Characterization of motor lubricating oils

Very important component for safe and undisturbed functioning of any internal combustion engine is a sound lubrication of vital parts with engine (motor) oil. Simultaneously with engines development, new requirements were also set for engine oils in order to get more power from the engines to withstand higher working temperatures, wear and load and to last longer. At first mineral engine oils were used, but synthetic engine oils that could fulfil the highest requirements are more and more implemented. Nowadays, technically and commercially, engine oils have gained more than 60% of market share on the global market of lubricants. For proper functioning of the engine, engine oil must fulfil requirements: minimizing wear, assisting in cooling, keeping the compression ratio, reducing corrosion and friction and controlling the deposits. Lubricant characteristics and performances are managed by standard or industrial organization as API, ACEA, and SAE through specific norms. Each norm defines technical requirements as physical properties, engine tests results and other various criteria. This paper describes the importance of grade of engine oil as per SAE and compare various properties of engine oil as per their grade and brand of engine oil. It gives idea about the selection of engine oil depends on the climate condition, load, speed, driving condition and local availability etc.