| Popis: |
In the internal combustion engine, the details surrounding the combustion chamber—the cylinder head and the piston—are exposed to stresses from the action of variable gas force and variable heat load due to the combustion of fuel in the combustion chamber, while the temperature stresses are much higher than the stresses from the power load. Therefore, at the design stage of the new design of the internal combustion engine is calculated on the durability of heat-stressed parts, as they limit the reliability of the piston engine. The stages of creating and preparing a solid-state model of the cylinder head to create a finite element model are shown on the example of the diesel 8CHN12/13 (KAMAZ 740.75-440). The shape of the elements for the finite element model of the cylinder head was chosen from the condition of reducing the design time. It is shown that the high-frequency temperature fluctuations that occur as a result of the working process of the piston engine do not affect the thermal strength of the cylinder head, and the influence is exerted by high-frequency temperature fluctuations due to changes in the operating modes of the engine. The changes in the main characteristics of the aluminum alloy, from which the cylinder head is made, with temperature changes and with cyclic thermomechanical loads of low frequency are presented. It is shown that when the temperature increases, the endurance limit of the material decreases under low-frequency loads. |
