and the amount of uranium lasts for no more than 60 years.
40 million tons of mercury look quite a little much to me for coal driven power plants, especuially if the exhaust is filtered. Did there someone do a calculation with a point error?
Radiocative fallout: If the neandertal men would have used the atomic power in our way, we would have no uranium left, but still sit on the nuclear waste.
May be that there is a lot of C14 coming out of a coal power plant.
But all of the plutonium in the sea is made by nuclear power plants.
And this is not a little amount! And a very strong poison.
So your last sentence is rubbish.
Coal plants release more radioactive waste than nuclear.
If you would indulge in reading the report "Coal Combustion: Nuclear Resource or Danger" by Alex Gabbard(http://www.mindfully.org/Energy/Coal-Combustion-Waste-CCW1jul93.htm), you will see from the conclusions that coal power releases five times as much radiation as the least regulated reactor, which is calculated to be one hundred times the population dose equivalent of nuclear power. Essentially, this is due to the fact that coal is an impure fuel that contains between one and ten parts per billion of uranium (and 2.5 times as much thorium). This is then released directly into the atmosphere (scrubbers are not required by federal regulations for these exotic metals) or accumulates in piles of fly ash (generally glass beads) that are distributed through water runoff, airborne contamination, and the food chain. Very startling, so see the results for yourself.
Question the method, not Mode
Nuclear energy is about Chemistry, as in putting two or more substances together in a way that make energy that people can use. The nuclear plants that the U.S. has are largely an offshoot of the weapons development program from WWII.
There are other ways to use uranium and other radioactive elements to create electricity which can be less dangerous or waste-producing if they were developed with the same vigor as weapons grade stuff. Most ideas stays on the blackboard because the nuclear age literally started with a bang and the fear factor among much of those inexperienced in nuclear chemistry is high. Canada has an active plant now that uses straight out-of-the-ground uranium and Deuterium Oxide (Sometimes Called "Heavy Water") to make heat to run Turbines. This is actually one of the earliest, Pre-KaBoom designs. Uranium decays to lead eventually. One that I hope is being developed re-uses the present waste until it is inert.
Deeper Truths
Nuclear Power is not as clean as solar photovoltaic cells, nor wind energy, considering the whole process and risks involved. Look at all aspects. There's the mining matter - it requires enormous mines to get the Uranium from low-grade ores, with all the associated risks and energy useage at that step. Then onto getting the miniscule amounts of fissionable Uranium from the Uranium Yellowcake. Then the fabrication of fuel pellets, use, and when done, all the radioactive parts of the plant that need replacement & go bad from metal embrittlement, in addition to the hot waste. Cooling water smoolng water! Never mind that! I agree - Coal is worse at present; but Brad's right when he says energy conservation will get us a five-fold increase in efficiency, with greater comfort levels! I've done this - taken one home and reduced it's energy demands to 1/5 th the original levels, and it's comfy! Fresh air with heat exchanger to boot! And there's room for even greater improvement - it could use more attic insulation and some solar hot water panels (which pay back in a few short years); perhaps taking less than a 10th of the original energy load when all is completed.
Now, let's look at solar cells, fer instance. The most common ones are made from Silicon, of which the supply is everywhere and virtually limitless. The industrial process runs some risks, true enough, but these risks are minimized in-plant risks, and there is no lasting radioactive waste to deal with. Once produced, silicon solar cells have, at a minimum, a 20-year life expectancy; probably more than 30 years in reality. The only things that really go bad on them are the coatings (i.e. PolyVinyl Acetate) that degrade, contact corrosion from condensation, and connections that come apart after decades from all the contration and expansion via day/night temp. swings. They pay back for the energy inputs is roughly 5 years (give or take the climate), and they are silent and very reliable. Power needs to be banked, but newer storage mediums can help there as well. (Nanotube ultracapacitors, Flywheels, etc.)
Simply put, it's not super-powerful Uranium that we need, but rather applied common sense. All we really want is cold beer and hot pizza! :>
Solar/Wind
Can someone explain to me why a solar plant covering acres and acres of land, is environmentally friendly? What about the plant life and animals that will be displaced due to the lack of sun and heat?
Can I put solar on my roof? SUre, but I will never have enough energy to run my A/C...and to store power for the night I need probably a ton of batteries...taking up room not only on my property but on landfills when I am done with the.
And as far as wind energy goes...what do you think happens to the environment when the wind is STOPPED at a certain point? Can you imagine the problem the birds will have in migrating? What about the changes in the weather due to unnatural high pressure and low pressure areas.
The ONLY reason nuclear is expensive is due to EXCESSIVE regulation. Believe me, I would rather have a NUCLEAR REACTOR next to my home, rather then a WIND TURBINE, SOLAR FARM, OIL or COAL BURNING plant ANYDAY. In fact, I WOULD PAY for a NUCLEAR SUB/AIRCRAFT CARRIER generator for use in my town.
Can you imagine the problem
Can you imagine the problem the birds will have in migrating? What about the changes in the weather due to unnatural high pressure and low pressure areas.
ANY bird that is too stupid to fly around a windmill deserves to be extinct
Why store power from solar
Why store power from solar cells in a battery.
It seems that storing it as hydrogen and oxygen for fuel would be better.
Bill
Storage
Hello Bill!
Hydrogen's good - zeolite storage may be the most green for H2 and O2. U might want to look at nanotube supercapacitors and flywheels as well. There's a lot of better ways than heavy metal batteries, that's for sure!! :>
Hydrogen
Creating hydrogen from water is only about 60% efficient, and then converting it back to energy is again about 60% efficient, resulting in you only getting out around 1/4 to 1/3 of the energy you put into your hydrogen 'battery'. Chemical batteries have efficiencies around 90%, and ultracapacitors have efficiencies of very nearly 100%. In truth, hydrogen is a very POOR energy storage medium. The only reason that it has been touted as a fuel is that a car using it could be refilled at a station much like conventional gas or (more closely) natural gas/propane.
Hydrogen as power storage
There is another issue here too, electrolysis and/or fuel cells produces DC current. Most components in the US use AC so you will have to rectify or (worse) burn the hydrogen to get your AC. It just doesn't make sense in most cases. Now you develop a case where you can use DC on site you may have a point. I have thought about this in the past and the most reasonable idea I can think of is Sever Farms (huge demand for DC in localized area).
Nuclear on the other hand is here now, works, and can provide most of the power needs for entire planet safely. Disagree with that comment, look no further then France.
The biggest hurdle to making nuclear work is dealing with the waste. We do have several options available to use now though; such as deep sea burial, glass pucks, and my favorite, launching it at the sun (fusion wins over fission) :-). Truth be told we Americans are just to damn scared of it.
There is no technological
There is no technological challenge with producing AC from a DC current. DC/AC inverters are widely available, and getting cheaper all the time as magnetics and switching technologies improve and we move to higher switching frequencies. Cheap small inverters are 80% efficient and everywhere. Big ones are 90 or 95% easily.
Once evidence of the improvement of the inverters is the switch to electronically commutated motors (ECM), which run on DC supply, and convert to AC for the motor. With the increased materials costs of copper and steel (for transformers) these high-tech motors are often cheaper than traditional AC induction motors -- the little cooling fan in your computer likely uses this technology (I hope!) ECM cooling fans are often half the price of comperable AC induction fans, and much more efficient.
Geo Solar with Stirling
Run Air Conditioning with geotubes providing passive cooling and dehumidification down to ground temperature at 55 degrees if u want it that cold. Much better and cheaper than using electricity to run a/c compressor. Then run solar thermal stirling to produce electricity on roof of passively heated and cooled house. This would provide enough electricity to run everything else you need with the excess for an electric vehicle or electrolysis of water into H2 and O2 for H2 car or hybrid electric and hydrogen.
Urainum vs. Solar
I agree - giant areas covered with solar panels is not the way to go! Solar rooftops is. The answer is INSULATION and VENTILATION. Think about it! Why gobble up oddles of energy to heat and cool a home, when it's so much cheaper to just insulate, seal, and ventilate properly? I did it, so it can't be all that hard!!
Hey, that's a good point! But, we've got a long ways to go before the wind stops!!
Nuclear regulation is there for a reason. It's a heavy metal, for one thing. Just ask the Uranium miners who are dying of cancer, because years ago, you were just supposed to "suck it up, soldier!" Maybe not the case today, but there's a reason for regulation. It's called the referee. Without one, the game would be pretty damn unfair (some might say, deadly at times). Good outfits need no regulation, but to allow for them to be competitive, there has to be that referee over there on the sidelines. Now, maybe the referee and the rules need checks and balances, as well as revamping to better fit the situation, but that doesn't mean we should throw out the baby with the bathwater.
I agree. Some applications are best fit with nuclear power. Aircraft carriers are one such application. And, for the time being, we're going to need Nuclear to get us through the transitions into the efficient future. But open up to a new way of seeing things. There are solutions that get us there, and they're not that hard to see!
> Can I put solar on my
> Can I put solar on my roof? SUre, but I will never have enough energy to run my A/C
Depending on your A/C, yes you can.
> taking up room not only on my property but on landfills when I am done with them.(sic)
Lead-acid batteries are one of the most recyclable things we have on the planet today, and have immense power densities (they use them on boats for a reason). Just because we do not recycle them in any significant quantity doesn't mean that they're unrecyclable.
> what do you think happens to the environment when the wind is STOPPED at a certain point?
Uhh ... nothing? Need I remind you that mankind has harnessed wind power since before we knew how to write?
> What about the changes in the weather due to unnatural high pressure and low pressure areas.
Oh ... you mean ... like the artificial pressure zones that MAJOR CITIES produce, what with all that massive coating of BLACK TOP all over the place? And highly solar-reflective buildings (especially glass-covered highrises used for businesses)?
At worst, the impact of solar panels would be comparable to a similarly sized metropolitan area.
