Slashdot Mirror
Toroidal Engine Ready for Production
FarceMajeur writes "Business 2.0 has a column on a recently prototyped "round engine," properly named a toroidal engine, by VGT Technologies, Inc. Nice Flash animations of the concept are here. I've always admired the Wankel engine, but it seemed more like a time bomb than a going concern. This engine is billed as the 'world's first practical Concentric Positive Displacement Engine,' meaning no eccentric rotation to generate vibration, meaning fewer catostophic failures, one would hope."
The Mazda RX-8. It's a wankel, not the same as the engine in the article.
If tits were wings it'd be flying around.
This engine was developed primarily by people at the University of Calgary, not SAIT. He only teaches at SAIT, they didn't have much at all to do with the development of the engine as far as I can see.
Anyway, it's an interesting piece of technology.
Random and weird software I've written.
Reciprocating pistons and poppet valves still live because they work well, can be manufactured with simple operations and have seals (piston rings and valve seats) that will last for years.
I thought about a design like this many years ago and concluded that there would be major difficulties sealing in the combustion gases. I guess time will tell whether the problem has been solved.
"Eve of Destruction", it's not just for old hippies anymore...
How does the main flywheel maintain its rotation? If it's transferring energy to another wheel, it will slow down, friction notwithstanding. One would think that pistons would still be needed to keep the big wheel turning.
"Times have not become more violent. They have just become more televised."
-Marilyn Manson
Well, I looked at the animations. Neat idea, I think. But what happens if that timing belt goes? It looks to me like the thing would smash itself to pieces.
What would happen if a timing belt gave out on a 'normal' cylinder-based engine? I'm not too knowledgable about engines, but it doesn't seem like it would be quite as catastrophic.
Page numbered 39 indicates performance would improve greatly if the residual volume were reduced. Couldn't that be acieved by making their sealing wheel hollow with the combustion chamber inside it? It would simplify the engine too.
No they are not useless from a technical POW. One of the alternative designs should be used if we had to redesign all of engines, factories, fuels, motor oil and car's form factors. The design we use now is not the best one, it just happens to be the one whole automobile industry is shaped around. So it can only be replaced if an alternative is significantly better, while -to my knowledge- no alternative design is.
Gentlemen, you can't fight in here, this is the War Room!
IANAE, but this is likely to be a crackpot/scam venture.
The phrasing I've quoted above, which come from the web site, are big red flags. They're trying to pitch Pekau instead of the engine. Along the lines of "he's really smart and knows what he's doing, so of course his engine works." This is how scam after scam after scam gets pitched. "Ignore all the nay-sayers, because they just don't understand what our guy has done."
The phrase "which is well-documented" is also a tip off. Nobody says that unless it's not quite true.
- light and medium petroleum distillates;
- petroleum byproducts such as propane;
- methane (fossil or biogenic);
- vegetable oils and derivatives such as biodiesel;
- heavy petroleum fractions;
- wood, wood gas and charcoal;
- coal.
For any one of those fuels, I can cite an example of one of the above families of engines running on it. If an engine isn't being widely used, it's because it's difficult to manufacture or requires expensive materials. Right now we are using the least-expensive (and thus most cost-efficient) technology we've got, and that's the right thing to do. In a word, hogwash. There are a host of different engine designs around, and some of them have even achieved some presence in the marketplace. Examples:- Wankels
- Stirlings
- Gas turbines
We don't use the Wankel because it has too much chamber surface area per unit displacement, causing heat losses to be greater than a piston engine and losing the efficiency race. We don't use Stirlings because they are external-combustion engines requiring very high temperatures to be efficient, and the materials for the hot-side heat exchangers are not cheap. We don't use gas turbines because they require (again) heat exchangers to be most efficient, and (for vehicles) nobody's come up with a design which isn't either too bulky or loses too much efficiency to leakage; for road vehicles, turbines remain the province of superchargers, not the main power producers.A lot of research money has been expended on these engines in the past. Superior technologies do win out, just as fuel injection has displaced carburetors from all US production cars. If you can come up with a way to beat the technical problems which prevent any one of these engines from being manufactured as cheaply as a piston engine while meeting the same efficiency, emissions, noise etc. requirements, the world will beat a path to your door.
Scientists restrict study to entire physical universe; creationist
The total gyroscopic moment of the wheels in the toroidal engine can be computed as the vector sum of the angular momenta of the two pieces. This isn't quite intuitive, but it's not rocket science either.
