Piston ring
A piston ring for an internal combustion engine is provided, having at least one indentation provided on a ring edge of the piston ring, wherein the at least one indentation in the circumferential direction of the piston ring has a varying depth profile.
1. A piston ring for an internal combustion engine, comprising:
an outer circumferential face;
an inner circumferential face opposite the outer circumferential face;
a first axial face;
a second axial face opposite the first axial face; and
at least two indentations provided on the first axial face for interfacing with a ring groove in a piston on which the piston ring is installed,
wherein the indentations have a varying depth profile that varies along a circumferential direction of the piston ring, and
wherein at least one of the indentations contains a soft material inserted therein and another of the indentations is unfilled.
2. The piston ring according to claim 1 , wherein an axial distance between the first axial face and a shallowest point of the indentation is no greater than 50% of an axial distance between the first axial face and a deepest point of the indentation.
3. The piston ring according to claim 1 , wherein the depth profile of the indentations varies in a sinusoidal manner along a circumferential direction of the piston ring.
4. The piston ring according to claim 1 , wherein the indentations are located at radially varying distances from an edge of the axial face.
5. The piston ring according to claim 4 , wherein the radial distances at which the indentations are located from the edge of the axial face vary sinusoidally in the circumferential direction.
6. The piston ring according to claim 1 , wherein at least two indentations provided on the first axial face comprise a first indentation and a second indentation, wherein the second indentation has a varying depth profile in the circumferential direction of the piston ring, which is phase-shifted relative to the depth profile of the first indentation.
7. The piston ring according to claim 1 , wherein the soft material comprises a material that is selected from a group consisting of copper, molybdenum, titanium, chromium, cobalt, nickel, tin, zinc, tungsten, and alloys thereof.
8. The piston ring according to claim 1 , wherein the soft material comprises a material selected from a group consisting of copper, molybdenum and lubricant varnish.
9. A piston ring for an internal combustion engine, comprising:
an outer circumferential face;
an inner circumferential face opposite the outer circumferential face;
a first axial face;
a second axial face opposite the first axial face; and
at least two indentations provided on the first axial face for interfacing with a ring groove in a piston on which the piston ring is installed, and
wherein at least one of the indentations contains a soft material inserted therein and another of the indentations is unfilled.
10. The piston ring according to claim 9 , wherein the indentations are located at radially varying distances from an edge of the axial face.
11. The piston ring according to claim 9 , wherein a depth profile of at least one of the indentations varies along a circumferential direction of the piston ring.
12. The piston ring according to claim 11 , wherein the depth profile of the at least one indentation that varies along a circumferential direction varies in a sinusoidal manner.