> I would rather have a NUCLEAR REACTOR next to my home, rather then a WIND TURBINE, SOLAR FARM, OIL or COAL BURNING plant ANYDAY
This might explain your lack of rational thought processes; perhaps you've lived too close to them for some time.
* Wind turbines do have an issue with bird deaths. This is a very valid concern, and is a problem being worked on today. But, if this is the *ONLY* problem, compared to the HORRIFIC problems associated with nuke plants, your sense of what's best is severely skewed.
* Solar farm. Well, so far, of all the solar farms in existance, NONE have shown detrimental effects to the surrounding environment. N O N E . As in, NO patches of dried up grass (there is enough ambient light to fulfill their solar requirements), wildlife seems to enjoy the shade, rather than hide from it, and sometimes, birds even nest underneath them. Meanwhile, our cities are just smothered with blacktop coated, full-solar-exposure parking lots creating lots of waste heat for nothing. We could solar-farm these parking lots (just like Google, Inc. is doing), providing both protective shade (preserving the life of car interiors too, thus improving resale value of cars!) and power generation. We can put solar panels on the rooftops and the sides of buildings, of all city buildings, which otherwise have black, tar-coated shingles and/or pebble beds exposed to the sun. And, let's not forget that the USA has a *massive* amount of desert land that is just begging to be harnessed for both wind and solar use.
* You don't list geothermal, which is also an important energy source too. Are you aware that the Earth is a giant heatsink? Dig six feet into the ground, and the temperature is a nice, cozy, 58 degrees, consistently (give or take a few degrees for which latitude you're at), year around. Large-scale, low-temperature differential Stirling-cycle engines can be utilized to take advantage of the temperature differences between surface air and subterranian temperatures, both in summer and winter times.
> In fact, I WOULD PAY for a NUCLEAR SUB/AIRCRAFT CARRIER generator for use in my town.
And if you lived in my town, I would make every attempt to have you removed from said town immediately, with force if necessary. I will not have any fissile material anywhere near my place of residence, nor place of employment. Your reckless abandon and disregard for your fellow citizens demonstrates precisely the results of the USA falling so far behind other countries in science education. You're just rehashing the same blah blahs that we've all heard from the nuclear industry before. And, yes, nuclear does have SOME advantages. But, history has shown time and again that the WASTE issues haven't been solved, and it is precisely the WASTE issues that cause the problems none of us want to deal with.
In particular, when a fuel rod is "used," it actually has transmuted only 3% of its Uranium. ONLY THREE PERCENT. The other 97% is totally wasted, because the reactions are too hot for the power plants to handle. So, we stuff 'em underground, where they'll just have to sit for at least a few million years while the dang thing decomposes to acceptable radiation levels. That's just brilliant. Real brilliant.
Ah, but you can always use neutron sources to hasten the decomposition, and then use a breeder to recycle the fuel rod. This is what France does, after all. But neutrons come from somewhere -- yes, they come from electricity produced by other fuel rods. So now, the "fuel economy" of the use of nuclear falls significantly. And, even then, the laws of thermodynamics says that you can never recycle a fuel rod to precisely its original state completely, so after a while, the rods have to be thrown away. And, yes, they're "hot."
So between the mining required for U238/U235, the necessity for breeder reactors, the necessity for neutron sources, and the horrible environmental impacts of spent rods and the decomissioning of nuke plants, I'll take a few dead birds in my backyard ANY day. They at least bio-decompose.
Wind farms
Actually wind farms do disrupt the wind. You can't stick one row of turbines right behind another. But I don't see this causing any environmental harm, it just causes disputes over "wind rights." Wind farms do disrupt the landscape, as to work really well they must be tall. On the other hand, they make great sense on the top of tall buildings in windy cities.
As for the nuke, I have to say there is a compelling argument if you believe the worse end of climate change predictions. That's because those predictions involve the displacement of billions, the deaths of millions and huge costs. You could take all the nuclear plants built and more, and take all their waste and grind it up in the wind and you would cause huge damage, but a drop in the bucket compared to those predictions for global warming, as a result of the coal we're burning while we are afraid of solving the nuclear waste problem.
I'd just like to note that
I'd just like to note that Geothermal is really just a special case of nuclear power, most of the heat that comes out of the earth is caused by radioactive elements decaying deep within the earth and giving out heat. Even solar energy (and it's resultant winds from heating of the air) is just given to us by our best and safest nuclear reactor - the Sun. It's really just a matter of how far and how well shielded we are from our nuclear energy. Thankfully the sun is a long way away, and we have a protective atmosphere and magnetic field deflecting a lot of the nastier forms of radiation the sun flings our way. Geothermal is good as well, since the reaction is deep in the earth, we are relatively safe from it (and well shielded by the earth under our feet).
Tidal energy is kinetic energy of the moons orbit being drawn off as far as I understand it, but this "gravititational" energy is the only other true source I can think of.
I agree with most of
I agree with most of this
I'd just like to note that these horrible cities are actually the most efficient way for humans to inhabit the world. It is the rural folks (like me) that have the biggest footprint.
In the desert where you have
In the desert where you have acres and acres of solar panels there usually isnt much plant life to begin with. If its personal use solar panels can go on your roof or be used as a porch awning. New glass mounting alow enough light through to still allow plant growth. Passive solar can be used for heating. In new arcitecture its even being uses for cooling. Most batteries can be recycled after the life of the battery, grid tied systems dont need batteries. The idea that wind and solar systems cause fluctuations in weather is a myth. I also dont have a problem with nuclear. I believe in improving all such technologies.
lol
lol these are the people who are against nuclear power. I dont have a long enough attention span to read all the other comments so i hope im not restating something but probably am.
1. heres full lifecycle: mine the uranium - purify it - get energy from it - store the waste
nope i dont see any bad stuff in there (or more accuratly worse then other power plants itd be great if all but get energy were gone)
2. i have no clue what you mean decommisioning cost i dont intend to be decommissioning my shiny new nuclear plant any time soon
3. no ones covering anything up about nuclear power plants with millions of you conspiracy dudes watching them constantly then making crap up when you cant find stuff their covering up.
4. OH CRAP THEY USE WEAPONS GRADE PLUTONIUM IN NUCLEAR POWER PLANTS!!!!! thats what id be saying if that were REMOTELY true in reality stuff used in nuclear reactors 1% pure weapons grade is about 97% pure. Infact i heard somewhere we are thinking of selling off the some of the stuff or other so other countries can use it.
5. wth? sounds like you think the building of the plant is gonna make people more money then the energy from the plant.
6. solar wind and wave are great but ever seen one of them? they in great huge fields and they dont produce as much (dont know the ratio sry) as nuclear plants do. im not so much worried about cars in this cause cars wont be running on nuclear in my lifetime and will be running on electric in a good while(im hopefull for soon but reality isnt so) so they wont be running off nuclear indirectly either. plus there was some deally about if we ran off biofuels wed have to use every crop made in the US and still wouldnt have close to enough.
7. so you wanna go the lazy route and conserve for a coupla years and let the later generations deal with the problem huh?
Sterling Engines
I am looking at the same idea only to power a narrow boat on the english canals. A company called WhisperTech in Australia, currently makes a stand alone sterling engine rated at 800 watts. These are available here in the UK and are being fitted into boats as generators with heat exchangers to provide hot water and heating.
sterling engine wispergen
I heard rumors that the engine burn out can anybody confirm it, this came from a dealer in the wispergen network the have a problem with quality controle
To Dartlavi:Which dealer
To Dartlavi:
Which dealer did you speak with? Have you developed any prototypes yourself?
Sarah
Stirling Engines and narrowboats
I believe WhisperTech is a New Zealand firm, not Australian (much as I'd love to claim them). Their main product is branded Whispergen. And I can easily see them used in that application - they're small, and you could (depending on the draft of your narrowboat) potentially run them with the cold sink in the water and the hot side exchanger plumbed above a small, cozy peat fire.
The major advantage of Stirlings is not their size:output ratio so much as the fact that their fuel is essentially free. Often the simple thermal differential between a body of water and the air above is enough to keep them spinning. Might be enough for your application - Narrowboats aren't exactly the sort you'd use for water skiing. Zero carbon footprint, very easy on the operating budget.
stirling engine vs. steam engine
How can steam engines be made to come to temperature quite quickly?
In the 1940's there was an
In the 1940's there was an american company that produced steam engine cars that could be run 30 seconds after start up.
With Flash Boiler?
I think the idea is not to heat the whole bunch of water in one large tank, but to heat a smaller steam generating chamber with heat exchanger mass hot enough then squirt small amount of water on it. The water will be converted into steam practically instantly.
The time required to rise heat exchanger temperature would be a lot less.
any fuel?
You say that diesels are "any fuel" engines,
try gasoline in one !
Any Fuel
In theory, at least, Herr Rudolf Diesel's Engine is supposed to be able to burn any liquid or gasseous fuel. Now, that might mean designing each engine to handle each fuel type best, and adjusting the timing of the injectors just so the burn occurs precisely when it should.. Diesel's actually spray a jet of fuel into a chamber of compressed hot air, whereupon the fuel burns as it gets sprayed in, so Diesels are supposed to be more universal. Methanol can be used in a properly adjuted and designed Diesel, as well as the oily fuel types. And, they're supposed to be more efficient than Gasoline engines, maybe because they run hotter? Anyhow, what happened when you put gasoline into the engine?? :> That must have been exciting!
OMG, you have no idea what a
OMG, you have no idea what a Stirling engine is, do you! They don't have to be huge, they don't need radiators and they don't need huge amounts of cooling. You work for Big Oil don't you? :)
One of the reasons it is the most efficient engine on the planet, is that it only requires a slight difference in temperature. A candle can power it. The size of the piston determines how much power you can make.
Have you seen the whispergen? It's a commercially available Power Producing Stirling Engine. It's completely self contained. There must be vents but I can't see them on any of the photos. Also a Stirling generator would triple the efficiency of any HEV or PHEV.
