Hydrogen-based Rotary Engine? 349
Seabird99 writes: "I came across this article at one of my car related forums and thought that I'd pass it on here. I have always been intrigued by "alternative" technologies where they relate to artificial locomotion." For some reason Slashdot gets a lot of submissions of wacko energy concepts - power from nothing, power from sand, power from a black box, engines that get 500 miles to the gallon... Perhaps this is more of the same, but at least it's an interesting write-up.
Next Problem (Score:3, Interesting)
Re:Next Problem (Score:2, Insightful)
Tom.
Hard to compress hydrogen (Score:4, Informative)
Hydrogen, on the other hand, has a boiling point of 20 K at atmospheric pressure (a bone chilling -423 degrees F)! So tanks would need some serious insulation in addition to handling high pressure. Due to its smaller molecules, it also leaks easier than LNG.
The best way to store hydrogen is probably in a hydrogen-rich compound like methanol, which is liquid at ambient conditions. My research group, among many others, is studying ways to efficiently convert methanol to hydrogen + carbon dioxide + water at the point of use. This would allow us to fuel our cars, RV's, or cell phones with convenient methanol and then run hydrogen fuel cells.
Don't worry about the carbon dioxide from that reaction. The methanol would presumably come from biomass or nuclear/solar-powered synthesis that consumes carbon dioxide. The carbon is just a carrier for the hydrogen, and there is no net CO2 pollution.
AlpineR
Re:Hard to compress hydrogen (Score:3, Informative)
A properly designed hydrogen=powered engine would be able to burn slightly "dirty" fuel - such as hydrogen containing a few percent methane.
Adding methane "gels" the hydrogen at low temperature, making it easier to liquefy, store and transport.
This mixture woud still have the advantage of having vapors that are lighter than air, and thus rise in the event of a spill, rather than pooling in low spots and creating an explosion hazard.
Most leaks in a tank come from the seals and joints of the tank, but hydrogen leaks mainly by diffuing throught the tank walls. At high temperatures, this is significant, but at low (~50K) temps, it's hardly a show-stopper.
I'm not bashing carbon-based fuels, just pointing out that there are many alternatives we should pursue in the quest for clean energy.
Methonol BAD / Methanol GOOD??? (Score:4, Insightful)
However, a lot of articles have been popping up in New Scientist essentially calling Methanol a demon fuel. It takes more energy to produce than it generates. By the time you use fertilizers, transport the stuff to the processing plant, run the plant, transport it to the pumps you've used more of the stuff than you can produce!
This sounds like Oil industry propoganda, but its getting a lot of column inches! anyone know anything?????
Re:Methonol BAD / Methanol GOOD??? (Score:2)
Plus, It also has the highest ration of carbon-hydrogen in emperical form, as far as i know, and the C-H bonds are single covalent bonds (methane is a tetrahedron) should be relatively easy to break, as opposed to a C=C triple bond.
Acetic acid (CH3COOH) might be also a posibility, since, by definition, its an acid and all acids give off H+ ions in water. The carboxal group at the end - i doubt you'd be able to get the hydrogen out of that, but whatever.
Course, i could be way off base, i'm only in 3rd semester chemistry:
while (ochem) {
pound_forehead(book);
fail(test);
cry();
}
~Z
Re:Methonol BAD / Methanol GOOD??? (Score:2)
This means that you're still talking about liberating additional CO2, which the sky is falling greenhouse effect backers hate. So the solution that's been proposed is to sequester the CO2 by injecting it back into oil and gas wells.
Re:Methonol BAD / Methanol GOOD??? (Score:2)
This sounds like Oil industry propoganda, but its getting a lot of column inches! anyone know anything?
For generating methanol from biomass, that might even be true. However, you have a lot of spare biomass left over from growing grops for food and fodder, so you could get *some* fuel "for free".
If you're generating methanol by direct sythesis, a) you're much more efficient (far fewer steps, and far less waste material synthesized), and b) you're using it as a storage medium for some other energy source (like solar or nuclear), so you aren't having to expend methanol to produce methanol.
Re:Methonol BAD / Methanol GOOD??? (Score:2)
Re:Methonol BAD / Methanol GOOD??? (Score:2)
The solution is to make methanol production more efficient.
Re:Next Problem (Score:4, Interesting)
Hydrogen, is also a metal, and a very active metal. It tend to form an alloy with the metal containing it which is more brittle than it previously was. Its small mollecular size also allows it to penetrate deep into the containers metal. This leads to sudden, catastrophic system failures, in lay terms it tends to blow up. I believe that NASA plates (or at least did) plate the insides of the fuel cells with gold to keep the hydrogen out of the container and from causing Hydrogen embrittlement.
As far as using nitros-ammonia system, not with my family you don't, actualy the same goes for H2-O2 to. LPNG is about as dangerous a gas as I care to have in my car. LPNG rarly blows up has some limited distro channels in place, and a fair amount of experience behind it. Once last year in my town, a car blew it LPNG tank while refueling, nobody hurt but the car and the gas comapnies reputation.
Re:Next Problem (Score:2, Informative)
I'm not a chemist, so I don't know how this compares to generating hydrogen and oxygen in terms of efficiency and environmental damage.
