The Influence of the Wear of Diesel�s Cylinder Group on the Temperature State of Piston

Abstract

Forcing of ship internal combustion engines at the average effective pressure is accompanied by an increase in the maximum cycle pressure, an increase in the thermal stress of the cylinder-piston group parts and an intensification of their wear. Wear of parts of the cylinder group leads to an increase in the gap between the piston and the cylinder mirror. The consequence of increasing the gap is a decrease in heat transfer from the piston to the cylinder walls and an increase in the breakthrough of gases having a high temperature from the combustion chamber to the gap. A critical increase in the temperature of the piston can lead to its destruction and engine failure. The most typical types of piston failure are presented in the article. The aim of the research was to assess the influence of these two factors on the temperature condition of the piston. Calculation of heat transfer processes in the annular channel, performed using differential equations of energy and continuity, as well as the criterion equations of fluid flow in flat channels allowed to determine the temperature of the gases and the lateral surface of the piston at different values of the gap between the piston and the cylinder sleeve and different gas flow rates in the gap. The calculation was performed for the engine CHN 18/20, having a piston made of aluminum alloy. It was found that the increase in the number of gases entering the gap from the combustion chamber has a more significant effect on the temperature condition of the piston compared to the gap, increasing due to wear of the engine cylinder group parts. It is concluded that the number of gases with high temperature entering the gap leads to a significant increase in the temperature of the piston. The increase in the temperature of the piston due to wear of the parts of the cylinder group must be taken into account when determining its heat-stressed state. To ensure the permissible temperature level of the piston during operation, it is necessary to develop design and technological measures aimed at reducing the flow of gases through the gap between the piston and the cylinder mirror. Keywords: marine internal combustion engines, parts of cylinder and piston, wear, gas breakthrough, heat transfer in flat channels, the temperature condition of the piston, the reliability of marine diesel engines.

Influence of operational factors on the properties of working fluids of piston engines

“…Internal combustion piston engines (ICE) are the main element of power plants of road, rail and water transport, as well as stationary installations for various purposes [1,2]. The economic, resource and environmental performance of the internal combustion engine is influenced by both the operating conditions [3,4] and the quality of operating materials, which include fuel, engine oil and coolant and the parameters of lubrication and cooling [5,6]. The problems of improving the quality of operational materials due to the impact on their composition are solved in works [7,8].…”