Piston and cylinder bore having improved scuffing resistance
AssigneeGeneral Motors Corporation
InventorsYucong Wang, Donald L. Brown
Life of this patent
Estimating the term…
Abstract
A piston assembly is provided for use in an engine. The piston assembly includes a piston body including a crown with a skirt extending from the crown. The skirt has an exterior surface. The exterior surface has a surface finish in a wave form with peaks and valleys, and having a roughness total between approximately 6 and 8 micrometers. The roughness total is defined as the difference between the highest peak and lowest valley within an assessment length. The surface finish has an approximate peak-to-peak distance between 0.18 and 0.23 mm within the assessment length. A composite coating is provided over the exterior surface.
Claims17
A piston assembly for use in an engine, comprising:
- a piston body including a crown with a skirt extending from the crown, said skirt having an exterior surface;
- said exterior surface having a surface finish in a wave form with peaks and valleys, and having a roughness total (Rt) between approximately 6 and 8 micrometers, said roughness total defined as the difference between the highest peak and lowest valley within an assessment length;
- said surface finish having an approximate peak-to-peak distance between 0.18 and 0.23 mm within the assessment length;
- and
- a composite coating on said exterior surface.
A piston and cylinder assembly for an engine, the piston including a piston body having a crown with a skirt extending from the crown, wherein the skirt has an exterior surface, and the cylinder being a cast-iron cylinder bore configured to receive the piston body and having a bore surface, the piston and cylinder assembly comprising:
- said exterior surface having a surface finish in a wave form with peaks and valleys, and having a roughness total (Rt) between approximately 6 and 8 micrometers, said roughness total defined as the difference between the highest peak and lowest valley within an assessment length;
- said surface finish having an approximate peak-to-peak distance between 0.18 and 0.23 mm within the assessment length;
- a composite coating on said exterior surface;
- and
- said bore surface having a roughness average (Ra) between approximately 0.34 and 0.52 micrometers.
Dependencies are inferred from the claim text.