I could even go one step further than just a Stirling. I could buy a steam configured Quasiturbine and use it as a Stirling. Look it up.
Actually, they do need a
Actually, they do need a radiator if you're going to maintain a constant temperature on the cold-side of the engine. Air-cooled, high-power engines don't have the heat dissipation surface area to maintain operation for extended periods of time. The engines you talk about are all "LTD" (Low Temperature Differential) engines or engines of insignificant amounts of power, and are thus able to be air-cooled. But, so was the VW Beetle engine.
If you want power, you need liquid cooling (and probably liquid heating too), because there is no better way to exchange heat.
Stirling Engines and narrowboats
It is about the most efficient engine on the planet, yes. But the size of the piston isn't the only determinant. The actual temperature differential that you're mining has a large part to play. The rest is basically plumbing.
Stirling engie based hybrid car
I like the idea for a Stirling Electric Hybrid, but not for a car. The combination of a very efficient Stirling engine, with a light enough battery pack and electric motor to augment the Stirling when it could not make optimum power, would be a theoretically superior light aircraft engine.
The problem of power to weight/size would have to be overcome, but I have seen several designs floating around the web that claim to be close. With funding and brains, someone will make it (or something like it) work.
Because Stirlings operate on a difference in temperature between the hot and cold sections of the engine, the efficiency (and theoretical performance) of this type of motor increases with altitude.
The Stirling's basic difficulty with quick power/rpm changes is far less relevant in an aircraft engine, where power settings are not changed quickly or often.
The need for large radiators on a Stirling engine would be offset by the constant flow of cold, high altitude air. The Stirling would not make very much power for take-off at sea level, where the temperature difference between the hot and cold side of the Stirling would not be very high (and difficult to increase artificially without adding weight and complexity to an already complex design). That is where a light battery pack and electric could be useful, although it would not be a hybrid in the same way a Prius is, because you would not have any real potential for regenerative charging of the battery - a propeller efficient enough to windmill power back to the battery during descent would be difficult to design in a way that passengers would buy into("Er, yeah, the engine actually isn't running; that's why it's so quiet...").
Speaking of batteries, until some major and scalable breakthrough happens in battery technology, the key advantage to a Stirling Hybrid for aircraft (like the Prius) would be fuel savings, not performance or payload gains. The best you could hope for is a net zero change in either, because the weight of whatever fuel you saved would certainly be offset by the weight of even small batteries and an electric motor. In fact, if you graphed the lines between what it would take in electrical energy to augment the weakness of the Stirling for sea level operations and take-off and what all of this would weigh, you'd likely end up (at least today) with something fairly underpowered with very little payload.
But remember, the Wright Flyer was grossly underpowered and had very little payload. So we just need to keep after it. Lycoming, Continental and Big Oil can't hold out forever.
KEEP IT UP! MAKE YOUR KIDS BECOME ENGINEERS!
PEACE...
solar stirling
Is t really possible to power stirling engine driven car by solar heat and wat r d really prob arises
Mmmm, as seen so often, an argument limited by the familiarity of current 'consumer available' technology! Potentially (without the $Bn's spent on the IC engine!!)the Stirling/Carnot cycle engine can be vastly more efficient - it just needs to be used in a different way. And why not spend the money on it anyway? The engine powering the car most of us go to work in (even allowing for recent variations) is one of the most horribly inefficient, dirty, noisy, machines invented by man! It's only still in use due to the laziness of the scrooges who run the motor/oil industries Oh, and their paid lackies in governments all over the world!!
Turbines, well they've been about for over 60 years now. The first 'production' car was a Rover in the 1950's. The fact they're not in common use should tell you something!
Nuclear power clean? Well, no CO2 emissions, but as to everything else; how can we tell how efficient it is when NO government tells the truth about construction and maintenance/running costs. Plus the security angle.
And you ask how clean nuclear power is of anyone who's had to have two guys with stiff brooms give every single inch of their body a going over after a leak.......
"Turbines, well they've been
"Turbines, well they've been about for over 60 years now. The first 'production' car was a Rover in the 1950's. The fact they're not in common use should tell you something!"
Ya, it tells you that Brayton cycle engines in a small / lightweight configuration have even LOWER thermal efficiency then otto cycle gasoline engines. Combine that with sluggish throttle response unsuitable for typical automotive use and you will realize that big oil has nothing to do with why turbines are not utilized in automobiles.
If anything, big oil would love it. I'm sure they smile every time they see an M1 Abhrams tank roll by. Turbine powered and the worst fuel economy of any tank in the world.
Gasump quote -
Turbines, well they've been about for over 60 years now. The first 'production' car was a Rover in the 1950's. The fact they're not in common use should tell you something!
By that logic the Stirling is also a dead issue.
For my part, I believe the best way to incorporate a stirling into a vehicle is to use it to harness the waste heat generated by a Diesel or Otto. How about a hybrid system like the "Through The Road" system proposed by Chrysler and others where the front or rear set of wheels is powered by a conventional engine and drivetrain and the other wheel pairing is driven by a battery set and wheel motors. With the two systems operating independently and a computer monitoring the interaction between the two. The idea being that the electric set would charge through regenerative braking, and while running at road speed pull a little on the IC engine to top up the battery set.
The practical upshoot of this proposed hybrid is reduced cost by using the exsisting driveline without needing to modify it to interface with the electric. The other benefit is that it actually offers a performance improvement by offering AWD and the availabilty of the high torque electric motors to move the car faster with a smaller more efficient IC engine. Making the Hybrid a performance enhancer will improve it's marketability.
The Stirling fits in by charging the batteries continuously during the IC operation, not by sapping the IC power on the road. The regenerating charge wouldn't be suffcient to keep the batts topped up without using some of the IC power charging. with the stirling on the job the IC will be able to be trimmed even more offering greater economy. If the batteries were charged the stirling could send power to the wheelmotors to ease the burden even more on the IC.
Introducing and gaining public acceptance of unfamiliar technology has to include a real tangible benefit for the consumer.
Just a thought. What would that be a Tri-brid? :)
Hi,
I've heard references to a some '70s GM stirling
engine based proto-types. These could start in
under two minutes, and where supposed to be part
of a solution to the oil crises at the time (now
we just invade other countries...). The 2 minute
start time was still too long. Sorry I can't
provide any solid references (I've been looking
for some for a while). But I feel that car sized
stirling power plants do exist....
iroxATixDOTnetcomDOTcom
Invade other countries
I am so sick of liberal tree huggers.....so what is it, invasion for cheap oil or invasion to make Cheney's oil barons richer....dude get over it all ready!
hug this.
Get over it? Why don't you tell that to the 100,000 + dead Iraqis. I may be a tree hugger but at least I'm not a Nazi lover.
Nazi
By the way Nazi is an acronym for The German peoples party, "of course in German" a leftist organization. Also the inventors of political correctness.
New nuclear reactors produce only 6 % of the waste of the old reactors. Europe is ripping out the old fossil fuel power plants and installing the new fast neutron reactors as fast as they can. Also the waste from these will only last 300 years instead of 10000 from the old and cannot be used for bombs. The waste from Coal and and other fossil fuel plants is greater than a complete nuclear plant, is chemical, and is forever and they are dumping it all over the place.
Power windmills kill migratory birds by the thousands and are noisy, foommm foomm foomm like water torture never stopping. Not even theoretical solutions to this one.
Solar has not enough horse power per square foot even at 100% conversion. And the waste is really nasty never go away poison.
Wave power looks good but will not work everywhere, Environmental impact on a large scale is still a question. A lot of the ocean life depends on waves. Smaller waves equals less oxygen in the water and some other problems. Good to reduce beach erosion though.
Sterling engines can stretch what we have though and can pull power out of thermal differences nothing else can, even if they are big. At least if they don't have to move it's not quite the problem.
We need nuclear power but we need to use as little as possible. Just replacing incandescent lights with the new white light LED lighting coming out just now would mean we didn't need a new power plant for close to thirty years.
Most of what you say is
Most of what you say is wrong:
burned out nuclear fuel is always the same amount and directly linked to the power production. The waste will last 10 half lives of plutonium and strontium, no way around that either. and this is more than 250000 years. Power windmills kill no nearly no birds. I looked under 2 600kW engines for a Year and I found none. I also had a holiday at the seaside, and within 3 weeks, I looked every evening and founs one seagull bviously hit by a flap. Around me were millions living and flying from land to sea in the mrning and comeing back in the evening.
I dont argue on noise, one goes into discos if he wants to dance and suffers from the hum of a bee if he wants to sleep.
Square One
Glad Nuclear is getting better, but everything has drawbacks. Best is to go with Intelligent Designs for efficiency. We could have a hoppin' economy on less than 10% of current energy consumption, but it requires common sense to go that route, and a little reflection on the matter. Keep all the possibilitied out there, but look at use, and therein lies the biggie; the veritable motherload of all energy solutions. Efficiency is the answer.
> Nazi is an acronym for The
> Nazi is an acronym for The German peoples party, "of course in German" a leftist organization.
What the heck? I wonder why they didn't get along with those other leftists in Russia then. While the definition is open to interpretation I think Nazism lands clearly in the fascist category:
http://en.wikipedia.org/wiki/Fascism_and_ideology#Fascism_and_Nazism
And fascism, being primarily authoritarian, skewing to the conservative/right, not left.
(more interesting discussion on various political spectra here: http://en.wikipedia.org/wiki/Political_spectrum )
"The main plank in our program is to abolish the liberal concept of the individual and the Marxist concept of humanity, and to substitute for them the Volk community, rooted in the soil and united by the bond of its common blood."
On balance, doesn't seem to support an affiliation with the left.
But anyway, I agree. Nuclear isn't as bad as its detractor's make it out to be (especially in comparison with other, dirtier, forms of energy that are already widespread and pollutant today), but that doesn't mean we shouldn't use common sense and new technology to conserve, be more efficient, and recycle. There's no reason we shouldn't do BOTH (find better energy sources, reduce waste of current energy).
