Octane number,
Definition of Octane number:
Measure of the ignition quality of gas (gasoline or petrol). Higher this number, the less susceptible is the gas to knocking (■■■■■■■■■ caused by its ■■■■■■■■■ burning in the combustion chamber) when burnt in a standard (spark-ignition internal combustion) engine. Octane number denotes the percentage (by volume) of iso-octane (a type of octane) in a combustible mixture (containing iso-octane and normal-heptane) whose anti-knocking characteristics match those of the gas being tested. In the older vehicles, high octane numbers were achieved by adding lead tetraethyl to the gas (the leaded gas), a pollutant that contributes to lead poisoning (see Lead). In the newer vehicles, the same result is achieved by the engine design that increases turbulence in the combustion chamber, and/or by adding aromatic hydrocarbons (such as xylenes) and oxygenates (oxygen-containing compounds such as alcohols) to the gas (the unleaded gas). Also called Octane rating. See also cetane number.
A figure indicating the antiknock properties of a fuel, based on a comparison with a mixture of isooctane and heptane.
How to use Octane number in a sentence?
- In particular, the formation of branched alkanes increases the octane number and combustibility of the resulting hydrocarbon.
Meaning of Octane number & Octane number Definition
