What is going on with Oxygen and Gasoline that makes it combust with heat?

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Offline briofuel88

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In an Internal Combustion Engine, what is Chemically happening to Oxygen and

Gasoline [when the spark plug ignites] that makes them combust with heat??



Offline acecharly

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the oxygen and gasoline are chemically reacting and rearranging there structures to produce new molecules, and a byproduct of this is a high release of energy.


Offline evan_au

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Gasoline = C8H18 (approximately - it's a mixture of many chemicals containing Carbon and Hydrogen in various ratios)
Oxygen = O2
Gasoline + Oxygen = liquid sloshing in a petrol tank
Gasoline + Oxygen + spark = CO2 + H2O + Energy (more spark) = Explosion

The purpose of the electric spark is to disrupt some of the gasoline & oxygen molecules, which then recombine to form carbon dioxide & water, releasing energy which can be harnessed to drive your vehicle.

To ensure that it works well, you need:
  • The right ratio of gasoline & oxygen
  • With the gasoline completely vaporised and completely mixed with the oxygen
  • At the right temperature and pressure
  • With the spark applied at just the right time to ensure complete combustion
  • All of these depend on the type of fuel that you use (gasoline for cars is a different hydrocarbon mixture than Diesel for trucks or Biofuel)

If you don't get it exactly right, you can get:
  • Pollution: carbon soot, carbon monoxide, nitrous oxide
  • Backfire: Uncombusted gas released into the exhaust pipe, where it explodes
  • Poor fuel consumption
  • An engine that overheats, or wears out too quickly
  • An engine that may actually run backwards(!)
  • An engine that doesn't start at all