Abstract
Now days most of the internal combustion engines are turbochargerd using different mehods. With in all this methods of charging engines this paper is focused on the issue regarding construction of turbochargers bearings. Turbocharging always raised from the very begining major problems related to noise and vibration traced to the turbocharger. Because European Union rules require a certain level of noise of the assemblies of the vehicle, requirements are imposed to decrease the level up to a threshold to counteract the phenomenon of noise poluttion produced by vehicles. Also at the level of the internal combustion engine and the auxiliary equipements in this case the turbocharger it is imposed a reliability of 160000 miles without maintenance interventions.
Currently the criterion of reliability is established in proportions of 50% which is approximatly 80000 miles of operation without maintenance interventions. Vibration and noise produced by the turbochargers come mainly from the elastic rolling bearings. Current models impose the use of hybrid bearings constructed of ceramic balls and steel runing track. The main problem of these hybrid bearings is the manifestation of vibration phenomena with high amplitude level resulting in some cases with the destruction of the bearing.
Elements considered in this paper work regard a compartive study on hidrodynamic bearings currently used in the construction of turbochargers and the ceramic ball bearings presented as innovations in the construction of turbocharges. The study aims a pertinent analysis of component data and construction elements of the two types of bearings described above. As critical points the paper evaluate issues of: reliability, vibration, noise and friction torques of turbochargers bearings.
Keywords: bearings , turbochargers, vibration, hydrodinamic