Abstract: A lubricating mechanism of a pin connection pair of an internal combustion engine having a piston, a pin, and a connecting rod. The pin may be mounted in two pin seat portions of the piston such that the pin and one of the two pin seat portions form the pin connection pair. The lubricating mechanism may include a lubricating passage through which a lubricating medium is flowable and an oil outlet orifice communicating with the lubricating passage. The lubricating passage and the oil outlet orifice may be disposed in a piston top portion of the piston. An opening of the oil outlet orifice may face in an axial direction and may be disposed directly below a corresponding portion of the lubricating passage such that the lubricating medium is flowable via the opening directly to a gap defined between the connecting rod and a pin seat portion.

Abstract: A piston for an internal combustion engine and a method for producing a piston are disclosed. The piston includes an upper piston part and a lower piston part that together delimit a circumferential cooling channel for receiving a cooling medium both radially inside and radially outside. The upper piston part and the lower piston part are connected to one another via a radially outer weld connection and a radially inner weld connection. The radially outer weld connection includes a radially outer weld bead that projects radially inwards into the cooling channel for forming a deflection element for the cooling medium received in the cooling channel.

Abstract: A piston for an internal combustion engine is provided. The piston includes an open inner cooling area in which the undercrown surface is exposed, and an annular outer cooling gallery. The piston also includes an oil outlet scoop for local cooling of the undercrown surface of the piston. The outer cooling gallery includes an oil outlet opening, and the oil outlet scoop is beneath and vertically aligned with the oil outlet opening. The oil outlet scoop includes a concave surface facing the oil outlet opening. During operation, oil exits the oil outlet opening, and the oil outlet scoop catches the exiting oil and directs the oil to the inner cooling area and the exposed undercrown surface.

Abstract: An oil supply element for supplying oil into a cooling channel of a piston in an internal combustion engine, may include a channel having a lateral opening with an oil discharge element and may be configured to direct a partial oil flow via the oil discharge element and the lateral opening to at least one of an underside of a piston crown, a hub, and a piston interior.

Abstract: A piston capable of operating at a high temperature and consequently contributing to a high in-cylinder temperature, as well as reducing engine oil temperature, when used in an internal combustion engine, is provided. The piston includes an upper portion and a lower portion welded together to present a cooling gallery therebetween. The cooling gallery extends circumferentially around a center axis of the piston and is spaced the center axis. A partition is located in the cooing gallery and extends from one inner surface to another inner surface of the cooling gallery. The partition extends circumferentially around the center axis, and divides the cooling gallery into at least a first gallery portion and a second gallery portion. The partition can be formed as one piece with the upper portion or the lower portion. Alternatively, the partition can be formed as a separate piece from the upper portion and the lower portion.

Abstract: A cooling cavity is provided inside a piston of an internal combustion engine. Inlet/outlet holes of the cooling cavity are provided in a bottom surface of the piston. A first oil jet that sprays oil toward the inlet/outlet hole, a second oil jet that sprays oil toward a part different from the inlet/outlet hole are included. The first oil jet is caused to spray oil in preference to the second oil jet.

Abstract: A piston and method of construction thereof are provided. The piston includes an upper crown having an upper combustion surface and a lower crown depending therefrom. The lower crown includes a pair of laterally spaced, axially aligned pin bores configured for receipt of a wrist pin. A substantially closed, annular outer cooling gallery is formed between the upper and lower crowns, wherein a bottom surface of the cooling gallery is formed by a floor of the lower crown. An oil inlet and an oil outlet extend through the floor. The oil inlet includes an upstanding toroid-shaped protrusion that extends upwardly from the floor into the cooling gallery, wherein the protrusion is formed as a monolithic extrusion from the material of the lower crown floor.

Abstract: A piston includes a combustion chamber that is formed at a piston top surface and an oil gallery that is formed so as to surround the combustion chamber. Wall thickness from a sliding side surface of the piston to the oil gallery is set greater on a piston skirt side than on a piston top surface side.

Abstract: A piston may include a piston crown including radially inner and outer crown mating surfaces, the crown defining at least in part a cooling gallery extending about a periphery of the crown. The piston may include a piston skirt including a pair of oppositely disposed pin bosses, the pin bosses each defining a piston pin bore. The piston skirt may have a radially inner skirt mating surface cooperating along a radially inner interface region with the radially inner crown mating surface, and a radially outer skirt mating surface cooperating along a radially outer interface region with the radially outer crown mating surface such that the cooling gallery is substantially enclosed. The piston may include at least one cooling fin extending from an interior surface of the cooling gallery.

