After the crisis “quarantine” drop, fuel prices at Ukrainian gas stations confidently climbed up. At the same time, as for diesel fuel, there is still a fairly solid price difference, which reaches 5 hryvnias. per liter And will there be the same difference in fuel quality? Specialists of the Institute of Consumer Examinations investigated the issue, for which they purchased the most expensive and cheapest samples of “heavy” fuel at Ukrainian gas stations, and sent them to the laboratory for research.
Test control of diesel fuel
The market does not stand still – and competition leads to segmentation. After the premium segment (OKKO, WOG), discounters appeared (BRSM – Nafta, Chipo, SunOil), and then super discounters (Avantage, Marshall), which work on the verge of dumping. In addition, there are networks focused on a specific group of consumers. For example, the fast-growing all-Ukrainian chain Prime offers preferences to truck drivers – for this, the chains create parking lots at gas stations with all the amenities for a comfortable stay, offer discounts, and sells AdBlue liquid for exhaust neutralization. This time, experts took samples of ordinary “Eurodiesel” in 11 networks: WOG, Parallel, ANP, KLO, Prime, OKKO, AMIC, BRSM – Nafta, SunOil, Chipo and Avantage. In the laboratory, all samples were tested for 5 parameters: cetane index, fractional composition, flash point in a closed crucible, sulfur content, and density. It is worth noting that all tested samples turned out to be “summer”, that is, they met seasonal requirements. But it was not without surprises.
Cetane index
First of all, experts calculated the cetane index of the tested samples. The cetane index is the cetane number of the fuel before the use of cetane-thinning additives. The general principle is that the more, the better. Unfortunately, not all test participants complied with the standard. In the sample purchased at the Avantage gas station, the cetane index was less than the standard by almost 5 units. The largest stock was demonstrated by Prime samples – 52.6 units, Parallel – 52.5 units each, and KLO – 51.9 units. That is why such diesel fuel will have less fuel consumption and smoke.
Fractional composition of diesel
The fractional composition of diesel fuels is important for diesel operation. When the content of light fractions in diesel fuel increases, the ignition pressure of the working mixture increases, knocks appear in the cylinders, and crankcase oil thins out. Fractions that are too heavy do not burn completely and increase soot deposits in the combustion chamber.Also, the fractional composition of diesel fuel indirectly characterizes its volatility, since fuel with a lighter fractional composition evaporates more easily. For automotive diesel, the most suitable fuel consists of fractions that boil at temperature ranges of 200-360⁰ C. The narrower the temperature range at which the fuel boils, the better the process of its combustion in the engine. According to this indicator, all participants did not have any problems, the values are approximately the same. The narrowest intervals are for “diesel” Parallel and BRSM – Nafta.
Another important indicator is the flash temperature in a closed crucible. It characterizes the ignition temperature of the fuel. In the event of an accident involving a car filled with fuel with a low ignition temperature, there are great risks of fire. In addition, indirectly, this indicator can show whether foreign components did not get into the “diesel”. The best results, 65 degrees at a standard not lower than 55, are obtained with fuel from Parallel and Prime. But the “diesel” purchased in the Avantage network had a value far below the limit – 37 ⁰ C.
Finally, the main “environmental” indicator of diesel fuel is the sulfur content. Sulfur combustion products hurt not only the environment, but also the engine. Sulfur is deadly for neutralizers and particulate filters, removing it from fuel is quite a difficult and expensive process. Therefore, with a sulfur concentration of less than 10 mg/kg, the “mileage” of the neutralizer is more than a hundred thousand kilometers – not a problem. For example, if there is 1000 mg/kg (this was the norm six to seven years ago), it may stop working effectively after ten to fifteen refuelings: sulfur, interacting with the precious metals of the neutralizer, multiplies their chemical activity to zero. According to Ukrainian standards (similar to Euro 5), the sulfur content in fuel is not more than 10 mg/kg. This time the results were generally pleasing, but there was also some sad news. Except for one sample, all samples corresponded to the Euro-5 level. Samples Parallel and Prime (5 mg/kg) turned out to be practically devoid of harmful sulfur. The sample purchased at the Chipo gas station was just short of the leader – 5.5 mg/kg. But in the diesel sample from Avantage – a considerable 216 mg/kg, that is, an excess of more than 20 times.
Conclusions
The picture of the study turned out to be ambiguous. On the one hand, only one sample turned out to be non-standard, which indicates the stability of supplies and a careful approach to logistics and input control in serious networks. It seems that fuel retailers do not want to risk their reputation and connect with “left” fuel, especially during the period of falling “straits”. On the other hand, the quality in the “average” networks has equaled and even exceeded the indicators of their counterparts from the premium segment, and the price difference is still quite noticeable. So do you need to pay more? However, each car owner is free to answer this question himself. However, motorists should still treat overly “sweet” offers on gas station shelves with great caution.
