(1) the suitable viscosity and good heat resistance performance lubricant viscosity in relation to the engine starting sex, parts wear degree, fuel and oil consumption and the size of the power loss. The oil viscosity is too large, poor liquidity, the friction surface into the time required for long, fuel consumption will increase, wear parts increases, cleaning and cooling sex differences, but good sealing; Viscosity is too small, can't make reliable oil film, can't keep the lubrication, sealing is poor, wear big, power down. So too small, viscosity is bad, shall be appropriate. Engine oil temperature of application range is very wide, in 300 ℃ or so require it to have enough that the viscosity lubricating; At 0 ℃ below, and even 40 ℃-requirement when it has enough liquidity, to ensure the smooth start. So the requirement viscosity properties and resistant temperature.
(2) clean scattered performance is good lubrication system to produce such as when too much from dirt sludge oil separation, cause the oil filter and the oil hole jams, oil for the poor liquidity, sticky, fuel oil consumption piston ring increase power, lowered. To prevent this problem, must be in the lubricating oil add come on soluble the purity of dispersant. Detergent-dispersants clean agent mainly divided into the metal type and lime-free type dispersant. Among them, the metal type detergent-dispersants can prevent the ring grooves sludge deposition, the purity of piston ring capacity is good, when used alone called clean agent; No ash type clean to prevent the ring groove agent sludge ability is poor, but make in oil sludge scattered ability, sometimes called dispersant alone. Both had better use composite.
(3) good lubricity engine use are most sliding bearing, and under a lot of load, such as the main bearing for 5 "10 MPa (air) and 10-20 MPa (wood), the connecting rod bearing of 7 to 14 MPa (vapor) and 12-15 MPa (wood), individual components more can be up to 90 MPa. Engine oil in high load, high pressure conditions, must have a good lubricity.
(4) acid and sex good fuel especially diesel, contains a lot of sulfur composition, combustion produces acidic gas and water formed with sulfuric acid or sulfite solution, etc. These acid within the engine for producing corrosion of metal. So demand lubricating oil has the very good and acid and ability, reduce combustion produces acidic substances in the engine damage.
(5) oxidation and thermal oxidation performance is good lubricants would under high temperature combines with oxygen, the oxidation, make oil metamorphic failure, this is cause many engine fault is one of the main reasons why. Oil shall be added in all kinds of antioxidant 1234 additives, avoid the oxidation.
(6) good resistance to bubble of crankshaft strong sexual due to stir and splash lubrication, easy to make oil generation bubble, the lubrication performance drop, and can cause oil pump failure. Therefore, lubricating oil must be in good foam inhibitors products, inhibit the generation of foam, keep lubricant effect.



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