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Wear of TiAlCN coatings deposited on HCR (High Contact Ratio) gears was studied by the Niemann test during which the tested gears were loaded up to the 12th load stage. The resistance against scuffing was evaluated based on the criteria of allowable roughness (max. Rz 7 µm) and weight loss (max. 10 mg). The extent and character of wear were influenced by coating thickness, contact pressure and meshing frequency. The wear of thicker TiAlCN coatings on the tooth face started with the smoothing of surface protrusions. The next stage of wear was characterized by depletion of TiAlCN coating. After depletion to a thickness of about 2 µm, the layer was pressed into the soft substrate, and it subsequently cracked. At higher load stages, the layer was partially detached, but the critical roughness indicating scuffing was not exceeded. Thinner TiAlCN coating on the tooth flank cracked and fully detached at lower load stages compared to thicker layers and wear of uncoated soft substrate caused the increase in roughness above the critical value representing scuffing.

The article is devoted to the use of low-energy synthesized gas (synthesis gas) as a fuel for internal combustion engines, which in turn transmit mechanical energy to a cogeneration plant (combined production of heat and electricity). Such power plants allow you to achieve high values of total effective efficiency when using a conventional internal combustion engine with spark ignition. The analysed synthetic gases can be obtained by the method of gasification of household waste with access to air. In this work, synthesis gases were obtained in laboratory conditions. The composition of the components of the studied synthesis gases corresponds to several gas mixtures that are created during the artificial gasification of household waste of certain categories. The influence of the composition of the synthesis gas components on the internal parameters of the internal combustion engine was studied. The process of supplying fuel to the engine was controlled by a standard block with several sensors connected to it in the combustion chamber and the exhaust manifold. Engine operation on all synthesis gas mixtures was compared with operation on pure methane mixture. The analysis shows that the drop in efficiency indicators in the form of indicator mean effective pressure (IMEP) ranges from 10% to 40% compared to work on a pure methane mixture. With an increase in the proportion of hydrogen in the synthesis gas, the stiffness of the engine, as well as the rate of heat generation, increases. When the synthesis gas contained a high proportion of carbon monoxide, the stiffness of the engine was the lowest. The main combustion time of synthesis gas is reduced when hydrogen is added to the mixture, and due to an increase in the proportion of methane or carbon monoxide, it increases on the contrary. The presented results make it possible to analyses the processes occurring in the internal combustion engine, as well as the influence of the components of the synthesis gas produced from renewable energy sources. This will make it possible to adjust the gas production process in such a way as to achieve the highest possible energy and economic indicators of its utilization in the cogeneration plant. Keywords: internal combustion engine, synthesis gases, analysis of pressure