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