Research And Experimention On Thermoelastohydrodynamic Analysis Of Engine Main Journal Bearings

Internal-combustion engine develops face small volume, high power density, high rotation rate and heavy load. The paper takes main journal bearings of Multicylinder internal-combustion engine as objects to research. Under Systems Principles, being considered with surface topography effect, with elastic-deformation effect and thermal effect, thermoelastohydrodynamic(short for TEHD) analysis of the main bearings have been done. Meanwhile, lubrication conditions of a Multicylinder internal-combustion engine have been tested.Reynolds, friction power loss, lubricant flux and calefaction equation which are suitable for main bearings of internal-combustion engine have been inferred on the basis of surface lubricity.Loads of five main journal bearings are respectively calculated with determinate and indeterminate load computing methods after the methods are researched carefully. It makes clear that indeterminate load computing method is precise than determinate method. Lubrication calculation of main journal bearings should be based on the indeterminate load computing method.TEHD theory for main journal bearing has been discussed in detail. Extended Reynolds equation contained with lubricant fill ratio is introduced. Equations of solid elastic deformation, oil film enery, thermal conduction and loading are given as well as their boundary conditions. Being taken a diesel engine as as example, lubrication performances of five main journal bearings of it are calculated and analysed. In the dissertation, some valuable conclusions are illuminated after that the calculation method of TEHD is compared with that of EHD and HD.Various influence effects of main journal bearings of ICE are considered roundly. They are oil groove, relative axial clearance, ratio of width and diameter, poor oil, types of lubricant and density of lubricant. Some valuable conclusions are illuminated.On the guidance of Systems Principles, tribological design of main journal bearings of ICE is put forward. Two tribological design schemes of NO 3 main bearing of 4100QB diesel engine are given. Both of them enhance minimum oil film thickness and reduce friction power loss.Lubrication performances of main journal bearings of multicylinder ICE are tested in state key laboratory of engines. Oil film thicknesses which are measured by two non contact electric vortex sensors are synthesized to form center orbital path. Inlet oil temperature, oil film temperature and oil pressure etc on different operation condition are also synchronously measured. It can be found that the minimum oil film thickness calculated by TEHD method is close to that of measurement.