Piston for an internal combustion engine and method for producing the piston

An internal combustion engine for a motor vehicle, comprising:

• at least one combustion chamber, and
• a piston adjustably arranged in the at least one combustion chamber, the piston including 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 connected to one another via a radially outer weld connection and a radially inner weld connection, wherein 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;
• wherein the radially outer weld bead defines a narrowing of the cooling channel that divides the cooling channel into a narrowing zone and into an axially upper channel zone and an axially lower channel zone, wherein the narrowing zone is arranged between the axially upper channel zone and the axially lower channel zone;
• and
• wherein a volume of the axially upper channel zone amounts to at least 40% of a total volume of the cooling channel.

A method for producing a piston, comprising:

• a) providing a first blank and a second blank that each comprise a radially outer joining surface and a radially inner joining surface, and wherein on at least one of the two radially outer joining surfaces of the first and second blanks, a weld bead steering element is provided,
• b) welding the first and second blanks at the radially inner and radially outer joining surfaces to form the piston such that during the welding process, at least on the two radially outer joining surfaces of the first and second blanks, a radially outer weld bead is formed, which is deflected from the weld bead steering element so that following the welding the radially outer weld bead projects radially to the inside into a cooling channel delimited by the first and second blanks;
• wherein the radially outer weld bead defines a narrowing of the cooling channel that divides the cooling channel into a narrowing zone and into an axially upper channel zone and an axially lower channel zone, wherein the narrowing zone is arranged between the axially upper channel zone and the axially lower channel zone;
• and
• wherein a radial width of the cooling channel at the narrowing amounts to maximally 50% of a maximum radial width of the cooling channel.