What's wrong with this idea?

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I'm a first and second grade teacher, about the most I teacher about water is the three states and mostly if it soaks through to your underwear it itches. So, I'm not an engineer of any sort. To all the engineers out there, please excuse my ignorance, but how come this is not more popular?

Thanks,
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http://www.water-4-fuel.com/
 
This has popped up more than once. Why isn't it more well discussed? Simple, because it's a scam and doesn't work.

Not saying you can't make a hydrogen powered vehicle, but not with something like this. If it were really that simple, everyone would do it.
 
Isn't this like the carborators they used to sell on the back of magazine. You could get like 120 mpg supposibly.
 
Ah that, well they want to to go outside and play after it rains or when the snow melts. They get one lesson and no phone call. It's not prison just life lessons.
 
simple hydrolysis "fuel cells" cannot produce enough H2 to be effective or efficient. let alone one made out of a 1L mason jar. my school has made experimental cars using much more advanced/complicated mechanisms, and they work, but still arent practical on a commercial scale. so ya, that jar will produce a little hydrogen gas (i've done it myself), but you couldnt run a go-ped off of it...so you can forget about it running your car. have you seen the car that runs on compressed air? that thing is ugly but it works! i'll try to find a link.
 
I love that they used freakin' Ball jars... that's tremendous!!!

Theyy didn't even bother to make the "vaporizer" out of something that looks manufactured.

I'm no engineer either but I'm fairly certain it takes a bit more than a foot of copper wire in a Ball jaf to produce enough hydrogen to add any kind of fuel economy to a car. If it was that easy, how come we aren't all just driving around with really big Ball jars in our cars, filled with water, and giving us 400 MPG???

LOL
 
The Mythbusters have a good read about this.
http://community.discovery.com/eve/forums/a/tpc/f/9551919888/m/2321969559

Water-for-gas? Let's have a look, shall we?

The standard reaction for the electrolysis of water is:
2H2O → 2H2(g) + O2(g)
For this process, 4 moles of electrons take place, therefore the standard free energy change is:
ΔG = -nFε
ΔG = -4*96487*1.229
ΔG = -474330 J

We can expect to extract -474 kJ from the products of the electrolysis and use it to do work.

This is also borne out by looking at the approximate bond energies. 4 H-O bonds must be broken, at ≈460 kJ each, but energy is released when the new bonds form. The O=O bond yields ≈498 kJ and the H-H bonds yield ≈433 kJ each. Our net free energy is:
-4(460000) + 2(433000) + 498000 = -476000 J

So we have to put ≈ 475 kJ into the system to separate the water, and we can get ≈ 475kJ back out in utilizing the free energy.

According to the "Oxyhydrogen" people (more on this later), burning the resulting gases gives off 576 kJ. If the TOTAL energy that can possibly be released to do work is 475 kJ, how are they magically getting 576 kJ? They're generally not.

Now, on to the electrolysis itself. The efficiencies for electrolysis of water are reported as anywhere from 50% to 94%. So, in the best case, we have to put 505 kJ in to be able to get 475 kJ out, and in the worst case we need an input of 950 kJ to be able to get 475 kJ out. Even before factoring in the other losses, we can see from the 50-94% efficiencies, that we will have a net loss of 6-50% of the energy used for electrolysis.

There are thermal losses from heat engines. From Carnot, the MAXIMUM possible efficiency from our engine is 70-75%. The real value is about 25% due to friction and the fact that the combustion is not spontaneously reversible.

So, with the maximum possible theoretical efficiency (which can NOT be obtained in practice) we are now needing anywhere from 675 kJ to 1357 kJ. Even if we allow for the inflated output numbers, and ignore the actual losses we'd encounter, you can NOT produce 576 kJ and use it to keep a process needing 675 kJ to 1357 kJ on-going. And this is before we try to extract any OTHER work from our engine -- we are solely using the output power to try and drive the input power.

In reality, what you end up with is needing to output around 3150 kJ to keep the cycle going, but you are only producing 475 kJ. This is why water-4-gas did not work when Adam and Jamie tried it. The losses completely overwhelm any energies "created". Water is not a fuel -- it is the ashes of hydrogen that has been burned once before.


Now, I know the "newest" schemes do not try to run the car solely off the hydrogen, but call for using it in a "hydro-assist" manner. The claim is that the hydrogen makes the gasoline burn better.

The first thing to note is the losses from above. If we need 3150 kJ to produce two moles of hydrogen gas, and can only get 475 kJ back from the system, then we need to burn an ADDITIONAL 2675 kJ worth of gasoline just to break even!! This isn't looking promising.

