Mahle International Gmbh

Mahle Metal Leve S/a

Mehle International Gmbh

Gisela Ablas Marques

Juliano Avelar Araujo

Jose Valentim Lima Sarabanda

Fabio Mendes De Araujo

Robert Richard Banfield

Paulo Roberto Vieira De Morais

André Ferrarese

Claudinei José De Oliveira

José Valentim Lima Sarabanda

Jan Vatavuk

Sandra Matos Cordeiro Costa

A piston ring and a method of manufacturing a piston ring for a piston of a reciprocating internal combustion engine. The piston ring comprises a body having an outer circumferential surface. A tribological coating is formed on the outer circumferential surface of the body. The tribological coating has a dual layer or a triple layer structure and includes a relatively hard base layer and a relatively porous top layer overlying the base layer. The tribological coating may be provided with varying thickness such that its thickness increases gradually from 90&#xb0; towards 0&#xb0; in a first radial direction of the piston ring and from 270&#xb0; towards 360&#xb0; in a second radial direction of the piston ring reaching its maximum value in the region of 0&#xb0; and 360&#xb0;, i.e. the tips of the piston ring.

Piston ring and method of manufacture

A piston ring for a piston of an internal combustion engine may include a body composed of a ferrous material. The body may have an upper portion, a lower portion opposed to the upper portion, an internal portion configured to face towards a piston groove and an external portion opposed to the internal portion. An upper chamfer may be disposed between the upper portion and the external portion. A lower chamfer may be disposed between the lower portion and the external portion. The upper portion, the lower portion and the internal portion may each have a nitrided layer. The external portion, the upper chamfer and the lower chamfer may include at least one ion plated coating layer. The nitrided portion in at least a superficial layer may have a hardness of 700 HV or less.

Piston ring and process for the manufacture thereof

A piston ring may include a stainless steel base having between 8% and 15% by weight of chromium, together with other elements and impurities, and having a hardness between 350 HV and 420 HV. The piston ring may also include a superficial nitrided layer having a depth of no more than 60 &#x3bc;m and an average hardness measured upon the surface exceeding 800 HV. The nitrided layer may include a plurality of nitride particles, which may have a maximum size of 5 &#x3bc;m and may be distributed over between 4% and 8% of an area of the nitrided layer.

Piston ring and internal combustion engine

A wet cylinder liner for internal combustion engines may include a cylindrical body composed of a ferrous alloy having a circumferential outer surface. The cylindrical body may include a first layer and a second layer disposed sequentially on the outer surface. The first layer may include at least one of at least one silicon and at least one two-component epoxy adhesive. The second layer may include a silane-elastomer compound. The silane-elastomer compound may include nanoparticles of silicon oxide and an adhesion modifier additive. The second layer may be configured as an interface between a cooling fluid and the first layer, as well as to resist erosion by cavitation. The first layer may facilitate an interface for resistance at high temperatures.

Wet cylinder liner for internal combustion engines, process for obtaining a wet cylinder liner, and internal combustion engine

This invention refers to the solution of problem of spalling of the nitrided layer in piston rings for Flex-fuel engines, without jeopardizing the wear resistance, suggesting for such purpose a nitrided piston ring () equipped with two nitrided layers (), with metallic base () composed mainly of iron and whose superficial hardness presented is of about 800 Vickers, decreasing in a substantially linear manner up to about 400 Vickers for a distance to the surface of up to 90 microns (&#x3bc;m).

Nitrided piston ring resistant to the propagation of cracks

The invention relates to a piston ring for internal combustion engines, the piston ring comprises a steel or cast iron base material with a coating of chromium nitride deposited by a physical vapor deposition process on a sliding surface of the piston ring, wherein the coating is composed of a columnar crystal structure of CrN with the following features:

Piston ring with chromium nitride coating for internal combustion engines

The present invention relates to a piston ring for an internal combustion engine, the piston ring comprises a sulphide rich compound layer forming a surface layer, said sulphide rich compound layer comprising an iron nitride matrix with iron sulphide (FeS) inclusions embedded in said matrix, said sulphide rich compound layer having a sulphur content of 1 to 4 wt % S and a nitrogen content of 10 to 20 wt % N.

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Gisela Ablas Marques