In the process of working, oil in engine is permanently submitted to impact of high temperatures, oxygen and oxide nitrogen that cause oxidation and lead to the forming of acids, sedimentations, lacquer formations, additive destruction and oil solidification. Antioxidant additives are aimed on elimination of all these negative consequences. Thanks to these additives it becomes possible to increase intervals of engine oil changing. The principle of activity consists in chemical reaction with products under the influence of high temperatures, causing oil oxidation. As a rule, as antioxidant additives can be used sulfurized ether, fenalates sulphide, aromatic amine, deplaced phenols and zinc dialkildithiophosphates (they have antiwear capacities). Antiwear additives are utilized in the process of engine working.
Corrosion inhibitors must protect details of engine surface from corrosion, caused by organic and mineral acids, formed under the oil and additive oxidation.
The mechanism of activity – formation of protective film on the surface of details and acid neutralization. The main function of corrosion inhibitors is protection of steel cylinder walls, plungers and rings. The mechanism of activity is almost the same.