Additives contents in PAG and synthetic motor base oils and their effect on electrostatic phenomena in a rotating shaft-oil-lip seal system

The paper presents the results of experiments on the electrostatic aspects of anti-wear (AW) and friction modifier (FM) additives (agents) when these are added to PAG (polyalkylene glycol) and PAO 6 (synthetic) motor base oils to obtain their blends. Experiments are carried out in a rotating shaft-oil-lip seal system (a friction junction) which is a specially built experimental facility to be the simplified model of an engine crankcase in the interior of which an earthed metal shaft rotates at given angular velocities from 500 up to 1000 rpm. The AW and FM additives contents in blends are 0.1 and 0.5 wt%. Oil temperature is controlled electronically and changed from 60 up to 110°C. An 88-mm diameter lip seal is used in the experiments. Electric potential of a stiffening ring of the lip seal tested is measured directly with an electrometer. The experimental results are the relationships of the potential induced in a stiffening ring to shaft´s angular velocity and to the temperature of pure base oils and their blends with AW and FM agents.