The Effect of Polymer Type Upon Performance of Multigrade Oils in Petrol and Diesel Engines

The three main VI Improvers for multigrade engine oils, Polyalkyl-Methacrylate, Ethylene-Propylene-Copolymer and Diene-Styrene-Copolymer were compared with respect to their effect upon

Viscosity-temperature relationship

Viscosity as a function of shear stress and thermal oxidation

Wear protection

Deposit formation

The results showed considerable differences in polymer effect. Interesting properties in one area are not necessarily an indication of satisfactory performance in others. Selection of different polymers appears necessary for diesel and petrol engine lubricants.