7 key parts of engine lubrication
author: Leila
2025-01-06
The engine can be said to be the busiest, hardest working part of the car with the worst working environment. Frequent power movements keep the engine in a high temperature state, and the high temperature causes the engine to need oil that meets the corresponding conditions to meet its normal operation and lubrication, thus putting forward higher requirements for the oil.
As a car's power system, what are the requirements of the engine for lubricating oil? What are its key lubrication parts? What problems will arise during the use of oil in these lubrication parts? The following will answer them one by one.
Valve mechanism - viscosity index, low temperature fluidity
The lubrication of the valve mechanism is splash lubrication through splashing oil, so the valve mechanism is basically in a boundary lubrication state, and the valve mechanism pressure is very high, so the valve mechanism has high requirements for lubricating oil when working. In this case, the oil needs to have very good wear-resistant additives, and the viscosity of the base oil should also be in a relatively wide range, and the low temperature fluidity is also very high.
The valve mechanism may also rust due to low temperature and water vapor, thereby corroding related parts and increasing wear. Therefore, in such a case, the engine oil should be prevented from rusting.
Generally speaking, some alkaline additives should be added to the engine oil, etc.
Piston - high temperature and high shear, clean dispersing performance
The piston is in an awkward situation in the engine. In terms of lubrication, the working state required for the engine oil is very demanding. If there is carbon deposit here, it will also cause excessive friction, additional wear, and increased oil consumption.
Carbon deposits will cause additional pressure on the piston ring, and after long-term use, it will fall off due to excessive wear. Therefore, the engine oil should have a high alkaline clean dispersing formula to clean up the carbon deposits. In addition, the engine oil must have good wear resistance.
Crankshaft bearings - kinematic viscosity, low temperature fluidity
The bearings of the crankshaft are all so-called sliding bearings, because when running at high speed, the kinetic energy loss will be smaller when using sliding bearings. When static, there is only a little oil in the bearing, which can only achieve boundary lubrication. After running at a certain speed, it can gradually become a mixed lubrication, and finally immersion lubrication.
In this case, if there are impurities in the lubricating oil, it will cause corrosion and damage to the bearings. Therefore, the engine oil is required to have good fluidity and viscosity, and an alkaline detergent to prevent corrosion. Of course, it must also have filtering properties, similar to the oil filter, and it must constantly filter out the dirty things, otherwise it will also lead to a decline in its performance.
Lubricating oil oil channel - cleanliness and dispersibility
The sludge produced in different parts of the engine can increase the viscosity of the engine oil, block the oil circuit and cause insufficient oil supply. The sludge formed for a period of time will become hard and brittle after being heated at high temperature for a long time. This is the so-called "black sludge".
Black sludge will increase the wear of parts and even cause biting. In order to reduce the harm caused by these sludges, the engine oil needs to contain better detergents and dispersants.
Crankcase - Oxidation stability, cleanliness and dispersibility
When the oil molecules are at high temperature, they will aggregate into larger molecules, causing the oil to thicken. At this time, the viscosity of the oil will increase, and the consumption will also increase when the engine is running at high speed, that is, the "stirring oil" loss, and it will also cause the pumpability to deteriorate, resulting in difficulty in starting and insufficient oil supply. Therefore, the oil needs to have good oxidation stability and dispersibility.
On the other hand, the viscosity index improver contained in the engine oil will be sheared by metals such as bearings or piston rings, and will become smaller molecules, resulting in a decrease in the viscosity of the oil and a decrease in the lubrication performance of the oil. The thinning of the oil and the thinning of the oil film will aggravate the wear between the parts. In order to avoid the shearing of the thickener molecules, the oil needs to contain a thickener with good shear stability.
Gasoline engine piston - dispersibility, cleanliness
After a period of use, the oil will have ash deposition. The ash deposition is formed by carbon particles formed by poor combustion and metal salts in the oil additives. High temperature will cause ash deposition before the spark plug ignites, causing pre-ignition, knocking, and increasing the burden on the engine, especially the bearings and crankshaft. This leads to uncontrolled combustion, overheating, power loss, and increased vibration and noise.
The ash aggregates on the piston are likely to spontaneously combust due to changes in the cylinder pressure, that is, detonation will occur, which is very detrimental to the engine. In the face of these problems, the engine oil needs to be a low-ash lubricant with good cleaning performance.
Supercharger and hydraulic tappet - oxidation stability
In the case of a supercharger, the turbine temperature is very high, which will cause the bearing to become very hot. At this time, the engine oil needs to have good oxidation stability. The hydraulic tappet is actually to buffer the knocking between the valve and the steel frame at high speeds, making the process softer. However, since the hydraulic pressure in the hydraulic tappet is actually pumped in by the engine oil, it is likely to be blocked if it is not handled properly. The engine oil may also foam and rust under different circumstances. Therefore, the engine oil is required to have good cleaning performance.
Due to the harsh working environment of the engine, different parts have many and different requirements for engine oil, which is also the concern of today's engine oil manufacturers. For ordinary car owners, it is also necessary to understand the working condition of the car's engine and choose the lubricant suitable for the car.
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