What is the highest grade of gasoline?
1 Answers
Currently, the highest grade is 100-octane gasoline. Gasoline can be divided into different grades, such as 90#, 93#, 97#, 98#, etc. Some regions also offer 100# gasoline. These different labels represent different octane ratings. The higher the grade, the higher the octane rating, which means the gasoline has better anti-knock performance. Octane rating is a numerical value representing the gasoline's resistance to knocking. The higher the anti-knock performance, the better the gasoline's quality. The octane rating of gasoline is a unit of its anti-knock performance in a lean mixture. Under specified conditions, when the anti-knock performance of the sample is the same, its value equals the volume percentage of isooctane contained in the standard fuel. For example: 93# gasoline has an octane rating of 93, meaning it has the same anti-knock performance as standard gasoline containing 93% isooctane and 7% n-heptane. Similarly, 97# gasoline has the same anti-knock performance as standard gasoline containing 97% isooctane. 100# base oil is produced from high-quality crude oil through vacuum distillation, solvent dewaxing (a process where lubricant crude oil is diluted with solvent and frozen to precipitate wax crystals, thereby reducing the freezing point of the base oil), and clay refining (a process using the adsorption capacity of activated clay to adsorb various impurities onto the clay, which is then filtered out to remove all impurities). Its performance advantages include good viscosity-temperature characteristics, low evaporation loss, excellent low-temperature fluidity, good oxidation stability, and strong solubility for oxidation products and additives. It is recommended that vehicles designed for lower-grade gasoline will not be damaged if higher-grade gasoline is mistakenly used, but the increase in octane rating may alter the fuel's ignition point, leading to delayed combustion in the engine. This means both the engine's power output and thermal efficiency will decrease, resulting in a noticeable drop in performance. Using lower-grade gasoline in vehicles designed for higher grades may cause engine knocking. Because the octane rating is too low, the gasoline's ignition point decreases, causing it to ignite prematurely during the compression stroke. If combustion occurs before the spark plug ignites, resistance will be generated during the upward stroke. This resistance can make the engine run very unstably. If the knocking is mild, it may only increase noise without significant damage to the engine. However, if the knocking is severe, it indicates serious engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in severe cases, cylinder scoring.
