ABSTRACT
Engine oils form the most important group of liquid lubricants. They amount to over 40 percent of all the lubricating oils. Existing properties of the mineral base oils which primarily relate to the physical properties are not sufficient to provide an adequate lubricant performance for modern engines. An engine oil additive is defined as a material designed to enhance or to impart the performance properties of the base stock. Usually they are materials that have been chemically synthesized to supply the desired performance features. Different additives can assist each other, resulting in a synergistic effect or they can lead to antagonistic effects. Engine oil oxidation products form varnish and sludge. Thus, the oxidation process of the oil must be retarded. This can be achieved by using oxidation inhibitors. To control buildup of varnish and sludge detergents have to be applied.