Re:Next Problem (Score:2, Insightful)
We need hydrogen (or fuel cells, or whatever) and a good primary source of energy like fusion power (still a sliding 10-20 years away), otherwise we'll still be burning dead dinosaurs to make the hydrogen.
The technical problems of storage and dispensing will be solved when we're willing to spend as much on it as we do on the petrolium industry.
Re:Next Problem (Score:4, Insightful)
You can't just dig a gasoline well either, what's your point? Even natural gas requires refining to remove impurities and other trace gases. With very few exceptions, you're going to have to do some work to get the energy in a form that's usable to you.
Re:Next Problem (Score:2, Insightful)
Making hydrogen is a physics problem: Energy out = energy in - losses. (By using fossil fuels, we are cheating the physics problem by using stored solar power, but it'll run out someday.)
Re:Next Problem (Score:2, Informative)
Re:Next Problem (Score:2)
(Where's Cloud City when you need it? Quick, somebody call Lando)
Re:Next Problem (Score:2)
What an annoying problem. The most common element in the universe, as well as the simplest, and we can't find any here all by itself. Grrr....
Re:Next Problem (Score:3, Informative)
A bottle of water doesn't have enough energy present to split it into hydrogen. You can say "yes, if it's at 30,000 feet or 99 degrees C" or whatever, but that bottle of water required EXTERNAL energy to raise it to that potential. And that external energy is the entire point. It had to come from somewhere, it's not free.
Until someone invents a way to "crack" water (with some off-the-wall fusion theory or whatever) there will always be a need for an external energy source to split it. Whether it comes from solar panels on your garage roof or a coal-fired plant in Montana over electric lines doesn't change the fact that EXTERNAL energy was required to make it useful.
John
Re:Next Problem (Score:2, Insightful)
whatever, but that bottle of water required EXTERNAL energy to raise it to that potential. And that external energy is the entire point. It had to come from somewhere, it's not free.
Note that the low pressure (30K feet)/high temperature (99 degrees C) are to boil water, which changes state from liquid to gas. It does not break the molecular bonds to separate into hydrogen & oxygen. The gas is still water molecules - H2O, not H2 and O2 molecules.
But the main point is correct - it takes an energy input to get the hydrogen that you then use in whatever reaction you're using to create your new energy. Hydrogen is a transmission and storage medium, not an energy source. Note that some companies are getting the hydrogen from gasoline or methanol, using the previously-stored solar energy.
kb
Re:Next Problem (Score:2, Insightful)
[..] otherwise we'll still be burning dead dinosaurs to make the hydrogen.
This isn't as bad as it sounds. Power plants can operate at much higher temperatures than automobile engines, and can therefore achieve much better efficiency. Not only that, but the combustion is more complete, and much more elaborate pollution-control measures can be used.
In short, if you make a power plant that would produced energy to drive a thousand cars, it would burn less fuel than those thousand cars would burn individually.
Addressed in article (Score:3, Informative)
Re:Addressed in article (Score:2, Interesting)
McMaster calculates that 1,200 square feet of solar panels on the roof of a garage receiving 2,200 hours of sunshine a year could, with the help of an electrolysis device no bigger than a washing machine, produce enough hydrogen and oxygen to drive an MRE-powered car 200 miles a day.
Right, 1200 sq. ft. is 34 ft. on side (10.5m for people using sensible units). Thats alot of solar panels, leaving aside how much that many panels would cost, that a very big garage roof you've got there!
2200 hours of sunshine per year is 6 hours per day, unless you're living somewhere (very) sunny its unlikely your going to get this each and every day. So, erm, what happens in winter when you get a long spell of bad weather, you stop driving?
Finally, 200 miles? I drive over a thousand one day last week. Most weekends I do trips that average more than 200 miles one way. This isn't a particulary impressive total unless you use your car to commute 5 miles into work, and then go shopping at the local store.
The oxygen would be bottled in scuba-like tanks that would snap into place under the hood. The hydrogen, more volatile and more dangerous, would be piped around the car's chassis through 180 feet of tubing, divided into 3-foot sections, each sealed off from the next by a set of valves.
The hydrogen would be stored where? Distributed throughout the entire chassis? I really don't like that idea, that just increases the target area for collisions and does very little to increase safety. Most of the designs I've seen for this sort of thing store the H2 in cryogenic form in a (very) well protected tank, safety is usually increased by using some sort of honeycomb structure inside the tank. To be brutally honest, that seems far more sensible.
Al.Re:Simple or complicated solutions for Commuting? (Score:2)
Re:Next Problem (Score:2)
And as for the nay sayers pointing out Hydrogen's explosiveness, wasn't there a story here not too long ago about how Hydrogen ain't that bad and even has had its name cleared in the Hindenberg incident? Spill gasoline on your selve and ignite it and you have a problem. Spill hydrogen on yourself and you... oh, wait, it would float away and disperse.
Re:Next Problem (Score:2)
Plus, when you have a SMALL leak, and burn it, it burns with an invisible flame.
(Plus there's all the storage "problems", migration, alloying, temperature/volume considerations)
I just don't think that hydrogen's feasible yet.
Re:Next Problem (Score:2)
Ethanol is probably more promissing. As long as we can grow grain or corn we can make it and burn it.
