COMPUTER-AIDED SIMULATION OF PISTON AND PISTON-RING DYNAMICS

A numerical computer simulation program was developed, aiding it findi ng optimum design parameters in the multibody-system piston, piston-ri ngs, and cylinder with respect to optimum sealing, minimal friction, a nd minimum noise stimulation (impact impulse). In the simulation of pi ston secondary movement and piston ring motion, forces arising from th e combustion process, subsonic/supersonic gas flow between the combust ion chamber and the crank case, inertial forces and forces resulting f rom the hydrodynamic lubrication between cylinder liner and piston sha ft and piston rings and between piston ring flanks and piston grooves are considered In addition it is possible to account for effects of gl obal, three-dimensional ring deformation as well as local piston defor mation, roughness effects in lubricated contacts, and variable viscosi ty and variable oil supply. The governing differential equations for t he pressure as well as the deformation are solved via finite element t echniques, while initial value problems are solved by efficient implic it time integration schemes. The application of the developed computer code is presented iii examples.