FIELD: mechanical engineering; internal combustion engines. SUBSTANCE: piston for double stroke engine with crosshead has number of grooves for piston rings. Piston is provided with channels to reduced pressure at some of rings with no running of channel axes onto piston ring on length from outlet holes. Total area of cross section of pressure reducing channels interrelated with separate piston ring being expressed in is within the internal from D2/68000 to D2/10000 where D is diameter of cylinder in mm. According to invention, piston provides controllable flow of limited amount of gas seeping at least past one piston ring to decrease wear of ring and to protect rings from heavy attacks. EFFECT: reduced wear of piston rings. 10 cl, 7 dwg
