Research On The Lubrication Of Piston Ring And Its Influence On The Torsional Vibration Of Shafting Considering The Particle Effects

Piston ring-cylinder friction pair has a significant impact on the internal combustion engine power,economy,reliability and so on.Due to external factors and their own wear will form solid particles in oil so that the piston ring-cylinder friction pair is in liquid-solid two-phase lubrication.Solid particles have an important influence on the lubrication characteristics of the piston ring-cylinder liner friction pair,and harder solid particles embedded in the cylinder liner which form furrows cause abnormal wear on the cylinder liner surface.The presence of solid particles in the lubricating oil will affect the friction torque during the movement of the friction pair,which will affect the torsional vibration of the shaft.Studying the effect of particles on the torsional vibration of the shaft contributes to detect this anomaly by torsional vibration.In this paper,the influence of solid particles on the lubrication performance was investigated by establishing a friction-pair lubrication model of piston ring-cylinder liner with solid particles.Then,a torsional vibration model was established for solid particles containing lubricating oil influences.First of all,based on the average Reynolds equation,the paper considered the circumferential ellipticity of the liner and established piston ring-cylinder friction pair three-dimensional hydrodynamic lubrication model which contained solid particals.Based on the assumption of spherical solid particles,considering the particle's elasticity,elasto-plasticity and complete plastic deformation,established the bearing model of solid particles.The furrow effect of the particles was considered,and the lubrication characteristics under the action of the particles and the equivalent wear depth of the cylinder liner surface was calculated and analyzed.The effects of different particle size,concentration and the structural characteristics of piston rings on the lubrication performance of piston ring-cylinder liner were investigated.Secondly,this paper simulated the friction pair lubrication of piston ring-cylinder liner with solid particles on reciprocating friction test machine,and obtained the influence law of oil film pressure,oil film thickness and friction force.The parameters of the particle size as well as the material property parameters such as the elastic modulus and yield strength were respectively measured through a microscope and an electronic universal testing machine.Then carried out the lubricant containing particles in the liquid-solid two-phase friction test on the reciprocating friction test machine to prove the accuracy of the lubrication model.Finally,based on the particle-containing lubrication model established above,the inertiaparameters of each part of the reciprocating friction tester were obtained by the finite element method,and the torsional vibration model of the shafting considering the friction torque was established.The torsional vibration of the friction tester whether contained particles or not was calculated and verified by experiments.The effect of solid particles on the torsional vibration of the shaft was investigated.Based on the fact that there are solid particles in the oil,the liquid-solid two-phase lubrication model of the piston ring-cylinder liner friction pair with solid particles was established and verified by experiments.At the same time,the influence law of particle lubrication on torsional vibration was analyzed.Analysis through lubrication shows that the particles pass thickening and bearing lead the minimum thickness of the oil film becomes thicker,the oil film pressure decreases and the friction force increases,which not only increases the friction energy consumption between the piston ring and the cylinder liner but also leaves the furrow surface of the cylinder liner destroying the cylinder liner surface;On the other hand,torsional vibration results show that the particles have a great influence on the2,4 harmonic torsional amplitudes of the torsional vibration of the shaft.These conclusions provide the basis for abnormal wear on the liner surface by torsional vibration testing.