A piston structure of an engine is provided, which includes a piston having a crown part including a crown surface defining a combustion chamber and an opposite back surface, an oil jet that injects oil toward the back surface, a center side first cavity and an outer-circumference side second cavity that are formed inside the crown part and partitioned from each other. Each cavity includes a ceiling surface on the combustion chamber side and an opposite bottom surface. The structure also includes a communicating hole that is formed in a partitioning wall between the cavities and communicates the first cavity with the second cavity, an introduction hole that is formed in the bottom surface of the first cavity and into which oil injected toward the back surface is introduced, and a discharge hole that is formed in the bottom surface of the second cavity and discharges the oil.

A piston structure of an engine is provided, which includes a piston having a crown part including a crown surface defining a combustion chamber and an opposite back surface, an oil jet that injects oil toward the back surface, a center side first cavity and an outer-circumference side second cavity that are formed inside the crown part and partitioned from each other. Each cavity includes a ceiling surface on the combustion chamber side and an opposite bottom surface. The structure also includes a communicating hole that is formed in a partitioning wall between the cavities and communicates the first cavity with the second cavity, an introduction hole that is formed in the bottom surface of the first cavity and into which oil injected toward the back surface is introduced, and a discharge hole that is formed in the bottom surface of the second cavity and discharges the oil.

A piston structure of an engine includes a piston having a crown part including a crown surface defining a combustion chamber, and an opposite back surface, an oil jet, a center-side first cavity and an outer-circumference-side second cavity formed inside the crown part and partitioned from each other, each cavity including a ceiling surface on the combustion chamber side and an opposite bottom surface, a communicating hole that is formed in a partitioning wall between the cavities, an introduction hole that is formed in the bottom surface of the first cavity and introduces into the first cavity oil injected toward the back surface from the oil jet, and a discharge hole that is formed in the bottom surface of at least one cavity and discharges the oil. The ceiling surface of the second cavity is located on the combustion chamber side of the ceiling surface of the first cavity.

A piston structure of an engine includes a piston having a crown part including a crown surface defining a combustion chamber, and an opposite back surface, an oil jet, a center-side first cavity and an outer-circumference-side second cavity formed inside the crown part and partitioned from each other, each cavity including a ceiling surface on the combustion chamber side and an opposite bottom surface, a communicating hole that is formed in a partitioning wall between the cavities, an introduction hole that is formed in the bottom surface of the first cavity and introduces into the first cavity oil injected toward the back surface from the oil jet, and a discharge hole that is formed in the bottom surface of at least one cavity and discharges the oil. The ceiling surface of the second cavity is located on the combustion chamber side of the ceiling surface of the first cavity.

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.

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.

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.

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.

An integrally formed piston has a crown portion having an upper crown surface and an undercrown surface. A ring belt extends from the undercrown surface at a periphery thereof. The ring belt includes an uppermost ring land and at least one oil galley contoured to extend around at least two surfaces of the uppermost ring land. The oil galley has an opening at the undercrown surface for receiving a cooling fluid therein for cooling the uppermost ring land. A skirt extends from the undercrown surface and the ring belt and has a plurality of stiffening features arranged in a truss formation. At least one of the plurality of stiffening features has an I-beam cross-section and another of the plurality of stiffening features has a negative draft angle.

An integrally formed piston has a crown portion having an upper crown surface and an undercrown surface. A ring belt extends from the undercrown surface at a periphery thereof. The ring belt includes an uppermost ring land and at least one oil galley contoured to extend around at least two surfaces of the uppermost ring land. The oil galley has an opening at the undercrown surface for receiving a cooling fluid therein for cooling the uppermost ring land. A skirt extends from the undercrown surface and the ring belt and has a plurality of stiffening features arranged in a truss formation. At least one of the plurality of stiffening features has an I-beam cross-section and another of the plurality of stiffening features has a negative draft angle.