The Effect Of The Lubrication System On The Stability Of The Turbocharger Rotor System

Turbochargers have been widely applied according to the development trend of the engine.The turbine which is driven by exhaust gas rotates with a high speed, leading to the impellerlinking with the turbine by the rotor compress the fresh air. Turbochargers’working speed couldeasily reach200000r/min,the working temperature700℃.Under such extreme workingconditions,even a weak vibration can lead to the failure and the whole turbocharger destroyed.Itis necessary to research the stability of turbocharger rotor.As the supporting,the dynamiccharacteristics of the floating bearing affect the stability of the turbocharger rotor system. Goodlubrication and cooling are basic guarantee. The purpose of this paper is to study the effect ofthe lubrication system on the stability of the turbocharger rotor system by testing, including thefollowing sections:1) Study the structure of typical turbochargers, its rotor system and lubricationprocess.The analytical expressions of the hydrodynamic pressure distribution in thefloating ring bearing are derived. Analyse the lubrication of the floating bearing underdifferent oil inlet pressure.2) Presents a method of calculation of the turbochargers’ critical speed.A finite elementmodel is then developed for the turbocharger rotor system.,then the natural frequencyis obtained. Under different stiffness coefficient, the influence of the floating bearingon the turbocharger rotor have been studied.3) A turbocharger test rig is then designed and developed to monitor the turbochargershaft motion. Write a program by using Labview to finish the test after completing thehardware and the software system.4) Process the data by Matlab. The trajectory of the turbocharger shaft,waterfalldirgram,the displacement and sepctrum of the turbocharger shaft under differentpressure are used to discuss the influence of the oil inlet pressure on theturbocharger rotor system.