Modelling of piston secondary motion in Diesel Engines
A numerical simulation model of the piston motion has been discussed in the present work. The proposed methodology was used to analyze the secondary motion of piston skirt about wrist pin axis as well as resulting vibrations of engine block due to impacts of piston skirt along cylinder liner. Various dynamic parameters used in the simulation of motion were calculated using mechanical mobility which was obtained by means of vibration measurements. The amplitude of lateral motion was found to be in -5μm to 20μm range with piston sliding for some crank angle duration before reaching TDC position. Furthur COMSOL software was used to analyze the piston motion. The simulated motion thus obtained correlated well with that obtained from solving motion of piston dynamics, thus validating the proposed model of piston secondary motion.