That's hardly the hard part, nor is this novel (Score:2)
And a hydrogen engine is hardly novel; converting a gasoline engine to hydrogen is fairly trivial. Maybe he has a better design than other hydrogen engines; maybe not.,
The problem that has plagued hydrogen engines for a very long time is the issue of carrying the hydrogen around in the car in a matter that can survive a collision. It' nasty stuff. It goes *BOOM* very easily. Solve *this* problem and there's a whole row of hydrogen engines already ready to produce . . .
hawk
Re:That's hardly the hard part, nor is this novel (Score:2)
Well, okay... haven't these guys [millenniumcell.com] solved exactly that problem?
Re:That's hardly the hard part, nor is this novel (Score:2)
Given that you can't buy a car with that even in California, I'd have to say no
hawk
Re:That's hardly the hard part, nor is this novel (Score:2)
Agree. You could run the electrolysis machine off of the power grid and you'd still come out ahead since even with the distribution loss the efficiency of the power plant is probably still greater than your car. Using a free energy source like the sun is icing on the cake.
converting a gasoline engine to hydrogen is fairly trivial
Really? That's good, I didn't know that. What do you have to do, anyway?
The problem that has plagued hydrogen engines for a very long time is the issue of carrying the hydrogen around in the car in a matter that can survive a collision. It' nasty stuff. It goes *BOOM* very easily.
Gasoline isn't exactly the most stable substance in the world, either. Assuming you are in an accident and the fuel tank is ruptured, you can either have the fuel dispersing into the air or dripping onto the ground all around your car. Take your pick.
Re:Next Problem (Score:2)
How about this.
The water tank resides on the _top_ of the car. And you use the potential energy of the stored water to drive the electrolysis.
Heck, you then use the buoyant hydrogen bubbles to turn another turbine to power even more electrolysis!
Patent Pending.
(pending the invention of really tall cars)
Re:Next Problem (Score:2)
Consider your very modes 100hp car. Assuming that you use it for about one hour a day and at and average of 20% maximum hp you need to generate about
100hp * 20% * 700watts/hp * 1 hour = 14 kilowatt-hours.
A typical solar panel (Siemens 110 [siemenssolar.com]) generates about 100 watts, takes up about
Keep in mind the following...
1) The car is only 100hp - how many people will give up their 300hp sport utilities for a compact car? And do you want to ride in a flimsy lightweight vehicle and let Bubba in his pickup truck smoosh you in a 15mph accident?
2) You better get 8 hours of good daylight or you are not going to work tomorrow.
3) I have assumed a 100% conversion from sunlight power to H2. There is a loss here, but I do not know how much it is.
Solar power is not as good as gasoline because you can't go to the store and pick some up. Hydrogen has all hinds of handling issues to be resolved in order to be safely handled by the public.
Good in theory, bad in practice.
Re:Next Problem (Score:2)
How about a solar chimney plant built next to a river? The power from the plant is used to split the available water and stores the H2 and O2. Solar power, fuel cell power, and greenhouse all in one.
Re:Next Problem (Score:3, Informative)
Re:production problem? (Score:2)
200,000 cubic meters of hydrogen at 1 atmosphere and room temperature is all that much. At STP, H2 is
Re:Obvious mechanical design problem (Score:2)
A coworker has a Mazda RX-7, and yes, he just blew a seal in it. However, he had over 200,000 miles on the engine, and much of that is high-speed driving on race tracks (well, as high speed as you can get in an RX-7, anyway...) The "problem" with the seals on the Wankel that you mention are note one of sealing, but rather stem from the fact that the surface area of the combustion area is so large that much oil is constantly being burned off, causing the pollution. The MRE is supposed to run without lubrication along these surfaces.
This engine might be even easier to seal than a normal Wankel. On the Wankel, you have nine separate seals in place on each rotor (one at each apex and one on each arc on each side of the rotor.) The seals meet at odd angles at the corners, and must be carefully manufactured and aligned to achieve a good seal.
The nutation plate in the McMasters engine has a single surface that requires sealing. The challenge with this seal is that the nutation plate changes its angle of contact throughout the cycle. Perhaps a round edge, or two rings, or other mechanism will be found.
McMasters is off-the-wall enought that he might try something completely different here. A ceramic cylinder, or seal, perhaps. He might even figure out a way to dynamically squeeze the cylinder walls to provide a seal from the outside, for all we know. He's proven himself a genius time and again, and if such a seal can be developed, I'm quite confident that he's the guy who can do it.
John
Wacky? (Score:5, Informative)
Here's a little more info [monito.com] if you weant to do some research.
Tom.
Re:Wacky? (Score:2)
"The setting was last month's Supertuner Challenge. The mini-Mazda was on hand as an errand boy and was being used as a shuttle en route to the next driver change during the road drive. But as we took off, we noticed there was no map in the Protegé5 -- so we had to keep up with the car ahead. The 650-hp Lingenfelter Twin-Turbo Vette had a 520-hp advantage plus a high-g tire-and-suspension setup, but the nimble little wagon managed to keep within view. And although public-road prudence restrained the Corvette to probably three- or four-tenths of its capability, the equally prudent Protegé5 pilot was enjoying the full potential of his mount and grinning from ear to ear."
