Abstract A piston for a reciprocating internal combustion engine includes at least one pressure ring installed in an outer surface of the piston main body adjacent to the piston head. The pressure ring has a double-angle butt end construction comprising an outer circumferential surface slidably contacting the inner circumferential wall of the cylinder, a radially extending first butt flat end face, and a side wall facing the combustion chamber side, namely the high-pressure side, of the engine piston chamber. Only a corner portion formed on the combustion chamber side of the pressure ring by the outer circumferential surface, flat end face and side wall is partially cut away to form a notch which is contiguous to the outer circumferential surface, end face and side wall. The pressure ring further includes a radially extending second butt flat end face opposing the first flat end face, and a rib projecting circumferentially from the second flat end face only at a position corresponding to the notch, the rib having a shape which is complementary to that of the notch for being gas-tightly received by the notch when the pressure ring is installed in an outer circumferential groove of the piston main body.
A piston for an internal combustion engine, comprising a piston main body having a piston head, only one pressure ring installed in a ring groove formed on an outer surface of said piston main body adjacent to the piston head, and only one oil ring installed in a ring groove formed on the outer surface of said piston main body below said pressure ring, said pressure ring having a double-angle butt end construction comprising an outer circumferential surface slidably contacting an inner surface of a cylinder bore, an upper surface facing a combustion chamber side of the engine, a radially extending first butt flat end face, said outer circumferential surface, the upper surface and said first butt flat end face defining a corner portion on a side of said pressure ring, only said corner portion being partially cut away to form a notch which is continguous to said outer circumferential surface, said upper surface and said first butt flat end face, said notch having a surface portion that extends downwardly from said upper surface to said outer circumferential surface, a radially extending second butt flat end face opposing said first butt flat end face, and a rib or projection projecting circumferentially from said second butt flat end face only at a position corresponding to said notch, said rib or projection having a shape which is complementary to that of said notch for gas-tight engagement with said notch.
Claim 2
Dependent Claim
237 words
A piston for an internal combustion engine, comprising a piston main body having a piston head, only one pressure ring installed in a ring groove formed on an outer surface of said piston main body adjacent to the piston head, and only one oil ring installed in a ring groove formed on the outer surface of said piston main body below said pressure ring, said pressure ring having a double-angle butt end construction comprising an outer circumferential surface slidably contacting an inner surface of a cylinder bore, an upper surface facing a combustion chamber side of the engine, a radially extending first butt flat end face, said outer circumferential surface, the upper surface and said first butt flat end face defining a corner portion on a side of said pressure ring, only said corner portion being partially cut away to form a notch which is continguous to said outer circumferential surface, said upper surface and said first butt flat end face, said notch having a surface portion that extends downwardly from said upper surface to said outer circumferential surface, a radially extending second butt flat end face opposing said first butt flat end face, and a rib or projection projecting circumferentially from said second butt flat end face only at a position corresponding to said notch, said rib or projection having a shape which is complementary to that of said notch for gas-tight engagement with said notch.