High Shear Rate Rheometry of Low-Viscosity Liquids.

A new instrument called LODGE STRESSMETER was developed to measure the shear elasticity and viscosity of general and multigrade oils at high shear rates. This will make possible the measurements of normal stress difference N1 for values of shear rate up to 5 x 10 to the 5th power is temperature of 150 C. New surprising data show as yet unexplained the the N1 contribution to the minimum oil film thickness could be as much as 75 of the contribution from viscosity. This raises hope for the use of oils with lower viscosity, leading to improved fuel economy and an increase in the range of motorized vehicles.