is the metal ring with larger outward expansion deformation, which is
embedded inside the annular groove with the corresponding profile. and
it can be divided into two types, the compression ring and the oil ring.
The compression rings can be used to seal the combustible mixed gas in
the combustion chamber, while the oil ring is used to scrape excess
Piston ring is the core part of the fuel engine, and it completes the sealing of the fuel gas together with the cylinder, piston, and the cylinder wall. Commonly used automobile engine has two kinds, the diesel engines and the petrol engines. Due to their different fuel properties, the use of the piston rings is not the same. Early piston ring is made by casting, but with the advancement of technology, steel piston ring with high power has been made. And with the requirements of better function of engine and environmental protection, a variety advanced surface treatments have been applied to the piston ring, such as thermal spraying, electroplating, chromium plating, gas nitriding, physical deposition, surface coating, and zinc manganese series phosphating treatment, so that the piston ring features have been greatly improved.