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Old 01-16-2012, 01:52 PM   #41 (permalink)
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Originally Posted by IamIan View Post

ICE's are fairly low efficiency devices ... it is not uncommon at all for ~70% or more of the fuel's energy content to be wasted going out the radiator and the exhaust.
Hi IamIan,
Yes, Otto cycle engines have thermodynamic efficiencies (at WOT) in the range of 25% to 35% so on average 70% of the heat is lost. However I know a little about this subject and dumping 175% of the shaft power into the cooling system at part throttle is incredible. The worst case design rules allow for 100% of full shaft power to go into the cooling system. At reduced power a considerably small percentage of power goes into cooling. As power is reduced peak temperatures, average temperatures and efficiency all fall and a higher percentage of heat goes out the exhaust. In general, high peak temperature provides higher efficiency, but the cooling system removes heat as if from the average temperature. At 2140 rpm and 36 bhp, the engine is throttled down to about 25% I would expect thermodynamic efficiency to be below 15% A common design rule for automotive cooling systems is the radiator must dump 14% of shaft power at cruise. So I see this engine as needing 12 times the cooling I would have allowed.

Sorry, that is completely off topic.

If the paper is to be believed, the addition of 1.5 lb/hr of hydrogen improved efficiency from 21.95% to 22.78% (bhp/fuel hp)
-m

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Old 01-16-2012, 02:38 PM   #42 (permalink)
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If the paper is to be believed, the addition of 1.5 lb/hr of hydrogen improved efficiency from 21.95% to 22.78% (bhp/fuel hp)
-m
Now factor in how much energy it takes to generate that much hydrogen, and the light bulb should go on.
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Old 01-16-2012, 03:08 PM   #43 (permalink)
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NASA is not perfect -- ask the Challenger and Columbia shuttle crews -- but, they are typically very thorough and precise. I'd accept there data, but maybe not their conclusion, as prima facia evidence of fact.
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Old 01-16-2012, 03:32 PM   #44 (permalink)
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NASA is not perfect -- ask the Challenger and Columbia shuttle crews -- but, they are typically very thorough and precise. I'd accept there data, but maybe not their conclusion, as prima facia evidence of fact.
But they used bottled hydrogen, and hydrogen from a methanol reformer. Come on, neither of those used electricity from the alternator to generate hydrogen by splitting water.
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Old 01-16-2012, 05:37 PM   #45 (permalink)
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So I see this engine as needing 12 times the cooling I would have allowed.
So if I am understanding you correctly ... you were expecting ~30% Energy content of fuel as heat to the radiator ( ~40% to Exhaust ) as a upper limit near 100% WOT ... down to ~2% of energy content of fuel to radiator ( ~83% to exhaust ) at ~25% throttle ... If that is what you were expecting ... I guess I can see your source of surprise.

Do you have any sources I can look at that would go into more detail about the distribution of the ratios of waste heat removal? I haven't seen this specifically yet myself from what I've read. It seems like it would be interesting reading.

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If the paper is to be believed, the addition of 1.5 lb/hr of hydrogen improved efficiency from 21.95% to 22.78% (bhp/fuel hp)
-m
Which is only a ~3.6% improvement.

Straight Lean Burn ICE's without HHO have been shown under testing to achieve a ~20% efficiency improvement during their Lean Burn operation ... thus ... even if you completely ignored the energy consumed to get the hydrogen in the first place ... and you ignore the additional weight and space of the HHO system ... even if we ignored all those things ... it is still an inferior system to improve ICE efficiency.
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Old 01-17-2012, 12:36 PM   #46 (permalink)
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Do you have any sources I can look at that would go into more detail about the distribution of the ratios of waste heat removal? I haven't seen this specifically yet myself from what I've read. It seems like it would be interesting reading.
Hi IamIan,
My reference books are in storage, so it may be sometime before I can cite chapter and verse. I'm think the best discussion is in one of the Wiley Engineering Series. Maybe Esbach's. I just looked at the Wiley web site and I guess all my favorites in the series are out of print. I'll get back to this later.

There is an introductory text "Engineering Fundamentals of the Internal Combustion Engine" by Pulkrabek which has something on energy balance, however the nice graph (from the 1st ed.) is energy balance vs engine speed at WOT.

-mort
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Old 01-17-2012, 05:59 PM   #47 (permalink)
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I wonder how they get those parts to add up to more than 100% of the energy in?

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Old 01-17-2012, 07:32 PM   #48 (permalink)
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My reference books are in storage, so it may be sometime before I can cite chapter and verse.
No need for chapter and verse type level ... at least not for me ... Just a point in the direction should give me what I am looking for.

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I'm think the best discussion is in one of the Wiley Engineering Series. Maybe Esbach's.
I'll take a look... thanks for the point.

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There is an introductory text "Engineering Fundamentals of the Internal Combustion Engine" by Pulkrabek which has something on energy balance, however the nice graph (from the 1st ed.) is energy balance vs engine speed at WOT.
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I wonder how they get those parts to add up to more than 100% of the energy in?
That would be the obvious 1st issue I have with that chart.

The Second thing I noticed is that ... that graph looks to contradict what mort was expecting ...
  • That Graph looks like it shows the coolant load being a significantly larger % of the energy content of the fuel than the Exhaust is for a large part of the graph ... the graph is showing the coolant system being over 50% of the energy content of the fuel on the left hand side ... way above the 30% max mort suggested as a upper limit.
  • That graph shows on the left side more than 250% of the drive shaft power going to the coolant system ... way above the 175% mort found to be incredible... and way above his worst case of 100%.

But to be fair ... I do not know the context of the graph.
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Old 01-17-2012, 08:10 PM   #49 (permalink)
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Ok thanks for the explanation. What about just using it as a sort of makeshift accelerant? It may be better used there, instead of what many people wanted to use it as, which is a partial fuel substitute.

It also brings to mind a question, about those hydrogen powered cars. If hydrogen is a powerful enough fuel to power a car, (which we all know it is) then it just seems like there would be something to the HHO generator after all. If using pure water, then 1/3 of the gas produced by the HHO generator would indeed have to be hydrogen.
The energy used to make the HHO (which itself is incorrect nomenclature -- it is a mixture of H2 and O2... this is part of the "magic" from the early fraudulent days of such stuff, with the first patent in 1914, IIRC) comes from the engine turning the alternator. If you work through the thermodynamics, you find that it takes about 5 times as much fuel going into the engine as the energy value of the HHO coming out of the electrolysis unit.

The issue is not that the stuff in there is H2 and O2. It is that it costs more energetically to create the stuff than you get from burning it in your engine.

For more detail, you can go here: CR4 - Thread: The Unlucky 13 HHO Lies
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Old 01-17-2012, 08:23 PM   #50 (permalink)
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This report has been used for ages by HHO flim-flam artists. It has absolutely nothing at all to do with HHO. It is about hydrogen injection, with the hydrogen obtained from a tank, not by converting your car into an inefficiency electrolysis machine.

For more info on the various scammy "explanations" offered through the 9 decades since the onboard electrolyser was patented, look here:
CR4 - Thread: The Unlucky 13 HHO Lies

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