It's not all about horsepower you know...
New "drivetrain" setup (Score:3, Insightful)
Would automakers be for it? Most likely not. They make a substantial amount of money from repairs and maintenance. And to think of the outrage from auto-repair shops, cutting their business as well.
It's an excellent idea - less weight, much better fuel, fewer moving parts, etc. But there's a lot of opposition ahead.
Re:New "drivetrain" setup (Score:2, Interesting)
You're right. They don't. Now Monsanto [monsanto.com] on the other hand... [corpwatch.org]
He's obviously not owned a Rotary engine either... (Score:2, Interesting)
Perhaps a little experience is in order for the original poster or he's abused one - been bitten - and is just upset about it? At least they don't cost a mint to replace, I could build two rotaries for what one decently built V8 runs...
Heh, and if you look at the animations of this new guy's engine it's obviously not a Wankel. I DO wonder where the heck the exhaust goes though. He claims no exhaust but I find that a bit hard to believe. In addition, if it's got anywhere near the temps that a Wankel has, due to the way it dumps damn near straight out of the cylinder, then the exhaust is going to be pretty hot. I'd like to see\hear one of those running. Wankels are pretty darned LOUD (exhaust) too!
free energy (Score:2)
Who knows.. (Score:4, Interesting)
(I wouldn't be surprised if these tanks are already widely in use now)
The problem is ofcourse to generate large amounts of hydrogen.
Given the succes of recent tests with fusion reactors, who knows.. we might be using hydrogen to create hydrogen from water.
quite a big if, but who knows.
Re:Who knows.. (Score:2)
You are correct sir (Score:2)
Making hydrogen. (Score:2)
Given the succes of recent tests with fusion reactors, who knows.
Why wait for fusion?
Hydrogen is just a way of transporting energy that you've generated elsewhere. Use a fission plant or a fossil fuel power plant or a solar array or a hydroelectric dam or any other conventional power plant to generate the power you produce the hydrogen with. This lets you handle pollution and energy-source switchover at a handful of power plants instead of having to re-tool a hundred million cars when you discover the Miracle Fuel (tm).
Re:Who knows.. (Score:2)
E+2H2O --> 2H2 + O2
Of course, I'm sure that the energy of fusion is much more than 50 times the amount of energy required for electrolysis.
(I use E for energy)
Re:Who knows.. (Score:2)
Really, really feeling old... (Score:4, Funny)
sPh
My piston engine Jeep runs on Hydrogen (Score:4, Funny)
Been purchasing at Exxon and several other outlets that specialize in this revolutionary fuel. They are trying so hard to get the word out that if you purchase more than $5.00 of the stuff you get a discount on a car wash!
Wacko Energy (Score:2, Insightful)
I don't think it's so odd the
Personally I've always associated the term 'Nerd' with all things mathematical and scientific. I think 'Geek' for all things computer and electrical (You can't even spell 'Geek' without EE.)
New Category? (Score:4, Interesting)
Sounds like there's a need for a specific category/icon.
Well.. if you read the article (Score:4, Insightful)
Revolutions in design have rarely come out of corporations... considering this site is supposed to be Linux based, I thought I would see more support for anyone trying to solve the energy crisis outside of the regular channels, since it's highly unlikely it will come from the gas companies anytime soon.
Rotary engines (Score:2, Interesting)
Ideas like twice the power to weight ratio and 10% of the moving parts are not of any interest to the likes of Ford, even if (as with my engine) you could stick with the existing fuels, and servicing skills.
Re:Rotary engines (Score:2)
IF the McMaster engine (or any other new engine design) does work out we'll probably see the existing automakers:
A> Try to buy the designs (get the patents for ourselves)
B> Try to copy the designs (but avoid infringing on the existing patents)
C> Try to destroy the designs (and protect their own patents)
It'll take someone with McMasters background and financial backing to get a new design off the ground. The average Joe doesn't stand a chance. Maybe you should contact McMaster and see what he thinks of your designs, 2 heads are better than one no?
Transmission (Score:2, Informative)
Another interesting transmission system, loosely based on similar principles can be found here [torotrack.co.uk]
Re:Transmission (Score:2)
500 mpg cars, revolutionary engine designs, etc. (Score:4, Interesting)
Re:500 mpg cars, revolutionary engine designs, etc (Score:2)
It's not the H2, it's the *simplicity*! (Score:5, Insightful)
It seems that everyone is completely missing the point of this new (and unproven as of yet) engine. The thing that makes it unique is NOT that the guy can theoretically run it on hydrogen and oxygen produced by electrolysing water. What makes it unique is the sheer simplicity of the engine.
As geeks and programmers, we all love to see someone come up with a truly elegant solution to a programming problem. When someone takes years of kludges and condenses them down into a few lines of clear, concise code, it is not only a thing of beauty and mastery, it is something to be desired.
What should strike people about this engine is that this somewhat eccentric but proven inventor has come up with a replacement module for that hideously kludgey block of code called the internal combustion engine. If pistons and rods and camshafts and all can be replaced with such a simple construct, isn't that a good idea? Now, of course, I'll stay in the "show me the code" mode until I actually see a working prototype, but if these guys think they can hash it out, I say more power to them.
