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Homework Help: Water-powered car?

  1. Jun 14, 2008 #1
    What happens when you break the molecular bond, and burn the hydrogen? Is the water "destroyed"??? And what happens to the hydrogen atoms when your burn them?

    Does it break the ecollogical water-cycle, or can there again be a recombination of hydrogen and oxygen atoms?
  2. jcsd
  3. Jun 14, 2008 #2
    That would just reverse the original reaction and result in a water molecule. H+O2 -> H2O
  4. Jun 14, 2008 #3


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    To be pedantic:

    H+O2<-->H2O + E
  5. Jun 15, 2008 #4


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    Better yet,
    2H2 (g) + O2 (g) --> 2 H2O (l)
    ΔG = -474.26 kJ under standard conditions.

    2 H2O (l) --> 2H2 (g) + O2 (g)
    ΔG = +474.26 kJ under standard conditions.

    When you break the bonds in the water molecule you form Hydrogen and Oxygen gas (H2 and O2). These gasses can be recombined by burning them to re-form water.
    You will not get extra energy out of burning the Hydrogen to reform water. The best you could do is just reclaim the energy one originally put into splitting the water, but actually you cannot even do this good since you will also loose some energy to heat.
  6. Jun 16, 2008 #5
    With a simple device that uses electrolysis to convert water into hydrogen, you can increase the fuel economy of your car. This link may be somewhat helpful: [Moderator note: crackpot link removed]. A cursory glance at its contents and the cost for the informative booklet may inspire thoughts of a scam, but the idea holds much merit. In fact, if you want to build such a device, you can easily build one from looking at the examples shown. However, I don't recommend a plastic mason jar since it will deform rather quickly due to heat. Depending on your driving conditions (highway/city) you may obtain as much as 50 miles per gallon or more. No joke!
    Last edited by a moderator: Jun 24, 2008
  7. Jun 16, 2008 #6


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    Yeah, sure. It does more than 'inspire thoughts of a scam'. It is a scam. What about mrjeffry321's point?
    Last edited: Jun 16, 2008
  8. Jun 17, 2008 #7
    I agree that mrjeffry321's point is absolutely correct, but be open-minded regarding the idea. Simply put automobiles require two energy sources to operate, gasoline and electricity. This device receives its energy from a car battery and proceeds with the reaction as described by mrjeffry321. Sure, energy is lost with the production of hydrogen, but an alternative fuel source is produced which conserves gasoline.

    I know for a fact that this device works because my father and I built one for his 2004 Nissan Sentra, and he averaged close to 50 miles per gallon on his trip to work. I would expect that the life of the car battery is shortened due to the extra load, but with these results it more than compensates.

    Dick, if you still are skeptical--which I completely understand, since a lot of ideas are only scams to make a quick buck--then build one yourself and report back to me. The necessary parts to build a device are cheap.
  9. Jun 17, 2008 #8


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    buffordboy23, the energy to charge the car battery comes from burning fuel turning a generator or alternator, not from the battery itself. I think the success of these devices is due more to a placebo effect. I.e. power of positive thinking. I'd have to invest in a car first before I could actually test one. But 'I don't have to go to the arctic to know it's cold'.
    Last edited: Jun 17, 2008
  10. Jun 17, 2008 #9
    Dick, you are correct in regards to the above statement. Perhaps, I should have been a little clearer.

    However, is it absolutely necessary to have your engine running to listen to the car radio or turn the head lights on? No, but your battery will eventually die and need recharged. When your car is jumped, we let the engine run so that the alternator recharges the battery. Now when we turn the vehicle off with the battery recharged, we are able to start the automobile again with no problem. This suggests that the alternator is able to supply more energy to the battery than the needs of the automobile require.

    In fact, an alternator is a self-sustaining, regulating device that tries to keep the car battery at a certain voltage for recharging purposes (a little above 14 V). The rotation speed of the serpentine belt that drives the alternator does not necessarily determine the power output of the alternator due to the alternator's design--the electric signal passes through a rectified diode bridge. So, some energy that was available will be lost as heat anyways. Therefore, why not attach the discussed device, which does increase the overall load on the battery, but diminishes the wasted energy produced from the alternator?
  11. Jun 17, 2008 #10


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    Every drop of energy in the car’s battery comes from the fuel which is burned in the engine (neglecting the energy initially there when installing a new battery).

