Reveliuk I. Selection and justification of the parameters of silicone damper of torsional vibrations of high-speed diesel crankshaft

The dissertation is devoted to solving the actual scientific and practical problem of choosing the main parameters of the silicone damper for damping torsional vibrations of the crankshaft system of the high-circulating fuel-efficient diesel 6ЧН8.8/8.2, which is designed as part of "Slobozhansky diesel" state investment project, one of whose tasks is to create a design and commercial production of a new series of in-line six-cylinder four-stroke diesel engines with capacity of 110 - 130 kW. The object of the study is the processes occurring in the crankshaft system as a result of the impact of torsional vibrations on the resonant modes of engine operation. The subject of research is the design characteristics of the elements of the crankshaft system and the parameters of the silicone damper of its torsional vibrations. The theoretical and experimental research is based on the fundamental principles of the theory of internal combustion engines, the theory of vibrations, hydrodynamics, applied mathematics and mathematical physics, the theory of strength and reliability. To determine the resonant frequencies of the crankshaft of a high-circulating fuel-efficient diesel engine, the AVL EXCITE Designer software was used. The calculated determination of the amplitudes of forced vibrations and tangential stresses of the crankshaft system was carried out by the method based on the numerical solution of a high-level system of nonlinear differential equations in the form of a model in the state space. Calculated and experimental study to determine the stiffness of the crankshaft crank was based on the application of the method of mathematical planning of the experiment. To build the mathematical dependence of the deformation of the crankshaft section as function of the applied torque and the point of fixation, a widely used and recognized method of approximation is used - the method of least squares. To determine the coefficients of approximating dependencies by the least squares method, we used the program ApproximationLSM, developed in the MatLAB environment, which allows us to solve optimization problems of the constructed function. The scientific novelty of the results obtained is as follows: the rationale for the use of a damping element in the crankshaft system of the high-circulating fuel-efficient diesel 6ЧН8.8/8.2; improvement of the method of experimental and calculated determination of the actual stiffness value of the crankshaft crank; refinement of the mathematical model of the in-phase flow of a viscous fluid in the gaps of the damper, which for the first time takes into account the inertia of the fluid; introduction of criteria for designing a crankshaft system of a high-circulating fuel-efficient diesel engine with acceptable tangential stresses and amplitudes from torsional vibrations; and developing a method for testing the performance of a silicone damper. The results of the dissertation research are used in Research and Development enterprises of Ukraine, in particular Research and Production Enterprise Diesel Group, and SE Kharkiv Engine Design Bureau, as well as transferred to the research laboratory of the department of internal combustion engines Kharkiv National Automobile and Highway University, and for use in the educational process of this department in preparing students for special spine 142 "Power Engineering", professional direction "Internal Combustion Engines". The results of the dissertation can be used to develop new and modernize existing designs of diesel engines.