Piston and piston rings unit for an internal combustion engine

Claim 2

A piston and compression and oil control piston rings unit for internal combustion engines comprising an open skirt hollow type piston, in a cylinder delimiting a combustion chamber with its head and said piston, compression ring and oil control ring grooves in said piston and metal rings in said grooves, said rings having their outwardly radial position limited only by their contact to the cylinder, and said rings and grooves having axially spaced faces, characterized by an efficient sealing means provided between at least one ring face and the contiguous face of its groove by interposing plastic sealing joint between said faces which is subjected to a variable sealing force including a force proportional to fluid pressures including any conbustion pressures acting on said ring.

Claim 3

A piston and piston ring unit for internal combustion engines comprising in an open skirt hollow type cylinder a piston having compression ring and oil control ring grooves and metal rings in grooves characterized by an efficient sealing means provided between at least one face of at least one compression ring and the contiguous face of its groove, the aforesaid contiguous faces of ring and groove being defined at their outside diameter by the cylinder, the sealing means being provided between said contiguous faces by interposing a plastic sealing joint between said faces which is subjected to a variable sealing force increasing with combustion chamber pressure including any combustion pressures acting on said compression ring.

Claim 4

A piston and piston ring unit for internal combustion engines comprising in an open skirt hollow type cylinder a piston having compression ring and oil control ring grooves and metal rings in grooves characterized by an efficient sealing means provided between at least one face of at least one compression ring and the contiguous face of its groove, the aforesaid contiguous faces of ring and groove being defined at their outside diameter by the cylinder, the sealing means being provided between said contiguous faces by interposing a plastic sealing joint between said faces which is subjected to a variable sealing force increasing with combustion chamber pressure including any combustion pressures acting on said compression ring.

Claim 5

A unit according to claim 1 wherein the sealing joint includes radial cuts extending from the inner and outer peripheries of the sealing joint and wherein the cuts extend less than the full radial width of the sealing joint.

Claim 6

A unit according to claim 1 in which the groove face contiguous to said sealing joint includes a circumferential step and wherein said sealing joint is located outwardly of said step.

Claim 7

A unit according to claim 1 in which the sealing means adheres to at least one face of at least one pair of contiguous piston ring and groove faces.

Claim 8

A unit according to claim 1 wherein the ring adjacent said sealing means includes a gap and in which the sealing means includes sealing material adhering to at least one contiguous surface of the ring gap.

Claim 9

A unit according to claim 1 in which the sealing means constitutes a sealing joint having a trapezoidal cross section and wherein said contiguous faces of said sealing joint and groove are inclined to the cylinder wall.

Claim 10

A unit according to claim 1 in which the sealing means includes an hydrocarbon, combustion temperature, friction, crushing, extrusion and ageing resistant material.

Claim 11

A unit according to claim 8 in which the sealing means includes a fluorocarbon polymer such as polytetrafluoroethylene.

Claim 12

A unit according to claim 1 in which the piston outside wall adjacent the groove face contiguous with said sealing joint includes a circumferential supporting flange extending into the clearance between the piston wall and cylinder wall and said contiguous groove face extends across said flange to support said sealing joint.

Claim 13

A unit according to claim 1 wherein said sealing joint circumferentially contacts said cylinder wall.

Claim 14

A unit according to claim 1 wherein said sealing means prevent fluid pressure acting on one face of a ring from access to the opposite face of the same ring.

Claim 15

A unit according to claim 1 wherein said piston and rings unit includes only one compression ring groove And ring in the groove with said sealing means interposed between at least one contiguous pair of faces of said compression ring and said groove.

Claim 16

A unit according to claim 1 wherein the surface of a compression ring, contiguous with the cylinder wall comprises a non-cylindrical surface of revolution symmetric about the piston axis and wherein said surface is specially adapted to recycle upper cylinder oil.

Claim 17

A unit according to claim 1 including piston skirts on said piston and in bearing mechanical contact with said cylinder and wherein the bearing mechanical contact of the piston skirts with the cylinder wall extends above the oil control piston ring.

Claim 18

A unit according to claim 1 wherein said piston wall includes a circumferential scavenging groove adjacent a ring groove and more remote from said combustion chamber than said ring groove.

Claim 19

A unit according to claim 16 wherein said piston wall includes axially directed grooves communicating between said scavenging groove and said oil ring grooves.

Claim 20

A unit according to claim 1 including access means for access of fluid pressure existing between piston and cylinder, between at least a substantial portion of at least one pair of the contiguous faces of at least one piston ring and its groove.

Claim 21

A unit according to claim 18 in which said access means is provided by an opening of said contiguous piston ring and groove faces towards the exterior of the piston.

