Results of modeling the secondary kinematics of the piston in the cylinder of a high-speed diesel engine
The relevance of the investigation of the processes of secondary kinematics of the piston in the internal combustion engine’s cylinder is due to their strong influence on such indicators as mechanical losses, wear, noise, vibration, oil consumption, and their insufficient knowledge concerning high-speed piston engines. The purpose of the research was an assessment of the influence on the character of the secondary kinematics of the piston of the high-speed internal combustion engine design factors, operating conditions and lubricant and on this basis finding the ways to improve the lubrication and friction conditions in coupling of the «cylinder-piston skirt». The tasks to be performed to achieve the research goal were in an identification the most significant parameters of the construction on the piston's secondary kinematics, mode of operation and properties of the lubricant; obtaining diagrams of the piston's secondary kinematics depending on the change in the values of the influencing factors, as well as the analysis of the obtained results and the development of recommendations aimed at reducing friction and wear in the piston-cylinder-unit. For the subject of the research the piston of the high-speed diesel engine 1CH 8,5/8,0, having a barrel-shaped profile of the piston skirt in the serial production and a negative dezaksial of piston pin, was chosen. The research method is mathematical modeling using the calculation program PISTON-DHT. Discussion of the obtained results made it possible to reveal the two most influential parameters on the character of the secondary kinematics of the piston: the dezaksial of piston pin and piston skirt profile. The variation of the sign and the values of these indicators were established an expedience to switch from a negative one to the positive dezaxial and an application of rational profile of the piston skirt. For the two most dynamically loaded strokes of the working cycle «Compression» and «Expansion», the dominance of the piston movement in the position of the scraper relative to the adjacent side of the cylinder wall was highlighted. The generalized recommendations aimed at eliminating the dominance of this undesirable situation can be taken into account and used in the design and completion of high-speed internal combustion engines pistons in order to minimize mechanical losses and wear.