公开(公告)号：EP4239227A1

公开(公告)日：2023-09-06

申请号：EP23157754.5

申请日：2023-02-21

申请人： MAN Energy Solutions, filial af MAN Energy Solutions SE, Tyskland

发明人： Samuelsson, Per Erik ,  Andersson, Henrik ,  Fogh, Jesper Weiss

IPC分类号： F16J9/14 ,  F16J9/20

摘要： A piston ring (4, 6) for use in a piston ring pack in an annular ring groove (3) in the sidewall of a piston (1) of a large two-stroke turbo-charged uniflow-scavenged crosshead internal combustion engine to seal against the pressure in a combustion chamber (2) above the piston (1), the piston ring (4, 6) having a ring body (11), a diameter (22), a height (21), an upper ring surface (22), a lower ring surface (23), an outer ring surface (12) and an inner ring surface (24), which outer ring surface (12) during operation of the engine slides against an inner side of a cylinder liner (7), and first- and second engaging end portions (8, 9) at a ring partition (10) that allows expansion and contraction of the piston ring (4, 6), where the first engaging end portion (8) comprises a circumferentially extending finger (13) and the second engaging end portion (9) comprises an circumferentially extending recess (14) shaped and sized for displaceably receiving the finger (13), where a gap area (15) is provided at the end of the finger (13), in which gap area (15) only the end portion (9) with the recess (14) constitutes part of the outer ring surface (12) sliding against the cylinder liner (7). The outer ring surface (12) of the piston ring (4, 6) at least in said ring section (10), as seen in cross section, is convex and part of a imaginary circle having a center (20) and a radius of curvature (25) of a least 0,8 times, preferably at least 1 times the diameter of the piston ring (4, 6). Hence, it will be possible to obtain an effective sealing in the gap area (15), where problems related to coating damages and blow by of combustions gases from the combustion chamber (2) above the piston (1) are avoided. By providing the ring section (10) with an outer surface (12) as defined above it is ensured that the sliding surface (12) of the piston ring (4, 6) which provides the sealing effect also includes a sufficient part of the end portion (9) with the recess (14) in the gap area (15) to ensure a proper sealing effect also in this gap area (15).