Abstract: A piston for an internal combustion engine including a piston crown and a combustion chamber recess recessed therein, the combustion chamber recess including a recess edge. The piston may also include a ring groove for receiving a piston ring. The piston may further include a cooling duct having a smaller spacing from the piston crown than that of a flank of the ring groove, the cooling duct defining a minimum spacing from the piston crown at a first location, and a minimum spacing from the combustion chamber recess at a second location. The cooling duct may have a rounded portion between the first location and the second location. The cooling duct may have a maximum spacing from the recess edge at a third location. The rounded portion may have a rounding radius defined at least at the third location that is greater than 4% of a piston diameter.

Abstract: A piston for an internal combustion engine including a piston crown and a combustion chamber recess recessed therein, the combustion chamber recess including a recess edge. The piston may also include a ring groove for receiving a piston ring. The piston may further include a cooling duct having a smaller spacing from the piston crown than that of a flank of the ring groove, the cooling duct defining a minimum spacing from the piston crown at a first location, and a minimum spacing from the combustion chamber recess at a second location. The cooling duct may have a rounded portion between the first location and the second location. The cooling duct may have a maximum spacing from the recess edge at a third location. The rounded portion may have a rounding radius defined at least at the third location that is greater than 4% of a piston diameter.

Abstract: A soluble and substantially ring-shaped casting core may include a cooling channel in a piston having at least one inflow and at least one outflow. The casting core may form a closed ring and the inflow may be arranged directly adjacent to the outflow. The casting core may have a cross-sectional taper for forming a choke in the circumferential direction between the inflow and the outflow.

Abstract: A soluble and substantially ring-shaped casting core may include a cooling channel in a piston having at least one inflow and at least one outflow. The casting core may form a closed ring and the inflow may be arranged directly adjacent to the outflow. The casting core may have a cross-sectional taper for forming a choke in the circumferential direction between the inflow and the outflow.