Experimental Investigation On Lubricating Oil Film Of Main Bearing For Internal Combustion Engine

The main bearing is one of the most important friction pair in internal combustionengine. The economy, reliability, durability and lifetime of internal combustion engineare affected directly by the status of the lubricating oil fim of main bearing. Thelubrication status and operating reliability of main bearing can be reflected anddetermained clearly by the transient lubrication oil film of main bearing measured inexperiment.In this paper, an internal combustion engine is taken as the studying object, the oilfilm thickness and temperature of the main bearing are measured at different conditionswith three kind of oil in the test bed of internal combustion engine. The collecting dataare dealed with by the program, and the orbit of journal center and the minimum oil filmthickness of main bearing are obtained. Based on the experimental data, the influencingfactors on the measurement error of the lubricating oil film of main bearing are analyzed.The results show that:The temperature of the main bearing, the oil in the main oil gallery and the oil in theoil pan will increase when the speed or load of engine increases. The larger the oilviscosity, the higher the temperature of the main bearing, the oil in the main oil galleryand the oil in the oil pan at same operating condition. The overall shape of the journalcenter orbit of main bearing is affected rarely by the engine load at same engine speed.The overall shape of the journal center orbit of main bearing is affected remarkably bythe engine speed at same engine load. The lubrication status of main bearing is notaffected obviously by different oil at same operating condition of engine. The minimumoil film thickness of main bearing in one engine operating cycle is affected notobviously by engine load at the same engine speed. The minimun value of the minimumoil film thickness of main bearing in one engine operating cycle will decrease when theengine load increases at low engine speed. There is obvious change rule of the minimunvalue of the minimum oil film thickness of main bearing in one engine operating cyclewhen the engine load increases at high engine speed. The location of the minimun valueof the minimal oil film thickness of main bearing in one working cycle of internalcombustion engine is different at different speed. The measuring accuracy of journal center orbit of main is affected not obviously bymounting angle deviation of eddy current sensor if the deviation is smaller than1°. Thelarger the maximum errors of the position angle and eccentricity ratio of journal centerorbit of bearing, the larger the devition of sensor mounting angle. The maximum errorsof the eccentricity ratio and position angle of main bearing in one engine operatingcycle decrease when the mounting angle of eddy current sensor increases at samedeviation of mounting angle of eddy current sensor.The measuring accuracy of journal center orbit of main is affected remarkably by thedeviation of bearing radius clearance. The larger the maximum errors of the eccentricityratio and position angle of main bearing in one engine operating cycle, the lager themounting angle of eddy current sensor at same deviation of bearing radius clearance.