Why is engine oil referred to as the blood of an engine?

[OCora]

Engine oil is referred to as the blood of an engine because it performs functions such as lubrication, cleaning, cooling, sealing, friction reduction, rust prevention, and corrosion protection for the engine. The specific roles of engine oil include: 1. Shock absorption and buffering: When the pressure in the engine cylinder rises sharply, suddenly increasing the load on the piston, piston skirt, connecting rod, and crankshaft bearings, this load is transmitted and lubricated through the bearings, cushioning the impact load. 2. Rust and corrosion prevention: The lubricating oil adheres to the surface of parts, preventing contact with water, air, acidic substances, and harmful gases. 3. Lubrication and friction reduction: There is rapid relative sliding between the piston and cylinder, as well as between the main shaft and bearing shells. To prevent excessive wear, an oil film of sufficient thickness is established between the sliding surfaces, separating the parts and reducing wear. 4. Cooling: Engine oil carries heat back to the oil tank and dissipates it into the air, assisting the radiator in cooling the engine.