Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: briofuel88 on 18/06/2012 17:02:21
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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??
THANKS!!
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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.
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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