Balance. (Score:2)
Except like all 'advances' it's actually a balance advantages and disadvantages, for example rotary engines rev higher, have higher wear and higher fuel consumption.
http://www.monito.com/wankel/advantages.html
We need more like him. (Score:3, Interesting)
He seems to have a good grasp of the issues, and makes a lot of sense. He also has quite a few things going for him, such as:
I think this needs watching.
Re:We need more like him. (Score:2)
Whackos who got one thing right and went on to use the money to make other things seem right, all the while continuing to be whackos.
He won't tell you how much he has, but he brags about how much he's given away?
Yeah. We have far too many like him.
--Blair
Several interrelated issues. (Score:5, Interesting)
But it should be noted this isn't anything new. The internal combustion engine is innefficient by nature. It takes a spherical force (an explosion), redirects that into a vector force (up and down in a straight line), redirects that into a circular force, which is redirected into another circular force, finally driving the car. Each of those redirections wastes energy. Moreover, the fact that you have carbon monoxide and other hydrocarbon emissions is a sign of innefficient combustion: complete combustion of a carbon molecule goes all the way to carbon dioxide. There are plenty of legitimate projects to find a better way. Ben Rosen, chairman of Compaq, has envisioned the automotive powertrain market becoming like microprocessors, with independent companies competing to supply the most efficient engine. His Rosen Motors produced a working prototype of a hybrid-electric motor; they've since been taken over but I forget by whom.
Of course, a serious problem is the huge combustion engine and gasoline infrastructure. Even a much better product is not going to take over overnight. The internal combustion infrastructure would keep the economics of conventional motors attractive for decades, barring a serious kink in the gasoline supply.
It is a myth, though, that the automotive manufacturers are blocking this kind of thing. They're all doing research of their own. There is nothing a manufacturer wants more than to obsolete their own product and give everyone a reason to buy the next big thing.
The other technology discussed here is photovoltaic (solar-electric) conversion of water to hydrogen for combustion. I think this is far more theoretical. Not that you can't very simply and reliably bang an electric current through water and get combustible hydrogen and oxygen. But from what I know (and I do have some knowledge on this subject) I seriously doubt whether existing photovoltaic cells are efficient enough to supply the power for even a very efficient automotive engine by splitting water. It should be noted that like anything else, this conversion of electrical power into chemical power represents a loss of efficiency, so the purpose for doing this is to get the benefit of a combustible fuel.
Direct solar cleavage of water to H and O is one of the holy grails of both hydrogen power and solar research; this photochemical process is at the heart of how plants utilize the energy of the sun and hence the source of most energy on earth including all fossil fuels. We aren't there yet. It can be done but it isn't sufficiently efficient to be practical. There are tons of novel catalytic techniques being experimented with, where rather than go through a photovoltaic cell (the conversion of sunlight to electricity of course represents another inefficiency), sunlight is used as the power source to directly, catalytically cleave water. I think within a few decades this kind of thing will start to make significant inroads, provided countries like Iceland and companies like Daimler Chrysler continue to pursue hydrogen research and a hydrogen energy economy.
I don't see anything in the article, however, that suggest this motor could only run on hydrogen. So it may be a valid concept that it much closer to commercial reality.
Re:Several interrelated issues. (Score:2, Informative)
Let's take things one at a time
But it should be noted this isn't anything new. The internal combustion engine is innefficient by nature. It takes a spherical force (an explosion), redirects that into a vector force (up and down in a straight line), redirects that into a circular force, which is redirected into another circular force, finally driving the car. Each of those redirections wastes energy.
Close but not quite. The problem is not with INTERNAL combustion engines in particular. All the engines being discussed here (except for fuel cells) are internal combustion engines. They change chemical energy to mechanical energy by burning their fuel directly. This is as opposed to EXTERNAL combustion engines which burn their fuel and use it to heat a working fluid usually steam which then is converted to mechanical energy by a thermodynamic process usually expansion of the heated working fluid against a piston. Steam engines are the usual example.
What makes the rotary concept interesting to engineers is the fact that the piston never has to change the direction of acceleration as much as it does in reciprocating engines. All else being equal: displacement, fuel, materials, etc. the way to get more power out of an engine is to make it turn faster. Because the pistons in reciprocating engines have to change their direction by 180 degrees at the top and bottom of a stroke there are mechanical limits on how high they can rev. Using exotic materials and small displacements Formula 1 engines can rev to about 18000rpm. The limits to revving these engines are actually the valves, but this technology would make a poor engine for a street car because the small displacement which is necessary to reduce the piston mass as well as being a result of F1 rules makes for very little torque at low revs. Think Honda S2000 (9000rpm redline 2.4 liter) versus Corvette (6500rpm redline 5.3 liter).
Anyway that's whats troubling about McMaster's claims. He says he can get rid of the transmission which is what allows you to rev the engine to a useful point in the power band at low speeds. So his rotary must produce a lot of torque which is not usually a characteristic of automotive rotaries, again compare the high revving but relatively slow off the line RX-7 to the big Detroit iron Vettes, Vipers and Mustangs.
Moreover, the fact that you have carbon monoxide and other hydrocarbon emissions is a sign of innefficient combustion: complete combustion of a carbon molecule goes all the way to carbon dioxide.
