Gasoline is a
highly volatile flammable liquid hydrocarbon mixture used as a fuel for
internal-combustion engines. Acomparatively economical fuel, gasoline is the primary fuel
for automobiles worldwide. Chemicals, called additives, such as lead, detergents, and
anti-oxidants, are mixedinto gasoline to improve its operating characteristics.
additives are used to slow down the ignition and burning of gasoline. This action helps to
prevent engine ping or knock (knocking sound produced by abnormal and excessively rapid
combustion). Leaded gasoline has lead antiknock additives. The lead allows a higher engine
compression ratio to be used without the fuel igniting prematurely.
gasoline is designed to be. used in older vehicles that have little or no emission
The fuel used
today is unleaded gasoline. Unleaded gasoline, also called no-lead or lead-free, does NOT
contain lead antiknock additives. Congress has passed laws requiring that all vehicles
meet strict emission levels. As a result, manufacturers began using catalytic converters
and unleaded fuel.
a good gasoline should have are as follows:
volatility (how quickly the gasoline vaporizes)
to spark knock, or detonation
inhibitors to prevent formationof gum in the fuel system Antirust agents to prevent
rusting of metal parts in the fuel system
to retard icing and fuel-line freezing
to help keep the fuel system clean