The piston ring-cylinder liner (PRCL) system,especially the top ring-cylinder liner pair,is under starved lubrication,which is beneficial for reducing the lubricant consumption and related emissions.Under starved lubrication,the lubricating oil film between the piston ring and the cylinder liner is difficult to re-form after rupture in the outlet zone.At the same time,the gas bearing effect is also difficult to ignore under the high boundary pressure near the combustion top dead center.Therefore,based on the average Reynolds equation and no-reform boundary conditions,the lubrication,contact and gas bearing of the top ring-cylinder liner of a diesel engine was analyzed.The research results show that under starved lubrication conditions,the influence of high boundary pressure is quite significant because there is no re-form after the oil film ruptures.For high combustion pressure engines,the gas bearing between the top ring and the cylinder liner is even greater than the oil film bearing capacity and contact bearing capacity.