Ans-: Determination of Viscosity index. Viscosity index of test oil is determined with the help of two types of standard oils viz. Pennsylvanian oils and Gulf oils having V.I.'s 100 and 0 respectively.
The V.I. of the test oil is given by the formula
V.I. = (L-U/L-H)X 100
where
V.I. = Viscosity Index of the oil under-test
L= Viscosity at 100°F of the low-viscosity standard oil having a V.I. of O (i.e., Gulf oil) and also having the same viscosity as the oil under test at 210°F
U = Viscosity at 100°F of the oil under test.
and
H = Viscosity at 100°F of the high-viscosity standard oil having a V.I. of 100 (i.e., Pennsylvanian oil) and also having the same viscosity as the oil under test 210°F.
Tags
lubricants