The concept of octane number of gasoline
The result of fractional distillation of crude oil under the influence of different temperatures obtained by various fuel types (including gasoline), lubricants and also products for petrochemical synthesis. This, no doubt, know all who have been in chemistry classes in school. However, approaching the gas station, you probably have repeatedly drawn attention to the mysterious numbers, podrazdelyayutsya gasoline on different types. What's their real difference?
These same figures in the markings of gasoline indicates its octane number. This is the main criterion by which classified various types of gasoline. The term "octane number describes a property of the fuel to burn freely in the engine to meet a variety of conditions. The higher the number, the gasoline is more resistant to ignition under compression. However, in the production of high-octane gasoline is somewhat more complicated, in addition, it needs to be clean enough.
Determining the antiknock properties of gasoline
Each engine is designed to operate on fuel with a certain octane rating. In Russia the majority of owners uses Ai92. These types of gasoline, as Ai95 and Аи98, as a rule, allow themselves the owners of the cars "premium" class. Diesel fuel and Ai80 to enjoy less demand.
Determination of the resistance of gasoline to detonation is performed using standard mixtures. The fact that the gasoline equivalent of the mixture of isooctane and heptane. Accordingly, if the octane number of gasoline is equal to 92, it will spontaneously ignite as a composition of 92% isooctane and 8% heptane.
Increase the gasoline octane number
In the manufacture of various types of gasoline used in the method of mixing the fuel components. Otherwise, the process is called "compounding". As a result of all the necessary processes should be products that fully meet state standards and have accurate octane value.
The primary fractional distillation of crude oil produces gasoline with an octane index in the range of 70. The quality of gasoline increases not only with the use of compounding, but through the use of special additives-antidetonators. Earlier to improve the detonation properties of the fuel used is tetraethyl lead. With all that for a man this substance is a potent poison. Currently, as high-octane additives are used ferrocene or methyl tertiary butyl ether, not with such a huge toxicity.