What Does the Octane Number of Gasoline Mean?

[StChristian]

Gasoline's octane number refers to its anti-knock property, and the commonly mentioned gasoline grade represents the octane number of gasoline. Petroleum is composed of various alkanes, among which isooctane has good anti-knock properties, while n-heptane has poor anti-knock properties. 90-grade gasoline indicates that the gasoline contains 90% isooctane and 10% n-heptane; 92-grade gasoline indicates that the gasoline contains 92% isooctane and 8% n-heptane. The type of gasoline a car uses is determined by the engine's compression ratio. The higher the compression ratio, the better the anti-knock property of the gasoline required, and thus the higher the gasoline grade needed.