Date of Award
Master of Science in Mechanical Engineering - (M.S.)
Walter J. Michels
The effects of engine mileage upon the viscometric properties of seven different brands of multi-viscosity engine oils were examined by subjecting each brand of oil to an average of 1500 miles of service in the crankcases of different passenger cars.
Oil samples were taken every 500 miles after the oil was put in the crankcase. The control oil sample was taken from a can of oil at the time the oil was put in the engine.
The viscosity indices and kinematic viscosities at 100° F and 210° F were calculated for each sample of oil. The percent change in viscosity index and kinematic viscosity for each sample of each brand was calculated relative to the control's viscosity index and kinematic viscosity. The viscosity index and kinematic viscosities of each brand's samples were plotted as a function of mileage.
All of the oils showed a decrease in kinematic viscosity at 210°F. Some of the oils showed a decrease in kinematic viscosity at 0°F. The viscosity index change varied from sample to sample of the same brand. The viscosity index increased for some brands and decreased for others. Six out of seven oils no longer qualified as the original SAE rating of the oil.
Philcox, William Charles, "The effect of internal combustion engine operation upon the viscometric properties of polymer thickened multi-viscosity crankcase oils" (1968). Theses. 1488.