Barrier ring and assembly for a cylinder of an opposed-piston engine

A method for making a barrier ring for a cylinder assembly in an opposed-piston engine, the method comprising:

• forming a strip of material with a length about equal to a circumference of a cylinder bore, the strip of material comprising:
• a first set of openings configured for communication between engine hardware and a combustion chamber, the combustion chamber partially defined by a first end surface on a first piston and a second end surface on a second piston when the first and second pistons are near their top dead center positions in the cylinder assembly in the opposed-piston engine;
• and
• a second set of openings configured to allow for pressure equalization across the strip of material when the material separates at least two volumes;
• and
• working the strip of material to have a radius of curvature equal to or slightly greater than a groove in the cylinder assembly,
• wherein the strip of material has a height 2 mm to 20 mm greater than a diameter of a largest opening of the first set of openings.

A method for using a cylinder assembly in an opposed-piston engine, the method comprising:

• situating a first piston and a second piston in the cylinder assembly, the cylinder assembly comprising:
• a cylinder tunnel;
• and
• a cylinder liner, comprising:
• a bore;
• longitudinally intake ports and exhaust ports;
• an intermediate portion located between the intake ports and exhaust ports;
• a groove located in the bore, in the intermediate portion, and positioned at the periphery of a combustion chamber that is partially defined by a first end surface on the first piston and a second end surface on the second piston when the first and second pistons are near their top dead center positions in the cylinder in the opposed-piston engine, the groove comprising opposed side walls and a back wall;
• and
• a barrier ring comprising:
• an open-ended tube with a wall defining a volume inside the tube, the tube comprising:
• wall edges configured to contact side walls in a groove in the cylinder liner;
• a first set of openings in the wall for communication between engine hardware and the combustion chamber;
• and
• a second set of openings in the wall, the second set of openings configured to allow for pressure equalization across the tube, between the volume inside the tube and a volume outside the tube,
• wherein the tube has a height of about 2 mm to about 20 mm more than a diameter of a largest opening of the first set of openings;
• moving the first and second pistons toward each other in the cylinder assembly in a compression stroke, creating the combustion chamber;
• injecting fuel into the combustion chamber;
• and
• preventing heat from combustion of fuel in contact with compressed air in the combustion chamber from moving through the cylinder.

A method for reducing heat loss in an opposed-piston engine, comprising:

• moving a pair of pistons disposed in opposition in a bore of a cylinder liner of the opposed-piston engine;
• in which the motion of a first piston of the pair of opposed pistons is in an axial direction of the cylinder liner between a first bottom dead center (BDC) position and a first top dead center (TDC) position;
• in which the motion of a second piston of the pair of opposed pistons is in an axial direction of the cylinder between a second bottom dead center (BDC) position and a second top dead center (TDC) position;
• combusting a mixture of air and fuel between end surfaces of the first and second pistons when the first and second pistons are near the first and second TDC positions during a compression stroke of the engine;
• preventing loss of heat from the combustion with a barrier ring embedded in the bore between the first and second TDC positions;
• and
• equalizing pressure across the barrier ring.

A method for thermal management in a cylinder liner of an opposed-piston engine, comprising:

• causing combustion of a mixture of fuel and air between the end surfaces of a pair of pistons disposed in the cylinder liner of the opposed-piston engine when the pistons are near respective top dead center locations in an annular liner portion of the cylinder liner between the respective top dead center;
• and,
• impeding flow of heat into the cylinder liner with a barrier ring embedded in the annular liner portion;
• and
• equalizing pressure across the barrier ring.