This is with onboard electricity used to operate the gas generator, a net loss as pointed out.

however...there is a way to 'cheat' a bit.

I find it fascinating that with a plug-in hybrid car, you can add energy to it 3 ways. one is put gas in the tank. another is recharging the battery on deceleration in regen mode, and the 3rd is plug it into the grid at home at night .. or maybe your own solar powered mini-grid, whatever.

so ...charge up your gas generator batteries with your home grid-power .. then while driving .. no energy from the vehicle itself, or it's fuel, is used to run the gas generator.

so 'maybe' ...you guys run the numbers .. there could be a slight gain using this method.

a Prius just was used to deliver a vanagon to my shop. They said the got 52 mpg driving down from Portland Oregon .. if that was a plug-in Hybrid, and one of our vanagon brothers retro-fits them for that btw, .. used carefully, and charged up before driving with home grid power .. they can deliver even 200 mpg I have read, since you are adding energy from another source while it's not running. and 'done right' grid power doesn't have to be that expensive.. and if you make your own sufficient power ...by a roundabout way that can turn into helping your wheels turn and better 'fuel' mileage.

Scott ----- Original Message ----- From: "David Beierl" <dbeierl@ATTGLOBAL.NET> To: <vanagon@GERRY.VANAGON.COM> Sent: Saturday, April 16, 2011 3:05 PM Subject: Re: HHO Kits

> At 11:45 AM 4/16/2011, Steve wrote: >>Long-time listener at least through the subject lines, and haven't >>remembered much discussion about HHO. Anybody make a recommendation >>on whether this is a good idea? Thinking of jumping in, not sure >>where to start. TIA Steve 82 diesel > > If you're willing to take an answer from thermodynamics, with *very* > rough numbers attached: > > Heat engines ( http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html > ) have a maximum possible efficiency which is noticeably less than > 100%. In practical terms, let's say your diesel can extract 40% of > the heat energy of the fuel it burns as usable work. This is > probably a high number. > > So, your gallon of fuel has 100 heat units and the engine gets 40 > equivalent work units from them. > > Of the 40 work units, let's say two are consumed to drive your alternator. > > Your alternator is let's say 75% efficient, so you get 1.5 equivalent > electrical units from it. You now have a net useful output from your > gallon of 40 - 2 + 1.5 = 39.5 units. > > Your battery is fully charged and your vehicle requires .25 > electrical units to operate. That leaves 1.25 units to operate your > gas generator, for a net useful output of 40 - 2 + 1.5 -.25 = 39.25 units. > > Your gas generator electrolyzes water by adding energy sufficient to > break the molecular bonds between the hydrogen and oxygen. It takes > slightly more energy to break those bonds than you will get back when > you recombine the two gases by burning them. For argument's sake, > let's say you'll get back 90% of the energy you put in. That leaves > you a net useful output of 40 - 2 + (1.5 -.25) *.9 = 39.125 > units. 38 of that is mechanical and 1.125 is the heat energy of the > hydrogen/oxygen mixture as fuel. > > So far it's cost you 1.125 / .9 / .75 / .4 = 4.17 heat units of > diesel fuel to obtain 1.125 units of HHO fuel. Now you run it back > into the engine and burn it at 40% efficiency, so your final work > output is 1.125 x .4 = 0.45 mechanical units obtained from burning > 4.17 units of diesel. If you'd simply *not done* all this stuff > you'd have netted 4.17 x .4 = 1.67 mechanical units from that same fuel. > > This is not a win. > > Yours, > David