What kind of gasoline is called low octane?
In Soviet times, 76th gasoline was considered low-octane. And today many fuel companies are calling AI-95 low-octane and calling for refueling with this fuel to be stopped!
This “decline” occurred for two reasons.
- The first is related to the requirement of car manufacturers. For them, switching to high-octane petrol is an opportunity to reduce fuel consumption and emissions without losing engine power. In this situation, fuel costs often fade into the background and the car itself becomes even more prestigious in the eyes of the consumer. Skoda, for example, has taken this route: all models are prescribed the 98th petrol as main petrol and the 95th as reserve.
- The second reason is not directly related to technology. Fuel company representatives often demonstrated engine parts damaged by detonation. Here, they say, what the use of low-octane fuels leads to! And as the “right” gasoline, they recommended the 98th with improved washing capacity (read, more expensive). Why it is impossible to fill such engines with the 95th, if it was originally recommended by the manufacturer, they answered evasively: because the 98th is better!
A funny fact from the communication with representatives of car companies. Kia recently told us that they recommend using 95th gasoline for their cars, but for higher octane gasoline, they can… refuse warranty repairs in the event of engine breakdown!
6 types of gasoline – which to fill?
Today, many gas stations actually offer as many as six different gasolines: 92nd, 95th, 98th, 100th, as well as “enhanced” Ecto or G-Drive types.
But you can only fill the car with the one recommended by the car manufacturer. And he, as a rule, indicates the main octane number of gasoline for constant use, as well as a reserve – in case the necessary gasoline was not at the gas station. Information about the fuel used is given in the instruction manual and is usually duplicated from the inside on the filler hatch – for example 95 (92).
But constantly riding on the 92nd isn’t worth it. Each motor has a design margin, which allows it to painlessly withstand a brief and slight deviation from the required octane rating. For example, if you are filled with 92 instead of the 95th petrol at an unscrupulous gas station, nothing bad will happen to the engine. And with the constant use of 92nd gasoline in the same situation, there is a risk of encountering 90th or even 89th. And the engine can no longer survive a decrease in octane by 4-5 units.
But few people want to constantly run on the 98th or 100th gasoline – it’s expensive! However, in conditions of intense heat, this makes practical sense: the probability of explosion is greatly reduced. And by the way, if signs of explosion appear after refueling with bad fuel, it makes sense to fill in high-octane fuel as an octane corrector at the nearest brand gas station.
Is it possible to mix AI-92 and AI-98?
We heard a popular horror story: if you add 98 to the 92nd gasoline, one of them will float, and the second will settle at the bottom of the gas tank. And first the engine will produce one type of fuel, then another. The car will go slower or faster and this experiment ends with engine repair.
In fact, not everything is like that. The requirements of the standard for the density of petrol are the same. It should be in the range of 725 – 780 kg/m. to be3 at 15 aboutS. And no commercial gasoline goes beyond these limits. The density of high octane gasoline may be slightly lower than that of low octane gasoline. However, these are quantities of the same order and therefore no layering will occur when mixed.
What kind of petrol do you need: winter or summer?
Unlike diesel producers, owners of gasoline cars are not interested in what kind of fuel they brought to gas stations: winter or summer. Meanwhile, the current standard provides for the production of 10 different grades of gasoline in terms of volatility. Two are in the summer, four in the low season and four in the winter.
When using summer gasoline with relatively low volatility in winter, the engine may not start. And the use of winter fuel in the summer is accompanied by the formation of vapor locks, which can cause interruptions in the operation of the engine, especially the carburetor.
With regard to the specific conditions of the applicability of certain petrols, the corresponding annex to the standard is currently only advisory in nature.
- “Behind the wheel” can also be read in Telegram.
And he answered a few more important questions about gasoline. It turned out to be interesting and useful.
Source: Z R
