| 摘要 |
<p>A piston ring (7) for a piston in an internal combustion engine is inserted in one of several axially separated annular grooves (3) in the peripheral surface of the piston. Each annular groove has an upper and a lower groove face (4, 5) as well as a groove bottom (6). The piston rings seal the working chamber (8) above the upper piston ring downwards during the compression and combustion strokes of the piston. The piston ring (7) has an axial height which is smaller than the axial distance between the upper and the lower groove face in the pertaining annular groove as well as a substantially gastight ring partition (9) allowing for an extension of the diameter of the ring at the mounting in the annular groove. Several leakage tracks (14) in the lower surface (15) of the piston ring are distributed over the periphery of the ring, said tracks being slit-shaped and having a slit width facing in the peripheral direction of the ring and being at least several times larger than the slit height (h) extending in the axial direction. When the bottom surface (15) of the piston ring abuts the lower groove face (5) leak gas may flow through the leakage tracks, which reduces the differential pressure across the piston ring.</p> |
