hydrogen power

[laki101]

I was watching mythbusters 2 days ago and they were testing fuel saving methods and one of them was that using electricity you extract hydrogen from water and use it to power up your car. It didnt work but they tested with hydrogen gas and the engine runs fine on it.

So to get to the point. I was thinking on making something to extract hydrogen from water using an fuel powered generator and to use the hydrogen to power up an outboard. Now you probably think its a bit stupid to use one gas motor to get hydrogen for the other but if the generator uses 2l an hour and you use it to get hydrogen for an outboard that normally uses 15-20l an hour you save 13-18l an hour.

so my question is how difficult would it be to get hydrogen from water using electrical power?

 

[cobra1]

this wont work, getting hydrogen from water using electricity is just too innefficient, and then burning it makes it even more inefficient, overall about 10-15% efficiency.

by running one generator to power a cell and then using that hydrogen to run another engine wont work.

i have seen cells that can put out 2lpm @ 20A so for you required 15-20lpm you need 200A input. plus hydrogen isnt dense enough to do proper work in an engine.

to match the power of a 2 litre petrol engine, you would need to feed it 400Litres of hydrogen per minute to get this would require around 400A input power

where abouts are you from??

 

[laki101]

lmp is liters per minute and my engine (ok the wont that I was thinking of) needs 20l per hour

then an petrol engines works just find with hydrogen the only an bigest problem is to get it from water somehow

I knew this is virtually impossible but as an idea it looks great

 

[cobra1]

20lph??? is that petrol consumption??

 

[laki101]

yes i was thinking on something like 60-70hp
of course there are smaller engines but these are the real environment and money issue

 

[Nigel Goodwin]

yes i was thinking on something like 60-70hp
of course there are smaller engines but these are the real environment and money issue

Sorry, but it's a completely ludicrous idea - sure you can run engines on hydrogen (although they would really need to be specifically designed to do so) - but producing the hydrogen takes MORE energy (considerably MORE) than burning the hydrogen produces.

 

[tcmtech]

Using hydrogen as a fuel works well If the engine is built specifically to work on it. If not its horribly under powered and very inefficient.

To use hydrogen you need to nearly double the engines compression and ideally need to have a more aggressive camshaft profile and change the spark advance curves.

If your just looking for hydrogen in a tank you can rent a tank and buy it from most welding supply chain stores. Its a fairly common gas that is easy to get if you know where to look. No special requirements are needed. Just sign the paperwork and your good.

The last tank I had cost me about $68 for the gas and $28 for the year lease on the tank but now and the price is going up on the hydrogen . I used to get the tanks for about $25 a few years ago.

You would also need a hydrogen compatible high pressure regulator to bring down the tank pressure from its 2500 PSI level down to the level a vapor carburetor system can handle as well. That may set you back another $100 or more.

 

[laki101]

well I dont have a motor like that so I dont really need it but it just looked like a good idea so I just wonted to hear someones opinion

 

[Nigel Goodwin]

well I dont have a motor like that so I dont really need it but it just looked like a good idea so I just wonted to hear someones opinion

It's like all perpetual motion machines, a little thought and the idea soon falls apart.

 

[Centretek]

The main problem with burning hydrogen is the air/fuel ratio. 2 hydrogen molecules (2 by H²) reacts completely with 1 Oxygen molecule (O²) which gives a fuel air mix of 2:1.

The required fuel air mix for LPG or CNG is 1:9.

Burning Hydrogen requires 18 times more fuel than burning LPG or CNG.

 

[cobra1]

i agree with the Fuel/Air ratio, for a complete burn you need 2:1, so why burn it??

its far too inneficient and uses up H2 quickly, an engine burning H2 will run at possibly 15-20% if your timing is spot on, the best hydrogen engine to date i think only achieves 50% and its not available to market yet. a fuel cell can achieve 50% easily, and as technology improves this can only get higher.

so for those saying they want to retro fit a HHO cell to there car, its pointless.

there are ways of getting sufficient H2 on demand but only to run a Fuel Cell.

 

[jpanhalt]

The main problem with burning hydrogen is the air/fuel ratio. 2 hydrogen molecules (2 by H²) reacts completely with 1 Oxygen molecule (O²) which gives a fuel air mix of 2:1.

The required fuel air mix for LPG or CNG is 1:9.

Burning Hydrogen requires 18 times more fuel than burning LPG or CNG.

In the first part, you seem to forget that air is only 20% oxygen. Are you talking about fuel:air ratios or fuel: oxygen ratios?

Considering CNG as an example:

CH4 + 2O2 = CO2 +2H2O

The molar ratio of fuel to oxygen is 1:2; not 1:9. Sure, it's still not 2:1.

John

 

[tcmtech]

Where do you get your numbers? 2:1 , 1:9?

In normal internal combustion engine fuel applications these are the accepted average numbers.

Gasoline is 14.7:1
Propane is 16.1:1
Natural gas is 17.2:1
Hydrogen is 34:1

These are the typical stoichiometric average ratios. That actual ratios can vary slightly due to different quality and purity of the fuel source and air source. In realistic applications the actual most efficient ratio can be slightly richer or leaner than the theoretical ideal ratio.

