A mixed lubrication model of the piston rings and cylinder liner system was developed,which considered the effects of the thermal deformation of the piston rings,the thermal and fitting deformation of the cylinder liner on the tribological performance of the piston rings and cylinder liner system.Meanwhile,the effects of the profile deformation of cylinder liner and piston ring and the conformability of piston ring on the ring leakage area,interring pressures,minimum oil thickness,frictional force and wear were taken into account.The results show that the deformation greatly affects the leakage area of top and second compression ring and the pressure between top and second compression ring.Considering the deformation,the frictional force of top compression ring is increased while the frictional force of second compression ring is decreased.It is found that the wear of top and second compression ring is uneven in circumferential and axial directions.Due to the good conformability of oil control ring,the deformation hardly affects its blowby and tribological performance.