Abstract: A steel piston for heavy-duty diesel engines designed with features that increase adiabaticity, reduce weight, and improve passive cooling without loss of power density is provided. The piston includes a pair of skirt walls extending longitudinally from a crown to a lower end. The skirt walls include a plurality of heat sink wells extending axially from the crown to a lower end of the skirt wall. Each heat sink well is at least partially filled with a cooling medium and is sealed. The piston also includes a plurality of ribs each radially aligned with one of the heat sink wells and extending inwardly and upwardly from a first rib end at an inner surface of the skirt wall to a second rib end at the inner surface of the crown.

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: 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 having an improved oil control ring is provided. The piston has a piston body providing an upper combustion surface and an annular outer wall depending therefrom. A ring belt region including a plurality of ring grooves is formed in the annular outer wall. A first compression ring is disposed in one of the ring grooves and the oil control ring is disposed in another of the ring grooves. The oil control ring has generally parallel, planar upper and lower surfaces, with the upper and lower surfaces having an annular groove recessed therein. A through opening can be formed to bring the annular grooves into fluid communication with one another. The annular grooves collect oil scraped from a cylinder wall and return oil to the crank sump and reduce the contact area between the oil control ring and the wall of the ring groove.

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 steel piston with anti-coking design features is provided. The piston includes an upper crown portion and a lower crown portion forming an outer cooling gallery therebetween. The outer cooling gallery is substantially closed except for an oil inlet, oil outlet, and optional oil passage(s) to a central cooling gallery. According to one embodiment, at least one anti-coking insert is disposed in the outer cooling gallery and sized to prevent escaping through the oil inlet or the oil outlet. For example, the insert(s) can comprise a helical coil, a plurality of steel balls, coil springs, or chips formed of polymer with abrasive filler. Alternatively, an outer gallery floor to the outer cooling gallery includes a plurality of anti-coking openings disposed sequentially in decreasing spaced relation from one another, or anti-coking openings with varying lengths.

Abstract: A steel piston for coupling to a connecting rod and wrist pin is provided. The piston includes a body with an upper crown presenting a combustion surface for exposure to a combustion chamber. The upper crown presents an undercrown surface which is openly exposed as viewed from an underside of the piston and not bounded by a cooling gallery. The body includes a ring belt and pin bosses depending from the ring belt and presenting a pin bore for receiving the wrist pin. The body also includes ribs disposed along the undercrown surface. The body includes a ratio of compression height to outer diameter (CH/D) ranging from 34.8% to 42.0%. The piston also includes a low heat transfer coating on the combustion surface, and the low heat transfer coating has a thermal conductivity of about 0.20 to 0.80 W/m·K.

Abstract: A piston capable of reducing undesirable “knock,” reducing hydrocarbon emissions, and providing more complete combustion, is provided. The piston includes a multilayer coating having a thickness of 500 microns or less disposed on an upper combustion surface. The coating includes a bond layer including nickel disposed on the upper combustion surface. A thermal barrier layer including a ceramic composition is disposed on the bond layer. A sealant layer formed of metal is disposed on the thermal barrier layer. A catalytic layer including at least one of platinum, ruthenium, rhodium, palladium, osmium, and iridium is disposed on the sealant layer. The catalytic layer can be disposed on select regions or the entire upper combustion surface to promote combustion through a catalyzed reaction.

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 ring includes a body portion presenting a running surface, and a spring member disposed between the body portion and a ring groove of a piston. A running surface of the piston ring presents an upper rail, a lower rail, and a fulcrum disposed between the rails and each extending radially outwardly. An outermost tip of the fulcrum is disposed radially outwardly relative to an outermost surface of the rails, and the running surface presents a convex shape along the fulcrum. The fulcrum contacts an oil film applied to a cylinder wall as the piston reciprocates along the cylinder wall. The spring member presses the body portion of the piston ring toward the cylinder wall and causes the body portion to pivot about the fulcrum to provide for improved control of the oil film, less friction, and reduced oil consumption.

Abstract: A piston for an internal combustion engine and method of construction thereof are provided. The piston includes an upper crown formed at least in part by a first metal material and a thermally insulating insert. The upper crown has an upper wall forming an upper combustion surface and a ring belt region. The upper combustion surface is formed at least in part by the thermally insulating insert. The thermally insulating insert has a base surface with pores extending upwardly therein. The first metal material is infused and solidified in the pores, with the first metal material forming a first bonding surface. The piston further includes a body portion formed from a second metal material. The body portion provides pin bosses having coaxially aligned pin bores and diametrically opposite skirt portions. The body portion has a second bonding surface bonded to the first bonding surface of the first metal material.

Abstract: A piston capable of reducing undesirable “knock,” reducing hydrocarbon emissions, and providing more complete combustion, is provided. The piston includes a multilayer coating having a thickness of 500 microns or less disposed on an upper combustion surface. The coating includes a bond layer including nickel disposed on the upper combustion surface. A thermal barrier layer including a ceramic composition is disposed on the bond layer. A sealant layer formed of metal is disposed on the thermal barrier layer. A catalytic layer including at least one of platinum, ruthenium, rhodium, palladium, osmium, and iridium is disposed on the sealant layer. The catalytic layer can be disposed on select regions or the entire upper combustion surface to promote combustion through a catalyzed reaction.

