In article , Bryan Martin
wrote:

Lets see. You take energy from the electrical system to crack water into H2
and O2. Then you pipe the H2 into the engine with the gasoline where it will
combine with oxygen to form water. The article I read doesn't say what you
do with the O2, I guess you just vent that to the atmosphere. Seeing as how
conversion of water into H2 and O2 is not 100% efficient due to losses in
the wiring and such and seeing as how burning H2 with air is also not 100%
efficient, there is no possible way to get a net energy gain out of this
system. In fact this system will result in a net loss and lower fuel economy
since the electrical energy to drive the electrolysis must come eventually
from the alternator which is driven by the engine.

That's the Second Law of Thermodynamics: in ANY energy conversion scheme
there is inefficiency and therefore loss.


The only way to get any kind of gain out of this is to inject the water
itself into the engine. This might give some power gain in the short term
but pumping salt water into your fuel system and engine will certainly do
them no good in the long run. The article specifically mentioned putting
water and an electrolyte (salt) into the booster tank.

Agree on the salt.
Water injection only works to increase power if you increase engine
compression. The higher compression ratio gets you more power, the
water injection cools the charge and acts like an octane booster.
Just don't run out of water...
If you run water without increasing compression ratio, you will get a little
due to the density increase of the air, but it's not major.

--
Harry Andreas
Engineering raconteur