Opposed-piston cylinder bore constructions with solid lubrication in the top ring reversal zones

1. An opposed piston engine having at least one cylinder with a bore surface for supporting sliding movement of a pair of opposed pistons, in which the bore surface comprises a solid lubricant material disposed in at least one of a first and a second top ring reversal zone and the cylinder includes at least one hole positioned between the top ring reversal zones for supporting a fuel injector nozzle, wherein:

the solid lubricant material is disposed in a first annular portion of the bore positioned on a first side of the hole and in a second annular portion of the bore positioned on a second side of the hole; and,

the first and second annular portions are separated by a third annular portion of the bore that does not comprise the solid lubricant material.

2. A cylinder, comprising:

longitudinally-spaced exhaust and intake ports;

a bore with a surface for supporting sliding movement of a pair of opposed pistons, the bore comprising a solid lubricant material disposed in each of a first and a second top ring reversal zone; and

at least one injector hole positioned between the top ring reversal zones in which the solid lubricant material is disposed in a first annular portion of the bore positioned on a first side of the hole and in a second annular portion of the bore positioned on a second side of the hole, and the first and second annular portions are separated by a third annular portion of the bore that does not comprise the solid lubricant material.

3. A cylinder liner for an opposed-piston engine, comprising:

longitudinally-spaced exhaust and intake ports;

a bore with a surface for supporting sliding movement of a pair of opposed pistons;

a coating layer comprising a solid lubricant material disposed respectively in a first top ring reversal zone of the bore;

a coating layer comprising the solid lubricant material disposed respectively in a second top ring reversal zone of the bore; and

at least one injector hole positioned in a zone of the bore between the top ring reversal zones that does not comprise a coating of the solid lubricant material.

4. The cylinder liner of claim 3 , in which the solid lubricant material is disposed in each of a pair of spaced-apart annular grooves in the surface.

5. The cylinder liner of claim 4 , in which the hole is positioned between the annular grooves.

6. The cylinder liner of claim 3 , in which the solid lubricant material is disposed in a first annular portion of the bore positioned on a first side of the hole and in a second annular portion of the bore positioned on a second side of the hole.

7. The cylinder liner of claim 3 , the cylinder liner comprising a steel material.

8. The cylinder liner of claim 3 , the solid lubricant comprising a nickel-silicon carbide or nickel-phosphorous silicon carbide.

9. The cylinder liner of claim 3 , the solid lubricant comprising an iron-based material.

10. The cylinder liner of claim 3 , the solid lubricant material comprising Ni—Mo—Al—CrO—Ba 2 F—Ca 2 F—Ag or Mo+NiCrBS.

11. The cylinder liner of claim 3 , the solid lubricant comprising a temperature resistant coating having a low dry friction coefficient.

12. A method of coating discrete ring reversal zones in the surface of the bore of an opposed-piston cylinder, comprising:

forming at least one annular groove in the bore surface that is aligned with a ring reversal zone and located in the vicinity of a hole location in a sidewall of the cylinder;

applying a layer of solid lubricant material to the bore surface and extending at least over the annular groove; and,

removing solid lubricant material from the bore surface while leaving the solid lubricant material in the at least one annular groove.

13. The method of claim 12 , wherein forming at least one annular groove includes forming a respective annular groove in each of first and second top ring reversal zones, in the vicinity of a hole positioned between the top ring reversal zones.