To estimate the effect of the axial movement of piston rings in the piston grooves on the blow-by in the internal combustion engine (ICE) by an experiment-calculated method. This contributes to the development of practical recommendations for the further improvement of the engine ring seal designs. Abstract theorems were used when modelling the effect of the axial movement of piston rings in the piston grooves on the blow-by in an ICE. They are based on the fundamental theory of heat engines, thermodynamics and hydraulics. The ICE running was analysed using design-theoretical research methods. The effect of the axial movement of piston rings in the piston grooves on the blow-by in the ICE was established. This creates prerequisites for a more accurate assessment of their sealing capacity and for ways to further improve them. Calculated dependences

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Розроблено метод експериментально-розрахункового визначення жорсткості кривошипа колінчастого вала. Спроектований і виготовлений спеціальний стенд для відпрацювання даного методу. Проведено апробацію цього методу на прикладі визначення жорсткості кривошипа колінчастого вала рядного чотирициліндрового автомобільного дизеля ДА10. Надано рекомендації щодо спрощення розробленого методу до інженерного способу експериментального визначення жорсткості кривошипа колінчастого вала. METHOD OF EXPERIMENTAL AND CALCULATED DETERMINATION OF THROW STIFFNESS OF CRANKSHAFT A.V. Gritsuk, I.S. Revelyuk, D.V. Levchenko The method of experimental and calculation determination of throw stiffness of crankshaft has been developed. A special stand for testing this method has been designed and manufactured. Approbation of this method on example of determining throw stiffness of crankshaft of DA10 inline four-cylinder diesel engine has been led. Recommendations concerned simplification the developed method to an engineering method of experimental determination of throw stiffness of crankshaft have been given.

The article considers one of the topical directions of increasing fuel economy and reducing the toxicity of exhaust gases, namely, cylinder disconnection of internal combustion engines (ICE) in idling and partial loads. Current internal combustion engines with cylinder disconnection have enough technical solutions to ensure high fuel economy and ecological indicators of the engine working process. Accordingly, such engines require solution of the following tasks: improvement of mass-size indicators, cost reduction and design improvement, increase of reliability, etc. One of the main tasks of transport vehicles is also reducing the level of engine vibrations. This task is especially relevant for internal combustion engines with disconnected cylinders. When cylinders are disconnected, the unevenness of total torque increases from working processes in active cylinders and, as a result, the unevenness of the engine stroke, which affects the dynamic characteristics of the vehicle as a whole. To solve this problem, the general provisions of torsional momentum unevenness of internal combustion engines were considered. Total torsional torque of different engines was processed and data on the unevenness of torsional torque was obtained. The method of investigating the influence of cylinder switching, particularly the number of active cylinders on the unevenness of total torque is developed. The notion of torsional torque change degree with cylinder disconnection is introduced and the equation for its determination depending on the number of active cylinders is proposed. The notion of torsional torque coefficient change at disconnection of cylinders is also introduced. The application of the calculation of a four-cylinder inline engine for the possibility to compare changes in the torsional momentum unevenness when the cylinders are disconnected in the given engine was made. As a result of the calculations it was found that the torque unevenness coefficient at operation of the engine with 3, 2 and 1 cylinders in the average increases in 1,5; 2 and 3 times. The results of calculations were analyzed and histograms for all possible values of the number of active cylinders have been provided.