But, but, but... the claims are that the hydrogen is a "catalyst" and makes the gasoline burn more efficiently.

So? That claim is just wrong. We know we can't affect the thermal efficiency of the Carnot cycle by very much, so 75% is still going to be "wasted". Even if the hydrogen did act as a "catalyst", there is no more energy to be released -- 99% of the gasoline does undergo combustion. A 300% gain in efficiency would imply that we are now getting 399% of the theoretically-retrievable energy that the gasoline contains (well, actually more than 399% because we also need to cover the losses from the electrolysis). This is just asinine and Carnot says otherwise. Energy can not be created from nothing -- the gasoline can NOT give more than 100% of what it has.

But, but, but... "it's not H2 gas that is produced, it's monatomic hydrogen!"

Ok, let's look at that. The ½H2(g) → H(g) reaction is NOT exothermic until you reach a temperature of about 4000K. At our temperatures you need to INPUT another 800 kJ (4*200 kJ) to get the 2H2(g) into 4H(g). Without even considering the thermal losses from the combustion cycle, we now need an input of about 1600 kJ to our electrolysis system in order to get the claimed 576 kJ of "oxyhydrogen" back out (and that calculation was made in the 19th century and is taken from a 1911 encyclopaedic entry -- wonder why they don't use more modern sources and numbers?). I'm still seeing a major net loss, aren't you?

But, but, but... "the hydrogen DOES improve the efficiency!"

Yes, it is reported that hydrogen can increase the lean limit from 1.7 to 1.85, and it is also reported that hydrogen can reduce the no-load idle consumption of gasoline by up to 50% in small engines.

Let's look at these. First off, these are for volumes of hydrogen that can't possibly be produced by these simple cells. And, the reported lamdas of 1.7 and 1.85 are for natural gas combustion, not gasoline. The lean limit for gasoline is a lamda of about 1.2. Until you get to the lean misfire conditions, leaning your gasoline down WILL reduce consumption. But you also get rough idle and loss of power. Except when idling, you car isn't fully leaned (and even then it's not maxed out) -- in fact, the more demand you're putting on the engine, the richer the computer (or even the carb in non-EFI engines) makes the mixture. By overriding the computer and approaching the lean limit, you can reduce consumption at idle even without hydrogen. But as you place demands on the engine, it can NOT be run this lean. The faster you go, the more engine power must be used to overcome drag, so at highway speeds, even if you are not accelerating, you are not running a lean mixture. The manufacturers do NOT lean the idle down as far as possible, because excessive leaning can burn the spark plugs and pistons and lead to detonation and preignition. Even if it was possible to reduce idle usage of gasoline by up to 50%, the long-term engine damage and the percentage of the time the engine is NOT idling dramatically reduce this savings. Plus, you STILL need extra gasoline to produce the hydrogen in the first place from all the above-mentioned losses.


"Ok, ok... so I can't get such phenomenal gains in mileage from 'hydro-assist.' But what about this PICC stuff?"

Ah, yes... The "pre-ignition catalytic converter". Let's take a look.

The claim is that the PICC will break the isooctane molecule of gasoline down into smaller molecules that will "burn better." Oh, really? When we looked at the energies involved in electrolysis, we noticed that breaking bonds takes energy and forming bonds releases energy. It doesn't matter what happens in-between. If our net result is 2C8H18 + 25O2 → 16CO2 + 18H2O, then we are breaking 37 C-H bonds, 14 C-C bonds and 25 O=O bonds, but re-forming 32 C-O bonds and 36 H-O bonds. Any bonds that form and break in-between are immaterial; we are left with a net change in bonds of about 37800 kJ. But, and this is important, it TAKES energy to make any smaller molecules. We have to put energy in, in order to have the higher bond energies of any smaller molecules. The net change from beginning to end, remains the same: whether you extract 37.8 MJ from the gasoline, or extract 57.8 MJ after putting 20 MJ into the bonds of smaller molecules, is immaterial -- the net change is still 37.8 MJ.

And besides, the PICC sites claim they're making a "plasma". Plasmas do not undergo normal chemical reactions. You won't get combustion in a plasma, nevermind factoring in the large energies necessary to create plasmas in the first place.



Every step of all these schemes consumes far more energy than it could possibly release. There is no magic way to get such phenomenal gains in fuel efficiency out of your existing car.
 
Way to break it down Kegerator, WOW!


If you really are interested in fuel economy take a look at [ame="http://www.google.com/search?hl=en&q=hypermiling"]hypermiling[/ame]. Granted some of the things these guys do are totally illegal, but just doing some of the basics (the same things they always have on the news), like keeping your tires at the right pressure, avoiding quick starts, etc... will make a difference.
 
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