* Fuel and Air Mixture: Gasoline (or other fuel) is mixed with air in the engine's cylinders. Ideally, this mixture is precisely balanced for complete combustion.
* Incomplete Combustion: If there isn't enough oxygen present, or if the combustion process isn't efficient enough (due to factors like poor engine tuning or a malfunctioning catalytic converter), the fuel doesn't burn completely.
* CO Formation: Instead of producing carbon dioxide (CO2) and water (H2O), which are the products of complete combustion, incomplete combustion produces carbon monoxide (CO) along with other byproducts. The chemical reaction can be simplified as:
2C₈H₁₈ + 17O₂ → 16CO + 18H₂O
This equation shows the incomplete combustion of octane (a component of gasoline) producing carbon monoxide and water instead of carbon dioxide and water.
* Catalytic Converter's Role: Modern cars have catalytic converters that help reduce CO emissions by oxidizing CO to CO2. However, a malfunctioning or damaged catalytic converter will allow more CO to escape the exhaust system.
In short, CO is a byproduct of a lack of sufficient oxygen or inefficient burning of the fuel during combustion in a car's engine.
