Piston ring is a large outward expansion of deformation of the metal elastic ring. Piston rings are used to insert the metal ring inside the piston groove, piston rings are divided into two types: compression piston ring and oil piston ring. Compression piston rings can be used to seal the combustion chamber of the combustible gas mixture; oil piston ring is used to scrap the cylinder of excess oil.
 

1. Thermal conductivity: the heat generated by combustion, through the piston ring to the cylinder wall, it can play the role of cooling the piston. Through the piston ring to the cylinder wall of the heat, generally up to the top of the piston to bear the heat of 30 to 40%.
 

2. Air tightness: The first role of the piston ring is to keep the piston and cylinder wall seal between the control leakage to a minimum. This effect is mainly borne by the air ring, that the engine in any operating conditions, the compressed air and gas leaks are to be controlled to a minimum, in order to improve thermal efficiency; to prevent leakage caused by the cylinder and piston or cylinder and ring To prevent the deterioration of lubricating oil caused by the failure.
 

3. Oil control: the second role of the piston ring is properly scraped attached to the cylinder wall of the oil, and to maintain normal fuel consumption. When the supply of oil is too much will be sucked to the combustion chamber, so that increased fuel consumption, and because of the combustion of carbon deposition, the engine performance is very bad.