Method and apparatus for rotating sleeve engine hydrodynamic seal

A method for sealing for a poppet valve rotating sleeve internal combustion engine, the engine comprising a rotating liner which may be rotated during the operation of the engine, and a cylinder head, the method comprising

• providing a rotating liner engine with an improved sealing system comprising
• a hydrodynamic face seal assembly comprising
• a primary sealing ring 1 comprising a mating face,
• a pre-load assembly which provides a uniform loading to the primary sealing ring, and
• a secondary seal between the primary sealing ring and the cylinder head, wherein the secondary seal is the only seal positioned between the primary sealing ring and the cylinder head, and
• an annular face of the rotating liner positioned in proximity to the mating face of the primary sealing ring;
• providing hydrodynamic face seal features on either the mating face of the primary sealing ring or on the annular face of the rotating liner, the hydrodynamic face seal features comprising
• an inner sealing zone, and
• an outer loading zone, such that the loading zone comprises
• an outer loading zone, such that the loading zone comprises a plurality of hydrodynamic tilted pads or step pads, and
• dam features, such that the tilted pads or step pads create converging surfaces, and tilted pad or step pad performance is enhanced by the dam features when cylinder pressure rate of change is high;
• and
• generating, with the pre-load assembly, a pre-load on the primary sealing ring;
• and
• providing lubrication to the annular face of the rotating liner via at least one hole extending through the rotating liner from a region of high pressure to the annular face, and such that a lubricant layer can be maintained between the mating face and the rotating liner annular face, such that the dam features reduce lubricant side leakage and therefore enhance the load support of the step pad features, and provide added support under squeeze film lubrication.

A poppet valve rotating sleeve internal combustion engine, the engine comprising:

• a rotating liner that is rotatable during the operation of the engine,
• a piston positioned for translational motion within the rotating liner,
• a cylinder head, and
• a sealing system for sealing the cylinder head and the rotating liner comprising a hydrodynamic face seal assembly comprising
• a primary sealing ring comprising a mating face, a pre-load assembly which provides a uniform loading to the primary sealing ring, and
• a secondary seal between the primary sealing ring and the cylinder head, w herein the secondary seal is the only seal positioned between the primary sealing ring and the cylinder head;
• an annular face of the rotating liner positioned in proximity to the mating face of the primary sealing ring;
• hydrodynamic face seal features provided on the mating face of the primary sealing ring or provided on the annular face of the rotating liner, the hydrodynamic face seal features comprising
• an inner sealing zone, and
• an outer loading zone, such that the loading zone comprises
• a plurality of hydrodynamic tilted pads or step pads, and dam features, such that the tilted pads or step pads create converging surfaces, and tilted pad or step pad performance is enhanced by the dam features when cylinder pressure rate of change is high, wherein the dam features comprise an outside dam at the outside of the step pad;
• and
• at least one lubricant supply for maintaining a lubricant layer between the face and the rotating liner.