Hydrogen-based Rotary Engine?

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.

Comments

Who knows..

[Sentry23]

Storage and transport of hydrogen isn't really the problem anymore. Years ago, there were already test with hydrogen tanks that contained alluminium particles, which bind the hydrogen, making it a lot safer to transport and store hydrogen. Safer actually then a tank of gasoline.
(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.

New Category?

[GeekLife.com]

For some reason Slashdot gets a lot of submissions of wacko energy concepts

Sounds like there's a need for a specific category/icon.

500 mpg cars, revolutionary engine designs, etc.

[StressGuy]

Years ago, there was all this hoopla about the "Gill Carb." and the supposed conspiricy to keep it out of production. This was supposed to give a normal car over 400 mpg. Eventually, it was finally shut down when it was demonstrated that there simply is not that much thermal energy in a gallon of gas. I've been fortunate enough to see a lot of these alternative engine designs. Many of them are pretty innovative and downright ingenious. So far, though, you always seem to run into something that doesn't work as planned. Bottom line is that the 4-cycle piston engine is hard to beat in terms of practicality and Carnot efficiency. So, this guy is telling me that his motor will not require a drive train. That tells me the engine is high torque with a really flat curve, already I'm skeptical. Add in no lubrication and I must assume his rpm's are low. I won't dismiss his engine out of hand, but I'd need to see the design.

Several interrelated issues.

[nanojath]

There are two distinct technologies here and their feasibility needs to be discussed separately. The first is a novel engine design for converting power into locomotion. I don't have the engineering knowledge to judge this, but there do seem to be some people who ought to know saying the concept is solid.

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:Next Problem

[budgenator]

He chose hydrogen because of its low-enviromental impact quality. The engine is inherently multi-fuel, air-LNG should work also, That is if this thing works period. Hydrogen also has other problems its high pressure requirements is complicated by Hydrogen embrittlement.

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.