Abstract: A reversible hot air engine system having operating modes for both engine and heat pump operation features a piston located in a piston cylinder that is located on a frame. The system features a displacer located in a displacer chamber that is horizontally located at a frame bottom. A rod first end is pivotally located on a piston second end. A rod second end is pivotally located on a displacer middle via a hinge. A rod housing is fluidly connected to the displacer chamber and the piston cylinder. The system features a flywheel located at a frame top. The system features, a crank having a wheel eccentrically and pivotally connected to a crank rod first end. A crank rod second end is pivotally located to a piston first end. The system features a heat source applied to a chamber end.

Abstract: A liquid cooled piston of an internal combustion engine includes a piston lower part and piston upper part which has a combustion chamber recess. These piston components are supported via joining lands which are spaced apart radially and together form a dividing plane, and are joined together with a material-to-material fit. In order to receive piston rings, the piston upper part has a ring area and includes an annular cooling channel which extends into the piston lower part and is connected to an inner cooling space via connecting channels. The cooling channel is adjoined by recesses which are oriented in the direction of a piston head, are configured as a blind hole and widen conically starting from the cooling channel as far as a recess bottom. The recess bottom can be of a pronounced undulating enlarged surface or a finely undulating configuration.

Abstract: An exemplary piston assembly and method of making the same are disclosed. An exemplary piston assembly may include a piston crown and skirt. The crown may include radially inner and outer crown mating surfaces, and the crown may define at least in part a cooling gallery extending about a periphery of the crown. The skirt may further include an inner collar wall disposed radially inwardly of a radially inner interface region and extending upwards to a free end. The collar wall may generally enclose the radially inner interface region from the central region.

Abstract: A method for the production of a piston made of steel, for an internal combustion engine, in which the upper piston part is produced using the forging method, and the lower piston part is produced using the forging or casting method, and they are subsequently welded to one another. To simplify the production method and make it cheaper, the upper piston part is forged using the method of hot forming and of cold calibration, to finish it to such an extent that further processing of the combustion bowl and of the upper cooling channel regions can be eliminated.

Abstract: The present invention relates to a piston (10) for an internal combustion engine, comprising a piston head (11) and a piston skirt (16), wherein the piston head (11) has a circumferential ring part (15) and a circumferential cooling channel (23) in the region of the ring part (15), wherein the piston skirt (16) has piston bosses (17), which are provided with boss bores (18) and which are arranged on the underside (11a) of the piston head (11) by means of boss connections (19), wherein the piston bosses (17) are connected to each other by means of running surfaces (21, 22). According to the invention, at least one axial bore (24a, 24b, 24c, 24d), which is closed to the outside and which is arranged between a running surface (21, 22) and a boss bore (18), is provided inside a piston boss (17), the at least one bore (24a, 24b, 24c, 24d) opens into the cooling channel (23), and the cooling channel (23) and the at least one bore (24a, 24b, 24c, 24d) contain a filling (27) of sodium and/or potassium.

Abstract: A piston assembly and method of making the same are disclosed. An exemplary piston assembly may include a multi-piece skirt secured to a piston crown having a ring belt portion defining a cooling gallery. The crown may include one or more a struts extending away from the ring belt portion to define a wrist pin bore(s). The piston skirt assembly may include two separate portions that each have at least one skirt support securing the respective skirt portion to the strut. A cover plate may be provided that is secured between a radially inner surface of the ring belt portion of the crown and a radially outer surface of the strut, such that the cover plate defines in part the cooling gallery.

Abstract: A method of making a piston with enhanced thermal conductivity. In one embodiment, the method includes providing a piston with an oil gallery, the piston made of a material; and depositing a layer of a material in the oil gallery, the material having a higher thermal conductivity than a thermal conductivity of the piston material. Another aspect of the invention is a piston having enhanced thermal conductivity.

Abstract: A method of making an aluminum piston is described. In one embodiment, the method includes placing a oil gallery core in a mold, the oil gallery core comprising a metal tube connected to a hollow inlet tube and a hollow outlet tube; introducing liquid aluminum into the mold around the oil gallery core; and allowing the liquid aluminum to solidify, the oil gallery core forming a channel in the piston. Aluminum pistons are also described.

