Gasoline is above all used as motor fuel and is produced by the majority of oil refineries. It is a mixture of light hydrocarbons (gasoline components) which contain oxygen and impurities. Gasoline easily evaporates and flows, is very easily flammable (flash point less than 0°C) and soluble in water. As a rule it is a colourless, transparent and clear liquid with a strong odour.

Distillation characteristics and octane number are of high importance to us. Octane number or octane rating is a standard measure of fuel knock resistance (ability to resist spontaneous combustion of fuel under compression). Octane rating is determined by two different methods: motor octane number (MON) and research octane number (RON).

Using gasoline with lower octane rating causes detonation. During such ignition the exhaust valve temperature grows to 800°C and the wearout of the cylinder and piston ring increases by 2-3 times. Sudden pressure rise breaks the engine mechanically. At higher speeds even the average knocking is not audible. Long detonation could destroy bearings and flasks, distort and burn the valves, cause cracks in the coating of the cylinder, cause loss of engine power, increase the fuel consumption and etc.

Using gasoline with high octane rating in engines with a small degree of compression is irrational. A well-known fuel specialist, professor of Tallinn Technical University Mihkel Naams once said – if your shoe size is 40, you won’t run faster in size 45 sneakers.

Distillation features show the level of gasoline evaporation (volatility), which affects the ability of gasoline to mix with air and therefore its combustion efficacy and motor power and efficiency. Engine start, its work stability and losses during storage also depend on evaporation.

In order to have a required vehicle driving performance during any season in all geographical areas of Europe, 10 volatility classes were defined: A, B, C, C1, D, D1, E, E1, F, F1.
In Estonia during summer period the volatility class of gasoline is B. During winter E and E1 classes are allowed. In Estonia summer period is considered from the 1st of May until the 30th of September and winter season is from the 1st of December until the 29th of February. During summer season gasoline sold at the fuel stations must meet all the requirements of the B class fuel and during winter it must meet the E, E1 class fuel requirements. The switching periods are considered to be the periods from the 1st of October to the 30th of November and from the 1st of March to the 30th of April. During the switching period the volatility class of the fuel can be B, E, E1 and fuels meeting winter and summer requirements can be sold.

Gasoline sold at Olerex corresponds with Estonian standard EVS-EN 228.