1.SAE viscosity
SAE is the Society of Automotive Engineers, Society of Automotive Engineers generally meaning.
classification of viscosity grade lubricants are used by the US Society of Automotive Engineers SAE classification criteria, divided into 0W, 5W, 10W, 15W, 20W, 25W, No. 20,30,40,50,60 eleven level. Our summer is generally used engine oil viscosity number of 40. Southern No. 50 a few places use engine oil. Our southern winter is generally a viscosity of 30 engine oil. North need to use 5W, 10W oil, a handful of cold regions need 0W oil.
In addition, there are common summer and winter, the north-south general, the energy saving effect while having a multistage oil (XW / XX). W represents (in winter), digital (0,5,10,15,20) in front of W, and W behind the figures (30,40,50) represents the kinematic viscosity of oil at 100 ℃ classification. 0W, 5W, 10W, 15W, 20W, 25W, maximum pumping limit temperatures of -35 ℃, -30 ℃, -25 ℃, -20 ℃, -15 ℃, -5 ℃. (The higher the number, the higher temperature grade suitable suffix W is applied to the winter; W grades with no suffix is suitable for summer and room temperature; if the two numbers together, said multi-stage oil which satisfies properties two viscosity grade requirements).
Similarly 10W-30 such representation, this is because we are using oils are generally multi-stage oil, so there are two sticky indicator is a 10W, a is 30, i.e., this can be seen as oil SAE 10W and has integrated features both SAE 30 motor oil.
Let me talk about what this number is in accordance with the test out of the way. Briefly time, the oil is heated to a certain temperature, given a certain amount of oil holes and the oil flow through the length of this hole, the oil is used to determine the viscosity index. But noHave found specific SAE testing standards, so I do not know the specific details of the test, but these are not important, it is important that the test is a very key indicators and relevant, and that is the temperature of the oil.
Now you can have two numbers for why the 10W and 30, the W is what it means. The test time will generally tested at two temperatures, one 0deg; C, is a 100deg; C (i.e., Fahrenheit 32deg; F and 212deg; F), the measured viscosity come at 0 degrees, will be added at a later W, i.e. where 10W, and the measured viscosity at 100 degrees, where 30 is the, in combination, is 10W-30.