Please keep your ignorance
Please keep your ignorance to yourself. Your invasion for cheap oil costs this country billions. In no way can it be justified morally, ethically, or financially. Your a moron and your parents were morons. Hug a tree, so your children have an Earth to grow up on, or better yet self sterilization would be best for society.
Nasa Sterling
The final report for this project is:
Ernst, William D. and Shaltens, Richard K. (1993), "Automotive Stirling Engine Development Project", Final Report, NASA Contractor Report 190780, MTI Report 91TR15
The Abstract, part of the Summary, the main headings from the Table of Contents and the Conclusions from this report are reproduced below.
ABSTRACT
The development and verification of automotive Stirling engine (ASE) component and system technology is described as it evolved through two experimental engine designs: the Mod I and the Mod II.
Engine operation and performance and endurance test results for the Mod I are summarized. Mod II engine and component development progress is traced from the original design through hardware development, laboratory test, and vehicle installation. More than 21,000 hr. of testing were accomplished, including 4800 hr. with vehicles that were driven more than 59,000 miles. Mod II engine dynamometer tests demonstrated that the engine system configuration had accomplished its performance goals for power (60 kW) and efficiency (38.5%) to within a few percent. Tests with the Mod II engine installed in a delivery van demonstrated combined metro-highway fuel economy improvements consistent with engine performance goals and the potential for low emission levels. A modified version of the Mod II has been identified as a manufacturable design for an ASE.
As part of the ASE project, the Industry Test and Evaluation Program (ITEP), NASA Technology Utilization (TU) project, and the industry-funded Stirling Natural Gas Engine program were undertaken to transfer ASE technology to end users. The results of these technology transfer efforts are also summarized.
SUMMARY (partial)
The objectives of the Automotive Stirling Engine (ASE) Development project were to transfer European Stirling engine technology to the United States and develop an ASE that would demonstrate 30% improvement in combined metro-highway fuel economy over a comparable spark ignition (SI) engine in the same production vehicle. In addition, the ASE should demonstrate the potential for reduced emissions levels while maintaining the performance characteristics of SI engines.
Mechanical Technology Incorporated (MTI) developed the ASE in an evolutionary manner, starting with the test and evaluation of an existing stationary Stirling engine and proceeding through two experimental engine designs: the Mod I and the Mod II. Engine technology development resulted in elimination of strategic materials, increased power density, higher temperature and efficiency operation, reduced system complexity, long-life seals, and low-cost manufacturing designs. ..........................
(The remaining part of the summary contains essentially the same material that is contained in the abstract)
MAIN HEADINGS FROM TABLE OF CONTENTS
SUMMARY
LIST OF FIGURES
LIST OF TABLES
1.0 INTRODUCTION AND BACKGROUND
2.0 MOD I ENGINE SUMMARY
3.0 MOD II ENGINE DEVELOPMENT
4.0 TECHNOLOGY TRANSFER
5.0 TECHNOLOGY STATUS AND DEVELOPMENT NEEDS
6.0 CONCLUSIONS
7.0 REFERENCES
APPENDIX A: BIBLIOGRAPHY OF RELEVANT ASE PROJECT PUBLICATIONS
APPENDIX B: ASE PROJECT DOCUMENTATION CATEGORIZED BY ENGINE NUMBER
CONCLUSIONS
This final report has summarized work performed in the ASE project. The project's success can be determined by comparing accomplishments to the defined project goals and contract requirements. In so doing, the following conclusions can be made:
The potential for improvement in fuel economy for Stirling engines over SI engines has been demonstrated. A 10 to 13% improvement in fuel economy for the Mod II over the SI engine has been demonstrated for the USPS LLV in the EPA driving cycle. Based on test data obtained with the LLV, if the original Mod II Celebrity vehicle had been retained for fuel economy demonstration, the project goal of a 30% improvement could have been achieved. The Mod II engine had been sized and optimized for the Celebrity. Component optimization would also provide further improvements for USPS LLV fuel economy.
The potential for low emissions has been demonstrated in the Mod II engine: CO=<2.2 g/mi, NOx=<0.9 g/mi, and HC=<0.4 g/mi with gasoline. The 1985 Federal emission limits were easily met without using a catalyst.
The ability to operate on a broad range of liquid fuels was demonstrated. This evaluation was achieved not only in an engine test cell but also in vehicle operation.
Measured Mod II SES [Stirling Engine System] power and efficiency performance was in excellent agreement with analytical projections, i.e., the differences were less than 4% in power and less than 1% in efficiency.
Vehicle performance of a Stirling engine can be predicted from engine dynamometer test results. The Mod II-powered USPS LLV prediction of a 10% fuel economy improvement in the EPA driving cycle over the comparable SI-powered vehicle was verified by experiment.
A manufacturable Stirling engine automotive design has been identified under the project. The engine is the Mod II (V-block design with annular heater head) concept modified per the Deere & Co. VA/VE study. Manufacturing costs of $3500 to $4000 were projected by Deere & Co. for commercial production of 15,000 units per year.
In accomplishing the objective of transferring European Stirling engine technology to the United States, the ASE project succeeded in establishing an extensive U.S. technology and vendor base capable of designing, developing, and commmercializing Stirling engines. As a further indication of successful technology transfer, MTI, along with a gas industry consortium (GRI, NYGAS, and others) and Hercules Engines, Inc. of Canton, Ohio, is developing a commercial Stirling engine based on ASE technology developed in the Stirling Natural Gas Engine Program.
The NASA TU project demonstrated the ability of a Stirling-powered vehicle to be operated over the road by non-Stirling personnel; it demonstrated adequate availability and drivability.
The above report is for sale by the National Technical Information Service, Springfield, Virginia 22161
Last updated: Wednesday, May 3, 1995
I had never heard of a sterling engine before today when I picked up a June 1974 popular science magazine. Very informative article concerning the research of the day. In short, Phillips research Germany, Ford, et al developed working modes using the sterling.
hey all,
it seems to me that pretty much all the energy we use ends up as heat, right? in our cars we produce primarily heat and we just throw it into the atmosphere out the radiator and the exhaust. my question is has anyone ever tapped into it and made that waste heat work for us? i.e run it through a low temp. stirling cycle to charge some batteries (which could be sometimes used to run the car)? I am keen to give it a go, but i'm going to need some help - has anyone out there tried anything like this before?
Engine Wast Heat
Dear Ravo
I will be graduating from the Goergia Institute of Technology with an MSME this December. My area of concentration is in the thermal sciences and experimental fluid mechanics. With regars to a waste heat recovery based TryHybrid system, I must mention ( in case you do not already know this) that due to the second law of thermodynamics heat transfer from a source at the temperature of a radiator (220-240 deg F) would yeild a maximum ideal efficiency of 23% and even a sterling cycle would only give you about 1/2 to 3/4 of that. Accomplising anything significant would require attacking the problem from multiple directions at once.
First of all one would need to minimize power consumption. Therefore cars need to be made lighter, while retaining thier structural strength. Some of the new carbon composite materials that have been developed might make this possible. Second while alot of work has been done on automotive aerodynamics, I am sure some additional investigations could yeild more practical solutions than the tiny two seatters you would see at a cars of the future show. For instance, active flow control, which is what I did for my masters thesis, could be used to reduce flow separation and hence reduce drag drag). Finally, a completly novel rearrangment of a car's power generation and powertrain system would be required in order to make a waste heat recovery based trihybrid practical. As an example, you want to run your engine hotter and transfer your waist heat directly from the engine and the exhaust as opposed to channeling it through a radiator system at less than 250 F or at least use a radiator and transfer fluid that works at higher temperatures say 350 - 450 deg F. Finally one must be completely open minded to the use of any type of engine technology weather its something tried and true or a new thermodynamic cycle that someone recently dreamed up. In general, when you begin you need to give at least brief consideration to everything you can draw on a P-V diagram that would not violate the second law of thermodynamics and see what the most practical configuration would be. Identifying one cycle as the holy grail is not the way to go. That has already been done one to many times.
If you or anybody else who participates in this blog have the capability to secure some startup capital,I would be glad to partner with you in starting up a energy systems/vehicle R&D and promotion company. If you or anybody else out their is serious about trying to do something please post another blog reply and mention that it is in reply to FluidMan.
Hi Fluidman,You mentioned
Hi Fluidman,
You mentioned several times about forming some startups, where are you now at? I have some ideas to talk about.
ivanvelikov@yahoo.com
I found an article on the net that a used air conditioning compressor out of a car and was used to make a Small Steam engine!!??
My eyes are going crossed trying to find out something more.. Any thoughts??
Mark Shaw --
steam engine from compressor
Mark, If you would email me the link for that steam engine from a frige compressor I would be very grateful. I've heard it is out there but I can't find it. greenlitebandit@yahoo.com Thanks!
BTW: to all - Nazi is the National SOCIALIST Party - by its own definition a LEFT wing organization. BUT if you ever wondered where all those NAZI scientists went after WW2, research Operation PaperClip. It should make you think long and hard afterward.
greenlitebandit
Very many social democrats
Very many social democrats were killed by the nazis, for sure not due to the fact that the nazis were left! It is extremly wrong to see national socialist party as left.
In american relations it was say republican, but with killing jews and other people not to believe in Hitler.
You need to re-read your
You need to re-read your history books. National Socialism is not the same as Marxist socialism. National socialism is so-named because it believes in a single, superior race (a "nation" being defined as members of that race). Marxist (leftist) socialism is diametrically the opposite -- the happiness of man is dependent on elimination of artificial barriers introduced by race. National socialism believes strongly in corporate rule. Marxist socialism believes in power being distributed to all, from those with abilities to those in need (I don't remember the precise quote). And on and on.
Also, National Socialism acquired its name in the heyday of rising Marxism, so it makes sense that they'd try to cash in on that popularity by proclaiming themselves to also be socialist, when in reality, they were anything but. Nazism is pure, unadulterated military junta plus severe racial discrimination (in the extreme case, genocide).