Abstract: A heavy duty piston for an internal combustion engine comprises a thermally conductive composition filling 10 to 90 vol. % of a sealed cooling gallery. The thermally conductive composition includes bismuth and/or tin. For example, the thermally conductive composition can be a single-phase binary mixture of bismuth and tin. The thermally conductive composition has improved thermal properties, for example a melting point around 139° C., a thermal conductivity around 22 W/m·K, and a thermal diffusivity around 1.43 E-5 m2/s. The thermally conductive composition is not reactive and does not include toxic or cost-prohibitive metals. During high temperature operation, as the piston reciprocates in the cylinder bore, the thermally conductive composition flows throughout the cooling gallery to dissipate heat away from the upper crown and thus improve efficiency of the engine.

Abstract: A component for exposure to a combustion chamber of a diesel engine and/or exhaust gas, such as a cylinder liner or valve face, is provided. The component includes a thermal barrier coating applied to a body portion formed of steel. A layer of a metal bond material is first applied, followed by a gradient structure including a mixture of the metal bond material and a ceramic material, followed by a layer of the ceramic material. The ceramic material includes at least one of ceria, ceria stabilized zirconia, yttria stabilized zirconia, calcia stabilized zirconia, magnesia stabilized zirconia, and zirconia stabilized by another oxide. The thermal barrier coating is applied by thermal spray or HVOF. The thermal barrier coating has a porosity of 2% by vol. to 25% vol., a thickness of less than 1 mm, and a thermal conductivity of less than 1.00 W/m·K.

Abstract: A piston for a diesel engine is provided. The piston includes a thermal barrier coating applied to a crown formed of steel. A layer of a metal bond material is first applied to a combustion surface of the crown, followed by a gradient structure including a mixture of the metal bond material and a ceramic material, followed by a layer of the ceramic material. The ceramic material includes at least one of ceria, ceria stabilized zirconia, yttria stabilized zirconia, calcia stabilized zirconia, magnesia stabilized zirconia, and zirconia stabilized by another oxide. The thermal barrier coating is applied by a thermal spray process or HVOF. The thermal barrier coating has a porosity of 2% by vol. to 25% vol., based on the total volume of the thermal barrier coating, a thickness of less than 1 mm, and a thermal conductivity of less than 1.00 W/m·K.

Abstract: A power cylinder assembly for an internal combustion engine includes a cylinder wall that surrounds a cylinder bore that extends along an axis. A piston assembly is positioned in the cylinder bore, and the piston assembly has a combustion surface that divides the cylinder bore into a combustion chamber on one axial side of the combustion surface and a crank case on an opposite axial side of the combustion surface. The combustion surface is partially defined by a first upper surface of a first piece and partially defined by a second upper surface of a second piece. The second piece is moveable relative to the piston body during operation of the power cylinder assembly to change a compression ratio of the power cylinder assembly.

Abstract: A piston for an internal combustion engine having an improved oil control ring is provided. The piston has a piston body providing an upper combustion surface and an annular outer wall depending therefrom. A ring belt region including a plurality of ring grooves is formed in the annular outer wall. A first compression ring is disposed in one of the ring grooves and the oil control ring is disposed in another of the ring grooves. The oil control ring has generally parallel, planar upper and lower surfaces, with the upper and lower surfaces having an annular groove recessed therein. A through opening can be formed to bring the annular grooves into fluid communication with one another. The annular grooves collect oil scraped from a cylinder wall and return oil to the crank sump and reduce the contact area between the oil control ring and the wall of the ring groove.

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 steel piston for heavy-duty diesel engines designed with features that increase adiabaticity, reduce weight, and improve passive cooling without loss of power density is provided. The piston includes a pair of skirt walls extending longitudinally from a crown to a lower end. The skirt walls include a plurality of heat sink wells extending axially from the crown to a lower end of the skirt wall. Each heat sink well is at least partially filled with a cooling medium and is sealed. The piston also includes a plurality of ribs each radially aligned with one of the heat sink wells and extending inwardly and upwardly from a first rib end at an inner surface of the skirt wall to a second rib end at the inner surface of the crown.

Abstract: A piston for an internal combustion engine and method of construction is provided. The piston has a robust, lightweight monolithic piston body including an upper wall forming a combustion bowl depending radially inwardly from an annular, uppermost combustion surface. An undercrown surface is formed on an underside of the combustion bowl, with at least a portion of the undercrown surface being bounded by diametrically opposite skirt portions, pin bosses and strut portions connecting the skirt portions to the pin bosses. The bounded undercrown surface has an openly exposed surface area, as viewed looking along a central longitudinal axis along which the piston reciprocates, providing an expansive area against which oil being splashed or sprayed can come into direct contact with to enhance cooling the piston while in use. Through channels extending over upper regions of the pin bosses can be provided to further reduce weight and facilitate cooling.