Causes and Preventive Measures of Lubricating Oil Quality Deterioration
Causes and Preventive Measures of Lubricating Oil Quality Deterioration
2022年3月19日
Grease for Motor Bearing
Grease for Motor Bearing
2022年3月19日

Ten Misunderstandings in the Use of Lubricating Oil

For the benefits of lubricating oil, some car owners may be able to say a lot, but how to use lubricating oil correctly. Ten Misunderstandings in the Use of Lubricating Oil

According to the reporter’s understanding, many car owners still have some misunderstandings. In this regard, the reporter specially asked the senior car repairman for advice, and summarized the 10 misunderstandings in the use process.

1. Domestic vehicles blindly use imported engine oil

Some car owners believe that imported engine oil must be better than domestic engine oil, so they use imported engine oil on domestic cars, especially new cars. As everyone knows, the gains often outweigh the losses, and there will be many disadvantages. For example, most imported engine oils have low viscosity, which can not meet the requirements of domestic vehicles for engine oil viscosity.

 In addition, the material thermal expansion coefficient and fitting clearance of various mating parts of domestic engines are larger than those of imported vehicles, and most domestic vehicle engines are not equipped with oil radiator. 

If imported oil is blindly used, the oil pressure will be low because the engine oil is too thin at normal working temperature, Breaing and even can not reach the specified working pressure, which can not meet the needs of normal lubrication, and the wear of the engine will be exacerbated.

2. Engine oil blackening means engine oil deterioration

Engine oil works under harsh high temperature conditions, which is easy to oxidize and deteriorate, produce acidic substances and stack them into polymer deposits, so as to destroy the lubrication. In addition, the combustion exhaust gas channeling into the crankcase will also promote the oxidation and deterioration of the engine oil.Ten Misunderstandings in the Use of Lubricating Oil

 Therefore, after a certain period of use, the engine oil will usually blacken and deteriorate and lose its due lubrication. However, with the continuous improvement of lubricating oil quality, especially the popularization and use of thickened engine oil, the blackening of engine oil does not necessarily mean the deterioration of engine oil. Ten Misunderstandings in the Use of Lubricating Oil

This is because the clean dispersant added to the thickened engine oil disperses the deposits on the parts into the oil, making the engine oil black. Whether it has deteriorated or not, the test of various indicators shall be carried out, and the oil shall be changed regularly according to the quality to reduce unnecessary waste. 

For example, the engine oil added with yyl02 and other engine protective agents will also blacken after being used for a certain period of time. Therefore, the blackening of engine oil does not mean the deterioration of engine oil.Ten Misunderstandings in the Use of Lubricating Oil3. Blindly select lubricating oil

Lubricating oil plays the role of lubrication, cooling, cleaning and sealing. The quality of lubricating oil is directly related to the service life of the engine. Therefore, do not blindly choose engine oil. New vehicles have very strict requirements for lubricating oil. What lubricating oil to choose, when to replace and how to replace should be carried out in accordance with the regulations of the manufacturer.

When selecting engine oil, we should pay attention to both quality grade and viscosity grade. First, select the service performance level according to the compression ratio and displacement; Then select the viscosity level according to the air temperature and load. The quality of engine oil should be higher than lower. Good quality engine oil can ensure good engine lubrication, reduce wear, prolong engine service life, prolong oil change cycle, and reduce the frequency and difficulty of maintenance and repair. When selecting the viscosity of engine oil, in addition to the temperature conditions, low viscosity engine oil should be selected as far as possible under the condition of ensuring engine lubrication and sealing, so as to save fuel.

4. Use multi viscosity lubricating oil

Multi viscosity lubricating oil (also known as multi-grade lubricating oil) has the properties of light oil at low temperature and heavy oil at high temperature. When multi-grade oil is recommended, a multi-grade oil can replace a variety of single-grade oil. Although multi-stage oil can meet the requirements of extremely cold and warm seasons and heavy load engine oil, especially those diesel engine oil that has no difficulty in starting in cold days, it is generally recommended to use lubricating oil with single viscosity, which is conducive to the lubrication of the engine and prolong the service life of the engine. Therefore, do not consider the use of multi viscosity lubricants.

5. Mix engine lubricating oil

Except for different viscosity grades, the base oils of various lubricating oils are the same. The only difference lies in the variety and quantity of added components. Therefore, the variety and quality grade of lubricating oil are generally divided according to the variety and quantity of added components. Lubricating oils with different types of additives cannot be mixed, otherwise the additives in the oil may have a chemical reaction and damage the due effect of the lubricating oil. With the continuous improvement of additives and their formula, some general oils have been developed and produced. For example, QE / cc, QF / CD and other lubricating oils for gasoline and diesel engines. They can be used in general within the indicated level range. Therefore, whether the lubricating oil can be mixed or not should be comprehensively compared with the name, variety and brand of the oil according to the requirements of the manual, and the use level and appropriate brand should be reasonably selected. It should not be used blindly according to the economic insurance, let alone mixed use.

