[Ken Fry]

Originally Posted by IamIan

Apologies to anyone / everyone for this posts length.

At least it's no longer than mine.

Average for average cars maybe ... but highly efficient ones , or the best case ... no ... I've already posted that ... you just ignore it.

I didn't ignore it, and in fact I think I responded directly. The Prius has the highest operating efficiency of any car sold in the US. (Its system works better than the Honda Insight's*, with the current Insight being 20% lighter, with similar aero drag, but with substantially lower fuel efficiency numbers.) Its hybrid system allows the engine to spend more time near its best operating efficiency than on any other car sold in the US, and its peak operating efficiency is the highest of any spark ignition car sold in the US. Although its engine can peak at 37-38% efficiency, it does not operate at anything close to that efficiency routinely. Unlike the typical car that gets less than 20% actual installed average engine operating drive cycle efficiency, the Prius gets about 24%.

I provided a link, but if you go to the calculator and enter 3400 lbs, .24 engine efficiency, .94 transmission efficiency, .25 Cd, 24 sq ft frontal area, (the two figures providing the generally accepted CdA of 6.0 sq ft for the Prius), and .006 Crr, you will get 50.49 at 60 mph, a reasonable figure for the Prius**. With the Delco figure for typical alternator efficiency (.55), the electrical generation efficiency comes out lower than .20, of course, at .132. But what if we go beyond alternator efficiency and instead use 90% for the Prius motor generator and .85 for its DC-DC converter. Then we end up with .24 x .9 x .85 = .184, still lower than my 20% figure. In fact, because a lead acid battery is involved in the cycle at times, (and because the DC-DC converter is fed from the main battery bank, with its own charge cycle inefficiencies) even this .184 this figure is too high to be realistic.

So the very best of the best current tech still does not exceed the 20% figure on which I base my need for 500% electrolysis efficiency to just break even.

But the Prius is a ridiculously efficient car to use as being representative of anything close to "average." Every other car or light truck is much worse and hybrids make up only .5 percent of the light vehicles cars on the road in the US. For 99% of the light vehicles on the road in the US my 20% figure is generous-to-very-generous, even for the most efficient of those.

So I think my approach was well-enough defined in this paragraph:

(per K Fry The requirement for 500% efficiency from the electrolyser device itself comes from the efficiency with which an engine and alternator produce electricity. The 20% I usually use for the sake of argument is actually high, because engines do not really operate at 25% efficiency, and alternators don't operate at over 75% efficiency. Realistically, engines in non-hybrid cars operate at more like 22%, and alternators are more like 65-70% -- we'll say 67%. So the efficiency from fuel to electricity is 15%. To just get to break even the electrolyser would have to operate at 666% efficiency.

(your quote) To me ... you seem to want to rule out any current production vehicles using more efficient devices ... and you want to use averages to claim upper end limits ... I showed you real production vehicle getting from gasoline to electricity in a window of a minimum of about ~24% and a Max of ~36% ... and you want to ignore it and pretend that 20% is still an upper limit or best case ... that does not agree with the data ... even for real production vehicles ... The Gen-1 Insight in my example is now 12 years old... the tech in it is even older than that.

Yes, I want to rule out "production vehicles with more efficient devices" than are representative of the market. The HHO scammers are not selling the product as an enhancement to some future science-fiction vehicle. They are selling it as an enhancement to current vehicles, and the devices cannot and do not work on such vehicles. My 20% figure is giving them the benefit of the doubt, because even on the Prius, the very best of the best, the 12 volt battery is not charged with significantly better than 20% efficiency, and I doubt that it is really 20% -- 18% seems likely. But that is of little consequence. On every other vehicle, (more than 99% of the vehicles on the road) my figure is very generous.

Sure, a fuel cell vehicle (with further development) could get close to 60% efficiency from H2 to electricity, But the HHO promoters are not selling to that market.

Yes, my 500% figure is "too high" for the scenario you created. It is not too high, (and in fact is conservative) for the market into which these devices have been sold, and for the scenario I defined.

BTW sorry for the 86% reference. It was intended to be 83%.

* Which I find disturbing, having worked for Honda, having raced Hondas, and being the current owner of three Honda cars.

** And, of course the ludicrously high figures produced (in the chart) for lower speeds mean that, at those lower speeds, engine efficiency is even lower than the 24% input.

HHO works just fine if you power it from a faired-in solar panel on the car's roof. Then you get an input energy gain without any additional use of gasoline. If you want to show what's scientifically possible, would that not be a better example?