Advice 1: How to lower the octane number of gasoline

Octane number is a measure of properties of the knock motor fuel. The higher the octane rating, the better and longer the engine is running. But what if the octane number should be lower?
How to lower the octane number of gasoline
Gasoline means a mixture of isooctane, which is conventionally assumed to be 100 units, as it is practically not volatile at elevated pressure and normal heptane is taken as 0 units. It is practically not resistant to detonation at higher pressures. The octane number of gasoline 92 so that it detonates as a mixture of 92% isooctane and 8% normal heptane. Usually after primary distillation of oil octane number less than 70. To improve the quality of gasoline antiknock additives are used. Currently, the most used ether methyl-tert-butyl (MTBE). It has huge advantages over the previously used lead antiknock additives, which adversely affect the environment and human health. There are gasolines with an octane number greater than 100 units. They use a different volume with isooctane additives.
The combustion rate of gasoline depends on the octane number. Gasoline with a high octane rating burns more durable and smoothly without causing shock loads on the pistons in the combustion chamber. The motor will work clearly and evenly. It is because of this modern auto industry produces cars with engines that run on high-octane gasoline.

Low octane gasoline ignites at a time when there are not closed intake valve, and the cylinder is at the top. Naturally, the engine will not operate at full capacity plus the wear and tear of valves, saddles for them, extra carbon etc.
To increase the octane number of gasoline are special additives that are added to the fuel. They can be purchased at any automotive store or automotive gas station.
there are times when you need to lower the octane number of gasoline. Sorry, not in the same technical literature does not describe a specific method how to produce, how to turn expensive high-octane gasoline in a cheap fuel with a low octane rating is not economical. Octane can lower it,
1. The addition to gasoline of tar and sulfur compounds.
2. Add in high-octane gasoline fuel lower-level lower octane first.
3. A long standing gasoline. Over time the gasoline left in any capacity, lowers octane. This decrease occurs from 0.2 to 0.5 units per day.

Advice 2 : How to reduce the octane number

Octane number is a measure of detonation resistance of gasoline and other motor fuel. It is considered that the higher the octane number, the better the qualities of this fuel, and therefore, it will significantly affect engine operation. But there is often a need to reduce the octane number of motor fuel used.
How to reduce the octane number
You will need
  • - odnomarshevoy engine;
  • - a portable device for determination of octane number;
  • - gasoline with a low octane rating;
  • - sulfur compounds.
Before considering ways to reduce the octane number, meet the indicator, and means for determining octane number. The origin of the scale in octane – detonation resistance of heptane (octane index equal to 0).
Over 100 attended the octane number isooctane. It is from these two liquids (heptane and isooctane) and is gasoline, the octane number which has to be reduced. So, the octane number of gasoline a-92 indicates that the combustible fuel has the same knock resistance as a mixture of 92% isooctane and 8% heptane.
To determine octane number, motor fuel is compared with a reference consisting of isooctane and heptane. There are the following methods of determination of octane number: research, chromatography, motor and via portable devices.
The motor method of determining the measure of detonation resistance of the fuel involves a simulated hard drive with the use of single-piston engine. However, this method is not perfect: the result obtained from this method may be somewhat understated.
The research method also involves the use of single-piston engine (no simulation ride): this method for determining the octane number may give falsely high results.
Chromatographic method is used as an additional method designed to detect all possible impurities in the fuel, for example, benzene. However, the most reliable method of determining the measure of detonation resistance of the fuel – measuring octane number of a portable devices.
Knowing the rate of detonation of sustainability of fossil fuels, you can bring it to the desired result, including reduced. One way to reduce the octane number is to add high-octane gasoline with a lower index of detonation resistance.
The octane number can be reduced if to add to the combustible fuel with high detonation stability of sulfur compounds. In addition, the low octane number of gasoline after the primary distillation of crude oil: this figure does not exceed 70.
In addition, the increased detonation resistance and decreases without human intervention − during long-term storage of energy: the day the octane number can be reduced to 0.5.
Before you start working with gasoline or other motor fuel, be sure to take care of individual means of protection!
Useful advice
On an industrial scale, the decrease in octane number is not practiced as a combustible fuel with a low detonation resistance is little demand.

Advice 3 : What is the octane number of gasoline

The division of gasoline into different categories depending on the value of its octane number. This is the main factor, which determines not only the actual quality of gasoline, but also its chemical properties.
What is the octane number of gasoline

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.
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