It's easy to answer this question, because it's been done.The real issue is that this engine probably can't be manufactured to the required tolerances (especially over temperature), and its large surface areas will probably keep its thermal efficiency lower than piston engines. This puts its claims well toward the "scam" category
Scientists restrict study to entire physical universe; creationist
You posted after I decided to post rather than moderate - I agree with you 100%.
Scientists restrict study to entire physical universe; creationist
I thought about a design like this many years ago and concluded that there would be major difficulties sealing in the combustion gases. I guess time will tell whether the problem has been solved.
An additional problem is the law of conservation of energy or Newton's third law. It'll be interesting to see how his "patentable" design keeps the pistons rotating within a common torus.
Healthcare article at Kuro5hin
This reminds me of a nutating (wobbling, essentially) sphere engine I read about at McMaster Motor.
I have a little more faith in McMaster's credentials, and the design seems more realistic.
the problem is always pressure seals, and take a look at what would be needed for the 'flywheel' on this one. wake me after they've dealt with that, and i expect it'll be some years, if ever.
/. editors: guys, there's 'brilliant new combustion engine' designs all the time, and they never go anywhere. don't touch these articles unless they get real backing. you're outside your expertise and sliding us towards the worst of Popular Science. no offense; i know you don't know.
the wankel worked, btw. it just didn't turn out to be much more efficient because the piston-crank method is so refined. it was more of a marketing disaster because mazda made them a little too cheaply after a big PR campaign. they had to remove it from their sedan line but could keep in their sports car because those customers read a little more.
and it's very hard to think of a simpler or more efficient seal than the piston ring & cylinder combination.
the compression rings [there's a few others doing things like oil] are very like split ring washers, and expand to meet the cylinder wall. in the piston they're still sitting in the ledge of their groove for support, and the pressure holds them tight against it. but they're free to rotate around the piston, so you get even wear between them, the cylinder walls, and their grooves. and because they expand to contact, they can take an amount of wear over time before they're not reaching the cylinder walls effeciently.
you'll have to at least match that before you can begin to test if this 'new' design is any more efficent.
and quotes for 'new' because they are indeed hundreds of really interesting concepts from the last century. many were successful in fields other than automotive. worth geeking out and digging into the history. [turbines are well known. whittle was looking at turbo assited piston engines and realized with a bit of work you could throw away the 'engine'. brilliant rotarty solution.]
oh, and a note for
I am not trying to challenge you. I'd really like to know. Why does the M1 Abrams tank use a turbine? And if there is a good reason for it doing so, why doesn't the M2 Bradley AIFV? I know they use the same fuel.
(I have heard the exhaust from an Abrams can be so hot that if it is trying to hide in undergrowth, the exhaust can ignite a brush fire.)
There are only about two major reasons why Rotary (or Orbital) engines are not in wider use (I used to work for a lab that worked on them). First the pins wear out causing gas leakage... we couldn't solve that one... not that the existing pins are not reliable... but they wear out, and repairs are *very* expensive. Secondly most leak oil, though ours didn't any more than a normal engine... and I am told that the new Mazda one's don't suffer that either.
--suzuki re5 bike, quite nice, weird sounding. You are thinking of kowalski mach III's for the fast two stroke triple. Nice but not quite as reliable, but wicked fast. Harley guys hated it as it went by them. Suzuki had their three cylinder 750 water cooled 2-stroke then too,"the water buffalo", and they had a 4 cylinder 2-stroke coming out, but they switched to a four stroke one liter instead. They also had a one cylinder 250 two stroke which was amazing fast, called the hustler. And the Titan, two cylinder two stroke, one of the best most durable bikes ever made. The old "solid as a rock" deal with them.
sigh, good olde dayezzzz......
Those tight fit parts that absolutely fly by each other have to meet, slide, and keep a pretty good seal. Each time the timing chain is a little off, say to increase or decrease in power, they will miss a little, bonk, and get worn. Hot exhaust gasses slipping through will probably cause preignition in the little transfer tube. Nasty.
Also notice how much physical distance the compression arms of the rotor have to move each cycle. Can you imagine the heat from friction and the lubrication required? And the kinds of seals that you would need? I guess you could get decent lubrication by using the rotor as some sort of centrifugal oil pump, but still the wear would be nasty.
Consider as well that it's basically a 2 cylinder 4-stroke engine. It's gotta be a pretty good size and run at a pretty high RPM to get enough power to be really useful.
