Piston for internal combustion engine

A piston for an internal combustion engine, the piston comprising:

• a body comprising, at an upper part of the body, a crown comprising a combustion chamber where fuel is burnt and comprising, at a lower part of the body, a piston pin boss into which a piston pin is inserted and a skirt corresponding to a cylinder wall;
• a cooling channel comprising a refrigerant channel provided in the body to allow a refrigerant to flow therethrough to cool the body, a refrigerant inlet provided at a side of the refrigerant channel, and a refrigerant outlet provided at the other side of the refrigerant channel;
• and
• a reinforced part having a shape of a fourth elliptical arc of a quadratic curve and provided at a lower surface of the crown and a part where the piston pin boss is connected to the skirt,
• wherein a cross section of the cooling channel has an overall elliptic shape to reduce stress occurring at an upper side of the cooling channel when the fuel is burnt in the internal combustion engine, and at least one of arcs of the ellipse is configured as a first elliptical arc of a quadratic curve, and
• wherein a ratio of a fourth minor axis to the fourth major axis of the fourth elliptical arc is 55% to 60%.