1、 Cooling of chainsaw engine
　　
The combustion temperature of the working mixture in the engine cylinder can reach up to 2000 degrees Celsius. After the work schedule ends, the temperature drops to 900-1000 degrees. Such high temperatures are extremely harmful to the engine. If no special measures are taken to cool down the engine, that is to say, if its body temperature is not reduced, the engine will not be able to continue working; The lubricating oil used to lubricate the cylinder and piston will lose its lubricating ability and may even ignite; At the same time, the piston undergoes strong expansion due to heating, while the lower part of the cylinder has a lower temperature and smaller expansion, making it easy for the piston to get stuck in the lower part of the cylinder; At high temperatures, it is also easy to cause premature ignition of the mixture in the cylinder, which can disrupt the normal operation of the engine.
　　
In order to eliminate cylinder overheating, the chainsaw engine adopts forced air cooling. This method is much simpler than the water cooling system typically used in larger engines. Due to the small volume occupied by the cooling mechanism, it is extremely advantageous for reducing the weight of the chainsaw.
　　
2、 Lubrication of chainsaw engine
　　
If an object moves along the surface of another object under a certain pressure, frictional force occurs that impedes its movement. Due to overcoming this friction, the machine consumes a certain amount of work, which is an irreversible loss. Eliminating this loss is impossible, and only by adding lubricating materials between the friction surfaces can this loss be reduced. The magnitude of friction force is related to the material properties of the friction surface, machining accuracy, and the pressure exerted on the friction parts.
　　
Under the same conditions, rolling friction is much smaller than sliding friction. So, ball bearings and roller bearings can be widely used in mechanical manufacturing. In order to reduce friction losses, the friction surface often needs to be ground, polished, and lubricated. Lubrication is the process of adding a layer of lubricating material between the friction surfaces of mechanical components to prevent direct friction between them. This can reduce frictional resistance and prevent accelerated wear of the components.
　　
In order to prevent the lubricating material from flowing out of the friction surface of the parts, the lubricating material should have a suitable viscosity. If the viscosity of the lubricating material is too high, it will increase its internal friction. Raising the temperature will reduce the viscosity of the lubricating material. Therefore, lubrication must be done at an appropriate temperature to effectively lubricate.
　　
The two-stroke engine of the chainsaw mainly relies on lubricating oil mixed in gasoline for lubrication. Lubricating oil is carried by highly volatile gasoline molecules and vaporized in the carburetor before being sent into the cylinder and crankcase. The mass of lubricating oil molecules is heavier than that of gasoline molecules, and their volatility is lower. Therefore, when they pass through various components, they stop and provide sufficient lubrication to the friction surfaces. These friction surfaces include: cylinder inner wall and piston and piston ring, piston pin and connecting rod small head bearing; Connecting rod big end bearing and crank pin; Crankshaft bearings, etc.