OK, Debunkers, is this for real? ? ? 2

[ccw]

.
see:

http://www.switch2hydrogen.com/.

I see big problems getting hydrogen to work in otto cycle engines with "minor" kits. From the photo's of these kits I have seen, it (the tanks look like SCUBA tanks) looks like they have enough compressed gaseous hydrogen in tanks to run them a few miles if they get any at all to the cylinders.

 

[ivymike]

I didn't have the inclination to read too much of the site... but the bits I did read didn't seem implausible. Don't see why you couldn't rig up a "hydrogen carburetor" upstream of the throttle, and meter previously-compressed hydrogen gas into the intake tract. Didn't bother doing any calcs for energy storage, but if you can switch gas-to-H-to-gas on the fly, then it might not matter. Likely a lot easier than "hybridizing" an existing car, and would allow some amount of running on home-supplied electricity (stored as hydrogen).

 

[bvanhiel]

The cheapest way to make hydrogen commercially is to use fossil fuels. That fact alone should tell you something about the economic feasibility of this system.

-b

 

[ccw]

.
Start to design that "hydrogen carburetor". This does not seem like a simple device: needle valve, float, butterfly, venturi, and spritzer, it ain't. Dynamic gaseous hydrogen flow control valves would look like what? Hydrogen is the lightest element in the universe, goes through metal, goes into metal, goes about wherever it wants to.

 

[GregLocock]

Well, plenty of people make LPG carbs, I wouldn't have thought a hydrogen carby was beyond the wit of man.

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[ccw]

-b,
Our hydrogen economy has got to have big Nukes perculating down by the seashore or hydrogen is a non-starter as a transportation fuel. DOA.

 

[ccw]

Greg,
I throttle LPG on the "Barbee" all the time. Throttling hydrogen is achievable I am sure. Look at the space rockets. But, a "simple kit"?

 

[IceStationZebra]

I'll have to second the comments:
"Well, plenty of people make LPG carbs, I wouldn't have thought a hydrogen carb was beyond the wit of man. "
"The cheapest way to make hydrogen commercially is to use fossil fuels"

My father (a non-engineering type) brought up hydrogen fueled cars as the answer to the energy question. I mentioned that currently we don't have a good source for hydrogen, which quickly deflated his enthusiasm. I wish people/companies/media outlets would STOP giving people the impression that a hydrogen infrastructure is just around the corner until an efficient source is developed.

ISZ

 

[GregLocock]

Add that the usual source for industrial ethanol is oil, to your handy list!

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Bribyk]

My engine's prof had a great slideshow on alternative fuels comparing the tank sizes of the popular alternatives to gasoline and diesel to achieve the same range. Hydrogen was in there and the kJ/L was horrible. Unless you compress it into liquid form...but it takes more energy to liquify it through compression than you get back out of the fuel.

 

[bvanhiel]

They're using a hydride to contain the hydrogen. Energy density ends up being similar to gasoline. They are claiming 350 miles out of a volume that looks smaller than a gas tank.

-b

 

[jmw]

Just for your information, these guys were at Sustainability Scotland conference:
itm Power (

http://www.itm-power.com)

All you need, it seems, is a home hydrogen generator (the electricity to power it is shown coming from wind farms...) and "existing piston engine technology". (slightly modified).
Their claim is a modest 25miles per overnight charge, which for many car journeys is useful.


JMW

http://www.ViscoAnalyser.com

 

[dgallup]

Shoot, they're all sold out of high grade uranium ore. I was hoping to score some yellow cake.

I like the "practically free" electricity part. I put in a small solar power system at my summer home this year (previously propane only for lights, stove & fridge). If I amortize the cost over 10 years my average cost will be $12/kW-hr. Admittedly, it would be cheaper if it was used more than 1 month a year but the place is ice bound 6 months every year.

 

[franzh]

Anyone who has tried to run H2 without any effective metering (throttling the fuel versus throttling air AND fuel) will encounter an intake backfire. Even if the metering is relatively accurate (H2 has an extremely wide AF ratio, what would be the target AF ratio?), the engine is a backfire candidate due to valve sealing.

Just running gaseous H2 through a modified LP or CNG carburetor MAY work, for a while, but that is as archaic as a three bolt Stromberg carburetor on a 2008 engine. Relying on just the fuel composition to provide emission and fuel substitution benefits is a pretty strong stretch.

In my opinion, and however much that is worth, I feel that fuel storage is and always be the problem. Hydride matrix works, but all indications show it has a finite life and must be refreshed regularly. Compressed H2 also works, but introduces additional problems with compression, storage and transportation at high pressure (around 3000 to 5000 psig, the same problem that chases the CNG customers away, even though it is mostly unfounded), and LNG is still a long way before it reaches economic practicality for the consumer.

Bring in Hydrogen imbrittlement and material selections excludes many previously acceptable components in favor of stainless steel or composites, which may not be a bad idea anyway.

I still think H2 is a generation away. In the 70's we were told that we have 20 years of fossil fuels left. Today, we are still told the same thing.

The H2 add on kits are mostly hype. The small amounts of H2 produced and supplemented into the current airstream displace such a small amount of fossil fuel that it is relatively insignificant. The claims that it improves the fuel economy 20 to 50% is just that, a claim, one that is unsubstantiated in a recognized lab.

Franz

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[dcasto]

to run H2 in an ICE, you need new cams to keep the H2 from back firing into the carb. It is well documented in tests at southwest research in Texas.

 

[franzh]

dcasto is absolutely correct. The overlap must be minimized and intake valve events delayed. One of the problems has been that even though the valves seal "pretty effectively", they are not perfect seals. Even the slightest combustion temp gas escaping back through the intake valve will ignite an H2 mixture.

SWRI is a world class engine test facilities in San Antonio, Texas, and one place where I have spent a LOT of time. If anything of any merit has been done, its been done there.

Franz

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