Abstract: A piston has a piston head, a piston pin support projecting from the piston head, and a mantle wall connected to the piston head. The mantle wall is formed with two tubular pieces that are disposed concentrically relative to one another and which are connected at a periphery of the piston head. A hollow space is formed between the tubular pieces.

Abstract: A pre-finished piston part is disclosed that may be used to form a piston assembly. A pre-finished piston may include a lower part defining a piston axis, the lower part having a skirt and forming a lower surface of a cooling gallery. The lower part may include a radially inner bowl surface defining a lower part radially inner mating surface. The pre-finished piston assembly may further include an upper part having a radially outer bowl surface meeting the radially inner bowl surface at a radially inner joint. The upper part may include a radially inner wall defining a radially inner upper part mating surface. The radially inner wall may define a radially inwardly facing surface that defines a non-parallel angle with the radially inner bowl surface where the radially inner bowl surface meets the radially innermost edge of the radially inner mating surface.

Abstract: A piston for an internal combustion engine has a piston head, a piston skirt, and a circumferential recess configured between the piston head and the piston skirt. The piston has a piston base body and a piston ring element. The piston base body has a crown region of a combustion bowl and the piston skirt. The piston ring element has a piston crown, a wall region of the combustion bowl, a circumferential top land, and a circumferential ring belt with ring grooves. The piston ring element has a circumferential cooling channel between the wall region of the combustion bowl and the ring belt, closed with a closure element. The piston base body and the piston ring element have a circumferential joining seam in the region of the combustion bowl, by way of which seam they are non-releasably connected with one another.

Abstract: A retort sterilization device includes a water steam generation device for generating water steam and a heating pot, connected to the water steam generation device, for accommodating retort food. The water steam generation device includes a heat exchanger for performing heat exchange between liquid flowing in a liquid path and heating vapor flowing in the vapor path. A top end of the liquid path of the heat exchanger is connected via a water steam supply pipe to a water steam ejection section located in an internal area of the heating pot. The heat exchanger is connected to a liquid container. A bottom end of the liquid path of the heat exchanger is connected to the liquid container via a communicating tube. The liquid container is coupled to the heating pot.

Abstract: A piston and method of construction is provided. The piston includes a top part fixed to a bottom part. The top part has an uppermost surface with annular inner and outer upper joining surfaces depending therefrom. The bottom part has a pair of pin bosses with pin bores aligned with one another along a pin bore axis; a pair of upwardly extending annular inner and outer lower joining surfaces and a combustion bowl wall. Inner and outer weld joints fix the inner and outer upper and lower joining surfaces to one another. An annular cooling gallery is formed laterally between the upper and lower joining surfaces. The inner weld joint joining the top part to the bottom part is located within the combustion bowl wall and configured to minimized the compression height of the piston.

Abstract: A piston assembly and a method of making the same. Exemplary piston assemblies may include a piston crown having a ring belt portion defining a cooling gallery, and a strut extending away from the ring belt portion to define a wrist pin bore. The piston may further include a piston skirt assembly secured to the strut. The piston skirt assembly may include two separate portions that each have a closure plate formed integrally with the portion, with the closure plate generally enclosing the cooling gallery. Exemplary methods of assembling a piston may include providing a piston crown having a ring belt portion defining a cooling gallery and a strut extending away from the ring belt portion to define a wrist pin bore. The methods may further include forming a piston skirt assembly having two portions having a closure plate integrally formed therewith, and securing the skirt to the crown.

Abstract: The present invention relates to a piston cooling device for cooling a piston. The piston cooling device according to an exemplary embodiment of the present invention includes: a cooling channel that is formed in a piston such that cooling fluid flows, and communicates with an intake port through which cooling fluid flows inside from the outside at a point and with an exhaust port through which the cooling fluid is discharged outside at another point; and a flow guide part that is formed in the cooling channel and guides the cooling fluid, which flows in the cooling channel through the intake port when the piston moves up or down, to flow to the exhaust port through the cooling channel.

Abstract: The present invention relates to a piston (10, 110, 210) for an internal combustion engine, having a first piston component (11) and a second piston component (12), which jointly form a circumferential cooling channel (23) that is open toward the second piston component (12), whereby the first piston component (11) forms at least a part of a piston crown (13) as well as an outer circumferential wall (34) of the cooling channel, characterized in that the outer circumferential wall (34) of the cooling channel (23) has a circumferential projection (32) below the piston crown (13), which projection is provided with a circumferential guide surface (33) for coolant, directed radially inward.

