The viscosity of the engine oil cannot be sloppy
author: Leila
2024-12-04
The viscosity of the engine oil must not be compromised! Because the appropriate viscosity of the engine oil is the primary condition for establishing an oil film on the friction surface. In order to prevent the wear of the contact area between the parts, the lubricating oil must have sufficient viscosity to ensure that an oil film can be formed in the moving parts at various operating temperatures.
However, the viscosity of the engine oil is not the greater the better. On the contrary, if the viscosity of the engine oil is too large or too small, it will cause a certain degree of adverse effects on the car.
The viscosity is too large
1. Difficult to start the engine at low temperature
The engine lubrication viscosity is too large and the flow is slow. Although the oil pressure is high, the amount of lubricating oil passing through is not much. Especially when starting at low temperature, the engine oil cannot be replenished to the friction surface in time. At this time, temporary dry friction or semi-fluid friction is most likely to occur, which aggravates the wear of the parts.
2. The effective power of the engine is reduced
Due to the high viscosity of the lubricating oil, the friction resistance of the friction surface of the parts increases. The friction area of the friction parts in the automobile engine is very large, generally more than 1 square meter. Covering these surfaces with a layer of lubricating oil, when the movement speed of the machine parts is very fast, even if the viscosity of the oil increases slightly, the loss of friction power will increase a lot. In order to overcome the increased friction, more fuel will be consumed.
On the other hand, the viscosity of the engine oil is high, and the stirring resistance of the crankshaft at high speed will also increase, so the loss of power inside the engine will increase, which will reduce the effective power of the engine.
3. Poor cooling effect
The greater the viscosity of the engine oil, the worse the fluidity, the slower the circulation speed, and the slower the speed of taking away heat from the friction surface, so its cooling effect is poor, which can easily cause the engine to overheat.
4. Poor cleaning effect
The viscosity of the engine oil is high, the circulation speed of the oil is slow, and the number of times it passes through the filter will be reduced. It cannot take away the impurities such as metal chips, carbon particles, dust, etc. from the friction surface in time, and its cleaning effect is poor.
The viscosity is too small
1. The oil film is easily destroyed
The oil viscosity is low. It is not easy to form an oil film of sufficient thickness on the high-temperature friction surface. The oil film has poor bearing capacity and is easily destroyed under load, so that the parts cannot be lubricated normally, which will increase wear.
2. The sealing effect is not good
The oil viscosity is low, the sealing effect is poor, and the cylinder is easy to leak, which will not only reduce the power, but also easily cause the exhaust gas to enter the crankcase, dilute and pollute the oil.
3. Increase the oil consumption
The oil viscosity is low, the sealing is poor, and the evaporation loss is large. In this way, it is easy for the oil on the cylinder wall to enter the combustion chamber, causing the oil to burn, which not only increases the oil consumption but also causes incomplete combustion and increased carbon deposits in the combustion chamber.
It can be seen that it is not good for the engine oil viscosity to be too large or too small. The correct selection of the oil viscosity is the kingly way.
It can be seen that it is not good for the engine oil viscosity to be too large or too small. The correct selection of the oil viscosity is the kingly way.
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