Cylinder liner for an opposed-piston engine
View Patent ↗A cylinder liner for an opposed-piston engine, and corresponding methods of extending engine durability and thermal management therewith, has opposite ends and a bore with a longitudinal axis for supporting reciprocating movement of a pair of opposed pistons. An intermediate portion of the liner extends between the opposite ends and includes an annular liner portion within which the pistons reach respective TC locations. A liner ring is seated in a portion of the bore in the annular liner portion, between the TC locations, for scraping carbon from top lands of the pistons and/or increasing the thermal resistance of the annular liner portion.
1. A cylinder liner for an opposed-piston engine, comprising:
a cylindrical wall with an interior surface defining a bore centered on a longitudinal axis of the liner, the bore having a first diameter relative to the longitudinal axis;
intake and exhaust ports formed in the cylindrical wall near respective opposite ends of the liner;
an intermediate portion of the liner extending between the ends and including an annular liner portion containing piston top center (TC) locations;
the annular liner portion defined between first and second top ring reversal planes extending orthogonally to the longitudinal axis, in which the first top ring reversal plane is at a first axial position where the topmost ring of a first piston is located when the piston is at its TC location, and the second top ring reversal plane is at a second axial position where the topmost ring of a second piston is located when the piston is at its TC location;
an annular groove in a portion of the bore in the annular liner portion; and,
a liner ring seated in the annular groove, in which the liner ring has an interior annular surface with a second diameter relative to the longitudinal axis that is less than the first diameter; wherein:
grooves on an outer annular surface of the liner ring that form one or more air resistors with the bore which act between the liner ring and the bore; and,
the liner ring is formed from a material having a first thermal resistance and the cylinder liner is formed from a material having a second thermal resistance less than the first thermal resistance.
2. An opposed-piston engine including one or more cylinders, each cylinder comprising a cylinder tunnel in a cylinder block and a cylinder liner according to claim 1 seated in the cylinder tunnel.