ตาราง
The incorporation of polymeric VI improvers confers measurably non-Newtonian properties on the oil. Under high shear rate conditions, above about 〖10〗^6 s^(-1), the effective thickening provided by the polymer can diminish significantly, as illustrated in Fig.4. This reduces friction in the critical contacts of the engine, where shear rates can be of the order of 〖10〗^7 s^(-1)or greater, but may also be expected to reduce the oil film thickness. This effect can be offset with certain polymers that confer visco-elastic properties on the oil, which has been shown to enhance the oil film thickness in engine bearings (Ref.2).