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 and method is provided that inhibits the potential catastrophic damage to an internal combustion engine, thereby reducing the risk of costly damage to the engine. The piston includes a piston body having an upper combustion surface separated from an internal cooling chamber by a wall. The a pocket extends into the upper combustion surface to a closed bottom surface of the wall. A tubular member is disposed in the pocket. The tubular member extends upwardly from the upper surface. Should a valve head drop from its normal operating position, the valve head impacts the tubular member and forms a blow-by through passage extending from the upper combustion surface into the cooling chamber.

Abstract: A piston has a piston body extending along a central axis. The piston body has an upper crown portion and a lower crown portion. The upper crown portion has an upper combustion wall and an at least one annular upper rib depending from the upper combustion wall to a free end. The lower crown portion has at least one annular lower rib extending to a free end that is fixed to the at least one upper rib and an inner gallery floor extending radially inwardly relative to the at least one lower rib. The upper crown portion has an upper post depending from the upper combustion wall along the central axis to a free end. The lower crown portion has a lower post extending upwardly from the inner gallery floor along the central axis to a free end. Together, the upper post and the lower post form a labyrinth passage.

Abstract: A single-piece piston body for an internal combustion engine includes a crown portion having a circumferential ring belt including an oil ring groove configured to accommodate an oil control ring and a skirt portion having a first skirt wall disposed on the major thrust side and a second skirt wall disposed on the minor thrust side of the piston, and two box walls that connect the skirt walls and which are set back with respect to the ring belt. A first plurality and a second plurality of axial drain passages extend from the oil ring groove to the bottom of the crown portion, the first and second pluralities of axial drain passages being substantially centered at opposite box sides of the piston and each plurality of axial drain passages spanning an arcuate portion of about 45-75 degrees.

Abstract: Disclosed is a piston cooling device wherein the cooling efficiency of a piston is improved by oil injected from an oil jet and supplied to a cooling passage provided in the piston, and the amount of cooling oil is reduced when an internal combustion engine is operated at maximum output. The piston cooling device is provided with a piston for an internal combustion engine, in which a circumferential passage and a cooling passage having an inlet passage and an outlet passage are provided, and an oil jet for injecting oil from an injection port to the inlet passage. The oil jet injects oil at every stroke of the piston so that a two-phase plug flow composed of gas and oil is formed in the cooling passage at least when an internal combustion engine is operated at maximum output.

Abstract: A method for producing a one-piece, lightweight piston consisting of steel and having a small compression depth (S) forms piston with at least one cavity in a shaft aperture region. A piston blank is produced in a first step using a forging or casting method. To form a cooling channel between an annular region and a combustion chamber recess an annular section is formed in one piece onto the wall of a cooling channel in the vicinity of the piston base. The joint produced between the annular section and an outer wall of the cooling channel is sealed by welding.

Abstract: A piston cooling channel cover is disclosed. The cover includes an annular lower cover, wherein the annular lower cover is at least one of a one part cover and a multi-part cover; at least one of a standpipe-like inflow and a standpipe-like outflow, wherein at least one of the inflow and the outflow are unitarily formed with the lower annular cover.

Abstract: A piston may include a piston upper part and a piston lower part. The piston upper part may be welded via a contact surface with the piston lower part forming a cooling duct therebetween. The cooling duct may define an inlet opening and an outlet opening extending from the piston lower part in the cooling duct. A welding bead may be formed within the cooling duct at each of the inlet opening and the outlet opening.

Abstract: The present invention relates to a multi-part piston (10) for an internal combustion engine, having an upper piston part (11) having a piston crown (13), and a lower piston part (12), whereby the lower piston part (12) has pin boss supports (32) and pin bosses (18) connected with them, whereby the upper piston part (11) and the lower piston part (12) each have an inner (21, 25) and an outer (22, 26) support element, which elements delimit an outer circumferential cooling channel (29). According to the invention, it is provided that the inner support elements (21, 25) delimit a cavity (31) that is open toward the pin bosses (18), and that the cavity (31) is provided with a separate cooling oil collector (35) that has at least one cooling oil opening (37, 38).