No, because of entropy combustion processes will produce a wide spectrum of byproducts. The more complex the thing you burn the more complex your end results. You can tune the spectrum, which is what most ULEV engines do, by carefully controlling the amount of fuel and temperature of combustion but you can never eliminate all byproducts. Hydrogen and oxygen combine to water alone only because hydroxide is unstable at the temperatures and pressures engines operate at, unlike carbon monoxide, and therefore if you add extra hydorgen the hydroxide will favourably combine into water too. Hydrogen burning internal combustion engines will also necessarily produce NHx and NOx (Nitrogen Hydrogen and Nitrogen Oxygen) compounds if they are obtaining their oxidant from the atmosphere but again thanks to favourable conditions we can limit the production of these by carefully controlling the temperature of combustion. Maybe that's why McMaster wants to use an oxygen cannister, that way he doesn't have to worry about nitrogen in his reaction.
The other technology discussed here is photovoltaic (solar-electric) conversion of water to hydrogen for combustion. I think this is far more theoretical. Not that you can't very simply and reliably bang an electric current through water and get combustible hydrogen and oxygen. But from what I know (and I do have some knowledge on this subject) I seriously doubt whether existing photovoltaic cells are efficient enough to supply the power for even a very efficient automotive engine by splitting water. It should be noted that like anything else, this conversion of electrical power into chemical power represents a loss of efficiency, so the purpose for doing this is to get the benefit of a combustible fuel.
This may be inefficient but you can localize the inefficiency and optimise for it since electrolysis doesn't have to be done at the car. Although that raises the problems of hydrogen storage due to the low density of hydrogen. We already do this with refining plants for gasoline and other petroleum based products.
McMaster Motor site (Score:5, Informative)
Looking at it helps me understand the way it works. I don't know if this will ever come to fruition, but I sure hope it does. Even if it doesn't, he's a revolutionary thinker with a significant record of success, and deserves our praise and respect for that.
Re:McMaster Motor site (Score:2)
The plate is welded to the shaft, if I understand correctly. It would either slide against or just pass very close to the surfaces of the conical end-caps and the outer wall of the combustion chamber.
I can see building a setup like this where the disc doesn't actually contact anything (just passes close to relevant surfaces). It would just lose efficiency from exhaust leakage through the resulting gap.
You'll still need bearings on the shaft, of course.
Re:McMaster Motor site (Score:2)
So I'm also confused. If the wobble plate is not spinning along with the shaft, then how is the plate momentum transformed into the shaft's circular motion?
Help! if someone understands this, please enlighten me! Their website just doesn't describe the concept very well.
Re:McMaster Motor site (Score:2)
The vanes are inside the cones, and so don't interfere with the plate's spin. The animation has a reasonably clear picture of this (the "vanes" are the radial fins inside the cone on the left).
Re:McMaster Motor site (Score:3, Insightful)
Further Information (Score:3, Interesting)
Yes, the guy's a little, er, fringey -- one of his other projects is an antigravity machine. I'm not saying such a machine is impossible, just that I'd not expect anyone who's not, say, Stephen Hawking, to come up with one.
That bit of weirdness aside, what do people think about the engine itself?
First, the fuel. The article implies that it uses Hydrogen. We've discussed to death the problems with using straight hydrogen as a fuel, which ultimately (putting aside safety and infrastructure issues) comes down to energy density -- pound for pound (or liter for liter), Hydrogen gas just doesn't pack as much punch, specatcular disasters caught on tape notwithstanding, as gasoline. However, the page talks about using a mixture of Nitrous Oxide and Ammonia, ignited with a glowplug, not straight hydrogen. It does speak of a catalyzed reaction being researched to derive the fuels from solar power, air, and water.
Questions: Is it likely that such a catalytic reaction exists? If not, will it take more fossil- or nuclear-fuel energy to create, using other reactons, the needed amounts of nitrous and ammonia? Would that added cost be worth it to reduce fossil-fuel emissions from cars? (let's ignore issues of infrastructure for now...)
Next, there's the design of the engine itself. Basically, it appears that it's an angled plate in a cylinder, with the reactive explosion happening first on one side (causing the plate to rotate around the axis it's mounted on), then on the other. Nifty idea, simpler looking than the Wankel rotary engine, and MUCH simpler than the internal combustion engine.
Questions: Can such an engine really operate, with any fuel? Could you really run it at many different speeds, and if so, how would you manage that? (I'm not personally convinced that you could do without a transmission). Would the "chambers" formed by the rotating plate provide any compression for the fuel (a major requirement for traditional engines)?
Let's not dismiss this entirely, out of hand, as a wacko idea. Look at the web pages in detail, ignore his strong claims and "past performance", and just focus on the ideas presented. I'm intrigued, but don't know enough about chemistry or mechanical engineering to pass any kind of judgement (and I suspect most of the people here don't qualify, either.) Those who do qualify...what do you think?
david.
hydrogen much maligned and misunderstood (Score:3, Informative)
Indeed, your statement:
Hydrogen gas just doesn't pack as much punch, specatcular disasters caught on tape notwithstanding, as gasoline
catches a part of this truth, though more in passing, namely that a tank of hydrogen is less explosive than a tank of gasoline. Meaning, as you say, that there is less energy / volume in hydrogen gas than there is in petroleum liquid (gasoline). Two approaches to this problem are, as implied in this article and the designer's web page, a more effecient engine or, alternatively, an innovative use of chemistry to allow a hydrogen-rich compound to exist as a more dense liquid/solid at room temperature without binding the hydrogen so tightly as to make it useless as a source of energy.
