Octane is a measure of how much compression a fuel can withstand before igniting. It is a hydrocarbon that is a typical component of gasoline. Octane ratings are measures of fuel stability based on the pressure at which a fuel will spontaneously combust (auto-ignite) in a testing engine. The higher the octane number, the more stable the fuel. In recent years, car manufacturers have been requiring or recommending premium gasoline (a high-octane grade of fuel) for use in more of their vehicle models. The difference in prices between premium and lower octane grades has also increased.
Octane plays a key role in engine performance and measures the ability to resist auto-ignition, which is commonly referred to as knock. As engine compression increases, so does the amount of power and efficiency generated by a given amount of fuel. The higher the octane, the greater the fuel can withstand compression and resist knock. Depending on a vehicles engine design, octane can affect engine performance.
In essence, higher octane fuels are compatible with higher compression engines that can increase efficiency and performance while potentially reducing emissions by combusting the fuel more completely. Higher octane fuels can allow for a variety of options that can increase power and efficiency while adding the ability to decrease emissions as well. These options include increasing the compression ratio, changing the timing of spark ignition, injecting less fuel into the cylinder, and more.
In summary, octane is used in gasoline to increase fuel stability and prevent pre-ignition in high compression engines. It is a measure of how much compression a fuel can withstand before igniting, and higher octane fuels can increase engine performance and efficiency while potentially reducing emissions.