Abstract: Exemplary piston assemblies and methods of making the same are disclosed. An exemplary piston assembly may include a piston crown and a piston skirt that is received in a central opening of the crown. The piston crown may include a ring belt portion defining, at least in part, a cooling gallery. The crown and skirt may each further include corresponding mating surfaces that extend about a periphery of the crown and skirt. The skirt mating surface and crown mating surface may generally be secured to each other that the crown and the skirt cooperate to form a continuous upper combustion bowl surface. The skirt and crown may cooperate to define a radially outer gap about a periphery of the piston crown.

Abstract: The invention relates to a soluble and essentially annular casting core (2) for forming a cooling channel that transitions into two areas (14, 15) which are approximately parallel to the piston axis (16) and are facing away from the piston head (3), via a respective bending of the core (17, 18) in the shape of a quadrant, wherein the second area (14) transitions into a part of the casting core (2) that forms the feed opening (12) of the cooling channel, and the first area (15) transitions into a part of the casting core (2) that forms the discharge opening (13) of the cooling channel. The two areas (14, 15) of the casting core (2) are disposed at a distance from one another, which corresponds at a maximum to two times the cross-sectional diameter of one of the two areas (14, 15). As a result, the throughflow of the cooling oil traversing the cooling channel is accelerated and the cooling of the piston improved.

Abstract: A one-piece steel piston that is made from a piston blank that includes a portion that is configured and designed to be displaced to form a cooling gallery and ring belt. The piston blank can be formed by a casting or forging process. The portion that is designed and configured to be displaced is a flange that extends radially outward. The flange is bent downward or upward so that a peripheral edge of the flange contacts another portion of the piston. The peripheral edge of the flange and the other portion of the piston can be welded together or mechanically engaged.

Abstract: A soluble casting core for forming a cooling channel in a piston has a formed-on part for forming an oil supply opening and a formed-on part for forming an oil drain opening. In order to improve the mechanical strength of the piston, the oil supply opening and the oil drain opening lie in a different pin boss support of the pin bosses of the piston. A third formed-on part, which lies in the circumferential direction and is configured in oblong manner, is disposed between the first formed-on part and the end of the casting core, which part has a shape that narrows conically towards the end of the casting core and forms a continuation of the cooling channel, which narrows conically towards the end of the cooling channel.

Abstract: A piston has an upper crown portion with an upper combustion wall against which combustion forces act and a lower crown portion with a pair of pin bosses spaced for receipt of a small end of a connecting rod therebetween. The upper crown portion and the lower crown portion form an outer oil gallery and a central oil gallery in fluid communication with one another. The central oil gallery is formed in part by an annular flange extending radially inwardly from the outer oil gallery and upwardly toward the upper combustion wall to a free edge spaced from the upper combustion wall. The free edge forms an opening about a central axis of the piston and has a non-planar uppermost surface with depressions aligned diametrically opposite one another across the opening to improve the oil flow throughout the central oil gallery.

Abstract: A piston assembly for an internal combustion engine is provided, including a piston and at least one insert. The piston includes an annular recess, a first surface, a ring belt and a skirt. The annular recess is located between the ring belt and the skirt. The insert may include a longitudinal portion and one or more opposing arms. The insert may be configured to be coupled with the piston. The arm(s) may extend laterally from the longitudinal portion and may be configured to abut the skirt, thereby orienting the insert relative to the piston. The insert may be disposed along the first surface, and aligned with the piston skirt such that the arms of the insert form a circumference about the piston skirt. The arms may at least partially enclose the annular recess at the piston skirt.

Abstract: A two stroke engine of a particular configuration can have its power output increased by running bigger pistons and using ports in the piston skirt through which to conduct compressed air within the skirt through short passages in the cylinder housing that conduct the air from within the skirt to above the piston. As a result a larger piston can be used for the same spacing and opening size in the block to save the need to redesign the block and the crankshaft. A position adjuster for the piston moves it axially without rotation of the piston ports out of alignment with inlet ports in the housing. The piston rod is held in the crosshead using a flat to prevent rotation while an adjuster nut that is turned creates axial movement in the piston rod with a lock nut securing the final piston position.

Abstract: A piston assembly and a method of making the same. Exemplary piston assemblies may include a piston crown having a ring belt portion defining a cooling gallery, and a strut extending away from the ring belt portion to define a wrist pin bore. The piston may further include a piston skirt assembly secured to the strut. The piston skirt assembly may include two separate portions that each have a closure plate formed integrally with the portion, with the closure plate generally enclosing the cooling gallery. Exemplary methods of assembling a piston may include providing a piston crown having a ring belt portion defining a cooling gallery and a strut extending away from the ring belt portion to define a wrist pin bore. The methods may further include forming a piston skirt assembly having two portions having a closure plate integrally formed therewith, and securing the skirt to the crown.

