PISTON FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide a piston for an internal combustion engine to burn unburnt air-fuel mixture by disposing an auxiliary piston ring. SOLUTION: An auxiliary piston ring 9 having a seal force lower than that of a compression piston ring 10 to prevent penetration of unburnt HC in a clevis part 12 is disposed in position nearmost a piston crown surface 1a of a piston body 1c in such a state that the auxiliary piston ring is inserted in an auxiliary piston ring groove 9a situated on the adjacent side of the compression piston ring 10.