Distillation profile

Gasoline is a complex mixture of different hydrocarbons with different properties. Consequently, when heated, different components will vaporize at different temperatures. How much gasoline vaporizes at low temperatures (front-end volatility), medium temperatures (mid-range volatility), and high temperatures (tail-end volatility) will affect performance across a wide range of dimensions and is known as the distillation profile of the fuel.

The performance affected includes:

• Front-end volatility (low temperatures):
  • Cold start
  • Hot start
  • Avoiding vapor lock
  • Minimizing evaporative emissions
• Mid-range volatility (medium temperatures):
  • Achieving quick warm up
  • Fuel efficiency on short trips
  • Good power and acceleration
  • Avoiding carburetor icing
  • Avoiding hot stalling
• Tail-end volatility (high temperatures):
  • Fuel efficiency after warm up
  • Avoiding engine deposits
  • Minimizing dilution of crankcase oil
  • Minimizing VOC emissions

Distillation properties are typically measured as the temperatures of initial boiling, at specific volume percent recovery (5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%), and end point or final volume recovery.