ДОСЛІДЖЕННЯ ВПЛИВУ КУТА МІЖ КРИВОШИПАМИ НА ЗАПАС МІЦНОСТІ НЕПОВНООПОРНОГО КОЛІНЧАСТОГО ВАЛУ ЦИЛІНДРОВОГО ОПОЗИТНОГО ДВИГУНА

Purpose. The purpose of the study is to reduce the loads acting on the elements of the partially supported crankshaft of a flat-twin internal combustion engine by choosing the optimal value of the angle between the crankpins. This will make it possible to increase the margin of safety of the crankshaft. Research methods. Theoretical (transition from specific to abstract), empirical (observation, measurement, comparison) and complex (abstraction, modeling, analysis and synthesis) research methods are used. The computer program Engine Calculation and Microsoft Office was used for the study. The object of the study is a four-stroke two-cylinder flat-twin gasoline motorcycle engine MT-10-36. The subject of the study is the influence of the angle between the crankpins γк of the partially supported crankshaft on the margin of safety of a crankshaft of flat-twin engine. Results. The current issue of increasing the reliability of a flat-twin gasoline internal combustion engine with a different angle between the crankshaft crankpins γк has been resolved. The forces acting on the connecting rod and main bearings of the crankshaft of the basic engine MT-10-36 and engines with a changed angle γк (5 variants) have been calculated. The impact moments on all main and connecting rod bearings of the crankshaft have been calculated for engines with different angles γк. The calculated numerical values of the safety margins of the crankshaft parts allow us to state that engines with angles γк = 210 °, γк = 240 ° or γк = 270 ° have improved reliability (in comparison with the basic engine). Scientific novelty. The known method of calculating the forces acting on the main bearings of internal combustion engines has been modified for flat-twin engines that do not have an intermediate (middle) main bearing. For the first time, load diagrams on the main bearings have been obtained for a partially supported crankshaft of flat-twin internal combustion engine with angles between crankpins γк = 210 °, γк = 240 °, γк = 270 °. For the first time, graphs of the impact moments on the connecting rods and main bearings have been obtained for a partially supported crankshaft of flat-twin engine MT-10-36 with cranks offset by γк = 210 °, γк = 240 °, γк = 270 °. Practical value. The method for determining the influence of the angle between the cranks of a partially supported crankshaft of a flat-twin internal combustion engine on the safety margin of the engine’s crankshaft can be used in the design of new flat-twin and V-twin internal combustion engines for various purposes.