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: 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.