Classification and difference of lubricating oil compound additives

1. Why use lubricating oil compound additive products

At present, the overall fuel quality in China is poor, the driving level of drivers is generally not high, and the driving environment is still unsatisfactory, which worsens the working condition of lubricating oil. Additives can be used to enhance or supplement the functions of lubricating oil, such as cleaning, protection and repair.

2. Types of additives

Additives are mainly functional antioxidants, antiwear agents, friction modifiers (also known as oiliness agents), extreme pressure additives, detergents, dispersants, foam inhibitors, anticorrosive antirust agents, flow improver, viscosity index enhancers, and so on. The additives sold in the market are generally the composite of the above single additives. The difference is that the composition of the single additive is different and the proportion of several single additives in the composite additive is different.

Now there are many additives in the market that claim to improve the protection function of engine oil, and different brands publicize them with different action mechanisms. Several types are briefly introduced below:

(1) Graphite and molybdenum disulfide solid suspension type are mainly used to reduce friction and wear, but they can only be used for solid lubrication and low-speed and high load equipment. They have no effect when the engine speed exceeds 1000r / min. In addition, its state in lubricating oil is unstable, and precipitation will occur under certain time and temperature conditions. Its precipitates will block the oil circuit and accelerate the formation of oil sludge.

(2) Teflon resin particle type was widely used as an anti-wear agent in the United States, but it is rarely recommended in the United States because it will deposit on the oil passage and oil pump filter at low temperature, cause blockage, and deposit in the piston ring groove to make it inactive and accelerate the formation of oil sludge.

(3) The coating containing copper, lead and other heavy metal particles can form a metal film on the friction surface, which plays the role of anti-wear and anti extreme pressure. However, the oil filter with slightly larger pore diameter of the filter element must be used, otherwise it will be filtered out and block the oil pump and oil circuit. In addition, if it is used for a long time, a film will be formed on the surface of the piston and cylinder block, resulting in adhesion between the two, and it is easy to stick the ring.

(4) Magnetic oil is a kind of surface metal magnetizing agent, which mainly plays the role of antifriction and anti-wear. The effective time of this kind of products is too short, it needs to be added continuously, the cost is high, and it will interfere with the normal operation of electronic components in the car.

(5) Chlorine containing "chlorine" is a good extreme pressure agent, but it is not suitable for the high-temperature and high-speed working environment of the engine, and it will produce acid under appropriate conditions, which will pose a potential danger to the metal in the engine. In addition, chlorine additives may have matching problems with existing additives in lubricating oil, causing other side effects.

(6) Lead free, fluorine-free and chlorine free chemical film-forming agents can simultaneously show extreme pressure resistance, oxidation resistance and certain wear resistance. Because the chemical reaction film formed on the metal surface acts for a long time, it can effectively prolong the service life of lubricating oil and metal parts.