Abstract: A piston has a one-piece, preferably cast aluminum, piston head with a cooling oil gallery completely surrounded by and within the head. The piston head has a pin bore for a piston pin that does not intersect with the cooling oil gallery. The pin bore is sized to maintain a substantially uniform clearance between the piston pin and the piston head. The piston head has a passage extending from the pin bore to the cooling oil gallery to allow cooling oil from the gallery to lubricate the piston pin. The passage is preferably drilled after the piston head is cast. Preferably, the pin bore does not have a recess at the passage. A method of manufacturing a piston includes casting the one-piece piston head and drilling a passage from the pin bore to the cooling oil gallery.

Abstract: The invention relates to a two-piece piston (1) for an internal combustion engine, comprising a piston upper piece (2) and a piston lower piece (2). A cylindrical molding (24) is arranged on the underside of the piston upper piece (2), facing away from the piston crown, lying coaxial to the piston axis (15), with two radial outward-facing hooked projections (27) on the end thereof facing away from the piston crown. The piston lower piece (6) has an opening (16) on the piston crown side, in which the cylindrical molding (24) with the projections (27) is introduced and rotated on assembly of the piston upper piece (2) on the piston lower piece (6), such that the projections (27) engage behind the edge of the opening (16).

Abstract: A method of producing a cooling channel piston for an internal combustion engine having a cooling channel in its piston crown, wherein a piston lower section with piston bosses, piston pin bores and piston skirts attach to the piston crown, wherein a piston blank is first produced with a circumferential collar radially projecting in the area of the piston crown, wherein the collar is then formed over, wherein, a seating area for the collar is formed in a transition zone between the piston crown and the piston lower section and the collar is formed over in such a way until its outer radially circumferential edge comes very close to or butts completely against the seating area to form a closed cooling channel.

Abstract: A piston for an internal combustion engine has an annular cooling channel provided with oil admission boreholes and oil discharge boreholes, the oil discharge boreholes being oriented in the direction of the bolt hubs for the cooling thereof.

Abstract: The object of the present invention is a piston for cold chamber die-casting machines comprising a body and at least one sealing band mounted around said body, wherein said body and said band are provided with coupling means suitable for concurrently obtaining both an angular locking and an axial locking of the band to the piston body.

Abstract: The invention relates to a piston of an internal combustion engine comprising an upper part (1) and a lower part (3) that consist of a respective light metal alloy (15) and to an associated method for increasing the thermal load-bearing capacity of a multi-part piston that is subjected to high thermal stress in an internal combustion engine. The piston is provided with at least one insulating element, in particular a gap (7) between the lower part (3) and the upper part (1), at least one piston ring carrier (6), which consists of a different material from that of the upper part (1) and the lower part (3), in particular of steel or grey cast iron, being located next to said gap as a component. A thermal current that is introduced into the piston base (2) is prevented from dissipating via the piston ring carrier (6) by means of the insulating element.

Abstract: A piston has an upper crown portion with an upper combustion wall against which combustion forces act and a lower crown portion with a pair of pin bosses spaced for receipt of a small end of a connecting rod therebetween. The upper crown portion and the lower crown portion form an outer oil gallery and a central oil gallery in fluid communication with one another. The central oil gallery is formed in part by an annular flange extending radially inwardly from the outer oil gallery and upwardly toward the upper combustion wall to a free edge spaced from the upper combustion wall. The free edge forms an opening about a central axis of the piston and has a non-planar uppermost surface with depressions aligned diametrically opposite one another across the opening to improve the oil flow throughout the central oil gallery.

Abstract: A two-part piston for an internal combustion engine consists of an upper part, a lower part and a circumferential, closed cooling channel radially on the outside and close to the piston crown. The channel is closed off, on its underside, by a cooling channel cover which is connected via a skirt connection with two skirt elements that lie opposite one another. In order to reduce the piston weight and nevertheless avoid secondary movements of the piston, circumferential recesses are provided in the region of the skirt elements, which are delimited by the cooling channel cover on the piston crown side and by the skirt connections on the skirt side. The skirt connections are connected with the radially inner region of the cooling channel cover on the piston crown side, and with the upper regions of the skirt elements on the skirt side.