Hydrogen is safer to store, transport, and use than gasoline, by virtue of the very fact that it packs less energy per unit than gasoline. Safety fears are really just that, fears, based on a widely debunked perception that dramatic explosions such as the hindenberg were a result of hydrogen, when in fact it was a result of painting the damn ship with a compound now used as rocket fuel, a compound much more combustible than hydrogen by orders of magnitude. That debunking aside, there remains the perception that hydrogen is this dangerously explosive gas, when in fact it burns too slowly to even explode with the same intensity that a 1972 Ford Pinto's gas tank would when rear-ended.
Re:Further Information (Score:2)
It does raise the interesting question about over what range of speeds the engine will work efficiently, and how easy it is to start and stop running. And although you may not need a transmission you will need a gearbox for reverse. And I suspect you'd need some pretty sophisticated fuel injection for this wacky looking thing...
My conspiracy theory... (Score:2, Interesting)
Re:My conspiracy theory... (Score:3, Insightful)
Quite a Range! (Score:2, Insightful)
So, is the guy a real inventor, or a hopeless crackpot dreamer, or somewhere inbetween?
Quasi-Turbine (Score:2, Informative)
You can't store enough H2 That way (Score:2, Informative)
Another Non-Wankel Rotary Engine (w/o vibrations) (Score:2, Interesting)
-Torawk
Rotary combustion engines (Score:2, Interesting)
I used to have an Arctic Cat snowmobile with a Wankel engine when I was much younger. We couldn't find anybody to service it when it started to die, but it was fun to take it apart, it's extremely different from the tiny chainsaw two-strokes and four-stroke lawnmower engines I had torn down before.
Quote at the end (Score:3, Funny)
I don't think he's all that wacky (Score:3, Interesting)
He revolutionized glass. Why couldn't he apply the same non-linear thinking to his first project, add modern materials, and make it work?
Might be wrong, but ... (Score:2, Interesting)
Gas turbines are effecient (insert something clever to do with thermodynamics here)and can run on anything from coal-dust to hydrogen. The problem is - IIRC - that they only really work well within a narrow range of speed so coupling them to either conventional (stick-shift) or auto transmissions never really worked. Coupling to CVT should allow the engine to always spin at an efficient speed. Piston engined cars with CVT get good gas mileage - but people don't like the fact that the engine note stays the same as they accelerate.
It would run good on hydrogen (should be very little H2O2 in the exhaust burning like that), but I still don't have a solution to producing and storing H2.
Re:Link to CVT description by Honda (Score:2)
I do have to say if that belt did break, it would probably be a mess...
Audi has it on higher-powered engines (Score:2)
However, Audi has overcome this problem with their Multitronic system, which uses a heavy-duty drive-chain belt instead of a metal-link belt. This means the Audi CVT can withstand up to 230 bhp easily; in fact, Multitronic is standard on front-wheel drive US-market Audi A4's fitted with the 1.8-liter L4 turbocharged engine and the 3.0-liter V6 engine.
My Gut Feeling (Score:2)
Right up /.'s alley (Score:3, Funny)
It's the ultimate intersection between conspiracy theories and nerd-dom. OF COURSE they come pouring in. ;-)
Are you embarrassed easily? (Score:2)
Dr Gruber: (Michael Palin) Hello my name is Carl Gruber. Thank you for inviting me into your home. My method is the result of six years work here at the institute in which subjects were exposed to simulated embarrassment predicaments over a prolonged fart, period, time (sound of him farting). Sorry. Lesson one, Words. Do any of these words (farts) embarrass you?
Assistant: (John Cleese) Shoe, megaphone, grunties.
Dr Gruber: Now lets go on to something ruder.
Assistant: Wankle rotary engine.
...
My apologies to Monty Python
Explanation of engine... (Score:3, Informative)
I have to admit, the fascinating thing is the fact that it is so simple - so simple that it looks like it could almost be homebrewed in a garage, provided the builder has sufficient machining skills and tools (ie, a metal lathe and mill would be an absolute necessity, as well as a wire-feed welder, among other tools).
Anyway, here is my explanation:
1. The engine is composed primarily of 6 parts: A shaft (1) which is fitted through a sphere (2) and two opposing, on either sides of the sphere, conical ends (3,4), a metal vane (5) which is slotted between the cones, and thus doesn't move - parallel to the shaft/sphere assembly, and perpendicular to the metal vane. Finally, there is the wobbly plate (6), which is fitted around the sphere, and has flattened ends that are up against the metal vane. This plate bisects the sphere, forming two independent combustion chambers. However, it is not attached to the sphere, it does not rotate, and it is not attached to the vane. It merely "slides" against these parts.
2. Now, imagine the metal vane lying at an angle. At the point where one end is touching the cone, and the vane, there is a fuel inlet and a glow plug. Fuel is admitted, and the glow-plug ignites the fuel.
