Because of the definition of synthetic oil
There are many so-called fully synthetic oils on the market, but none of them are fully synthetic oils in the real scientific sense. Most of them are highly refined mineral oil.
Before 2000, only lubricants based on PAO or esters were printed with the words "fully synthetic" on the packaging. In 1999, the American consumer rights organization Better BusinessBureau ruled that Mobil's accusation that Castrol should not print the word "fully synthetic" on the products made of the third base oil was unfounded, because "fully synthetic" was a marketing word, not a scientific word on the packaging. Since then, many lubricant manufacturers have called their products fully synthetic oils.
Now some irresponsible small brands or irresponsible lubricant practitioners even claim that the products made from low-quality base oils are synthetic oils.
Common misconceptions about oil
1) Identify the quality of engine oil from the package.
Many car owners tried in vain to identify the quality of an engine oil from the packaging when buying it. The packaging of a lubricating oil will only tell you the specifications, viscosity and quality of the oil, and you won't know until you have used it. If you don't want to test randomly, you can consult a senior and pertinent mechanic, or search different people's comments on different brands of lubricants through the Internet. Everyone's comments will give you an objective answer.
2) The higher the viscosity of the oil, the better.
This is a very common misunderstanding. Generally, the higher the viscosity of oil, the thicker the oil film formed, the poor fluidity and the large resistance, so the energy consumption is high. Old cars generally use high viscosity oil, and thick oil film helps to strengthen the seal. New cars or newly overhauled cars should use low viscosity oil to save fuel. Of course, under severe driving conditions such as high temperature, idle speed and start-stop in summer, low-viscosity engine oil with poor quality is easy to dilute, and it is difficult to maintain normal oil film thickness, which is always unfavorable to the life of the engine. Proper selection of high viscosity oil is beneficial in some cases, but it does not mean blind pursuit of high viscosity. If you are not sure about the choice of viscosity, you can refer to the suggestions in the user manual.
3) Change the oil to see the mileage.
Many car owners are used to changing oil by mileage, which is unscientific. The oil change interval depends on many factors. Driving mode, road conditions (highways, traffic jams in urban areas, climbing, air turbidity), outdoor temperature, fuel quality and engine oil quality will all affect the life of engine oil. Mileage is just a reference. The best way is to check the oil condition frequently, at least once a week. If the color has become darker, the feel is a little rough, the viscosity is quite different from that of new oil, there is a strong smell of gasoline or burning, or the oil change time is too long, it should be changed. Of course, the simplest thing is that if you feel you need to change, you can change.
4) As long as the certification is newer, the quality is better.
Many lubricating oil practitioners who don't know much about oil products often call the oil products with newer certification as the oil products with better quality, which leads to a great misunderstanding of the concept of oil product certification in the workshop.
For example, if the owner's manual of your car requires the use of API SL engine oil, will an API SM certified semi-synthetic engine oil make your car perform better than an API SL certified all-synthetic engine oil? The answer is "no". Undoubtedly, the new specifications are generally higher than the old specifications, but we must know that the specifications are only the lower limit. The performance of many high-quality (of course, more expensive) engine oil products often far exceeds the requirements of self-certification or even renewal of certification, but many times the certification is not updated only for market strategy or time consideration.
Products with reasonable prices, even if they have relatively new certification, often just pass the customs, and the quality will soon decline after a long time. Therefore, if you love a car, when choosing lubricating oil products, don't blindly pursue updated certification, but choose products with better quality.
Is the specified product used correctly?
Every time the oil is changed in 4S, the receptionist will always warn the owner: "We don't need to specify the original product, and we are not responsible for the car failure." Therefore, many car owners can only accept the products of 4S stores helplessly or blindly. In fact, as long as you pay attention to the text in the owner's manual, you can find that the owner's manual only requires the specifications of the vehicle products and does not impose any restrictions on the brand. You know, in any case, any similar provisions will conflict with laws and regulations on anti-monopoly and consumer rights. Therefore, only frontline personnel will say this to the owner. As long as the products that truly meet the requirements of the user manual are used, the automobile manufacturers will be responsible for the quality of their products, regardless of whether the vehicles in the 4S shop are guaranteed or not.
The characteristics of ester oil engine oil can be roughly divided into five categories.
Oil-like low-grade mineral oil
2. Oily intermediate mineral oil
3. Oil-like refined mineral oil (if the peak performance score of mineral oil is less than 3 points, it shall be regarded as up to standard. )
4. Fully synthetic oil PAO (such as Jinmeifu 1, ash shell, etc.). ). The performance is close to 6 points, fair)
5. All-synthetic oleoyl ester group, aviation grade. (such as red line, MOTUL, etc.). ). Performance above 8 points)
The types of base oils are divided into the following five categories:
First, traditional solvent refining mineral oil;
The second is hydrocracking mineral oil;
The above two kinds are called mineral oil, and the base oil of mineral oil is the fraction of useful light substances (such as aviation oil, gasoline, diesel oil, etc.). ..................................................................................................................................... essentially uses inferior components in crude oil, which contains thousands of different mixture molecules. Even if refining technology is refined again, bad substances and impurities can not be completely removed.
Third, highly hydrocracked or hydroisomerized wax;
This base oil raw material, like the first two, is the most deceptive in the market now. Typically, Castrol began to use class III base oil VHVI (with extremely high viscosity index) instead of the original formula of PAO from 1999, and marked it as "synthetic oil"-synthetic oil, and now many domestic brands are imitating it. With the improvement of processing technology, Chevron has a patent on VHVI: 1DW (hydrocracking-isodewaxing). MSDW (hydrotreating-hydroisomerization and hydrocracking-selective dewaxing) ExxonMobil patent; XHVI (Hydroisomerization to Produce Ultra-high Viscosity Index) is a patent of Shell Company, and now it is called synthetic base oil. Among them, ExxonMobil semi-synthetic oil basically adopts MSDW technology, which is called synthetic technology.