Here's the link you requested, but...
http://www.endtimesreport.com/home_bred.html
I have researched this thouroughly with the A6 compressor and in my oppinion it's not practicle. All the reed valves have to be completely re-designed and there exists a mechanical disadvantage on the swash plate working in reverse.
realworlio.com
I've been working on a Stirling/Electric Hybrid (in my head) for several years. I think it is a very viable idea. I plan to build one for myself someday.
Michael
I've read thru these post and seen ideas that look cute. Somehow I think we all tend to overlook the fact the others, likely much smarter than us, have had the same concept year ago with out any success.
If you want some good detail about engines checkout howstuffworks.com.
Sterling engines are poor for cars b/c they have a constant rate of rotation and are slow to wind-up and then wind down. As stated, the internal combustion engine is muc hbetter at 'quick' access to power.
For all of the great stuff you'll hear about hybrids try to do some research of your own. Howstuffwork's shows that hybrids really only offer about 4% more efficiency over gas cars. What should be attractive is freeing yourself from costly arab oil, not engine efficiency.
They point out that people often forget to factor in the fact that that energy (in this case electric cell) need to come from somewhere at a given cost.
Before you buy your Hybird think about this. The battery in a Ford or Honda hybrid only lasts for five years max. After that it costs $2000-3000 to replace it. Yep, that's no Typo! calculate out how much money you would have spent in UNLEADED for 5 years and I bet your savings doesn't seem so hot after all.
Today's best alternative is likely Bio-diesel. Yes, vegtable oil that the folks at Wendy's and McDonalds need to get rid of. Sadly, it looks like most Americans won't even think about going back to diesel engines.
So, unless the Gov't does more to promote its adoptance we'll likely have to ride razor scooters to work.
Your Comments
Dear Ken,
your points are good, but Bio-diesel though renewable has a certain maximim rate of production, while the country's and the world's energy needs grow exponentialy. Bio-diesel and wood alchohol probably won't keep pace. So it makes sense to invest both time and effort to exploring ideas to make cars lighter and more aerodynamic. In addition if the primary engine system can be modified to premit adiquate wast heat recovery it might at least improve the performance of a hybrid system to a level that would make it worth while.
Shape and Weight and Engine
Some time ago, I was informed by wind enthusiasts and energy gurus that wind power, as well as wind resistance, is a cubic function. This is the biggest energy cost of the car - pushing wind! Probably why hybrids get better mileage in town than on the open road.. Of course, the ideal body shape would be something like a long teardrop, but we could do a lot better than the current bull-dog "muscle" look of these latest body styles.
On the weight matter, I agree - lighter would be better. But there are a lot of traction and control issues. On gooshie snow, one needs body weight for greater tire surface contact. Wind as well. So, body shape can cut the effect of side-winds, and maybe some type of newer tires could aid in grip? Seem to recall tires designed for light vehicles that do just that, but not remembering their exact design.. I thought about adding a snow-mobile track beneath my own car, maybe a studded track, that could be hydraulically lowered in emergency stops (heavy pedal to the brakes), to both align and quickly stop the auto. Also, light weight means more impact in collisions. Better crumple zones, and more interior padding? Better seat belt designs?? Thoughts welcome!
-from Chuck
> we could do a lot better
> we could do a lot better than the current bull-dog "muscle" look of these latest body styles.
Indeed. The Dymaxion car, from Buckminster Fuller (same guy who invented the geodesic dome and the space-frame), was an astounding piece of work for its time. The body of the VW Bus was inspired by it to some degree. Unfortunately, he want too far with the teardrop design, because it only had a single, rear wheel which proved to be unstable. At least one accident occured because of it.
However, if you're willing to use racecar-like suspensions, you can put two wheels in the back, recovering stability without impacting aerodynamics too much.
The traction thing isn't
The traction thing isn't really too much of an issue- a lighter car doesn't need to generate as much force to accelerate and so therefore the lower traction is acceptable. If you work out the physics, the mass actually cancels out of that equation.
You are correct in that wind resistance is a major factor in fuel economy. One thing to note is that on the highway running at steady speed, a hybrid car may as well be a regular car with a lot of extra baggage. The hybrid components have absolutely no gains whatsoever in fuel economy on the freeway. Their principle advantage is allowing you to recoup some of the energy which would normally go to heating the brake rotors, and use it for propelling the vehicle. The battery reserve / electric motor system also allows you to get acceptable acceleration out of a smaller electric motor by supplementing its power output (from the batteries) in a pinch. Anyways, as I said, none of that helps you at all in steady state, freeway operation- so you see freeway economy numbers similar to non hybrid models.
If you want to further improve, you can switch the gasoline motor in the hybrid to a diesel- the reason this isn't being done commercially is cost. Go look at the cost premium of a volkswagen "tdi" diesel model, then the premium for any automakers hybrid. Add them together, and you get a cost that would be unacceptable for most consumers.
The small weight of a vehicle does not hurt it much in collisions with a fixed object, a bridge / telephone pole / etc. While it has less support, there is less energy to be absorbed, and the acceleration tends to be about the same. Go check out the crash test video for the smart car...
Now, when it runs into a fully loaded ford excursion powerstroke, towing a trailer- that is when things will be bad. Due to the laws of momentum the huge car will have very little acceleration and the light compact car many times what it would have even if it hit something that was fixed (bridge, pole, etc). You can chase your tail trying to add more crumple zones etc, without increasing the weight- some gains are possible that way but it really isn't that practical. In reality, it just isn't possible to make it a fair fight, and there is little you can do about the large accelerations which will be present, other then to try to minimize the peak values (crumple zones).
Crumple zones can't really solve this problem as a zone that would work well against a pole wouldn't be optimum against a vehicle 3-10x its weight. Seat belts IMO are at the limit of what people will actually wear- odviously past it to some morons... Same goes with interior padding- that's basically what an airbag does and we've sort reached the limit for that especially in higher end cars, with front bags, side impact curtains.
"Somehow I think we all tend
"Somehow I think we all tend to overlook the fact the others, likely much smarter than us, have had the same concept year ago with out any success."
Everybody, quit inventing! It's all done! There are no more good ideas to be had! On your way out, please don't forget to thank Ken for realizing we are all too stupid to contribute anything new to the world.
Thanks, Ken!
"Everybody, quit inventing!
"Everybody, quit inventing! It's all done!"
I don't think that is a good idea. "It's all been done" has been stated far to many time's in the past and has constantly been disproved. Scientist's will continue to discover phenomena that have yet been found or correlate existing phenomena to new applications.
Your self-defeating attitude is only defeating yourself and the others that follow you. Lift yourself and other up... not bring them down.
Also, check out the VW Lupo and Audi A2 specs. Those cars are the way to go. Especially, if you can use carbon fiber composite body structures and couple with re-generative breaking to re-charge your electric motor. Man, 81mpg would be your low end consumption.
your lack of appreciation
your lack of appreciation for sarcasm is hilarious!
There HAVE been Sterling engines in commercial sized usage for many years. One use has been with a Sweedish submarine powerplant. Now if the military uses it, I think that a bit of development could make it more practical for civilian usage.
Regarding complaints about turbine engines lacking automotive performance, tell that to an M-1 tank driver. They are turbine powered. Quiet, fast, very high automotive performance. Fuel efficiency isn't great, but better than conventional internal combustion engines.
Now harness the heat of their exhaust and you could power a small town!
Of course we could still settle with the current arguement regarding the technology being impractical due to lack of it being developed the same way as previously: Under Abraham Lincoln the patent office director suggested the office be closed as "Everything possible has already been invented"...
Fuel economy is far worse
Fuel economy is far worse then regular internal combustion engines. Even from a theoretical point of view, the brayton (turbine) cycle cannot come close to even the OTTO cycle, let alone the diesel cycle. The M1 abrams gets approximately 3x worse fuel economy then any comparable tank. It was designed to fight the soviets within 100 miles of bases in western europe- fuel economy and range were not an issue at the time. The main priority at the time was a huge amount of power for very fast speeds in a 70 ton tank, in a small package. These same constraints are why turbine engines are so prevelant in aircraft.
All that heat coming out the exhaust (~1000degF) in large quantities (big mass flow rate) should tell you something about the efficiency right off the bat. You know this by just intuition- even in your post you say "Now harness the heat of their exhaust and you could power a small town!". Also, the tanks are NOT direct drive off the turbine, so the slow throttle response of the turbine itself does not matter in that application. It does matter in an automotive application.
To really get a stirling engine cooking, you need high pressure of a small gas molecule (lots of moles). That is why hydrogen or helium are common choices. It's also why they are a real pain in the ass to manufacture. Then you need a lot of heat transfer through into the hot chamber- no big deal- but on the cold side, you also need a lot of heat transfer to get rid of the waste heat. In the end, you are talking about moving a lot of air and heat back and forth, and some high pressure vessels and dynamic seals that must be SPOT ON to have any sort of useful lifespan. Keep in mind that the throttle responce of a sterling engine is only as fast as you can heat up or cool down and cause heat transfer across the chamber of the hot side- so it would only be practical if used in a sterling / electric configuration.
Someday it might work, put enough pressure in it and get enough temperature differential across it and you might just get the power output you need for a car. Currently however, commercial sterling setups aren't even close to the energy density we need.
Look at those units on the dishes from sterling energy systems. Each dish is 25kw peak. They are concentrating heat on the collector up into the thousands of degrees, and the low temperature resourviour is ambient temperature. Now, consider the size of that engine package- and 25kw = 33 horsepower.
Here is a picture right on their homepage: http://www.stirlingenergy.com/
A lackluster automobile these days is ~120-140 hp, and the latest heavy hitting iron is 550+..... The energy density is not even in the ballpark yet.
