Oil Film Thickness Measurement And Lubrication Analysis Of Cylinder Liner And Piston Ring Of The Opposed Piston Opposed Cylinder Engine

The opposed piston opposed cylinder(OPOC)engine has the advantages of light weight,high power density,good balance and the advantages of small vibration,greatly improving the fuel economy and power.However,compared with the traditional engine,arrangement of piston ring of the OPOC engine is changed.The piston ring is positioned in the piston pin hole on both sides,and the oil ring with the increasing distance of the top ring,resulting that the lubricating oil transportation in the oil ring to a ring becomes more difficult,which will affect a ring lubrication state of the top ring.Cylinder along the circumferential direction of the design of the inlet and outlet,reciprocating piston movement,the oil is taken away through the gas port,resulting in increased oil consumption.The horizontal arrangement of the cylinder body,due to the gravity factor,causes the lubricating oil to accumulate in the bottom of the piston skirt,so that the lubricating oil is relatively small.These problems have a great influence on the lubrication state of the cylinder piston ring of the OPOC engine,so it is necessary to study the lubrication state.According to the structural features of OPOC engine cylinder-piston ring group,through the transparent cylinder testing machine,the effects of different lubricating oil temperature and reciprocating piston speed on the lubrication film thickness of cylinder piston ring were studied;and the influence of piston rings barrel surface height and cross-section shape of piston ring change the law of piston ring lubrication oil film thickness of cylinder;and by numerical simulation method to calculate the thickness of cylinder piston ring close to the oil film under the actual conditions,providing the basis for the structure optimization of cylinder piston ring of OPOC engine.The results show that,when the piston reciprocating speed is constant,only changing the temperature of lubricating oil,the lubricating oil temperature has a great influence on the oil film thickness at low speed.When the piston reciprocating speed is higher,the oil temperature increases to the oil film thickness change is small.When the lubricating oil temperature is constant,only when the piston reciprocating speed is changed,the oil film thickness is affected greatly by the piston reciprocating speed at lower temperature.At higher temperature,the film thickness is affected by the piston reciprocating speed.Changing the height of the barrel and the section shape of the piston ring can improve the lubrication state of the OPOC cylinder piston ring.The numerical simulation results of the oil film thickness of cylinder piston ring of OPOC engine are presented.The minimum oil film thickness appears in the vicinity of the TDC,and the oil film thickness is distributed unevenly along the circumferential direction of the piston ring.