Patent ID: 7543557

Claim:
A piston and cylinder assembly for an engine, the assembly comprising: a piston including an aluminum piston body having a crown and a skirt extending from the crown, the skirt having an exterior surface; the exterior surface having a surface finish in a wave form with peaks and valleys, and having a roughness total between approximately 6 and 12 micrometers, the roughness total (Rt) being defined as the difference between the highest peak and lowest valley within an assessment length; the surface finish having an approximate peak-to-peak distance between 0.17 and 0.25 millimeters within the assessment length; a nickel ceramic composite (NCC) coating applied directly on the exterior surface of the skirt; and an aluminum alloy cylinder bore disposed in an engine block and configured to receive the piston body, the cylinder bore having a bore surface; wherein hard intermetallic phases of the aluminum alloy protrude between approximately 1 and 3 micrometers from the bore surface; the bore surface having a roughness average (Ra) between approximately 0.09 and 0.25 micrometers.