Abstract A piston ring assembly 10 comprises a piston ring 12, a spring 28 for providing an outward force on the ring 12, and a rail 30 for engaging a cylinder wall 20. The piston ring 12 is retained in a piston groove 14 in a piston 44. During upward movement of the piston 44 in a cylinder 22, oil 48 above the ring face 32 is forced between the first front edge 34 and the top edge 16 into the piston groove 14 to an inner portion of the piston groove. During downward movement of the piston 44, the downward force urges cocking of the piston ring 12 about the ring face 32 to tilt the ring face 32 away from the cylinder wall 22, leaving the lower edge 40 of the ring face in scraping abutment with the cylinder wall 22.
A piston ring assembly comprising: a piston ring for positioning in a piston groove in a piston; a spring positioned to radially force said piston ring against a cylinder wall; a rail extending radially outwardly from said piston ring for contacting said cylinder wall; and means for causing rotation of said piston ring to urge said rail into scraping abutment with said cylinder wall during downward movement of said piston.
Claim 2
Dependent Claim
73 words
A piston ring assembly as claimed in claim 1 wherein said piston ring includes an edge for positioning closest to the top of said piston, said top extending downwardly along a top side of said piston groove and toward said cylinder wall at a first angle of between one and ten degrees with respect to a horizontal, and further having a bottom edge extending inwardly along a bottom side of said piston groove.
Claim 3
Dependent Claim
21 words
A piston ring assembly as claimed in claim 2 wherein said first angle is three degrees with respect to a horizontal.
Claim 4
Dependent Claim
18 words
A piston ring assembly as claimed in claim 1 wherein said piston ring is an oil control ring.
Claim 5
Dependent Claim
16 words
A piston ring assembly as claimed in claim 1 wherein said rail forms a ring face.
Claim 6
Dependent Claim
29 words
A piston ring assembly as claimed in claim 5 wherein said spring provides an outward force on said piston ring such that said ring face contacts said cylinder wall.
Claim 7
Dependent Claim
28 words
A piston ring assembly as claimed in claim 1 further comprising at least one oil drainage slot for allowing oil to drain to an interior of said piston.
Claim 8
Dependent Claim
52 words
A piston ring assembly as claimed in claim 5 wherein said rail includes a first front edge extending outwardly and downwardly from said top edge of said piston ring toward an upper corner of said ring face at a second angle of between ten and thirty degrees with respect to a vertical.
Claim 9
Dependent Claim
44 words
A piston ring assembly as claimed in claim 5 wherein said rail includes a second front edge extending downwardly and inwardly from a lower corner of said ring face at a third angle of between three and fifteen degrees with respect to a horizontal.
Claim 10
Dependent Claim
23 words
A piston ring assembly as claimed in claim 9 wherein said lower corner is situated on a horizontal center line through said spring.
Claim 11
Dependent Claim
33 words
A piston ring assembly as claimed in claim 5 wherein said rail includes a third front edge extending vertically downwardly from said second front edge toward said bottom side of said piston groove.