What do 95, 92, and 98 mean?
2 Answers
Gasoline grades 92, 95, and 98 represent different levels of isooctane content in the fuel, while the quality of the gasoline and the heat value per unit volume remain the same. Octane Rating: The numbers indicate the octane rating of the gasoline. The higher the number, the higher the octane rating, which means better anti-knock performance. For example, 92-grade gasoline has an octane rating of 92%, 95-grade has 95%, and 98-grade has 98%. Anti-Knock Performance: When the air-fuel mixture is injected into the cylinder, the piston moves upward to compress the mixture. As pressure increases, so does temperature. If the gasoline's anti-knock performance is too low, the mixture may start burning before the spark plug ignites it, leading to knocking (commonly known as engine knock). Higher octane ratings provide better anti-knock performance, reducing potential damage to the engine.
I've driven conventional cars for many years and often see numbers like 95, 92, and 98 at gas stations. These represent the octane ratings of gasoline, primarily indicating the fuel's anti-knock performance. For example, 92-octane fuel is cheaper and suitable for family cars like mine with lower engine compression ratios. 95-octane is slightly more expensive with better anti-knock properties—if your car’s manual recommends it, don’t try to save money by using 92, as it may cause increased engine noise or even damage. 98-octane is the premium grade, reserved for sports cars, and would be wasteful for regular vehicles. I’ve encountered drivers who used the wrong fuel, resulting in severe engine knocking and costly repairs. Remember, the most reliable way is to check the recommended octane rating on your fuel cap—don’t just look at the price. Seasonal changes can also affect your choice; for instance, using 95-octane in high summer temperatures ensures better stability. In short, choosing the right fuel benefits both your car’s longevity and your wallet.
