Abstract: A robust engine assembly having reduced weight and efficient cooling, without an increase in fuel consumption or carbon dioxide emissions, is provided. The engine assembly includes a double-wall cylinder liner clamped between a cylinder head and a crankcase. A manifold is disposed along a portion of the cylinder liner and includes fluid ports aligned with fluid ports of the cylinder liner to convey cooling fluid to a cooling chamber located between the walls of the cylinder liner. For example, the manifold can be a low-loss hydraulic manifold cast integral with the crankcase. Tie rods connect the cylinder head to the crankcase to clamp the cylinder liner in position. Alternatively, the tie rods can be connected to a main bearing cradle located beneath the crankcase. No attachment features extend into the walls of the cylinder liner, which is especially advantageous when the cylinder liner is formed of aluminum.

Abstract: A piston for an internal combustion engine and method of construction thereof is provided. The piston has a piston body including an upper part and a lower part. The upper part has an upper combustion surface configured for direct exposure to combustion gases within a cylinder bore with an undercrown surface beneath the upper combustion surface. The body has a ring belt region configured for receipt of at least one piston ring adjacent the upper combustion surface with an annular cooling gallery configured radially inwardly from the ring belt region. The cooling gallery has a floor, wherein the floor has at least one through opening. A coolant medium is disposed in the cooling gallery, and a sealing member is disposed in the at least one through opening to seal off the coolant medium in the coolant gallery.

Abstract: A piston assembly, piston therefor and methods of construction are provided. The assembly includes a piston head and connecting rod operably coupled thereto via a wrist pin. The piston head has an upper crown with a combustion bowl and an undercrown surface. The lower crown includes axially aligned pin bores receiving the wrist pin. An upper wall of the lower crown has an oil inlet, an oil outlet and a concave, saddle bearing surface that bears against the wrist pin. A toroid-shaped outer cooling gallery is formed between wall portions of the upper and lower crowns, wherein the outer cooling gallery surrounds an inner cooling gallery. The connecting rod is fixed to the wrist pin for conjoint oscillation. The connecting rod has an oil passage in fluid communication with a through hole in the wrist pin to allow oil to flow therethrough into the inner cooling gallery via the oil inlet.

Abstract: The invention provides a low tension piston ring having a finished outer diameter and negligible tangential tension. The method includes the steps of machining a stock bar to an initial outer diameter slightly greater than the finished outer diameter of the piston ring, finishing the initial outer diameter of the stock bar to a rounded profile having a nominal diameter equal to the finished outer diameter, and machining the stock bar to the preferred cross-section. Dykes-type piston rings can have keystone or semi-keystone shaped cross-sections. The method continues by detaching the piston ring from the stock bar using a parting tool in response to completing all tension inducing operations including the steps recited above. The method continues with the steps of lapping the piston ring to a final longitudinal thickness and cutting the piston ring longitudinally to form a final gap.

Abstract: The invention provides a low tension piston ring having a finished outer diameter and negligible tangential tension. The method includes the steps of machining a stock bar to an initial outer diameter slightly greater than the finished outer diameter of the piston ring, finishing the initial outer diameter of the stock bar to a rounded profile having a nominal diameter equal to the finished outer diameter, and machining the stock bar to the preferred cross-section. Dykes-type piston rings can have keystone or semi-keystone shaped cross-sections. The method continues by detaching the piston ring from the stock bar using a parting tool in response to completing all tension inducing operations including the steps recited above. The method continues with the steps of lapping the piston ring to a final longitudinal thickness and cutting the piston ring longitudinally to form a final gap.

Abstract: A piston assembly and method of construction thereof for an internal combustion engine are provided. The assembly includes a piston head having an upper combustion wall with an undercrown surface and a ring belt region. The piston head has a floor with an upper surface and a bottom surface. The floor is spaced beneath the upper combustion wall in radial alignment with the ring belt region. A substantially enclosed, annular cooling gallery is bounded by the undercrown surface and the floor. A pair of pin bores depends directly from the floor of the cooling gallery. The assembly further includes a pin having ends configured for oscillating receipt in the pin bores. A pin bearing surface extends within the pin bores and between the pin bores in the lower surface of the floor. The assembly includes a connecting rod with an end fixed to the pin for conjoint oscillation therewith.

