What is the difference between AI-92 from AI-95, and is it better to pour ai-98

If the marking of gasoline at the refueling does not tell you anything, except for his "number", or if you think that "the more the figure, the better gasoline," it was time to get rid of these delusions. Today we will find out what the number in the marking of gasoline, we will deal with its quality, and also learn whether it will be better to become a car if you pour more expensive fuel.

What do the numbers 92, 95 and 98 mean?

Person how to go to the "numbers" of gasoline brands, in two words will deal with the fact that there are different varieties in general, and we will define a couple of key concepts.

The basic principle of motor operation is simple: gasoline and air is supplied to the cylinder, the piston moves up, about at the time of reaching the upper point of the ignition candle, it fuel the fuel mixture, and the combusting fuel pushes the piston down. In this process, it is important that the fuel began to burn on time - when the ignition candle is set on. If the fuel flashes spontaneously before, when the piston is still going up, it harms the motor, destroying it. Therefore, one of the characteristics of any gasoline is detonation resistanceThat is, its property is to resist spontaneous ignition. And this detonation resistance depends on octane number Gasoline, which is indicated in its marking: For example, AI-95 has an octane number 95.

The greater the number - the better gasoline?

No, different octane number does not mean that 95 gasoline is better than 92: they are just different And created for different motors. Some have a lower compression ratio, and the risk of detonation in them below. Therefore, more low-octane variety is suitable for them - AI-92. In other motors, the degree of compression is higher, or the fuel mixture can be more enriched with oxygen due to the turbine, which simultaneously increases the final compression in the cylinder, and as a result, the risk of detonation is also growing, so such engines require higher octane fuel to avoid it.

So think that "95 gasoline is better than 92" as logical, as it is necessary that "absinthe is better than vodka, because there are 70 degrees against 40." The quality of gasoline by its octane number is not determined: the content of sulfur, manganese, resins and other impurities is set not to the gasoline brand, but by the technical regulations. So that do not assume that "95 gasoline cleaner and better 92": The quality of both meets modern fuel requirements and meets current euro standards.

High octane gasoline more useful for the machine

Another misconception associated with gasoline is the opinion that the higher the octane number, the more useful gasoline for the car. It has a truth in it, but in general, the habit of some owners of old cars "pamper them after salary", the Bay of AI-98, deprived of meaning.

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Of course, in fact, the processes occurring in the engine is more complicated than simply "fuel injected, burns and ejected", but if you can not delve into the nuances, you can select a key fact: in the conditions of a depleted mixture, high-octane gasoline burns a slightly longer, extinguits later than the specified moment and the It most causes an increase in temperature in the cylinder and overheating adjacent parts - in particular, valves. Simply put, if you pour into the car with a simple atmospheric motor with a low compression of 98 gasoline and drive in a calm rhythm, you make a motor only worse - its application is justified exclusively if you want to "drive" when the fuel-air mixture has the optimal composition at high speeds, And high-octane gasoline does benefit, highlighting more energy during combustion.

But for motors with a high degree of compression or equipped turbine logic "The higher the octane number - the better" is quite justified: and the degree of compression, and the amount of air supplied to the cylinders is sufficient for the optimal combustion of high-octane gasoline, and the increase in detonation resistance is only on favor. At the same time, the decrease in the octane number on the contrary, negatively reflects on the operation of the motor and its resource: the likelihood of detonation increases, which gradually destroys the engine.

Briefly conclusions can be formulated as follows: Machines with low compression atmospheric motorcycles Application of 98 gasoline is justified only with very active ride, and in other cases it may even harm, and high-compression engines are harmful with octane number below that recommended Manufacturer. That is, for example, the VAZ "seven", whose motor has a compression ratio of 8.5, the high-octane gasoline will not bring a special benefit, but I definitely pour into 1.2 TSI with a turbine and a degree of compression 10.5 NOSTOSKY AI-92 is definitely not worth it, While AI-98 does not hurt him at all.

On the lid of the gas tank, AKI 91 is written, so I Lew AI-92

Another complexity for inexperienced car owners is different methods for determining the octane number and, accordingly, the differing designations suitable for a gasoline car. The problem here, as a rule, is reduced to the difference between European and American systems.

To speak briefly, the fuel marking systems differ in the octane number: in Europe it is marked by the research method, and in the United States, Canada, Brazil and some other countries - on the "anti-knock index". Actually, our abbreviation Ai is just "automobile" gasoline on the "research" method. But AKI means "Anti-Knock Index", that is, the same "anti-knock index", which is an average arithmetic between the two results of different methods for determining the octane number (research and engine), and its value is obtained belowthan a pure research method. That is, AKI 91 is not at all the same as AI-92.

The approximate match of our AI and foreign AKI is: AKI 87 is AI-92, AKI 91 is AI-95, and AKI 93 is already AI-98. So, buying a used car, pay attention to what is written on the lid of the gas tank and in the instruction manual, so as not to be mistaken in the choice of fuel.

"Corporate" fuel is better "usual"?

Well, perhaps, the last question is related to whether to overpay for "branded" gasoline at large gas stations. It is worth understanding here than the price increases: it is also not an abstract "improvement improvement", but first of all, adding washing additives. Additives These affect the quality of gasoline work in the engine, but on its conditional "purity for the motor", preventing the formation of deposits in the fuel system. But considering that gasoline and itself is quite clean and is an excellent solvent, these conditional deposits do not score the fuel system for the month or year. So the use of branded gasolines with washing additives makes sense, but absolutely not necessarily and does not give a momentum effect, possessing a prophylactic effect.