FYI, NASA has built stirling engines for electricity generation in space, i find the radioisotope based systems the most interesting, and promising.Also Stirlings can be used to turn solar heat into electricity (through mechanical energy ofcourse), at efficinecies around 30 %.
Just do a google search on "solar stirling", or "NASA stirling". Btw it's spelled "Stirling" not "Sterling". "Font Sterling" is a currency.
There is nothing technological that would stop stirlings from being used in vechicles.
Oh, and about "much smarter" guys thinking about something, and seemingly failing...thats what they want you to think...but that's another topic.
Patience. The sterling has a place in the hybrid scheme. But first the hybrid has to be accepted, and it's a brand new baby.
Sterlings lack flexibilty - that's the technical term for 0-60 acceleration followed by a quick shutdown when the cops spot you. By hitching the sterling to a generator/motor for final drive you put the flexibility back in - the electric motor can smoke an IC engine off the line. And it can be a very effective brake on the other end. Meanwhile the sterling putt-putt-putts along (not!) under the load of its generator. Surplus energy can be stored in a battery or capacitor.
More efficient? no. The laws of thermodynamics dictate that your lose power every time you change states. So in theory an IC engine directly using the energy of burning gas is going to be more efficient than burning fuel and then using it to expand a gas, then using that to swing a magnet, then using the resulting energy to swing another magnet.
On the other hand, given the choice of a 427 hemi or a 97HP wheezomatic, the consumer buys the hemi -- way more engine than she needs. That's where, when the engineer designs a hybrid, he may make better choices. Or not. But a compact car _only_ needs a 20 hp electric motor to feel peppy, due to the inherent flexibility of the power plant.
Cheaper fuels are another good cause to get behind. Because they burn in a steady state, furnace burners are more efficient than an IC engine. They can also be optimized for the kerosene/bunker oil/soy oil family instead of demanding complex high-octane gasoline.
Good design would keep the air fresher, and since the low-grades are virtually interchangable, offers more choices for filling the tank. My point? A sterling uses an external burner, just like your house. It's a fun model to think about - especially since some vans now have a refrigerator and closet space. How many MPG does your house get?
Last thought. My flight of fancy leads me to a sterling hybrid that runs 24/7 in the yard (not in the house - whose idea was it to give the car in its own room, next to the kitchen?) where it charges the family electric cars and heats water for your morning shower. The electrics are for the short errands, the hybrid for the long or heavy hauling. Hot water keeps, sort of, so the car can contribute to the overall heating capacity of the house. (Now there's a car that deserves to live in my house!) Live in the woods? Let your car power the evening TV time.
Now isn't that worth waiting for?
We can take a conversion step out if we have the output shaft of the Stirling engine coupled to the shaft of the IC engine to provide power more directly. No electric motor or battery back needed. You would need some kind of electronically controlled linkage (a planetary gearset, perhaps?) to allow them to work together efficiently at whatever speed each engine is currently running at.
As someone else suggested, the Stirling should run off of the waste heat that the IC produces. This can be done by putting the Stirling inline with the IC's cooling system, so to speak. Instead a coolant loop between the IC engine block and the radiator, there would be two loops: one between the IC block and the Stirling's hot side, and one between the Stirling's cold side and the radiator. If you REALLY want to get creative, perhaps a block could be designed that contains both IC cylinders and Stirling cylinders.
Good luck getting a sterling
Good luck getting a sterling to run happily at 6000+ rpm and still produce any useful torque.
Now a reality
Apparently this is not all that far fetched. I caught this article posted on Slashdot. It describes a prototype Stirling hybrid electric car.
Re: Good luck getting a stirling
You don't directly turn the wheels with one. Torque is immaterial - you run the armature of a generator at the speed where you get maximum rpm. The generator either drives electric motors directly (you want torque?) or charges batteries that drive electric motors. You don't whack a clutch on it and drive it like a conventional car.
First off, no one has addressed the primary problem with this concept which is that
Stirling engines are not efficient at all!! Anyone who has done their homework knows
that the IC engine is no less than THREE TIMES as efficient as the current crop of
hot-air engines in regards to fuel burnt vs. watts of power generated: 7-15% claimed
efficiency for Stirling power and 25-39% demonstrated efficiency for IC power. At the
end of this post are some addresses that you should check out detailing this.
Now then, the otto-cycle engine took off largely because it worked, and the others
didn’t. Even Stirling advocates will admit that a Stirling engine has to be quite large to
produce a given amount of power. I don't think that anyone who has posted yet
actually realizes exactly how big these things are!! They are not a little bigger, they are
ten times as big!! A ½ hp Stirling weighs about as much as a 6hp Briggs and Stratton,
which is not exactly a power dense IC engine–and that’s not including the burner,
shrouding, and chimney. Let us remember that the otto-cycle engines that won out
over steam and Stirling power were enormous contraptions that produced little power,
operated over a very limited rpm range, and used a then-scarce and expensive fuel.
Let us also recall that most of these engines were used in stationary applications,
where you would expect a Stirling engine to have a chance at competing and the
otto-cycle engine still won out!! And it wasn’t because of big oil companies–there
weren’t any!
But let’s just say that someone has built a Stirling engine that approaches the
“theoretical” possible efficiency (no one has come anywhere near yet by the way, not
even Kohemms of Sweden.) Beyond “theoretical efficiency” of an engine we must
consider power to weight ratios if we expect this engine to move its self down the road,
and further some useful payload (That‘s you.) Also true is that to power a motor vehicle
in traffic this engine must be able to cope with the demands of traffic: It must be able to
start and stop somewhat quickly, though in reality no where nearly as quickly as we
seem to believe or demand. The generally low power density of the Stirling engine will
provide serious problems with a machine that must move itself down the road. I
suggest that you look at the ST-5 5 hp Stirling engine, which is the highest hp output
Stirling that is commercially available. Look at the pictures. This thing is the size of
two 55 gallon oil drums. And the low power density is something that won’t be easy to
overcome, chiefly because of issues regarding how fast the working gas can be heated
and cooled through the conduction of the cylinder walls without applying ludicrous
amounts of heat to it (and therefore losing much of it- the very problem we are trying to
solve here.) But this post is not about the Stirling engine per sei, but rather the sterling
hybrid, so I digress. An average small car doesn’t need that much power to maintain
speed, usually 10-20 hp. One could reason that the Stirling hybrid could average this
much power and use a battery-electric motor setup to smooth out the lumps in traffic.
The problem here is that unlike the otto-cycle hybrid, in which the car is capable of
being powered directly by the otto cycle engine, with a “boost” from an electric motor,
(meaning that the motor/battery could be smaller,) the Stirling hybrid would require a
motor/battery combination that was capable of 100% of the vehicles power needs,
which would mean that they both would have to be very large and HEAVY. Which
leads us to the next problem. Inefficiency. As stated, the Stirling engines that are
available today, even those being used by NASA and the military, are much less
efficient than an IC engine. I guess if your car were running on trash or cow dung, you
wouldn’t care how much of the stuff that it burned, but neither of these fuels is very btu
dense, like diesel or gasoline. And because diesel and gasoline are so easy to store
and dispense, it’s highly unlikely that anyone would be willing to give up their fuel tanks
in favor of a “coal car” that trailed behind holding the solid fuel. Also, fuel prices are
high enough right now that I don’t think that you would ever be able to convince anyone
that it was good to drive a car that burned three times as much of it.
Which takes us back to the problem with hybrid car in the first place: The electric part.
Electric cars are a bad idea. They are heavy and slow. In order to have any
performance at all the chassis must be kept as light as possible, which makes them
unsafe in accidents, considering all the weight that is tied up in batteries. When the
vehicle stops, the batteries are going to keep right on going. And while there is no
emission at the vehicle, that electricity had to come from somewhere, and that means
fossil fuels and so forth. It boggles my mind that “environmentalists” think that driving
around in cars that have over half their weight tied up in expensive, fragile, plastic
boxes that are filled with toxic chemicals and heavy metals is a good idea!! Or that
people concerned with efficiency would think that it was a good idea to add weight or
changes of energy states to a moving vehicle.
For going down the highway, nothing that you add in the way of electric motors and
batteries will help squat. They will hurt, actually. For highway driving, the most
efficient arrangement that you could imagine would be to have the driving wheel bolted
to the crankshaft without even a transmission (this is impossible for a number of
reasons...) Where the hybrid cars make up is in the possibility of having regenerative
braking. I knew a person who was considering a hybrid and I asked them, "How often
do you push on the brakes?" For this person, hardly ever, as most of their mileage was
commuting to town from the suburbs. "Do your self a favor, get a VW diesel Jetta- it's
bigger, more comfortable, and will turn in better highway mileage."
I would like to see what kind of performance one of these hybrid cars would turn in with
the same engine, a standard 6 speed transmission, and all the weight from the hybrid
garbage stripped off. They would definitely get better highway mileage, and my guess
is that the around town figure wouldn't be hit too bad, since they are only marginally
better anyway.
As far as the devices used by NASA and the military go, a submarine and a spaceship
have far different operating requirements than an auto. For one, weight is not an issue.
Also, in the case of the submarine, it is surrounded by water that is FREEZING cold,
which helps with the power density. And as a stealth weapon, silent running is more
important than efficiency. The sub in question, by the way, is powered by IC diesel
engines whenever that is possible, with the Stirling gen-set only kicking in when silent
running submerged is needed, and then only at very low sustained speeds.
There is much work to do in the area of efficience, and sadly there are many real world
solutions that we could implement today but simply won't. For one, most of us drive
cars that are MUCH bigger than they need to be, and we drive them places that would
be reached more quickly on foot or with a bicycle. We keep our houses lit up like the
day when we are not at home. We heat the house to 80 Fahrenheit in the winter and
run around in our underwear to keep from sweating, and then we cool them to 60 in the
summer, and curl up on the couch in blankets to keep from freezing. This is madness!!
If I see another person driving down the road in a 10,000lb. off-road commando-wagon
that gets 8mpg by themselves I think that I am going to vomit!
