Piston with abradable coating to generate appropriate contact geometry on running surface

A piston assembly for use in an internal combustion engine, comprising:

• a piston including a body portion presenting an outer surface,
• said body portion including a crown and a pair of pin bosses depending from said crown and spaced from one another about a center axis, each of said pin bosses defines a pin bore;
• a connecting rod including a connecting end disposed between said pin bosses of said piston;
• said connecting end presenting a connecting surface defining a pin opening, said pin opening being axially aligned with said pin bores of said piston;
• a wrist pin extending through said aligned pin bores of said piston and pin opening of said connecting rod for connecting said piston to said connecting rod, said wrist pin presenting a contact surface facing said outer surface of said pin bosses and said connecting surface of said connecting rod;
• at least one of said outer surface of said piston, said connecting surface of said connecting rod, and said contact surface of said wrist pin including a portion presenting a shape being not greater than 0.1 mm from a circular shape;
• and
• an abradable coating applied to said portion of said at least one surface.

A method of manufacturing a piston assembly for use in an internal combustion engine, comprising the steps of:

• providing a body portion of a piston, the body portion presenting an outer surface, the body portion including a crown and a pair of pin bosses depending from the crown and spaced from one another about a center axis, and each of the pin bosses defining a pin bore;
• providing a connecting rod for being disposed between the pin bosses of the piston, the connecting rod including a connecting end with a connecting surface defining a pin opening for being axially aligned with the pin bosses of the piston;
• providing a wrist pin for extending through the aligned pin bosses of the piston and pin bore of the connecting rod for connecting the piston to the connecting rod, the wrist pin presenting a contact surface for facing the outer surface of the pin bosses and the connecting surface of the connecting rod;
• and
• applying an abradable coating to at least one of the outer surface of the piston, the connecting surface of the connecting rod, and the contact surface of the wrist pin including a portion presenting a shape being not greater than 0.1 mm from a circular shape.