Engine lubricating oil has performance characteristics such as lubricity, low-temperature operability, and viscosity-temperature properties. Lubricating Oil: Engine oil, also known as engine lubricating oil, serves multiple functions including lubrication and friction reduction, auxiliary cooling, sealing and leak prevention, rust and corrosion protection, and shock absorption. It is often referred to as the "blood" of a car. Engine oil consists of two main components: base oil and additives. The base oil is the primary constituent, determining the fundamental properties of the lubricating oil, while additives compensate for and enhance the base oil's shortcomings, providing additional performance benefits. Additives are a crucial part of lubricating oil. Functions of Lubricating Oil: Lubrication: There is rapid relative sliding between components such as pistons and cylinders, and between main shafts and bearings. To prevent excessive wear, an oil film must be established between these sliding surfaces. A sufficiently thick oil film separates the sliding surfaces, thereby reducing wear. Auxiliary Cooling: Due to its relatively low specific heat capacity, engine oil does not inherently cool the engine. However, during engine operation, heat generated by fuel combustion is carried back to the oil pan by the oil and then dissipated into the air, assisting the radiator in cooling the engine. The actual cooling is performed by the water (or antifreeze liquid) outside the engine block. Cleaning: High-quality engine oil can carry away carbon deposits, sludge, and worn metal particles from engine components through circulation, flushing contaminants from the working surfaces of parts. Sealing and Leak Prevention: Engine oil forms a seal between piston rings and pistons, reducing gas leakage and preventing external contaminants from entering. Rust and Corrosion Protection: Lubricating oil adheres to component surfaces, protecting them from contact with water, air, acidic substances, and harmful gases. Shock Absorption: When pressure in the engine cylinder rises sharply, the load on pistons, piston rings, connecting rods, and crankshaft bearings increases suddenly. The lubricating oil helps distribute this load, cushioning the impact. Anti-Wear: The addition of lubricants between friction surfaces reduces the coefficient of friction, thereby decreasing frictional resistance, saving energy, and minimizing wear. Lubricants can also reduce wear caused by abrasive particles, surface fatigue, and adhesive wear.
