The piston ring is a vital component in an engine, specifically designed to fit into the grooves of the piston. Its primary roles include maintaining a tight seal between the piston and the cylinder wall, preventing combustion gases from escaping into the crankcase, and thus ensuring efficient engine performance. Additionally, it helps regulate oil on the cylinder wall by scraping off excess oil during the piston's downward stroke and distributing a thin layer during the upward stroke, which reduces friction and wear. Made from materials with excellent wear resistance and thermal properties, the piston ring operates under extreme temperatures and pressures, contributing significantly to the engine's overall durability and reliability.