Abstract: A piston ring may include a spacer or expansion element and/or two segments. The segments may have a radial dimension between approximately 1.50 mm and approximately 1.90 mm and a height between approximately 0.30 mm and approximately 0.40 mm. The segments may have a concave profile with recesses between approximately 0.015 mm and approximately 0.030 mm and a clearance of approximately 0.150 mm. The segments may be wound via a matrix box device and a roller. The piston ring may have a circularity, expressed in the form of a decomposition as a Fourier series, with an amplitude for orders higher than 10 which is not greater than 0.10 ?m.

Abstract: The present invention relates to a relief valve (1) for a turbocharger, in which the crank arm (3) is made of a first material and the shaft (4) is made of a second material different from the first material used for manufacturing the crank arm (3), each of the materials containing a composition that provides the necessary properties according to the application of each component of the relief valve (1). The present invention also relates to a process for manufacturing the relief valve (1), which allows the crank arm (3) and the shaft (4) to be manufactured separately, using different materials for the manufacture of each component.

Abstract: A cylinder liner for an internal combustion engine may include a hollow cylindrical body. The body may include an internal surface having a longitudinal/axial length. The internal surface may be divided into at least two portions along the longitudinal/axial length. The at least two portions may respectively include a specific value of roughness and a predefined length.

Abstract: A cylinder sleeve for an internal combustion engine may include a bore-through cylindrical body having an inner sliding surface. The inner surface may have a surface finish with a rugosity defined by a valley-and-peak structure. The rugosity of the inner surface may have a ratio between a peak density and a mean radius of curvature of peaks that is higher than 150 and lower than 400. The rugosity may also have a ratio between the mean radius of curvature of peaks and an average height of peaks that is lower than 1500.

Abstract: A cylinder liner for insertion into an aluminum internal-combustion engine block may include a cylindrical body of cast iron having a circumferential external surface. The cylinder liner may also have a coating deposited on and surrounding the external surface. The external surface may have a specific roughness, and the coating may include at least 98% by volume of pure nickel, and a remainder composed of impurities.

Abstract: A cylinder liner for an internal combustion engine may include a hollow cylindrical body. The body may include an internal surface having a longitudinal/axial length. The internal surface may be divided into at least two portions along the longitudinal/axial length. The at least two portions may respectively include a specific value of roughness and a predefined length.