How does the viscosity index of the lubricating oil be calculated?

How does the viscosity index of the lubricating oil be calculated?

Abstract: The viscosity index indicates the degree to which all fluid viscosity varies with temperature. The higher the viscosity index, the smaller the effect of fluid viscosity on the temperature, the less sensitive the viscosity to the temperature.

IVS400 Viscometer

According to the different viscosity index, the lubricating oil can be divided into three grades: 35-80 for the medium viscosity index lubricants; 80-110 for the high viscosity index lubricants; 110 above the special high viscosity index lubricants. Viscosity index of 100-170 in the oil, high-grade multi-grade lubricants, it has a viscosity curve changes smooth and good viscosity temperature. At lower temperatures, the polymer molecules in these viscosity index improvers have little solubility in the oil and the molecules are curled into small clusters, so that the viscosity of the oil increases little; and at high temperatures it is in the oil The viscosity increases, and the curly-like linear molecules expand and elongate, so that the viscosity increases greatly, making up the viscosity of the base oil due to the temperature rise. So the higher the viscosity index, the smaller the viscosity changes with temperature.

Calculation of Viscosity Index

Viscosity index should be calculated using the formula, the viscosity index of less than 100 and higher than 100 are uses different formula. ASTM D2270 method is divided into two parts, one for the A method, another one for the B method. A method is actually ASTM D567 old method, the use of calculation method to determine the viscosity index. The B rule is intended for use with fuels with a viscosity index greater than 100.

Viscosity index (Viscosity index) formula A:

Viscosity index between 0 to 100 between the use of this formula. The formula is: viscosity index

VI = [(L-U) / (L-H)] * 100

H = viscosity of 100 known oil at 100 ° F (or 40 ° C), but its viscosity at 210 ° F should be the same as the viscosity of the unknown oil at 210 ° F (or 100 ° C). Because of its high viscosity index, so the H (High) alphabet.

L = viscosity of the known oil at 100 ° F (or 40 ° C). But its viscosity at 210 ° F (or 100 ° C) should be the same as the viscosity of the unknown oil at 210 ° F (or 100 ° C). Because of its low viscosity index, so the L (Low) alphabet.

U = unknown viscosity index of the raw material at 100 ° F (or 40 ° C).

Viscosity index (Viscosity index) algorithm B:

Specially used to calculate the viscosity index of more than 100 for the use of oil.

IVS800 Viscometer

If a result of an oil calculated by the old method is more than 100, it must be recalculated in this way and calculated as a result of the B method. And expressed as VI (E), VI (Extended), VIe, or "epitaxial viscosity index". The formula is as follows:

(N) = [(Antilog N) -1 / 0.0075] 100 where N = the viscosity of the oil sample at 210 ° F, which is equal to the desired index at the ratio of H and U at 100 ° F. which is

N = (㏒H-㏒U) / (㏒KV210), or

KV210N = H / U

KV210 = kinetic viscosity of oil sample at 210 ° F (or 100 ° C) (KV is abbreviation for Kinemetic Viscosity)

H = A known oil having a viscosity index of 100 is obtained by the A method, its kinematic viscosity at 100 ° F (or 40 ° C) (which can be determined by the 24th table)

U = the kinematic viscosity of the oil sample at 100 ° F (or 40 ° C) (where H> U)

Hangzhou Zhongwang Technology Co.,ltd provides IVS400 and IVS800 series viscometer.

It can tests the viscosity index easily.

Kent Yuan (Mr.) Hangzhou Zhongwang Technology Co., LTD.

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