A piston for an internal combustion engine, configured as a gallery-cooled piston of two-piece construction includes a main body and a ring element. The ring element which has a ring zone and a fire land encloses a cooling gallery on the outside, which cooling gallery is delimited on the inside by an intermediate wall which separates the cooling gallery from a combustion chamber recess which is made in a piston head of the main body. The main body and the ring element together form two circumferential dividing planes which are offset with respect to one another, to which end in each case two interacting joining webs of the ring element and of the main body are connected with a material-to-material bond.

A power cell unit may include a piston assembly having a piston crown and a piston skirt. The piston crown may include a ring belt portion extending circumferentially about a combustion bowl and at least one boss portion extending downward from the combustion bowl. The power cell unit may also include a connecting rod having an elongated portion and a funnel portion, and at least one piston pin configured to connect the connecting rod with the piston assembly. A bottom surface of the at least one boss portion may engage with a corresponding surface of the funnel portion such that a gas load is substantially transferred directly from the piston crown to the connecting rod during downward motion of the piston assembly, and such that only inertial loading from the piston crown and/or piston skirt is transferred to the piston pin during upward motion of the piston assembly.

A power cell unit may include a piston assembly having a piston crown and a piston skirt. The piston crown may include a ring belt portion extending circumferentially about a combustion bowl and at least one boss portion extending downward from the combustion bowl. The power cell unit may also include a connecting rod having an elongated portion and a funnel portion, and at least one piston pin configured to connect the connecting rod with the piston assembly. A bottom surface of the at least one boss portion may engage with a corresponding surface of the funnel portion such that a gas load is substantially transferred directly from the piston crown to the connecting rod during downward motion of the piston assembly, and such that only inertial loading from the piston crown and/or piston skirt is transferred to the piston pin during upward motion of the piston assembly.

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.

The control apparatus operates an engine water temperature adjustment apparatus so that the temperature of cooling water that passes through an engine head enters a first temperature region in a lean mode, and operates the engine water temperature adjustment apparatus so that the temperature of the cooling water enters a second temperature region that is lower than the first temperature region in a stoichiometric mode. When knocking is detected after switching is started from the stoichiometric mode to the lean mode, the control apparatus performs any one of a first operation to operate a variable valve apparatus so as to retard the closing timing of an intake valve, a second operation to operate an oil jet apparatus so as to increase an oil jet amount, and a third operation to operate an EGR apparatus so as to increase an EGR amount.

The control apparatus operates an engine water temperature adjustment apparatus so that the temperature of cooling water that passes through an engine head enters a first temperature region in a lean mode, and operates the engine water temperature adjustment apparatus so that the temperature of the cooling water enters a second temperature region that is lower than the first temperature region in a stoichiometric mode. When knocking is detected after switching is started from the stoichiometric mode to the lean mode, the control apparatus performs any one of a first operation to operate a variable valve apparatus so as to retard the closing timing of an intake valve, a second operation to operate an oil jet apparatus so as to increase an oil jet amount, and a third operation to operate an EGR apparatus so as to increase an EGR amount.

The present disclosure relates to a piston for a reciprocating-piston internal combustion engine, comprising a piston head and a piston barrel, wherein the piston head has an encircling ring belt with at least one ring groove for a piston ring and has, in the region of the ring belt, an encircling cooling duct. The cooling duct extends from the ring belt as far as a wall of the piston barrel in order to increase an oil film temperature of the oil film in the cylinder liner between the piston barrel and cylinder and to thereby reduce the piston barrel friction.

The present disclosure relates to a piston for a reciprocating-piston internal combustion engine, comprising a piston head and a piston barrel, wherein the piston head has an encircling ring belt with at least one ring groove for a piston ring and has, in the region of the ring belt, an encircling cooling duct. The cooling duct extends from the ring belt as far as a wall of the piston barrel in order to increase an oil film temperature of the oil film in the cylinder liner between the piston barrel and cylinder and to thereby reduce the piston barrel friction.

A galleryless piston having a reduced temperature during operation in an engine is provided. The piston includes an upper wall with an exposed undercrown surface. A ring belt and pin bosses depend from the upper wall, and a pair of skirt panels depend from the ring belt and are coupled to the pin bosses by struts. The piston includes an inner undercrown region and outer pockets extending along the undercrown surface. The inner undercrown region is surrounded by the skirt panels, the struts, and the pin bosses. Each outer pocket is surrounded by one of the pin bosses, a portion of the ring belt, and the struts adjacent the one pin boss. A plurality of holes extend through the pin bosses and/or the struts from the inner undercrown region to one of the outer pockets to convey cooling oil from the inner undercrown region to the outer pockets.

A galleryless piston having a reduced temperature during operation in an engine is provided. The piston includes an upper wall with an exposed undercrown surface. A ring belt and pin bosses depend from the upper wall, and a pair of skirt panels depend from the ring belt and are coupled to the pin bosses by struts. The piston includes an inner undercrown region and outer pockets extending along the undercrown surface. The inner undercrown region is surrounded by the skirt panels, the struts, and the pin bosses. Each outer pocket is surrounded by one of the pin bosses, a portion of the ring belt, and the struts adjacent the one pin boss. A plurality of holes extend through the pin bosses and/or the struts from the inner undercrown region to one of the outer pockets to convey cooling oil from the inner undercrown region to the outer pockets.