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Plain bearings limit the performance of the crankshaft of an internal combustion engine (ICE) to major repairs. Their reliability is determined by heat resistance, wear-resistance and endurance limits of the materials of which the bearing is made. Dynamic loads reduce bearing life. Plain bearings, heavy-loaded and operating at a high rotational speed of the crankshaft, require a constant supply of oil under pressure to maintain the hydrodynamic friction mode and to remove heat generated during friction. In the hydrodynamic regime of friction, heat generation is determined by the viscosity of the oil, the thickness of the lubricating layer, and sliding speed. In operation for plain bearings, it is necessary to provide liquid lubrication at all established operating modes of the internal combustion engine. The oil in the gaps between the neck of the crankshaft and the liner should come under the action of the necessary overpressure, thereby ensuring: complete separation of the working surfaces of the contacting parts of the bearings of the crankshaft during operation; lack of direct friction between the metal surfaces of the shaft and bearing; insignificant value of the coefficient of friction; low friction and heat loss. The paper presents the results of studies on the impact of operational changes in lubrication conditions on the thermal tension of the connecting rod bearings of the crankshaft.

Actuality. Meaning of efficiency coefficient of internal combustion engine fully depends on type and construction. Common world practice of automobile construction is directed on increasing of quality of indicators of usage of internal combustion engine, which is linked to directions of increasing efficiency. Leading overseas firms that “dictate” the engineering direction of the design improvement of internal combustion engines in connection with the improvement of the technology of processing fuel into mechanical work in the engine use various technological opportunities in conjunction with the design developments in the cylindrical piston group. That’s why modernization elements research of cylinder piston group is relevant. Goal. Research possible ways to increase efficiency internal combustion engine by modernization of cylinder piston group due to the scientific work plan. Task. Design measures for internal combustion engine modernization for increasing of quality of its usage. Research methodology. Due to methodology [2] we performed theoretical calculations of efficiency of real engine and efficiency of engine which cylinder piston group was upgraded. While we defied indicating efficiency of patrol engine ZMZ-406 we used auxiliary equation of B. Stechkin. We performed theoretical calculations of functional dependence of efficiency because of working body parameters changes simultaneously.

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