ABB HT574400 Operation Manual page 35

Operation Manual / 4 Product description / A100-M axial
1 Introduction Page 5 / 113
Mode of operation
The turbocharger is a turbomachine and consists of the main components turbine and com-
pressor. These components are installed on a common shaft and form the rotor.
In the turbocharger shown in the illustration (see Figure 1), the exhaust gas flows through the
gas inlet casing (06) and the nozzle ring (07) and then reaches the turbine (08). The turbine
uses the energy contained in the exhaust gas to drive the rotor. The exhaust gases then reach
the atmosphere through the gas outlet casing (05) and the exhaust gas pipe connected to it.
The rotor runs in two radial plain bearings, which are located in the bearing bush (04) between
the compressor and the turbine. The axial bearing is also in the form of a plain bearing. The
plain bearings are connected to a central lubricating oil duct which is normally supplied by the
lubricating oil circuit of the engine. The oil outlet lies at the deepest point of the bearing cas-
ing (09).
The compressor wheel (02) connected to the shaft sucks in fresh air through the filter silencer
(01) or the air suction branch. The air is compressed further in the compressor and the down-
stream diffuser (03) and subsequently supplied to the charge air cooler via the compressor
casing (10).
Turbocharger version with compressor wheel cooling
Figure 2: Connection of the compressor wheel cooling
Depending on the application, the turbocharger is equipped with compressor wheel cooling.
With compressor wheel cooling, after the compressor air has cooled down by passing through
the charge air cooler on the engine side, it is supplied to the turbocharger for cooling the com-
pressor wheel.
Cooling of the compressor wheel is compulsory to ensure the reliability and replacement inter-
vals for the relevant operating conditions. In the turbocharger version with compressor wheel
cooling, the cooling air is supplied through the lateral connection (15) in the bearing casing
© Copyright 2016 ABB. All rights reserved. HZTL4033_EN Revision A July 2016