Claim 22

A unit according to claim 19 wherein said access means is sufficiently limited to prevent deflection of said piston ring beyond the elastic limit of said piston ring.

Claim 23

A unit according to claim 18 in which said access means is provided by a relatively rough surface of at least one of said contiguous approximately parallel piston ring and groove faces.

Claim 24

A unit according to claim 18 wherein at least one face of the groove includes a circumferential recess extending radially outwardly from the groove bottom beyond the inner periphery of the ring.

Claim 25

A unit according to claim 18 in which said sealing contact between contiguous piston ring and groove faces is located on a portion of the piston ring face, adjacent the inner periphery of the ring.

Claim 26

A unit according to claim 23 wherein said sealing contact is located on at least one pair of contiguous piston ring and groove faces on the conbustion chamber side.

Claim 27

A unit according to claim 23 wherein said sealing contact is located on at least one pair of contiguous piston ring and groove faces on the crankcase side.

Claim 28

A unit according to claim 1 wherein a groove bottom joint is interposed between the inner periphery of a compression ring and the bottom of the compression ring groove.

Claim 29

A unit according to claim 26 wherein the bottom joint includes a hydrocarbon, combustion, temperature and age resisting material.

Claim 30

A unit according to claim 27 wherein the bottom joint includes a fluorated elastomer.

Claim 31

A unit according to claim 26 wherein the bottom joint includes a resilient material preloaded upon installation to assure radial pressure against the inner periphery of said compression ring.

Claim 32

A unit according to claim 26 wherein said bottom joint is substantially circular in cross-section.

Claim 33

A unit according to claim 26 wherein said bottom joint comprises four lobes in cross-section.

Claim 34

A unit according to claim 26 wherein said bottom joint is quadrangular in cross-section.

Claim 35

A unit according to claim 32 wherein said bottom joint includes resilient joint material having expansion accommodating bubbles.

Claim 36

A unit according to claim 18 including oil relief passages extending inwardly from the piston wall on the crankcase side of the oil control ring and groove and communicating with the piston interior, wherein the oil control ring is of fixed height, the axial clearance of the oil control ring in the groove allows sufficient fluid flow to limit the maximum fluid pressure in the clearance between the piston wall and cylinder Wall on the combustion chamber side below the contact pressure of the oil control ring against the cylinder wall and the axial clearance is limited to maintain the minimum pressure in the clearance between the piston wall and cylinder wall on the combustion chamber side above the dynamic pressure of fluid in the groove bottom.

Claim 37

A unit according to claim 18 wherein the face of the oil control ring groove on the crankcase side is circumferentially continuous, the oil control ring is of fixed height, the axial clearance of the oil control ring in the groove allows sufficient fluid flow to limit the maximum fluid pressure in the clearance between the piston wall and cylinder wall on either side of the oil control ring below the contact pressure of the oil control ring against the cylinder wall and the axial clearance is limited to maintain the minimum pressure in the clearance between the piston wall and cylinder wall on the combustion chamber side above the dynamic pressure of fluid in the groove bottom.

Claim 38

A unit according to claim 18 wherein a variable height oil control piston ring is characterized by discontinuities on at least one face contiguous to a groove face and adjacent the outer periphery of the oil control ring.

Claim 39

A unit according to claim 18 including a variable height oil control ring and characterized by face discontinuities on at least one groove face adjacent the piston wall and contiguous to a face of the oil control ring.

Claim 40

A unit according to claim 18 including oil relief passages extending inwardly from the piston wall on the crankcase side of the oil control ring and groove and communicating with the piston interior, a variable height oil control ring in the oil control ring groove, whereby the maximum axial clearance of the oil control ring in the groove allows sufficient fluid flow to limit the maximum fluid pressure in the clearance between the piston wall and cylinder wall on the combustion chamber side below the contact pressure of the oil control ring against the cylinder wall, whereby the pressure of the fluid flowing through the axial clearance opposes the expanding force of the variable height oil control ring to determine the axial clearance, and whereby the axial clearance is limited to maintain the minimum pressure in the clearance between the piston wall and cylinder wall on the combustion chamber side above the dynamic pressure of fluid in the groove bottom.

Claim 41

A unit according to claim 18 wherein the face of the oil control ring groove on the crankcase side is circumferentially continuous, the oil control ring is of variable height and whereby the maximum axial clearance of the oil control ring in the groove allows sufficient fluid flow to limit the maximum fluid pressure in the clearance between the piston wall and cylinder wall on either side of the oil control ring below the contact pressure of the oil control ring against the cylinder wall, whereby the pressure of the fluid flowing through the axial clearance opposes the expanding force of the variable height oil control ring to determine the axial clearance, and whereby the axial clearance is limited to maintain the minimum pressure in the clearance between the piston wall and cylinder wall on the combustion chamber side above the dynamic pressure of the fluid in the groove bottom.