 

[jpanhalt]

@tcmtech

Not sure to whom your question is addressed. It appeared to me that Centretek was talking about the chemical equivalents, not actual mixtures used for an engine. The values I gave were based on molar equivalence. If you do the calculation for volumes of air, the results are different (but you can still assume that 22.4L of air at STP contains approximately 0.2 mole of oxygen), and if you do the calculation by weight or by liquid volumes, then the differences are even greater.

John

 

[tcmtech]

It was directed towards centretek.
He was the first one to post those numbers.
Typical A/F ratios for use in engines are given as the mass of air to the mass of the fuel. Hence the term A/F ratio being used since engines are considered to use air as their primary source for oxygen to drive the combustion processes.

 

[gary350]

I have tried many experements to make hyrdrogen it costs $10 to make a $1 worth of hydrogen. It is a loosing battle. Dissolve 8 tablespoons of salt per gallon of water makes the electricity work much better. Try different frequencies, different amps and different voltage. Once you make hydrogen you have to use energy to pump it into a tank so it can be saved and used later. Hydrogen has the ability to burn with an extremely out of balance air mixture, very rich or very lean it still burns fine.

It is much easy to run your vehicle on saw dust than hydrogen. Read about how natural gas is made first. Get a coffee can and mount it to your vehicle carburetor. Put a piece of screen wire in the bottom and fill it with saw dust. Disconnect the gasoline fuel line from the carburetor. Crank the engine so it sucks air through the saw dust and you can ignite the saw dust just like lighting a tobacco pipe. When the engine starts you can drive the vehicle down the road. As you push the gas pedal it sucks more air and burns more saw dust and makes more natural gas. If you use a small 12 oz coffee can you can get the speed up to about 20 mph before it starves for fuel. If you use a larger coffee can or a 1 gallon paint can you can get the vehicle up to about 40 mph.

 

[cobra1]

then dont use electricity to produce the hydrogen then, by putting in electricity into water to get hydrogen out is simply a waste of time. frequencies, high voltages, etc do no good, you will not get a gain in output from any electrolysis,
If you want a useful source of hydrogen it needs to be made via reversable/regenerative chemical reactions.

i.e aluminium in sodium hydroxide + water has the potential to produce 1200l of hydrogen gas @ stp
this occours at a near uncontrollable rate, once the aluminium is consumed it can be recycled back into aluminium.

however by simply adding colloidal lead @ 20ppm this causes the aluminium to be regenerated after being consumed, this makes the reaction continue for longer, i saw someone do this experiment and achieved over 1700l of hydrogen from 1kg of aluminium.

it is on this regenerative basis that i am able to produce hydrogen gas in excess of 150l from just 40g of zinc

 

[tcmtech]

Sounds like a simple wood gasification process of sorts. However I would suspect that it doesn't work very well in long term usage though!

One likely problem is that the wood tar that open gasifying creates will likely gum up the throttle, intake, and combustion chambers to the point the engine clogs itself and eventually quits. If not, the combustible gasses given off from the wood have some ammonia and other corrosive chemicals that will eventually eat up your engines aluminum pistons and intake system components.

For further experimenting a person can easily make a sealed can that has a tube that feeds the wood gas to the intake of a small lawn and garden engine.
By having a slightly larger container that fits over the wood gasifier container the hot engine exhaust can be effectively circulated in the space between the two in order to drive the gasification process.
By using the hot exhaust from the engine to further heat the gasifier it can be made self sustaining. Basically its just a can in a can with hot exhaust circulating in the space between them.

It would be interesting to see how long it runs before the engine becomes all gummed up or corroded to the point of failure. I bet it is not all that long.

Good dry hard woods will probably run longer than soft sappy woods but still without proper filtering its likely rather limited as to how long it will work.

Has anyone ever built one that worked and continued to work for some time without having to add other steps to the process?

 

[shortbus=]

This is very old school! from around the early 1900's. It was called "Producer Gas"

There were a few farm tractors that used wood, coal, or even grain to make the gas. If I remember right it is only effective with low compression engines, under 5:1 compression.

Lindsay publishing has a book or two on the subject.

 

[Oznog]

Well, a 5L engine running at 2000 rpm, IIRC a 4-stroke replaces about 80% of the cylinder capacity in a cycle, and it runs a cycle every 2 turns of the crank. So it takes in 4000L of fuel/air charge every min. Now in a gasoline engine, almost ALL of that is air because the liquid fuel takes up very little volume. Running H2, the H2 takes up 2/3rds of your intake volume so it can only oxidize 1/3rd the air. How much force you get out of it then depends on the temp reached, which I don't know for 2*H2+O2 in an engine.

But the engine size is not the issue so much as the basic problem that it will only return 10%-20% of the energy inside H2, and the production of H2 varies but it's generally like 50%. So, for every HP you need out of the engine, your alternator needs over 13HP to turn into electricity to make it.

The HHO people keep touting a theory that small amounts of H2 make the gasoline burn much better, adding more hp than required to make the H2. It's more plausible than the "over unity" perpetual motion concept, but not all that plausible, and I have not seen any convincing scientific proof of this.