My shop is less than 100 meters from the corner store. When I need to go over there, I
walk. Everyone that works for me drives!! Of course, I can't make them walk, by I do
make fun of them for driving across the street.
One last thing. Everything that I’ve said might make it seem like I don’t, but the fact is
that I LOVE Stirling engines (Though I hate calling them that, since Stirling did not
invent them, but rather patented the “economizer” a device that improves their
efficiency). I think that there is real potential for waste heat recovery and for total
house energy provision. A number of the sites that I’ve listed are companies that are
doing just that. Also I like the fact that the big, low-power, slow turning Stirlings, like
the ST-5 are perfect for application in third-world environments, where maintenance
and clean fuel are unheard of.
These first sights talk about REAL engines that are in production today:
www.sunmachine.de/english/main.html
www.odts.de/esg/st5engl.html
www.stirling-tech.com
www.kockums.se
This next one is for the Stirling Engine Society USA, and it has a number of links to
other sites.
www.sesusa.org
One thing that you need to look out for when doing research are words like “promises”
and “will deliver.” These are sure signs of a quack. They can “Promise” and “Will
Deliver” ‘till they are blue in the face, but with out the numbers it means nothing. Any of
the honest sites that actually have products don’t include “efficiency” as a quality of the
Stirling engine. “Clean running” “Multi-fuel” “low-vibration” “low maintenance” are real
honest claims. Most of the Stirling products available today are either gen-sets or
whole house co-generation/heating. All the gen-set manufacturers that provide data
about fuel burn per. watt of electricity show that they burn on average three times as
much fuel as an IC engine to deliver the same electrical output. If they can’t back up
their claims of efficiency with a number based on the btu/h input per kilowatt of
mechanical or electrical energy output then their claim means nothing.
This next site is an off-shoot of the American Stirling company. In the opening
paragraph they speak a bunch of double-talk, then quote some meaningless numbers,
and then never answer the question posed at the beginning of the paragraph: “Is the
Stirling engine the most efficient heat engine?” They don’t answer the question,
because the answer is a resounding “NO.”
They also mention the 1979 AMC spirit Stirling experiment, again with double-talk like
“promised to deliver.” Well what did it actually do? My thought is that no numbers
were posted because it was an absolute failure. And anyone who believes that it’s all
government coverup funded by big oil companies needs to do their homework and see
for themselves that so far, even companies with BIG military budgets like Kockums of
Sweden haven’t made a fuel efficient Stirling engine yet.
Http://users.fdn.com/~nomad01/stfaq.html
Also check out the California DER site. There are links to other sites and also
strengths and weakness of the various power generation systems. Note that under
“Stirling weaknesses” is “Low efficiencies”
http://www.energy.ca.gov/distgen/equipment
I think that the hot air engine has yet to discover it’s real potential. And on that front,
I’m working out a design for a small external combustion engine that I hope might
address some of the inefficiency of the Stirling, though I’ve only gotten as far as
working out the volumes and locating a few of the source components. Maybe
someday...I’m not betting my pension on it, though!!
Hope this has all helped out,
Andrew,
Hot Air Engines
You seem like a knowlegible person with experiance in this field. What are some the problems you've run into with your design. I am also an engineer I might have some sugestions that would help you along. Alternately, I might be notify that your idea has been tryed before unsucessfully. In which case we could brainstorm on line online that could result in a better idea. Heck, may be could start an R&D operation together. I believe sterling engines are not the only answer too.
FluidMan
"I would like to see what
"I would like to see what kind of performance one of these hybrid cars would turn in with the same engine, a standard 6 speed transmission, and all the weight from the hybrid garbage stripped off. They would definitely get better highway mileage, and my guess is that the around town figure wouldn't be hit too bad, since they are only marginally better anyway."
FYI: Several weeks ago a small group of enthusiasts filled the gas tank of a Prius and ran it to empty to see how good they could get their mileage. They got over 110 MPG. That's marginally better?
Not So
Sorry, but that's definitely bull. I am a Prius owner, and I love my car, but you're not going to get > 50MPG in any reasonable mix of realistic driving. Sure, I can drive it down from the top of Mt. Diablo in California and get >100MPG, but on normal streets, stop and go or highway, driving carefully, I've never seen a whole take average over 48MPG and I've been doing this for three years now.
Still, the Prius is a great car, and I'd say it gets about 20% better milage than any other car of it's size with similar performance charicteristics. That's not utopia, but it's not bad at all.
(And no, it's not about saving money, it's about using less oil, polluting less, and voting with my dollars for using technology to solve our oil/pollution problems)
Cheers.
Bull is in the eye of the beholder
Not bull at all. I get 60+ miles per gallon in "regular" driving. So just because you don't, doesn't mean it's not possible. I'll be happy to send you a picture of my consumption screen if you don't believe me. Right now it's reading 61.8 mpg with over 300 miles on this tankful.
Fuel Efficiency
In the 1990's I drove a Metro, which had a 1.0 litre 3 cylinder engine. I drove the hell out of it as is my habit. For th most part I got from 45 to 52 miles per gallon, based on a tank of gass used. Like I said I drove the hell out of it. The motor lasted 65,000 miles. The A/C compressor went out about the same time. I lived in Iowa at the time and the body did last the 100,000 miles promised. I bought it in 1990 and got rid of it in 2004. The second engine was still operating O'K. The body was still in terrific condition as I had never had an accident in this car. Well that is not entirely true as there was that time I was trying to cross a street and I was hit on the rear corner and I spun like a top. But still, the car was in great shape when I got rid of it in 2004.
Now here is my point, I'm sure the engine would have lasted much longer, if it had been combined in a hybrid scenario. The fuel economy would have been greater, but the cost of operation would not have been low enough to justify a hybrid scenario. If I were to use it in Southern California, It would have to have the A/C compressor replaced. Since I drive a lot in Southern California I see a lot of hybrids with thei windows down. If the air conditioner in on I have to believe the engine is running. This now defearts some of the benefits of the hybrid. So, Green has to be the major issue in building and using a hybrid at this time. It certainly is not one of efficiency. As someone suggest earlier the added cost of the car and my issue of the air conditioning, I can't see the benefit. Toyota suggests that their batteries will last 150,000 miles and they seldom say what the cost to replace is. This must be added to the cost of operation. Further, it was suggested on the Radio on Tuesday, November 6, 2007 that the real cost of gas is $15 dollars per gallon. This calculated in medical costs, taxes, artifically high price through the emotion of war. The cost of getting the oil out of the ground has stayed around 3-4 dollars per gallon. So what is the real problem here? Is it the managed cartel price of oil today? When the Democrats last left office the price of a gallon of gas was about $1.25 dollars per gallon. Forcast are for over $4.00 per gallon next year.
If you all want a soap box to get on why not get on this one. Predictions are that the war will now cost over 2.4 Trillion dollars. I know its hard to imagine, but do we have our priorities right?
Cost of barrel of oil
In my first reply I said that the cost to get a gallon of oil out of the ground was 3-4 dollars per gallon...what I meant to say is that a 55 gallon barrel of oil cost 3-4 dollars at the well head. This means that a gallon of oil at the well head is about 0.07 cents based on 4 dollars to get it from the ground. Refining adds to the cost of gasoline as well as distribution.
So, when you hear any oil company executive or Republican defend the current administration, remember as George Carlin the comedian would say, "Bend over and spread your Cheeks." Be carelul if you are in the restroom at the airport in Minneapolis, though.
The cost to the oil company
The cost to the oil company to get a barrel of oil out of the ground depends on several factors. In certain places, like Saudi Arabia, oil is fairly cheap to get out of the ground. The technology there is mature and the formations are easily accessible. However, easy oil is getting harder to find and more challenging fields will need to be developed in order to meet demand. Some of these fields require market prices at $60 a barrel or higher in order to be profitable. The point being that as oil reserves deplete (according to most of the accepted theories on oil formation) oil will get more expensive over time.
The current price for oil is inflated to a degree for many factors. However, the main reason oil is at a high price is because we and the rest of the world like to go places in our car that use diesel or gasoline. The only real way to decrease the cost of gasoline is to either increase supply, i.e. more drilling, or decrease demand through conservation. Likely both are necessary to prevent hardships. Exxon Mobil or Chevron cannot produce enough oil on American soil to meet American demands. Even if it could, supply and demand would determine the cost and not necessarily what it costs to get it out of the ground. When arguments are suggested that the price of gasoline should be based on the price of production without regard to market principals, then a national or state-owned oil company is what I hear. Venezuela for example offers gasoline to its people at $0.22 a gallon (or thereabout). Maybe socialism is a solution to this problem, but its one that I think the American people will find hard to accept.
Engine efficiency of Sterling Per NASA MEMOS
The final report for this project is:
Ernst, William D. and Shaltens, Richard K. (1993), "Automotive Stirling Engine Development Project", Final Report, NASA Contractor Report 190780, MTI Report 91TR15
The Abstract, part of the Summary, the main headings from the Table of Contents and the Conclusions from this report are reproduced below.
ABSTRACT
The development and verification of automotive Stirling engine (ASE) component and system technology is described as it evolved through two experimental engine designs: the Mod I and the Mod II.
Engine operation and performance and endurance test results for the Mod I are summarized. Mod II engine and component development progress is traced from the original design through hardware development, laboratory test, and vehicle installation. More than 21,000 hr. of testing were accomplished, including 4800 hr. with vehicles that were driven more than 59,000 miles. Mod II engine dynamometer tests demonstrated that the engine system configuration had accomplished its performance goals for power (60 kW) and efficiency (38.5%) to within a few percent. Tests with the Mod II engine installed in a delivery van demonstrated combined metro-highway fuel economy improvements consistent with engine performance goals and the potential for low emission levels. A modified version of the Mod II has been identified as a manufacturable design for an ASE.
