Energy released in an exothermic reaction depends on bond energies of reactants and products. Since molecular bonds are electric in nature, at the first glance, increasing Coulomb's force should increase bond energy and, thus, combustion energy. With that in mind, here is the setup I'm considering:

Take an ordinary internal engine of a typical car. Attach a handwavium device that increases electric constant inside engine's combustion chambers by a certain amount (around 10-20%). Try and start is as usual. Everything beside changing vacuum permittivity still follows laws of physics. Would it work? Would it increase efficiency of the engine?

Some things to note:

  • Only inside of the chamber is affected, do not consider what happens to the walls.
  • Presumably, when petrol enters modified chamber, it will release some energy (as its bonds grow stronger). If that may cause any problems (e.g. spontaneous ignition), handwavium device consumes that energy directly to prevent them.
  • If too high combustion energy causes problems for the engine, it is modified so that less petrol is injected per cycle.
  • All I care about when saying "efficiency" is amount of mechanical energy per litre of petrol (or kilometres per litre, which should be the same). Do not account for whatever energy handwavium device requires for its operation.

Things I'm worried about:

  1. Nucleus binding energy is pretty high, so I think slight increase in Coulomb's force shouldn't cause any qualitative changes to atoms, just making nucleus slightly bigger, and electron orbitals slightly closer. Would it mess something significantly, or will atoms fall apart for some reason?
  2. At some point changes to bond energies would be big enough to break down chemistry of petrol and air. Where is that point, is it far enough that I can get my 10% explosions increase?
  3. I have no idea how such changes would affect physical properties of air. Will the same amount of air molecules occupy less space? Then it may negate (partially or completely) whatever gains in thermal energy I obtain (since air pressure as it expands is what produces work). Or will it actually be more spacious, thus further improving efficiency?
  4. Is there something obvious I'm missing?

Bonus question: If you think this can work at lower increases, how high can I crank up the boost before things break down?

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    $\begingroup$ Changing the electric permittivity of the vacuum would directly change the strength of all electromagnetic forces, thus changing all chemistry. (Chemistry is all about electric attraction between the electrons of an atom and its nucleus, and the repulsion between electrons.) With altered chemistry, there would be no life as we know it. There may be life, and even intelligent beings, but not the kind of life we have on Earth and definitely not humans. $\endgroup$
    – AlexP
    Commented Nov 25, 2019 at 9:40
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    $\begingroup$ If you use handwavium why it woulnd't work? $\endgroup$ Commented Nov 25, 2019 at 10:00
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    $\begingroup$ Wouldn't it just be easier to buy a Tesla? $\endgroup$
    – Slarty
    Commented Nov 25, 2019 at 10:50
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    $\begingroup$ This is a really complicated way to solve an easily solvable problem. Although it shouldn't matter, can you explain why this form of efficiency boost is needed and not something simpler like dropping the car weight by 20%? $\endgroup$
    – Trevor
    Commented Nov 25, 2019 at 18:07
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    $\begingroup$ This is like using antimatter to improve steam train performance, surely. If you can establish local jurisdiction and precedence over the laws of nature, surely there are more interesting things you can do than make cars run a bit more cheaply? $\endgroup$ Commented Nov 25, 2019 at 19:27

1 Answer 1


Your handwavium device works only in the combustion chamber.

Let's assume for a moment it has a 100% yield.

It means that upon entering the chamber every moleculehas to gain a certain energy surplus which will be then released upon combustion.

But also the combustion products will have a higher energy, and will release that surplus only upon leaving the chamber, that is after the piston as extracted work from the gases.

I suspect that your only result would therefore be to have hotter exhausts.

  • $\begingroup$ If the device is heavy you might get worse range instead of better. And considering spare tires are being removed to save weight... wired.com/2015/11/… $\endgroup$
    – Trevor
    Commented Nov 25, 2019 at 18:25

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