MAINTENANCE MANUAL OF GW4D20/GW4D20B TURBOCHARGED DIESEL ENGINES
446
Great Wall Baoding Internal Combustion Engine
Manufacturing Company Limited
Chapter IX Turbocharging System
Section I General
Fig. 9-1-1 VGT turbocharger assembly
Fig. 9-1-2 WGT turbocharger assembly
Fig. 9-1-3 Gas compressor and turbine of the
turbocharger
1. Turbocharging system composition
The turbocharging system is made up of the intake and
exhaust systems and the turbocharger. Based on
different
configuration
requirements,
GW4D20
turbocharged diesel engine is equipped with the VGT
turbocharger (variable geometry turbocharger, see Fig.
9
–1-1), while GW4D20B turbocharged diesel engine is
equipped with the WGT turbocharger (turbocharger with
bypass valve, see Fig. 9
–1-2).
2. Turbocharger structure
The turbocharger is generally made up of the following
three parts: the turbine, the intermediate body and the
gas compressor. The VGT turbocharger is equipped
with the VGT actuator while the WGT turbocharger is
equipped with the bypass valve.
2.1 Turbine part
The turbine part mainly consists of the turbine housing
and the turbine, which act as energy converters.
Through the turbine housing, the exhaust gas produced
by the diesel engine enters the nozzle and injects to the
turbine impeller with a certain angle. Thus the heat and
pressure energies of the exhaust gas are converted into
kinetic energy, which rotates the turbine at a high
speed, as shown in Fig. 9-1-3.
2.2 Intermediate body
The intermediate body is the middle support used to
support the rotor assembly and fix the turbine housing
and the gas compressor housing, and the lubricating oil
tank used for lubricating and cooling floating bearing, as
shown in Fig. 9-1-4.
2.3 Gas compressor part
The gas compressor part mainly consists of the gas
compressor impeller, the diffuser, and the housing of the
gas compressor, as shown in Fig. 9
–1–3.Through the
air cleaner, the air is sucked into the gas compressor
impeller rotating at a high speed so that the air flow
velocity and pressure are boosted. Through the diffuser
and the gas compressor housing, the kinetic energy of
the air flow is converted into the pressure energy, which,
after further boosting, will enter the cylinder via the air
intake manifold pipe of the diesel engine, so as to
increase the density of its inlet air.
The turbine shaft and the turbine are connected by
friction welding. The impeller of the gas compressor is
installed at the turbine shaft by means of transition fit
Gas compressor
housing
Turbine housing
Turbine exhaust
outlet
Air inlet of the
gas
compressor
Gas
compressor
impellor
Turbine
impellor
Turbine
exhaust inlet
Air outlet of the
gas compressor