6. The lubricating oil is only added and not replaced

Many car owners only pay attention to checking the oil quantity of lubricating oil and adding it according to the standard, but do not pay attention to checking the quality of lubricating oil and ignore the replacement of deteriorated oil, which leads to the moving parts of some engines always operate in a poor lubrication environment, so as to accelerate the wear of lubricating parts. Therefore, generally speaking, the lubricating oil of the engine should be changed when the vehicle travels 3500 ~ 5000km.

7. Fill lubricating oil more than less

The harm of too little engine lubricating oil is well known. Therefore, some car owners are afraid of burning tiles due to lack of oil and think that adding more lubricating oil is better than adding less. Therefore, they often do not add oil according to the regulations to make the lubricating oil exceed the standard. In fact, too much lubricating oil has many hazards:

1. When the car is running, the crankshaft stirs up, causing the oil foam to deteriorate and increase the rotation resistance of the crankshaft. Therefore, it not only increases the fuel consumption of the engine, but also reduces the power of the engine.

⑵ the oil consumption increases due to the increased combustion of the oil from the cylinder wall to the combustion chamber.

⑶ it accelerates the formation of carbon deposit in the combustion chamber and makes the engine prone to deflagration.

Therefore, it is a misunderstanding to prefer more engine oil to less. Generally, the oil level should be kept slightly lower than the scale on the dipstick. Too high oil level will be counterproductive.

8. The higher the viscosity of lubricating oil, the better

In order to prevent the indirect contact surface wear of moving parts, the lubricating oil must have sufficient viscosity so that an oil film can be formed between moving parts at various operating temperatures. However, the viscosity of the lubricating oil shall not be higher than the degree that affects the start of the engine, and the friction generated under the condition of continuous operation is required to be small. The use of lubricating oil with excessive viscosity will increase the wear of parts because:

⑴ the viscosity of engine lubricating oil is too high, the flow is slow, the upward flow is slow, and the oil pressure is high, but the passing amount of lubricating oil is not large, so it cannot be supplemented to the friction surface in time.

⑵ due to the high viscosity of the lubricating oil, the friction between the friction surfaces of the parts increases. In order to overcome the increased friction, it is necessary to consume more fuel and reduce the output power of the engine.

⑶ if the viscosity of lubricating oil is high, the circulation speed of oil will be slow, and its cooling and heat dissipation effect will be poor, which is easy to overheat the engine.

(4) due to the slow circulation speed of lubricating oil, the number of times of passing through the lubricating oil filter is less, so it is difficult to clean the worn metal debris, carbon particles and dust from the friction surface in time.

Lubricating Oil

Impact on vibration and noise:

Influence on Vibration: NSK bearing test results show that cleanliness seriously affects the vibration level of rolling mill bearing, especially the vibration in high frequency band. The bearing with high cleanliness has low vibration speed, especially in high frequency band.The Cleanliness of NSK Bearing is Important to Heating

c. Effect on lubrication performance:The Cleanliness of NSK Bearing is Important to Heating

The decline of NSK bearing cleanliness will not only affect the formation of lubricating oil film, but also cause the deterioration of lubricating grease and accelerate its aging, which will affect the decline of lubricating performance of lubricating grease.The Cleanliness of NSK Bearing is Important to Heating

Under popular conditions, the filling amount of NSK bearing grease always exceeds the practical demand of direct intervention lubrication, fills the cavity on the holding frame and the bearing cover of the rolling mill, and forms a contour on the periphery of the rolling element. During this process, the bearing temperature rises rapidly due to the resistance of excess grease. Although most of the excess grease is squeezed out at the initial stage of operation, and the grease squeezed in the accessories of the raceway may still be migrated and transformed into the rolling element and brought into the raceway.

In the initial stage of rolling mill bearing operation, most of the lubricating grease is quickly squeezed out of the raceway (less than one minute), and the accumulated lubricating grease is discharged in a small amount one after another in the cycle of bearing migration and transformation.

At this time, the bearing temperature continues to rise until all the excess grease is discharged, which can be called the running in stage of grease.

According to the quality and filling amount of grease in the bearing structure of the rolling mill, this period may last for more than ten minutes or even several hours.