Abstract: A piston assembly and method of construction thereof for an internal combustion engine are provided. The assembly includes a piston head having an upper combustion wall with an undercrown surface and a ring belt region. The piston head has a floor with an upper surface and a bottom surface. The floor is spaced beneath the upper combustion wall in radial alignment with the ring belt region. A substantially enclosed, annular cooling gallery is bounded by the undercrown surface and the floor. A pair of pin bores depends directly from the floor of the cooling gallery. The assembly further includes a pin having ends configured for oscillating receipt in the pin bores. A pin bearing surface extends within the pin bores and between the pin bores in the lower surface of the floor. The assembly includes a connecting rod with an end fixed to the pin for conjoint oscillation therewith.

Abstract: A piston for an internal combustion engine comprises a sealed cooling gallery extending circumferentially around a center axis beneath a bowl rim of an upper crown. A metal-containing composition having a high thermal conductivity fills a portion of the sealed cooling gallery to dissipate heat. The metal-containing composition includes a base material having a melting temperature less than 181° C. and a plurality of metal particles having a thermal conductivity greater than the thermal conductivity of the base material. For example, the metal-containing composition can comprise copper particles dispersed in silicone oil, or copper particles dispersed in a mixture of alkali metals. During high temperature operation, as the piston reciprocates in the cylinder bore, the base material is liquid and flows throughout the cooling gallery to dissipate heat away from the upper and lower crowns.

Abstract: A piston assembly including a piston body pivotally connected to a connecting rod by a wrist pin. The wrist pin includes a sealed cavity therein partially filled with a heat transfer medium. The heat transfer medium may be composed of a fusible alloy. The sealed cavity may be comprised of discrete compartments. The wrist pin may be integrated with the connecting rod and share a conjoined sealed cavity therewith so that heat transfer medium can draw heat effectively away from the piston body.

Abstract: A piston for an internal combustion engine and method of construction thereof are provided. The piston includes a piston body having an upper combustion surface and an annular cooling gallery surrounding an undercrown region. An outer wall depends from the upper combustion surface. An annular ring belt region is formed in the outer wall adjacent the upper combustion surface. The ring belt region has at least one ring groove formed therein. At least one oil passage extends from the at least one ring groove to the cooling gallery. The oil passage has a first portion depending radially inwardly from the ring groove and a second portion ascending radially inwardly from the first portion to the cooling gallery.

Abstract: A piston, piston ring and method of construction thereof is provided. The piston ring is L-shaped, having a first portion configured to extend upwardly from a ring groove of a piston along a top land of the piston and a second portion configured for receipt in the ring groove. The first and second portions of the ring have an enclosed hollow cooling chamber with a cooling medium disposed therein such that the cooling medium is free to flow internally to the piston ring groove and upwardly from the piston ring groove along the top land.

Abstract: A piston for an internal combustion engine has a body including an upper combustion wall having an upper combustion surface; cylindrical outer wall with a ring belt region adjacent the upper combustion surface, and a closed annular cooling gallery located in radial alignment with the ring belt region. A cooling medium is contained in the cooling gallery. The cooling gallery has an inner surface including a radially outermost portion extending along the ring belt region. The outermost portion converges from the upper combustion wall toward a longitudinal central axis. During reciprocating motion of the piston, the cooling medium flows and remains in contact with the cooling gallery walls, thereby maximizing the capacity for heat to be transferred from the upper combustion wall to the contained cooling medium and from the cooling medium to the piston body, ring belt region and ultimately to the engine cooling system.

Abstract: A piston for an internal combustion engine including a piston body (20). The piston body (20) defines a first cooling chamber (46) that is sealed closed and contains a first cooling medium (48) other than air. During operation of the piston, the first cooling medium (48) extracts heat from the surrounding regions of the piston body (20) to cool the piston body (20). The piston body (20) also defines a second cooling chamber (50) adjacent to the first cooling chamber (46). A cooling oil (51) is projected into the second cooling chamber (50) and against the portion of the piston body (20) separating the first and second cooling chambers (46, 50) to extract heat from the first cooling medium (48). The cooling oil (51) is redirected within the second cooling chamber (50) to extract additional heat from the first cooling medium (48) or directly from the piston body (20).

