A substance added to gasoline to increase its octane rating. This additive works by inhibiting premature combustion, also known as knocking or pinging, within an internal combustion engine. An example would be a commercially available fuel additive designed to raise the octane number of pump gasoline by a few points.
The importance of raising the octane number lies in optimizing engine performance, especially in high-compression engines designed to operate with premium fuel. Utilizing a fuel with an insufficient octane rating can lead to engine damage over time. Historically, lead-based compounds were used for this purpose, but due to environmental concerns, these have been largely replaced by other chemicals.
