Turbocharger NR 12 / S – Introduction of splash oil cooling Modification of locating bearing General
Cus 244 • 10/07
Splash oil cooling - already approved in larger MAN Diesel radial-flow turbochargers - stops coking of the lubricating oil on turbine side in case of high operating temperatures. Splash oil cooling is now also introduced into series for turbocharger NR12/S.
Reason
Depending on the condition and quality of the lubricating oil in connection with high operating temperatures, the area between sealing cover and piston ring was occasionally subject to oil coking in the past.
Function of splash oil cooling
Lubricating oil is splashed into the upper range of the sealing cover (517.017) and distributed by means of a borehole in the bearing casing (517.001). The oil flows into the lubricating oil drain via a U-shaped annular groove in the sealing cover. The surface temperature of the sealing cover is reduced until the formation of oil coke is stopped. The turbine rotor (520.001) and the sealing cover have been modified in this area (detail X) so that the lubricating oil is hindered from escaping between piston ring (520.032) and sealing cover (517.017) in each operating condition. NR12/S turbochargers can now be pre- or post-lubricated with the full oil pressure of max. 2.2 bar.
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A good post-lubrication after engine stop cools the casings of the turbocharger. It prevents an intrusion of heat into the bearing on turbine side and also the formation of oil coke in the piston ring area. In addition the varnishing of the turbine-side t urbine-side bearing bush (517.003) is prevented and consequently the service life of bearing bushes increased.
Modification of locating bearing
The introduction of splash oil cooling and corresponding increased service life of bearing bushes required a modification of the locating bearing (517.002). The splash ring (520.006) and the thrust ring (520.028) were also revised as a consequence there of.
Figure 2. Splash ring, locating bearing and thrust ring Please pay attention that a splash ring and a thrust ring of the Caution! Please
Montage
latest design is installed when fitting a new locating bearing. Otherwise a bearing damage is risked.
Lube oil pressure
Please check and, if necessary, adjust the lube oil pressure of 1.3 - 2.2 bar before turbocharger after installation of the new components.
Retrofitting
New turbochargers and cartridges are already equipped with splash oil cooling and modified bearing. Independent of splash oil cooling, future spare parts orders will exclusively delivered with the new locating bearing (517.002) including a new splash ring (520.006) and a new thrust ring (520.028). The rotor (520.001) and the sealing cover (517.017) are only available in the revised version.
MAN Diesel SE 86224 Augsburg Germany Tel. +49 821 322-4020 Fax +49 821 322-3998 E-Mail:
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Spare parts
Corresponding spare parts can be purchased via the turbocharger service of MAN Diesel SE.
Contact
Should you have any questions, please do not hesitate to contact our Technical Service Department: MAN Diesel SE 86224 Augsburg Germany Tel.: 0821 322-4020 Fax: 0821 322-3998 E-Mail:
[email protected]
Please forward this information to your technical operating personnel!
MAN Diesel SE 86224 Augsburg Germany Tel. +49 821 322-4020 Fax +49 821 322-3998 E-Mail:
[email protected] [email protected] 1
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