Could the exhaust from a piston gas engine be run to another engine that uses Carbon Monoxide as the oxidizer? Would the engine work the same as a gas engine mechanically?

This link has inspired this question: https://chemistry.stackexchange.com/questions/48216/how-is-it-possible-to-safely-use-carbon-monoxide-as-a-fuel

closed as off-topic by Solar Mike, Chenmunka, mike65535, Bob Cross Apr 15 at 16:49

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  • 3
    I'm voting to close this question as off-topic because it is not about vehicle maintenance or repair. – Solar Mike Apr 15 at 4:43
  • Considering that the exhaust from an emission controlled engine (by current UK vehicle testing regulations) contains less than 0.4% CO by volume, this isn't going to be a very useful fuel option. – alephzero Apr 15 at 7:39
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    Carbon Monoxide is a fuel, not an oxidizer. – HandyHowie Apr 15 at 8:03

Yes, the exhaust can be fuel / useful source of energy. It contains lots of pressure and energy as heat.

You can for example:

  • Use the exhaust heat to heat up the heating system of the car, speeding up engine and cabin heating
  • Use the exhaust pressure to drive a turbocharger which compresses more air into the engine, meaning a smaller engine is sufficient, using less fuel

I'm sure you'll find many cars already use either or both of these options.

Now, for carbon monoxide and unburnt hydrocarbons: yes, they contain some energy, but very little as @alephzero found. Far more energy is in the pressure and heat of the exhaust.

Also, if you could somehow store the carbon dioxide, you could combine it with hydrogen produced by electrolysis using clean electricity (solar, wind, hydro, nuke) in water gas shift reaction to produce lots of carbon monoxide, which using Fischer-Tropsch and more hydrogen can be converted into liquid hydrocarbons.

Unfortunately, there is no practical way of storing the concentrated carbon dioxide in exhaust, and there is so little carbon dioxide in the atmosphere that capturing it for use with water-gas shift reaction and Fischer-Tropsch synthesis is expensive.

  • @alephzero was talking about 'carbon monoxide', you are using his quote as 'carbon dioxide'. – HandyHowie Apr 15 at 10:08
  • "Lots of pressure" - most of the useful pressure was used acting on the piston then turbo... – Solar Mike Apr 15 at 10:19
  • @SolarMike Well not actually, in a non Atkinson cycle engine, the exhaust has some significant pressure left. Just imagine running your engine without a muffler and you see what I mean! But yes, if there is a turbo, then it reduces the pressure, but not completely to ambient air pressure. – juhist Apr 15 at 11:18
  • @juhist done that - the sound energy is not as useful as you seem to think - try powering something significant with it... after the turbo as I mentioned in my previous comment. – Solar Mike Apr 15 at 11:20

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