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Lean Burn Generators for Hydrogen to Electricity Conversion

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Engimuneer

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Feb 25, 2009
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thread71-252760

Great information included in the above thread that pertains to my current project 3 years later. I'd just like to toss out some details on the project in case it helps anyone else taper down their own projects.

I am using GM 5.3 & 8.1L, turbocharged V8s running multi-point fuel injection of Hydrogen gas to create electricity. A byproduct of our process is excess H2, so might as well make some use of it. The 8.1Ls stopped being made by GM & have been replaced with 8.8L units; however, only 2-3 vendors in the country have these. Fortunately, I have 3 coming in next month!

Since automotive engines are a dime a dozen compared to industrial grade, we decided to make use of them for our testing. Not one industrial engine manufacturer had any interest in working with us on Hydrogen fuel, no matter the ratio of CH4 (methane) added.

I found at least 6 CNG/H2 fuel injector manufacturers [Bosch SMP, Delphi Multec, Quantum, Keihin, Westport]. We've worked with the Bosch NGI-2 but will be going to higher flow with our next version.

Hydrogen does not like hot spots [carbon buildup, valve seats, spark plug, blowby oil] and has shown to predetonate just as it enters the combustion chamber with batch fire (flooded intake manifold methods), so MPFI or Direct Injection are required for safe operation with this fuel.

Low RPM can have issues if the camshaft has too much overlap. The air-fuel mixture hitting the hot exhaust gases can cause backfire through the Intake Manifold due to the extreme flame speed & low ignition energy required.

Hydrogen can burn at much leaner ratios than most fuels used in internal combustion engines. Slightly lean increases NOX emissions, but large amounts of excess air bring the emissions to almost zero. Running Hydrogen lean also slows down the flame speed to reasonable levels for ICEs. Stoichiometric H2 mixtures will burn 5 times quicker than Methane alone! Ignition timing ends up being darn near TDC.

Still selecting industrial engine control units and a high energy ignition system for the scale up to production.Hope some of this information helps H2ICE development. Feel free to ask any questions & suggest away.

 
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What is your rationale for running a hydrogen powered generator to make electricity instead of a hydrogen fuel cell?

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz
 
Why are you only using the 8.8L engine? There are several companies producing 8.0L and 10.3L GM engines for dry fuels. There are a ton of aftermarket intake manifolds for these engines that are designed for multipoint injection.
 
Engimuneer,

I like what you are doing; I wish I were involved. I did some similar testing a few years back and had occasional problems with backflash into the intake manifold until we limited the max equivalence ratio to about 0.55. See link to graph of min ignition energy of H2 compared to typical hydrocarbon at various equivalence ratios. Sorry about lack of labels, but I think that you will be able to guess which line is hydrogen. See also link to article below.



 
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