Properties Of Lubricants

PROPERTIES OF LUBRICANS The duties of the lubricant in an engine are many and varied in scope. The lubricant is called upon to limit and control the following: •Friction between the components and metal to metal contact •Over heating of the components •Wear of the components •Corrosion •Deffects To accomplish the above functions, a good lubricant should posses properties : •Suitable viscosity •oilyness to ensure the adheerence of the bearings ,and for loss friction and wear when the lubrication is in the boundary region, and as a protective covering againsst corossion. •High strength to prevent the metal to metal contact and seizure under heavy load. •Should not react with the lubricating surface. •A low pour point to allow the flow of lubricant at low temperature to the oil pump. •No tendency to form deposits by reacting with air, water, fuel or the products of combustion •Cleaning ability •Non foaming characterisstic •Non toxic •Non flamable •Low cost ADDITIVES FOR LUBRICANTS : the lubricating oil should posses all the above properities for the saticfactory engine performance.The modern lubricants for heavy duty engines are highly refinedwhich otherwise may produce sludge or suffer a progressive incrase in viscosity.For these reasons ,the lubricants are seasoned by the addition of certain oil soluble organic compoundscontaining inorganic elements such as phosphorus sulphur,AMINE derivatives. METALS are added to the minearl baesd lubricating iol to exhibt the desired properties. the oil soluble organic compounds added to the present day lubricating to impart one or more of the following characteristics. •Anti-oxidant and anti-corrosive agents •Detergent-dispersent •Extreme pressure addition •powre point depression •viscosity idex improver •antifoam agent •oilness and film-strength agents.