
Operation Manual / Power2 650-M / Low-pressure stage
1 Introduction / 1.5 Layout and function of the low-pressure stage
© Copyright 2022 ABB. All rights reserved.
HZTL4065_EN
Rev.E
March 2022
Mode of operation of the low-pressure stage (Power2 LP)
Fig. 3: Function of the low-pressure stage
Power2
Two-stage turbocharging
21
HP compressor
Power2 LP
Low-pressure stage
22
HP turbine
Power2 HP High-pressure stage
23*
Gas piping (bellows)
A
Exhaust gas inlet from internal combus-
tion engine
24
LP turbine
B
Exhaust gas outlet
25
LP compressor
C
Air or air/gas mixture inlet
26
Intercooler
D
Air or air/gas mixture outlet and supply
to the charge air cooler
- - -
Not included in the Turbo Systems
scope of delivery
*) If present
The low-pressure stage (Power2 LP) is a turbomachine and its main components are a tur-
bine and a compressor. These components are installed on a common shaft and form the ro-
tor.
In the low-pressure stage (Power2 LP) shown in the illustration
tion of the low-pressure stage
, the exhaust gas coming from the high-pressure
stage (Power2 HP) flows through the gas inlet casing (09) and the nozzle ring (10) and
reaches the turbine (11). The LP turbine uses the energy contained in the exhaust gas to
drive the rotor. The exhaust gases then reach the atmosphere through the gas outlet cas-
ing (07) and the exhaust gas pipe connected to it.
The rotor runs in two radial plain bearings (08). These are located between the compressor
and turbine and are guided in the bearing bush (06) and axial bearing (05). The plain bear-
ings are connected to a central lubricating oil duct which is normally supplied by the lubric-
ating oil circuit of the engine. The oil outlet lies at the deepest point of the bearing cas-
ing (12).
The LP compressor wheel (03) connected to the shaft sucks in fresh air or an air/gas mixture
through the filter silencer or the air suction branch (01). The air is compressed in the LP com-
pressor and the downstream diffuser (04). The compressed air is passed on to the inter-
cooler (26) via the compressor casing (13). The air is cooled in the intercooler (26) and sub-
sequently supplied to the HP compressor (21).
Using the injection ring (02), an air flow can be supplied upstream of the LP compressor
stage.
The blowby air can be supplied upstream of the LP compressor stage via the injection
ring (14).
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