Structural And Functional Outline - Yanmar 3TNV Series Service Manual

8.1.3 Structural and functional outline

No. Part name
1 Turbine shaft
2 OiN thrower
3 Turbine side seal ring
4 Seal plate
5 Journal bearing
6 Thrust bearing
7 Compressor housing
8 M5 hexagon bolt
9 M5 spring washer
10 Compressor side clamp
11 Turbine housing
12 M6 hexagon bolt
13 Turbine side clamp
14 Lock washer
15 Bearing housing
16 Retaining ring
17 M3 countersunk flat head screw
18 Compressor wheel
19 Shaft end nut
20 Heat protector
(1) Turbine
The exhaust gas from the engine is accelerated at the nozzle portion in the turbine housing and blown
onto the turbine impeller to rotate the turbine shaft.
This is called the turbine. A seal ring and heat insulating plate are installed to prevent the bearing from
adverse influence of the gas.
(2) Compressor
The compressor impeller installed on the turbine shaft rotates with the shaft to suck and compress air
for feeding into the intake manifold.
This is called the blower or compressor.
(3) Bearings
Thrust bearing
As the turbine shaft is constantly applied with a thrust force, this bearing prevents the shaft from
being moved by the thrust force.
Radial bearing
A floating bearing is adopted. Since the bearing moves with the turbine shaft as the oil films are
formed both inside and outside the bearing, the bearing sliding speed is slower than the turbine shaft
speed, resulting in higher dynamic stability.
(4) Compressor side sealing mechanism
To prevent the intake air and oil form leaking, a seal ring and a seal plate are provided to form a double
wall structure on the rear side of the compressor impeller.
(5) Waste gate
When the blower side pressure (intake air pressure) exceeds the specified level, the exhaust gas at the
turbine inlet is partially bypassed to the exhaust discharge side to control the turbine rpm so as to
maintain the intake pressure at the specified level for improving the response to load variation in the low
to medium speed range and to minimize black smoke generation. It consists of a control assembly
separated from the turbocharger and a valve assembly installed in the turbine impeller chamber.
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8. Turbochager