Abstract
<jats:p>Piston rings are the parts that determine not only the power, but also the efficiency of the engine. Their presence makes it possible to ensure the tightness of the combustion chamber, while they are one of the main reasons for the decrease in efficiency due to interaction with the “mirror” of the cylinder. In order to increase power while increasing efficiency, a new sealing of the cylinder piston group parts is proposed, consisting of two piston rings installed in the first bored piston groove and a structurally modified piston ring installed in the second regular piston groove. This configuration of the piston makes it possible to increase the sealing efficiency of the parts of the cylinder piston group, with the condition of reducing the contact area of the structurally modified piston ring installed in the second piston groove, by cutting an annular groove on its working surface. Minimizing the contact area makes it possible to reduce the friction force to the value of the standard piston configuration, and at best to ensure operation at lower values. The sliding friction force is determined by the product of the coefficient of friction and the reaction of the support. Since the coefficient of friction is difficult to determine in the real O-ring seal of a marine diesel engine, and the reaction of the piston ring support is a value available for measurement, it is necessary to use this value to reduce the friction force. A calculation technique is proposed that makes it possible, taking into account the forces acting in the piston ring – cylinder sleeve contact zone, to determine the height of the notch on the working surface of a structurally modified piston ring, which reduces the friction force.</jats:p>