Open AccessANALYSIS OF THE ENGINE STRUCTURAL AND THERMAL STRESS
Author(s) -
Liviu Constantin Stan
Publication year - 2021
Publication title -
journal of marine technology and environment
Language(s) - English
Resource type - Journals
eISSN - 2501-8795
pISSN - 1844-6116
DOI - 10.53464/jmte.02.2021.09
Subject(s) - piston (optics) , mechanical engineering , four stroke engine , cylinder , cylinder head , stress (linguistics) , flow (mathematics) , thermal , engineering , mechanics , combustion chamber , internal combustion engine , combustion , physics , linguistics , chemistry , philosophy , organic chemistry , wavefront , meteorology , optics
The paper aims to analyse the demands of four-stroke naval pistons. To begin with, a brief analysis of the evolution of shipbuilding was made. Mechanical requests are produced by the gas pressure force and inertial force of the alternate moving masses. Under its action the piston suffers an axial deformation. The thermal demands appearing in the engine are all the more important as the engine power is higher. The possibility of calculating them is more difficult due to the complexity of the thermogazodynamic phenomena in the engine cylinder. Thus, in the piston head, which comes in contact with both the hot gases and the fresh (much cooler) load, a non-stationary heat flow is installed which leads to a certain thermal regime of the engine. Considering the demands outlined in the last chapter, they lead to the final conclusion that although the most unfavourable loading situation was considered as the maximum pressure during the processes and even exaggerated in establishing the working conditions, the piston is still close to the elastic limit. This demonstrates that the way of calculating the dimensions of the piston is correct and safe, as long as its constructive dimensions are not oversized.