Don't count on this one.
Yes, there are many, many possible designs for internal combustion engines. Here is an interesting site which links to many different designs. My favorite among them is probably the ball piston design. http://www.monito.com/wankel/alteralter.html
I notice that the engine is being plugged for cogeneration. This actually makes sense in context, because an engine which gets as little as 10% conversion of fuel to work is infinitely more efficient than a furnace which gets 0% conversion of fuel to work! However, I still think that piston engines are going to be better in such applications, for these reasons:
- They are more efficient,
- They can share manufacturing technology,
- The noise problem can be solved other ways, and
- The higher thermal efficiency of the piston engine is going to give a higher return on investment in the cogenerator.
As always, I might be wrong - this is my off-the-cuff appraisal.Scientists restrict study to entire physical universe; creationist
Nope. Read the white paper. It describes the compression and expansion clearly. Here's the process:
Advantages:
Disadvantages:
Overall, this is one of the more promising alternative designs that I have seen.
This thing is financed by the same geniuses in Ottawa who put up the money for the plastic internal combustion engine. Combustion engines run more efficiently at low temperatures, you understand. yeah, right.
It's supposed to vibrate less than a Wankel. That's why the power-take-off from the toroidal rotor is through hammering on this two-bladed offset wedge. Hey, there's another winning idea.
Still, it's a definite leap forward in one regard: it's better than the $27 million in genetic engineering the Ottawa folks spent trying to develop a red heifer. Sounded Biblical, so it must be sound, right? What they didn't notice was that all the ones that were one or more hair short of being fully red were being sold off as beef, with the "developers" pocketing the money.
Let's hear it for government financed research!
...the problem with hydrogen is that overall, it is not the slightest bit cleaner. It's cleaner to BURN, but to make it, the current popular proposal is to make it from, guess what, petroleum or natural gas. You just lost, best case, half the argument for alternative energy- ALTERNATIVE :-) Worst case, you're creating just as much pollution because, say, it turns out the cheapest/easiest way to make hydrogen involves all sorts of pollution, either from the stuff you don't need anymore(carbon atoms) or stuff used as a catalyst.
The only clean way, that I know of, to make hydrogen, is by cracking water- but that takes enormous amounts of energy, which COULD come from wind, solar, wave-action, etc...but because it requires -so much power-, it's not practical. Alternative energy solutions produce very little power, and hydrogen takes enormous amounts of power to make. That's a horrible combination.
There's also the massive public perception problem- despite hydrogen requireing a heavier concentration than gasoline to ignite, dispersing almost instantly(whereas gasoline sinks and pools), safer to store(the cylinders are far more durable than most gasoline tanks. Sure, we could all be using racing fuel-cells with internal bladders, but...) and NOT being the cause of the Hindenberg fire(it was the paint; notice all the yellow, sooty flame? Hydrogen burns nearly invisibly, and 100% cleanly)...the public still says "Hindenberg!" when you say "Hydrogen".
If a hydrogen tanker truck flipped over and broke open, you'd have a massive spill that evaporated almost instantly, and some people might die from getting frozen to death(think the scene in Goldeneye)- but it would simply, and VERY quickly, dissappear up into the atmosphere. Gasoline sticks around and becomes a significant health, fire, and ecological hazard.
Please help metamoderate.
A reciprocating piston engine generates maximum combustion chamber pressure when the angle of the crankshaft is least effective.
That's -sort of- correct, but the diagram is VERY misleading; it's implied that compression = the explosion. and worse, that the instant you start the explosion, you get all your power, which is simply not true.
In a reciprocating piston engine, combustion is far from instantaneous. It's called the flame front speed, and it varies with compression, air/fuel mixture ratio, the fuel itself, air/fuel temperature, and combustion chamber design...for starters. At the speeds engines work at, believe it or not, this speed is actually -very- important...and to boot, higher compression equals more power; sports cars usually have pretty high compression ratios(and as a result require higher octane gas so the air/fuel mixture doesn't preignite, since the more you compress something, the hotter it gets.)
The consequence it that right off the bat, their first diagram is wrong; it implies that all the energy is released into a system positioned so that it can't use most of the power it just made because of the alignment of the components, namely the connecting rod(the rod that connects the piston to the crankshaft). Trust me, engine designers are NOT that stupid! Countless hours are spent on designing just the shape of the combustion chamber to get the right flame propagation etc.
Please help metamoderate.