3. As the fuel combusts, it expands, pushing against the plate and the vane, as it races around the chamber, which looks like a expanding wrapped wedge around the sphere. This expansion causes the plate the nutate (wobble) - but not rotate - around ("around" is not a good word, as it implies that the plate is rotating - I must stress that it does not rotate) the sphere. This opens up the chamber, and as the plate slides around the sphere (*), it rotates the sphere 180 degrees, which is connected to the shaft, which turns the shaft 180 degrees.
4. Once the combustion is started, of course the fuel inlet is closed. When the combustion is completed, the plate is now lying at the opposite angle. An exhaust port is opened (I would imagine the opening and closing of exhaust and inlet ports to be accomplished by solenoid valves of some sort), and the inlet port on the other side is opened to cause the other side to fire, to rotate the shaft 180 degrees more, while simultaneously pushing the exhaust out (by action of the plate) on the opposite side.
5. The cycle repeats.
(*) - Notice how many parts are sliding against each other? I can't understand how this thing is supposed to run dry - ie, no lubricant - unless the fuel is to provide the lubrication of some sort. All that friction will get it damn hot if it isn't lubricated and cooled in some manner.
Furthermore, I am not certain how the plate, rubbing up and acting on the sphere (nutating "around") spins the sphere, unless is it by some strange vector motions being imparted by friction.
The interesting thing about this, though - is if that is the case, if the motor shaft is somehow stalled for whatever reason, the engine shouldn't die - it should only become hotter than normal, which may or may not be a good feature.
---
I hope this explanation helps - I hope it is right, I am pretty certain it is. Please discuss below, and comment on it - I would be pleased to know what others think...
It's a water meter (Score:2)
Engine designers keep trying to use various pump geometries [animatedsoftware.com] as engines, but the problems are different. Modern engine design is about combustion management, not just fluid flow.
Obviously you didn't... (Score:2, Insightful)
Re:Read the article before commenting... (Score:2)
Hydrogen + oxygen burns to make pure water over a wide range of temperature and pressure. Dilute the oxygen and it takes more pressure. At some combinations of temperature and pressure, it'll also combine some oxygen with nitrogen and make stuff that isn't so clean.
At best, it's decades away from something practical for a car.
Re:Read the article before commenting... (Score:2)
Many brilliant scientists throughout history have been labelled as "quacks" or "kooks" at one point or another. I'm willing to give the McMaster engine a chance, it's better than having to rely on volitile middle-east politics to "regulate" the gas supply.
Re:Read the article before commenting... (Score:2)
And I said "a lot of brilliant people have been labelled "quacks" throughout their careers", not "a lot of quacks turned out to be not-quite crazy after-all"... there is a difference.
Re:Read the article before commenting... (Score:2, Informative)
Burning pure hydrogen/oxygen will allow much high combustion temperatures without NOx production and will produce more power (no N2 to dilute the combustion process), but it is not clear that carrying the oxygen along is worthwhile. The mass of the O2 would be eight times greater than that of the necessary H2.
Re:Really really cool, but... (Score:2)
They've got some more info on the engine (including a neat little animated pic of the theoretical engine in operation).
Re:500mpg engines (Score:2, Informative)
The math for fuel economy is as follows: other than pure hydrogen, methane (CH4)(you know, natural gas -- most qty's derived from "dead dino dinner" aka antediluvian vegetation) at around 22,000 btu lb. LHV ["low heating value"], gasolines come in at about 20,500 btu/lb, diesel and jet fuels about 18,800 or so. [IIRC without the book in front of me.]
Using gasoline as the example fuel, you get about 6-1/2 lbs per gallon, or about 130K BTU. 1 HP = 2547 btu, so 135K/2547 equals about 50hp per gallon used per hour. Now then, my little subcompact gets about 35 mpg at that speed on the freeway, at around 12 hp in cruise gear. This particualr engine was rated about 25% thermally efficient under lab conditions. So even if my little car could get a 100% efficient engine (not possible in the real world), the max would be about 140 mpg.
Now then, pure hyrogen is pound for pound about three times more powerful as a fuel, but by the time you get the storage problems resolved, so far you've either added so much weight or drag, you've negated the fuel advantage.
Of course, if we were all flying around in low-drag H2 powered and lifted personal airships -- the weight component would go away. ;-)
Finally, as has been noted in comments posted to other threads, H2 isn't an easy commodity to come by -- don't forget that 2000 sq. ft of solar panels will cost about the same as a medium size new car, or enough to buy fuel for my little car and a 35 mile round trip for somewhere around the next 20 years...
Re:Where is the compression? (Score:2)
BTW - wasn't the Wankle engine's combustion chamber cardoid shaped, not peanut shaped?
Re:Where is the compression? (Score:2)
The wobbly plate does not spin - there is a stationary vane on one side fitted into slots on the cones. The plate appears to wobble because it is fired on one side of where the plate and the cone and the stationary vane come together. As the explosion expands and progresses, it causes the plate to move and wobble. I am not sure how this gets the sphere spinning, though, unless just by frictional contact and through various motion vectors the sphere moves.
I would still think all of this would need severe lubrication and tight tolerances...