Abstract: The invention provides a low tension piston ring having a finished outer diameter and negligible tangential tension. The method includes the steps of machining a stock bar to an initial outer diameter slightly greater than the finished outer diameter of the piston ring, finishing the initial outer diameter of the stock bar to a rounded profile having a nominal diameter equal to the finished outer diameter, and machining the stock bar to the preferred cross-section. Dykes-type piston rings can have keystone or semi-keystone shaped cross-sections. The method continues by detaching the piston ring from the stock bar using a parting tool in response to completing all tension inducing operations including the steps recited above. The method continues with the steps of lapping the piston ring to a final longitudinal thickness and cutting the piston ring longitudinally to form a final gap.

Abstract: A piston for an internal combustion engine comprises a sealed cooling gallery extending circumferentially around a center axis beneath a bowl rim of an upper crown. A metal-containing composition having a high thermal conductivity fills a portion of the sealed cooling gallery to dissipate heat. The metal-containing composition includes a base material having a melting temperature less than 181° C. and a plurality of metal particles having a thermal conductivity greater than the thermal conductivity of the base material. For example, the metal-containing composition can comprise copper particles dispersed in silicone oil, or copper particles dispersed in a mixture of alkali metals. During high temperature operation, as the piston reciprocates in the cylinder bore, the base material is liquid and flows throughout the cooling gallery to dissipate heat away from the upper and lower crowns.

Abstract: A piston assembly and method of construction thereof for an internal combustion engine are provided. The assembly includes a piston head having an upper combustion wall with an undercrown surface and a ring belt region. The piston head has a floor with an upper surface and a bottom surface. The floor is spaced beneath the upper combustion wall in radial alignment with the ring belt region. A substantially enclosed, annular cooling gallery is bounded by the undercrown surface and the floor. A pair of pin bores depends directly from the floor of the cooling gallery. The assembly further includes a pin having ends configured for oscillating receipt in the pin bores. A pin bearing surface extends within the pin bores and between the pin bores in the lower surface of the floor. The assembly includes a connecting rod with an end fixed to the pin for conjoint oscillation therewith.

Abstract: An internal combustion engine and piston therefor is provided. The piston has a body including an upper combustion wall, a cylindrical outer wall including a ring belt region depending from the upper combustion wall, and a pair of pin bosses having axially aligned pin bores. The piston has a first cooling gallery in radial alignment with the ring belt region with a cooling medium contained therein. An insert member is fixed to the body in axially spaced relation beneath a lower wall of the first cooling gallery. The insert member bounds a second cooling gallery beneath the lower wall of the first cooling gallery. The insert member has an inlet opening configured to allow oil to flow into the second cooling gallery against the lower wall of the first cooling gallery and a separate outlet opening configured to allow the oil to flow outwardly from the second cooling gallery.

Abstract: A piston for an internal combustion engine including a piston body (20). The piston body (20) defines a first cooling chamber (46) that is sealed closed and contains a first cooling medium (48) other than air. During operation of the piston, the first cooling medium (48) extracts heat from the surrounding regions of the piston body (20) to cool the piston body (20). The piston body (20) also defines a second cooling chamber (50) adjacent to the first cooling chamber (46). A cooling oil (51) is projected into the second cooling chamber (50) and against the portion of the piston body (20) separating the first and second cooling chambers (46, 50) to extract heat from the first cooling medium (48). The cooling oil (51) is redirected within the second cooling chamber (50) to extract additional heat from the first cooling medium (48) or directly from the piston body (20).

Abstract: A piston for an internal combustion engine and method of construction thereof are provided. The piston includes a piston body having an upper combustion surface and an annular cooling gallery surrounding an undercrown region. An outer wall depends from the upper combustion surface. An annular ring belt region is formed in the outer wall adjacent the upper combustion surface. The ring belt region has at least one ring groove formed therein. At least one oil passage extends from the at least one ring groove to the cooling gallery. The oil passage has a first portion depending radially inwardly from the ring groove and a second portion ascending radially inwardly from the first portion to the cooling gallery.

Abstract: A piston for an internal combustion engine including a piston body (20). The piston body (20) defines a first cooling chamber (46) that is sealed closed and contains a first cooling medium (48) other than air. During operation of the piston, the first cooling medium (48) extracts heat from the surrounding regions of the piston body (20) to cool the piston body (20). The piston body (20) also defines a second cooling chamber (50) adjacent to the first cooling chamber (46). A cooling oil (51) is projected into the second cooling chamber (50) and against the portion of the piston body (20) separating the first and second cooling chambers (46, 50) to extract heat from the first cooling medium (48). The cooling oil (51) is redirected within the second cooling chamber (50) to extract additional heat from the first cooling medium (48) or directly from the piston body (20).