Piston having ceramic-coated ring groove
First Claim
1. A piston for an internal combustion engine, said piston having at least one peripheral ring groove extending around the outer surface thereof, wherein the ring groove has an internal surface which is coated by a hard ceramic layer, said hard ceramic layer being formed by plasma electrolytic oxidation.
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Accused Products
Abstract
In conventional pistons for internal combustion engines made from aluminum, magnesium, or the like, protection must be provided in the area in and around the ring grooves due to the wear and resultant microwelding between the piston ring groove and associated piston ring. One solution has been to cast the piston head around a separate protective ring made from steel or a similar material, which is costly and can negatively effect reliability and durability. In accordance with this invention, a hard ceramic reinforcing layer is provided on the outer surface of the piston in the area within the ring groove using a plasma electrolytic oxidation process. In this manner, the complexity and cost of the piston assembly is reduced while improving the reliability and durability. A piston according to this invention can be used to improve existing engine design that use a separate protective ring or can be used in new, cleansheet engine designs.
41 Citations
20 Claims
- 1. A piston for an internal combustion engine, said piston having at least one peripheral ring groove extending around the outer surface thereof, wherein the ring groove has an internal surface which is coated by a hard ceramic layer, said hard ceramic layer being formed by plasma electrolytic oxidation.
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10. A method of manufacturing a piston for an internal combustion engine, said piston having at least one annular ring groove extending around the outer surface thereof, the ring groove having an internal surface, and said method including the step of:
forming a hard ceramic layer on the internal surface of said ring groove by plasma electrolytic oxidation. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of improving a design for an internal combustion engine comprising the steps of:
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creating an initial engine design having an engine piston design in which a piston has as at least one annular ring groove extending around the outer surface thereof, said ring groove being protected by a separate protective ring secured to the outer surface; and
replacing said piston design with a new engine piston design in which a piston has at least one annular ring groove extending around the outer surface thereof, the ring groove having an internal surface that is coated by a hard ceramic layer formed by plasma electrolytic oxidation, said new engine piston design not including a separate protective ring. - View Dependent Claims (20)
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Specification