Vehicle smooth oil selection criterion

1, how to select the internal combustion engine oil ( 1) According to the characteristics of internal combustion engine and vehicle, namely choose oil load and speed. Load of high speed low, for example, some large bulldozers, cranes, and drill, etc. , general use viscosity larger smooth oil, such as SF40, CD50, light load of high speed, such as cars, jeeps, small power equipment of general use smaller smooth oil, such as SG15W / 40, SF30, etc. （ 2) According to the internal combustion engine work demanding level. Such as diesel engine is a temperature higher than 230 - ring area - 250 ℃, strengthening coefficient greater than 5, supercharged diesel engine oil with CD or more oil, such as CD40, SG/CD40, etc. Gasoline engine can according to the contraction ratio and a crankcase positive pressure ventilation, exhaust gas recirculation, and catalytic converters to choose oil, contraction ratio, the greater the choose the oil level is higher, with the additional installation, more than ordinary choose SG engine oil. （ 3) The elements of power ratio is also choose oil and engine oil capacity. The elements of power ratio is also choose oil and engine oil capacity. Large capacity of the oil quality of oil quantity request is not strict, high oil capacity small request about the quality of the product. Common European consumer launch machine is small in size, big power, request to use high quality oil, such as SHSJ. （ 4) On the basis of geographical, time, temperature oil. Winter cold area, should choose low viscosity, low pour point oil or multistage oil, such as the northeast region in China, can choose SF10W / 30, SH5W / 30, etc. ; Higher temperature region for the whole year, such as hainan, guangdong, can choose the oil of high viscosity, such as SF40, CD50, etc. （ 5) On the basis of a machine wear condition choose oil. New machine should choose smaller viscosity oil ( Thinking about energy saving) And wear large, large cylinder wall and piston clearance launched machine should choose larger viscosity ( Think about seal) 。 2, how to select the gear oil ( 1) Automobile driving axle hyperbolic gears must choose GL - 4、GL— Level 5 oil, GL - 3 oil and old brand 18 #, # 24 hyperbolic gear oil should not be used. （ 2) According to environment temperature with different viscosity gear oil. For example of 75 w / 90 is particularly suited to the cold of winter; 80, the 85 w / 140 w / 90 oil in east China, central China, north China region general during summer and winter seasons, south China, southwest region winter use; 90, oil all over the country in the summer of 140 gm, south China region winter is available. （ 3) Chosen on the basis of vehicle load case performance levels. GL— 4 is suitable for middle and low load vehicles, GL - 5 suitable for heavy duty vehicles. （ 4) Car manual transmission requests using gear oil, general use 80 w / 90 or 85 w / 90 oil, had better use GL - 4、GL— 5 oil level.