The fourth category, polyalphaolefin (PAO);
Poly (α-olefin) (PAO) is a patented technology of ExxonMobil. It uses gas or natural gas to disperse ethylene and propylene in crude oil, and then it is refined into a basic liquid composed of macromolecules through complex chemical reactions such as polymerization and catalysis. In essence, it is to use the better components in crude oil to achieve the expected molecular morphology through chemical reaction and artificial control. Its molecules are arranged neatly, and its ability to resist external variables is naturally strong. Therefore, synthetic oil has a good constitution, and its ability to resist thermal stability, antioxidant reaction and viscosity change is naturally much stronger than that of mineral oil.
The fifth category, other synthetic oils.
Generally called lipids, there are diesters, polyol esters, polyethers, silicone oils, phosphate esters and so on. Chemical synthesis from animal and plant (biological) fatty acids and alcohols. Esters are inherently oily, and other base oils (including PAO) need additives to achieve this property. Moreover, the polarity of esters can make oil film molecules adhere to the metal surface, so esters are the best in terms of lubrication performance.
So to sum up, the lubricating properties are as follows: esters >; PAO & gtXHVI, MSDW, VHVI and other three base oils.
Although ester-based oil has good high and low temperature resistance and wear resistance, it is unstable in water, easy to corrode, poor in compatibility with oil seals and coatings, and high in production cost. Polyether is slightly better than esters in water and oil, but it is incompatible with mineral oil and additives, and its price is high, so it can not be widely used.
Poly α -olefin (PAO), as an automobile base oil, has good compatibility with additives, oil seal materials, coatings, mineral oil and so on. And its price is relatively low. In fact, many brands are using Mobil's PAO now, but I am embarrassed to explain.
MOTUL300V and other lipid synthetic oils actually belong to racing oil (McLaren team sponsored by Mobil will not use Mobil10W-40; Ferrari, too), that's because this car doesn't care about economic performance (MOTUL 300V is more than twice as expensive as Jinmeifu) and its compatibility requirements are not high (engine, gearbox, etc. ). Always change and correct). The oil change cycle of MOTUL300V (generally 1500 km) is also much shorter than that of Jinmeifu 1 (tens of thousands of km can be used properly). The reputation of lipid synthetic oil such as MOTUL300V also comes from the modified car market, which is different from the pursuit of ordinary car owners. This also explains why the three major brands have not pushed lipid synthetic oil to the automotive oil market, so MOTUL is not a top brand and is not suitable for ordinary car owners. It also explains why top car brands such as Mercedes-Benz, BMW, Ferrari and Porsche don't choose MOTUL 300V (this sentence seems to imply that red line oil is the best and can be ignored).
Mobil 1 is PAO synthetic oil.
PAO cannot be used as base oil of lubricating oil alone for two reasons: 1. Pao has poor compatibility with rubber; 2.PAO is difficult to be compatible with additives. So at present, Mobil 1 adopts trisynthesis, namely tetrapao, pentaester and pentaalkylnaphthalene.
Esters are not only soluble in PAO, but also in additives. In addition, esters have natural lubricating ability, and rubber parts can swell properly, thus overcoming the shortcomings of PAO. Alkyl naphthalene, as the future lube base oil, belongs to five types of base oils, with low freezing point and strong oxidation resistance. Therefore, in order to achieve the purpose of high mileage, that is, the service life of 1.5W miles, Mobil 1 is also doped with alkyl naphthalene. Moreover, all four base oils have natural cleaning ability, so the cleanliness does not depend on additives.
Is the performance of engine oil decreased because the molecular chain of engine oil base oil was destroyed?
It is estimated that many riders think so, but this is actually wrong.
Even if the old engine oil is replaced due, whether it is mineral oil or synthetic oil, more than 95% of the molecular chains in the base oil are not destroyed. Hydrocarbon molecules of base oil in waste engine oil remain intact after treatment procedures such as clay refining, and new additives can still be used in a certain range. In Europe, especially in Germany, the proportion is 65%.
The attenuation of engine oil performance is most related to the loss of additives, dilution of fuel, carbon deposition, mixing of sludge, increase of water content and change of pH value. Many riders always judge the performance of oil by listening to the sound, which often misleads your judgment. Most people feel that the engine sound at 2000~3000KM is not good, which is actually an illusion caused by excessive carbon deposition under urban road conditions. At present, the oil above SL level can be used stably 10000~ 15000KM (is this number right? ), running at high speed, removing carbon deposits, and the engine sound is normal again.
Is the wear resistance of synthetic oil base oil better than mineral oil?
Most people may think that synthetic oil is more wear-resistant than mineral oil because it uses PAO or ester-based oil. This is actually a wrong idea.
As far as single base oil is concerned, neither mineral oil nor synthetic oil has anti-wear ability before adding additives. The anti-wear performance of engine oil is provided by composite anti-wear additives, which has nothing to do with base oil. This is also a cognitive misunderstanding of many people. The antiwear performance of modern engine oil is mainly provided by compound additives, while the base oil, whether mineral oil or synthetic oil, has almost no antiwear performance. Although mineral oil contains trace active elements of sulfur, nitrogen and phosphorus, its content is too small to provide anti-wear ability. Pao or esters also need to add anti-wear agents to make up for their own shortcomings. Pao is similar to mineral oil. To achieve the same anti-wear effect, the amount of anti-wear agent needed is equivalent to that of mineral oil, while the oil mixed with esters needs more anti-wear agent.