About the relationship between diesel oil viscosity and pressure
- Categories:Oil Knowledge
- Author:
- Origin:
- Time of issue:2021-03-17
- Views:
(Summary description)For truck drivers, many drivers think that the higher the oil pressure, the better, the red light is not lit, the pressure of the engine oil pressure gauge is high and stable, and it feels energetic when running. The quality of the oil is good or bad.
About the relationship between diesel oil viscosity and pressure
(Summary description)For truck drivers, many drivers think that the higher the oil pressure, the better, the red light is not lit, the pressure of the engine oil pressure gauge is high and stable, and it feels energetic when running. The quality of the oil is good or bad.
- Categories:Oil Knowledge
- Author:
- Origin:
- Time of issue:2021-03-17
- Views:
Information
For truck drivers, many drivers think that the higher the oil pressure, the better, the red light is not lit, the pressure of the engine oil pressure gauge is high and stable, and it feels energetic when running. The quality of the oil is good or bad.
So is it scientific to judge in this way?
From the principle of engine lubrication | The size of the oil pressure is determined by the viscosity of the oil. In layman's terms, if the oil is thicker, the viscosity will be greater and the pressure will be greater. However, if the viscosity of the oil is too high, the engine piston is in motion. The piston receives more resistance, which means more fuel will be wasted.
A lot of professional data on lubricants show that 80% of engine wear is mainly caused by the cold start of the engine, so the simpler reason is that the thicker the lubricant, the longer it takes for the pump to the part required for lubrication during cold start, which is caused by cold start. The greater the friction damage to the vehicle engine.
Let's take a look at the evolutionary route of lubricants on the market | Originally all are single-grade oils, and now they are all 15W40/20W50 multi-grade oils. The fundamental difference between multi-grade oils and single-grade oils is:
The viscosity of multi-grade engine oil is not too low at low temperature, and the viscosity is not too high at high temperature. That is to say, multi-grade engine oil takes care of low-temperature flow performance and reduces friction caused by cold start.
When the engine is cold-started, the actual sensory viscosity of the multi-grade oil 20W50 is thinner than that of the single-grade oil 50. Therefore, the continuous evolution represents the trend of market development, proving that the oil is not as thick as possible, and that the pressure is not as high as possible.
For example, if someone just bought a new car, if he just knows the oil, he will be directly replaced with 15W40 oil. The pressure is just right, the feeling is good, and it is fuel-efficient, and the protection of the engine is very good. , From then on, 15W40 oil can always be used, and 20W50 oil is not necessary.
But if you change 15W40 to 20W50 for this same car and run for a period of time, you will no longer be able to use 15W40. If you use it, it will probably turn on a red light to show that the oil pressure is low. In fact, it is replaced with 20W50. Abnormal wear appeared after oil.
There will be some situations. For example, a trolley often changes the oil at the dealer, and has been using a 20W50 of a certain brand A. Suddenly, it was replaced with a 20W50 of another brand B. The oil lamp lights up to indicate that the pressure is low, and the oil is discharged. , And then change back to A, it's normal.
This situation is very common. Manufacturers or distributors usually pay a barrel of oil in order to maintain customers in the market, but they are not clear about the reason, and it is good to even test the oil. In fact, this is still It is related to the viscosity of the oil itself, but not directly related to the quality.
Here is a more professional knowledge. In the viscosity grade of lubricating oil, when 20W-50 represents 100℃, the viscosity range of the oil is 16.3-21.9, which means that the viscosity of the same grade of oil is a wide range. A fixed value.
The specific blending viscosity adopted by different manufacturers may also be quite different, and the use effect will also be different. The low viscosity is more fuel-efficient and better for new cars, and the high viscosity is better for overloaded cars and old cars. This is easy to explain. That's the problem.
We can also analyze another problem. You may find that there is a phenomenon. The higher the level of the oil of the same brand, the thinner the oil looks. For example, when comparing CF-420W50 and CI-420W50, it is also 20W50. The viscosity of the two oils, but the two oils feel completely different in thin consistency.
This is because the higher the oil grade, the higher the base oil grade used. For example, mineral oil can be used when blending CF-4, and the pour point of mineral oil itself is basically above -20°C, but the blending In the case of CI-4, it is necessary to use oil blends above hydrogenated base oil.
And the pour point of these oils is below -30℃, so although their viscosity grades after blending are the same, the quality of the oils themselves determines the difference in viscosity at room temperature between them.
At present, some drivers have a misunderstanding about the pressure of diesel vehicles: due to the serious overload of diesel vehicles in the domestic market, most drivers have a major misunderstanding about oil pressure, that is, the higher the oil pressure, the better. In fact, this is a serious mistake. of.
Engine oil pays attention to balance. It is actually easy to increase the viscosity of the oil. Starting with the viscosity modifier, it can indeed solve the problem of low pressure, but why the current international major brand lubricant companies do not increase the viscosity of the oil? ?
Scan the QR code to read on your phone
Previous:
Lubricating oil price surge hits again
Next:
None
Previous:
Lubricating oil price surge hits again
Next:
None
下一条 :
None
下一条 :
None
