What is the Difference Between High and Low Gasoline Octane Ratings?

[Lois]

Gasoline octane ratings are determined by the octane number of the gasoline. The higher the octane number, the stronger the anti-knock capability of the gasoline, and the higher the octane rating. The anti-knock performance indicator of gasoline is called the octane number, which is the gasoline octane rating. Generally, engines with high compression ratios require gasoline with higher octane ratings, while engines with low compression ratios use gasoline with lower octane ratings to ensure normal vehicle operation. Below is a related introduction: 1. Principle: Generally, engine operation consists of a repetitive cycle of "intake-compression-combustion-exhaust-intake" in the cylinders. The compression ratio is the ratio of the cylinder volume when the piston is at the farthest and nearest points in its stroke. The best way to reduce fuel consumption costs is to increase the engine's compression ratio. Increasing the compression ratio can alter the piston stroke, compressing the air-fuel mixture more intensely, which results in a stronger combustion reaction and more complete combustion. However, the compression ratio of a car is not easily changed and is matched with an indicator, namely the gasoline's anti-knock performance indicator, known as the octane number, which is the gasoline octane rating. 2. Composition of gasoline: Standard gasoline consists of isooctane and n-heptane. Isooctane has excellent anti-knock properties with an octane number of 100, while n-heptane has poor anti-knock properties and is prone to knocking in gasoline engines, with an octane number of 0. Generally, if a gasoline's octane rating is 0, it means the gasoline contains 90% isooctane and 10% n-heptane.