If continued, it will result in equipment malfunction. The zinc dithiophosphates are widely used for this purpose and are particularly effective in reducing wear in valvetrain mechanisms. These compounds are described under oxidation and bearing corrosion inhibitors. Other effective additives contain phosphorus, sulfur, or combinations of these elements. Abrasive wear can be prevented by effective removal of particulate matter by filtration of both the air entering the engine and the lubricant during engine operation.
Corrosive wear is largely the result of acidic blowby products formed during fuel combustion.
This type of wear can be controlled by using alkaline additives such as basic phenates and sulfonates. This modification of rheological properties results in increased viscosity at all temperatures. The viscosity increase is more pronounced at high temperatures which significantly improves the viscosity index of the lubricant. Viscosity modifiers are generally oil-soluble organic polymers with molecular weights ranging from about 10,000 to 1 million. The polymer molecule in solution is swollen by the lubricant, and the volume of the swollen entity determines the degree to which the polymer increases viscosity.