Crap, I had this all typed out and my login timed out. Here goes again....
Water has exactly three uses in automobiles - no more:
- in a 50/50 mix (or there abouts) with antifreeze as coolant
- as the primary ingredient in windshield washer fluid
- for water injection to cool the intake charge in some high performance applications (especially turbo or super charged ones)
WATER DOES NOT BURN!!! Water is a by-product of combustion. You cannot combine water and oxygen and get heat out. It is not possible. Water injection systems cool the intake charge by using the heat in the air to evaporate the water. Cooler intake charges may enable a very slight increase in efficiency in turbo or supercharged applications with high intake temperatures, but not enough to bother keeping your water tank full in a street car.
As for using water as a source of hydrogen in an on-board electrolysis system; that doesn't work either. The following is directly out of Wikipedia
(link):
“Electrolysis of water
Main article: Electrolysis of water
One important use of electrolysis of water is to produce hydrogen.
2H2O(l) → 2H2(g) + O2(g)
This has been suggested as a way of shifting society toward using hydrogen as an
energy carrier for powering electric motors and internal combustion engines. (
See hydrogen economy.)
Electrolysis of water can be observed by passing
direct current from a battery or other DC power supply through a cup of water (in practice a salt water solution increases the reaction intensity making it easier to observe). Using
platinum electrodes, hydrogen gas will be seen to bubble up at the
cathode, and oxygen will bubble at the
anode. If other metals are used as the anode, there is a chance that the oxygen will react with the anode instead of being released as a gas, or that the anode will dissolve. For example, using iron electrodes in a sodium chloride solution electrolyte, iron oxides will be produced at the anode. With zinc electrodes in a sodium chloride electrolyte, the anode will dissolve, producing zinc ions (Zn++) in the solution, and no oxygen will be formed. When producing large quantities of hydrogen, the use of reactive metal electrodes can significantly contaminate the electrolytic cell - which is why iron electrodes are not usually used for commercial electrolysis.
The
energy efficiency of water electrolysis varies widely. The efficiency is a measure of what fraction of electrical energy used is actually contained within the hydrogen. Some of the electrical energy is converted to heat, a useless by-product. Some reports quote efficiencies between 50% and 70%
[1] This efficiency is based on the Lower Heating Value of Hydrogen. The Lower Heating Value of Hydrogen is total thermal energy released when hydrogen is combusted minus the latent heat of vaporisation of the water. This does not represent the total amount of energy within the hydrogen, hence the efficiency is lower than a more strict definition. Other reports quote the theoretical maximum efficiency of electrolysis as being between 80% and 94%.
[2]. The theoretical maximum considers the total amount of energy absorbed by both the hydrogen and oxygen. These values refer only to the efficiency of converting electrical energy into hydrogen's chemical energy. The energy lost in generating the electricity is not included. For instance, when considering a
power plant that converts the heat of nuclear reactions into hydrogen via electrolysis, the total efficiency is more likely to be between 25% and 40%.
[3]
About four percent of hydrogen gas produced worldwide is created by electrolysis, and normally used onsite. Hydrogen is used for the creation of ammonia for fertilizer via the
Haber process, and converting heavy petroleum sources to lighter fractions via
hydrocracking.”
Think of it in these terms. Suppose you had a HUGE alternator. The alternator requires 100 horsepower to turn. Nothing is 100% efficient per the first and second laws of thermodynamics. Assume a generous 95% efficiency for your alternator. You have now converted 100 horsepower at the crank into 95 electrical horsepower. That is about 5900 amps at 12 volts. You wouldn't actually use 12 volts because of the enormous I^2xR losses, but that is another story.
Now suppose you could get the maximum theoretical electrolysis efficiency of 94% (you can't get that high, more likely 25-40% per the Wiki). You have now converted 95 electrical horsepower into 89.3 potential chemical horsepower (95 x 0.94).
Now you can burn your hydrogen. But wait there's more. The best you can hope for with an internal combustion engine is about 25% efficiency. So now you can convert your 89.3 potential chemical horsepower into 22.3 horsepower at the crank (89.3 x 0.25). That is a loss of 77.7 horsepower and that was being generous, more likely you would loose 90 horsepower or so! There is no possible way to come out ahead with that setup.
Electrolysis has a place in stationary applications, but it does not makes sense on board vehicles.
Flame on!
Maybe your reading comprehension skills need a little work.