As part of the ASE project, the Industry Test and Evaluation Program (ITEP), NASA Technology Utilization (TU) project, and the industry-funded Stirling Natural Gas Engine program were undertaken to transfer ASE technology to end users. The results of these technology transfer efforts are also summarized.
SUMMARY (partial)
The objectives of the Automotive Stirling Engine (ASE) Development project were to transfer European Stirling engine technology to the United States and develop an ASE that would demonstrate 30% improvement in combined metro-highway fuel economy over a comparable spark ignition (SI) engine in the same production vehicle. In addition, the ASE should demonstrate the potential for reduced emissions levels while maintaining the performance characteristics of SI engines.
Mechanical Technology Incorporated (MTI) developed the ASE in an evolutionary manner, starting with the test and evaluation of an existing stationary Stirling engine and proceeding through two experimental engine designs: the Mod I and the Mod II. Engine technology development resulted in elimination of strategic materials, increased power density, higher temperature and efficiency operation, reduced system complexity, long-life seals, and low-cost manufacturing designs. ..........................
(The remaining part of the summary contains essentially the same material that is contained in the abstract)
MAIN HEADINGS FROM TABLE OF CONTENTS
SUMMARY
LIST OF FIGURES
LIST OF TABLES
1.0 INTRODUCTION AND BACKGROUND
2.0 MOD I ENGINE SUMMARY
3.0 MOD II ENGINE DEVELOPMENT
4.0 TECHNOLOGY TRANSFER
5.0 TECHNOLOGY STATUS AND DEVELOPMENT NEEDS
6.0 CONCLUSIONS
7.0 REFERENCES
APPENDIX A: BIBLIOGRAPHY OF RELEVANT ASE PROJECT PUBLICATIONS
APPENDIX B: ASE PROJECT DOCUMENTATION CATEGORIZED BY ENGINE NUMBER
CONCLUSIONS
This final report has summarized work performed in the ASE project. The project's success can be determined by comparing accomplishments to the defined project goals and contract requirements. In so doing, the following conclusions can be made:
The potential for improvement in fuel economy for Stirling engines over SI engines has been demonstrated. A 10 to 13% improvement in fuel economy for the Mod II over the SI engine has been demonstrated for the USPS LLV in the EPA driving cycle. Based on test data obtained with the LLV, if the original Mod II Celebrity vehicle had been retained for fuel economy demonstration, the project goal of a 30% improvement could have been achieved. The Mod II engine had been sized and optimized for the Celebrity. Component optimization would also provide further improvements for USPS LLV fuel economy.
The potential for low emissions has been demonstrated in the Mod II engine: CO=<2.2 g/mi, NOx=<0.9 g/mi, and HC=<0.4 g/mi with gasoline. The 1985 Federal emission limits were easily met without using a catalyst.
The ability to operate on a broad range of liquid fuels was demonstrated. This evaluation was achieved not only in an engine test cell but also in vehicle operation.
Measured Mod II SES [Stirling Engine System] power and efficiency performance was in excellent agreement with analytical projections, i.e., the differences were less than 4% in power and less than 1% in efficiency.
Vehicle performance of a Stirling engine can be predicted from engine dynamometer test results. The Mod II-powered USPS LLV prediction of a 10% fuel economy improvement in the EPA driving cycle over the comparable SI-powered vehicle was verified by experiment.
A manufacturable Stirling engine automotive design has been identified under the project. The engine is the Mod II (V-block design with annular heater head) concept modified per the Deere & Co. VA/VE study. Manufacturing costs of $3500 to $4000 were projected by Deere & Co. for commercial production of 15,000 units per year.
In accomplishing the objective of transferring European Stirling engine technology to the United States, the ASE project succeeded in establishing an extensive U.S. technology and vendor base capable of designing, developing, and commmercializing Stirling engines. As a further indication of successful technology transfer, MTI, along with a gas industry consortium (GRI, NYGAS, and others) and Hercules Engines, Inc. of Canton, Ohio, is developing a commercial Stirling engine based on ASE technology developed in the Stirling Natural Gas Engine Program.
The NASA TU project demonstrated the ability of a Stirling-powered vehicle to be operated over the road by non-Stirling personnel; it demonstrated adequate availability and drivability.
The above report is for sale by the National Technical Information Service, Springfield, Virginia 22161
Last updated: Wednesday, May 3, 1995
Hybrids are slow?!
"Which takes us back to the problem with hybrid car in the first place: The electric part.
Electric cars are a bad idea. They are heavy and slow. In order to have any
performance at all the chassis must be kept as light as possible, which makes them
unsafe in accidents, considering all the weight that is tied up in batteries"
This is a common misunderstanding. But completely wrong! Hybrids aren't necessarely slow. On the contrary. Combining the huge zero rpm torque of electromotors with the excellent high rpm performance of ICE's can give really quick cars. As proven by Dr Frank of the University of California in Davis. (see http://www.team-fate.net or various other internet sources)
The latest vehicle, Yosemite, a Ford Explorer converted to a 1.9L ICE with electromotors, outperformes a BMW X5 4.4 V8, on speed AND on fuel economy!!!
(source: http://www.team-fate.net/technicalreports/UCD2003TechReport.pdf)
Removing the heavy ICE and replacing it by a smaller, lighter one helps a lot. Electromotors and battery packs can be made small and light as well nowadays. Don't base your judgement on hybrids on biasses, but on facts please.
As for crash safety, you can see that the weight gain isn't that high at all, and if a bigbucks car manufacturer would invest in this technology you would see the mass going down real quick as well. Besides, mounting bigger brake discs and calipers solved that for the UCD vehicles.
actually Ford built one 39% more efficient thanICE
Q: If Stirling engines are so efficient, why don't I have one in my car?
A: The best answer for that is to pick the MM-1 engine up after it gets up to speed. Notice that it keeps running for a minute or so. While it's very easy to build a Stirling engine that will stop instantly, there is not one thing in the world anyone can do to make one start instantly. When I get in my car I want it to start immediately (if not sooner) and be able to burn rubber off the tires as I leave the parking lot! Stirling engines can't do that. In spite of these limitations, Ford, GM, and 1979 AMC SpiritAmerican Motors Corp. spent millions of dollars developing Stirling engines for cars, back in the 1970's. Ford even built a Stirling that could drive away from the curb (with relatively low power) twenty seconds after you turned the start key! Many prototypes were built and tested. Then oil prices came down in the 1980's, and people started to buy bigger cars. Suddenly there was no compelling reason to build an engine that was substantially more efficient than internal combustion engines, but wouldn't start instantly. Here is a picture of a 1979 AMC Spirit. It was equipped with an experimental Stirling engine powerplant called the "P-40". The Spirit was capable of burning gasoline, diesel, or gasohol. The P-40 Stirling engine promised less pollution, 30% better mileage, and the same level of performance as the car's standard internal combustion engine. [From "An Introduction to Stirling Engines"] The French Research Sub Saga is Stirling engine powered. Stirling engines also work exceptionally well as auxiliary power generators/heaters on yachts (see Victron Energy.), where their silence is valued and good cooling water is available. They would also work very well in airplanes where the air gets colder as the plane climbs to altitude. There is no aircraft power plant (jets included) that gets any improvement in any operating conditions from climbing. Stirling engines won't lose as much power as they climb as do either piston engines or jets. Also wouldn't you like to have silent airplanes with very efficient engines that also have exceedingly low vibration levels?
Check your facts
"Do your self a favor, get a VW diesel Jetta- it's
bigger, more comfortable, and will turn in better highway mileage."
The Prius runs on gasoline. You are comparing apples and oranges. Diesel is a more compact fuel than gasoline. It weighs more per litre, pollutes more per litre (CO2) and contains more energy per litre. In each case around 10-15%. You should therefore NEVER compare diesel and gasoline mileages without applying this correction. I'm sure the Prius wins after multiplying the Jetta's consumption by 1.12.
However it won't beat the VW Lupo 3l or Audi A2, though. Reality is that diesel engines are much more efficient than gasoline engines. It's just not as much as it seems when you simply compare mileages. You should always take the basic properties of different types of fuel into account.
It should, the jetta is
It should, the jetta is twice its size with 3x as many luxuries and will bomb down the freeway at 100+ mph without breaking a sweat. If the prius didn't beat a gasoline powered jetta in MPG, something would be seriously wrong.
FWIW, even disregarding differences in fuel, the diesel cycle has inherently higher thermal efficiency then otto / gasoline cycle. Combine that with higher energy fuel and of course the MPG is better. Plus, the VW tdi is actually quite a good diesel.
We don't have any of the smaller VW / Audi cars available to us here in america though, the Jetta / Gti is as small as it gets. I agree though, if city driving is not a priority, the jetta / gti will kill the prius in every category except for what comes out of the tailpipe.
On the other hand, one could easily make the same arguement, because the jetta doesn't have (lots) of li-ion or lead acid batteries to deal with when it's junk. Lithium mining is not exactly "green"....
Diesel vs Hybrid is a non arguent
See here for two diesel hybrids.
Hybrids fundamentally make sense, and diesel hybrids make even more sense.
So reiterating what others have already stated.
Petrol vs diesel is a valid comparison.
Hybrid vs non hybrid also.
But Hybrid vs diesel doesn't make sense when you can have diesel hybrids.
http://www.treehugger.com/files/2008/02/volkswagen_to_i.php
http://www.treehugger.com/files/2008/02/dieselhybrid_pi.php
Efficiency
So is it not even possible for a stirling to drive a generator with enough power to run an electric motor at car-friendly levels? The 37" Wide Solar Dishes from SES are boasting an electrical output to power a house for a year. Wouldn't this be good enough?
I keep wanting to research this or at least do a mathmatical model but I don't really have the time or resources to devote to it.
stirling
I think it is obvious that an engine has to be designed to capture the explosion and the heat, both. everyone can stop comparing heat and otto. Both must be utilized and one engine can do it. By the way I worked for a time at the largest small engine manufacturer in the US. I have a design that acomplishes this by the way. I need to find backing. andy
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