02
2025
-
08
Truck Encyclopedia (25): Good oil performance depends on additives
Today we will talk about how those additives in engine oil help lubricate and protect the engine.
机油为什么需要添加剂呢？
Because the engine needs to be continuously lubricated, cooled, cleaned, and protected, and also has the characteristics of long-mileage oil change, it cannot be completed by relying on the lubricating oil itself alone. Therefore, our engine oil is not pure lubricating oil, but also some additives.
Just like a 1:1:1 edible oil advertisement, engine oil is also made from base oil and additives. In motor oil, base oils account for about 80-90% and additives account for about 10-20%.
Previously, there was an article in the Truck Encyclopedia that mentioned the hard parameters of engine oil, and many parameters in it must rely on the realization of additives in the oil. What are the specific additives, let's talk about them one by one.
碱性添加剂
This additive is directly related to the total base value of the oil composition.
Because a small amount of sulfide remains on the cylinder wall after fuel combustion, these sulfides have a certain weak acidity, so in order to ensure that the cylinder is corroded, weakly alkaline detergents will be added to the oil additives to enhance the cleaning effect of the oil.
In the article "Truck Encyclopedia (23): ACEA, the strongest competitor of API", the ACEA E6 and E9 standard engine oils clearly state that they need to be used with low-sulfur fuel, one of the reasons is that there are fewer alkaline additives in the engine oil for more environmental protection.
清净剂、分散剂
In order to maintain the normal operation of the engine, a certain amount of detergent needs to be added to the engine oil to remove it.
If the detergent fails to clean up the gelation and carbon deposits in time, and continues to be under the action of high temperature and oxidation, high-temperature deposits, that is, paint film and carbon deposits, will be formed, which is also the early form of oil sludge.
Dispersants in oil clean metal surfaces and disperse dirt. When we change the oil, this dirt will be discharged with the old oil, which is why the old oil will be darker.
Many uninformed card friends think that it is wrong to think that the oil is easy to turn black is a sign of poor quality. The blackening of the oil just shows that the oil's ability to clean plays a role. If your oil has not turned black after a period of use, you should change the oil as soon as possible.
极压添加剂
Extreme pressure additives, also known as anti-wear agents, are generally composed of phosphorus, zinc, organic tungsten, molybdenum disulfide, etc. Its function is that when the engine is just started, when the friction pair in the engine is not lubricated by the oil film, or the oil film is destroyed when the engine is under heavy load, the extreme pressure additive can form a layer of solid lubricant between the friction surfaces, which can replace the lubricating oil film to prevent wear and bite marks on the metal surface.
However, extreme pressure additives are mostly heavy metal substances, and in order to reduce the content of heavy metals in the exhaust gas and reduce pollution, the newer API standards, such as CJ-4 and CK-4, have restricted these substances.
抗氧化剂
Engine oil is prone to oxidation reaction with air at high temperatures in the engine. The viscosity of the oil will increase after oxidation, which will increase the running resistance of the engine, and the organic acids produced after oxidation will also corrode the engine. Therefore, antioxidants need to be added to the oil.
抗腐蚀添加剂
When fuel is burned, it produces small amounts of acidic substances that can corrode the engine over time.
The function of anti-corrosion additives is to protect the parts in the engine from sulfide and organic acids.
消泡剂
The oil circulates inside the engine, which will continue to be washed, stirred, and sputtered, and some foam will be produced in the process, which will affect the lubrication of the engine, and the foam will also accelerate the oxidation of the oil. Therefore, it is necessary to add defoamers to the oil to reduce foam production.
染色剂
Dyes have two functions.
One is to use it as identification. For example, transmission oil may be stained red or green, which can be easily identified if the vehicle has an oil leak.
The second is the role of aesthetic advertising. For example, a brand in the United States dyes motor oil purple to match its marketing strategy.
Stains do not improve or degrade oil performance, only recognition.
In addition, some motor oils will also give the oil a certain color under the action of chemical element additives.
乳化剂
Emulsifier, yes, this is the initiator of the recent popular oil emulsification phenomenon in passenger cars.
Why add emulsifiers to motor oil? Because the engine will be mixed with water vapor during work, in order to prevent corrosion caused by the contact between moisture and metal surface, people add emulsifier to lubricating oil, and the emulsifier will produce emulsification phenomenon after the emulsifier encounters water.
粘度指数改进剂
Due to the limitations of human nature, the viscosity index is not high, but the chemical stability is high. Therefore, in order to improve the temperature adaptability of base oils, viscosity index improvers need to be added. And it is precisely because of the viscosity index improver that there is now a multi-stage lubricant.
倾点下降剂
Pour-point depressants are also called decoagulants. Everyone knows that the pour point is the minimum temperature at which the oil solidifies.
There is more or less a part of the wax in the base oil extracted by humans, and when the wax solidifies into crystals at low temperatures, it will block the flow of oil. In order to make the engine start smoothly in a low temperature environment, it is necessary to add a decondensing agent to the engine oil to reduce the flow point and prevent the wax from crystallizing.
其他添加剂
There are many separately sold oil additives on the market, which claim to play a similar role in anti-wear, increase lubrication, and save fuel, and the principle is to add a certain component of additives to the oil weight. However, neither lubricant manufacturers nor automobile manufacturers recommend or explicitly prohibit the addition of additives of other brands to the engine oil used.
Because oil manufacturers have done sufficient compatibility tests on various components of engine oil and additives in the process of research and production. If other types of additives are added, it may lead to unpredictable situations in the engine oil, resulting in abnormal lubrication and aggravated emissions.
Truck Home also recommends that you do not easily add third-party oil additives.
● Editor's postscript
The additives in engine oil have been introduced here, and now everyone should know what role the additives in engine oil can play. Engine oil can pass the stringent certifications of API or ACEA, in addition to the good foundation of the base oil, it is all thanks to these chemical preparations.
Previous Page
Previous Page
Focus on the research and development of automotive brake systems and pneumatic brake valves to promote the development of the auto parts industry!
Contact Information
Telephone:86-575-87438928
Mobile:8613252110178
QQ：1185450863@qq.com
Address: No. 461, Advanced Village, Fengqiao Town, Zhuji, Zhejiang Province
Online message
Submit your information and we will contact you as soon as possible.