    If you attempt to run the engine solely on Hydrogen produced using the battery and/or alternator (which, in turn, gets its energy from the engine) you are bound to fail since you are forming a closed loop in your energy flow diagram and effectively are trying to make a perpetual motion machine. Even if we ignore the fact that in order for this to be practical you would need to be able to extract extra energy from this closed loop to make the car move (instead of merely discharging then recharging the battery), you are also bound to loose some fraction of your energy as heat. Over some time period, the battery will just drain down to nothing and the car will stop.

    Another, less blatantly illegal, approach would be to merely supplement your gasoline fuel with Hydrogen, as you describe. Some theories suggest that the Hydrogen itself may not be so much an energy source as it is something to increase the efficiency / completeness of the combustion of the gasoline fuel.
    With all the modern day gadgets and computers cars have now-a-days to try to control the fuel delivery to the internal combustion energy under different conditions, I am not sure how much I believe some of the explanations given.

    The only way I can see something like H2-supplemented gasoline fuel working is with sacrificing a lot of engine’s output power. That way your gasoline mileage will increase and at the same time the law of conservation of energy is preserved.
  12. Jun 17, 2008 #11


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    buffordboy23 is making this sound somewhat more plausible by claiming the alternator is wasting some largish amount of energy which can be reclaimed for splitting the water. This doesn't violate any conservation laws, but it does imply the alternator/recharging system is so badly designed it turns a substantial portion of the engines output into waste heat. I remain deeply skeptical.
  13. Jun 17, 2008 #12
    The alternator has an efficiency of 50-60% when it is operating, so a lot of potential energy for output is wasted. Also, since alternators are controlled by a computer, when the battery is fully-charged when the car is running, the alternator shuts itself off. Therefore, the mechanical energy from the serpentine belt that turns the coils of the alternator is also wasted during this condition.

    The purpose of this electrolysis device that splits water is to increase the fuel efficiency of the automobile, as also suggested by mrjeffy321. The electronic control module (ECM) controls many functions of how the car engine operates and makes modifications accordingly. In this case, the most important one is the amount of fuel that is injected into the cylinders. With the addition of hydrogen and oxygen, the combustion of gasoline is more efficient, so the ECM "tells" its attached components to inject less fuel into the cylinders because the car's energy needs are satisfied.

    The best results from this device occur when driving at a steady speed, such as on a highway. This is because the ECM makes adjustments according to the car's energy needs. For example, approaching a large hill and then accelerating heavily to compensate for the increased energy needs to get the car up the hill causes the ECM to make drastic adjustments relative to driving at a steady speed on a level highway. This scenario is less stable, and therefore, the increase in fuel economy is lowered. The same analysis applies to city driving, where there are many stop-and-goes.
  14. Jun 21, 2008 #13
    Can we run our car with water and gas?
    Can anybody tell me is the HHO Gas is real working or is another scam?
  15. Jun 21, 2008 #14
    Carnot, Thompson, Kelvin, Otto,....
  16. Jun 21, 2008 #15


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    Sure, but it might not be nearly as efficient as other fuel systems, much less practical, and could result in a drop in power output of the engine relative to gasoline fuel.

    I do not understand why so many people insist on referring to “HHO” gas. I am not specifically referencing you in particular (johnandrews52) this is just something I have noticed happening a lot over the years.
    When you split a water molecule you produce Hydrogen gas (H2) and Oxygen gas (O2), not some type of ‘new’ water molecule that has a differently written chemical formula.
  17. Jun 21, 2008 #16
    It has an official chemical name and a trade name, actually; Oxyhydrogen and Brown's Gas.

    It's been used in welding for decades.
  18. Jun 21, 2008 #17
    HHO may have a trade name but it is not an "official" chemical name, whatever that means. Gunsmiths have used sweet spirits of nitre for generations but that still doesn't make it a chemical name.
  19. Jun 22, 2008 #18
    An official chemical name would be one created using IUPAC's nomenclature system. But, you're right, the word I should have used was 'common' chemical name, which is 'oxyhydrogen.'
  20. Jun 22, 2008 #19
    But, isn't the common name for HHO "water"?
  21. Jun 22, 2008 #20
    I usually see water written as "HOH," as it makes it more clear what you have. Otherwise it'd be [tex]H_{2}O[/tex].
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