Engr Maliha Maisha Rahman
Bannichi Enterprise limited
Literature Review:TBN: In short, a TBN (total base number) measures the amount of active additive left in a sample of oil. The TBN of a used oil can aid the user in determining how much reserve additive the oil has left to neutralize acids. The lower the TBN reading, the less active additive the oil has left. Oil’s function is to lubricate, clean, and cool the engine. Additives are added to the oil to enhance those functions.Viscosity: Technically, viscosity is defined as resistance to flow. Commonly though, we think of it as an oil's thickness. To be more specific, it is the thickness of an oil at a given temperature.The viscosity of an oil could be reported at any temperature, but to standardize things, most laboratories report either a low temp (100F or 40C) or a high temp (210F or 100C) and stick with either SUS or cSt. The standardized temperature reading allows us to compare apples to apples for judging the thickness of the oil.Single Grade & Multi Grade Viscosity: today since most gas- or diesel-engine manufacturers recommend multi-grades. At operating temperature, a straight weight performs just as well as a multi-viscosity oil, and there is nothing wrong with using a straight weight. It's just a simpler form of oil. Some diesel fleets still use straight weights, as do about half the piston aircraft operators. The difference between multi-grade and straight-weight oil is simply the addition of a viscosity improving (VI) additive. The most common grade of automotive oil in use today is the 5W/30, which is a mineral oil refined with VI additives that leave it reading as an SAE 5W viscosity when cold, yet an SAE 30W when hot (210F). The advantage to the multi-weight is that when starting the engine, the multi-viscosity oil (with its thickness of an SAE 5W when cold), allows the engine to spin over more easily. The most common diesel use oil is 15W/40. It is an