Claim 42

A unit according to claim 1 including an interior cavity in said piston, oil orifices which extend inwardly from the oil control ring groove bottom communicate with the piston interior cavity, and wherein the walls of the orifices adjacent the groove face on the combustion chamber side slope toward the combustion chamber from the groove face to the piston interior cavity.

Claim 43

A unit according to claim 1 including an interior cavity in said piston, oil orifices which extend inwardly from the oil control ring groove bottom and communicate with the piston interior cavity and wherein a wall of the interior cavity is directed inwardly and toward the combustion chamber, whereby thE oil orifices issue into the interior cavity closer to the combustion chamber than at least a portion of the interior wall.

Claim 44

A unit according to claim 1 including an interior cavity in said piston, and oil orifices which extend inwardly from the oil control ring groove bottom and communicate with the piston interior cavity.

Claim 45

In a piston and ring assembly for use in an internal combustion engine wherein a piston includes a head and a cylindrical body portion having means for mounting the piston on a connecting rod for reciprocating movement in a cylinder, said body portion of said piston including at least one compression ring groove between said head and said means for connecting a rod, a metallic compression ring received in said groove, said metallic compression ring including radially disposed spaced faces which are in essentially parallel relationship, the improvement comprising at least one auxiliary compression ring associated with said metallic compression ring, said ring groove including at least one radially disposed inclined face, said auxiliary compression ring being a continuous annular wedge ring of a filled fluoro-carbon resin and having an inner peripheral dimension less than the outer peripheral dimension of the ring groove but greater than the peripheral dimension of the base of said ring groove thereby forming a space between the inner peripheral surface of said wedge ring and the base of said groove, the said auxiliary compression ring including a continuous generally annular surface portion in sealing engagement with the opposed surface of the corresponding compression ring for providing a continuous gas seal therewith during reciprocating movement of said piston and an inclined face in sealing engagement with the radially inclined face of said ring groove during reciprocating movement of said piston, and the said auxiliary compression ring including a continuous outer peripheral surface free of radial seams and joints and having a dimension measured axially which is greater than the axial dimension of the inner periphery for reception in conformational gas sealing relation with a cylinder.

Claim 46

In a piston and ring assembly for use in an internal combustion engine wherein a piston includes a head and a cylindrical body portion having means for mounting the piston on a connecting rod for reciprocating movement in a cylinder, said body portion of said piston including at least one compression ring groove between said head and said means for connecting a rod, a metallic compression ring received in said groove, said metallic compression ring including radially disposed spaced faces which are in essentially parallel relationship, the improvement comprising at least one auxiliary compression ring associated with said metallic compression ring, said ring groove including at least one radially disposed inclined face, said auxiliary compression ring being a continuous annular wedge ring of a filled fluoro-carbon resin and having an inner peripheral dimension less than the outer peripheral dimension of the ring groove but greater than the peripheral dimension of the base of said ring groove thereby forming a space between the inner peripheral surface of said wedge ring and the base of said groove, the said auxiliary compression ring including a continuous generally annular surface portion in sealing engagement with the opposed surface of the corresponding compression ring for providing a continuous gas seal therewith during reciprocating movement of said piston and an inclined face in sealing engagement with the radially inclined face of said ring groove during reciprocating movement of said piston, and the said auxiliary compression ring including a continuous outer peripheral surface free of radial seams and joints and having a dimension measured axially which is greater than the axial dimension of the inner periphery for reception in conformational gas sealing relation with a cylinder.

Claim 47

A piston and ring assembly as set forth in claim 43 wherein said piston includes two axially spaced compression ring grooves each of which receives a metallic compression ring, and wherein said metallic compression rings and said auxiliary compression rings are so arranged that said auxiliary compression rings are spaced from each other by said metallic compression rings.

Claim 48

A piston and ring assembly as set forth in claim 43 wherein said fluorocarbon resin is filled polytetrafluoroethylene.

Claim 49

A piston and ring assembly as set forth in claim 43 wherein two auxiliary compression rings and one metallic compression ring are received in each compression ring groove, and each auxiliary compression ring including a face in sealing relation with the opposed faces of said metallic compression ring.

Claim 50

A piston and ring assembly as set forth in claim 43 wherein said auxiliary ring is trapezoidal in cross-section.

Claim 51

A piston and ring assembly as set forth in claim 45 wherein the said metallic compression ring operates as an expander during movement of said piston to urge the corresponding auxiliary ring into sealing engagement with said piston and cylinder, and wherein the said auxiliary piston ring is of filled polytetrafluoroethylene.