WÄRTSILÄ PAAE051728, Instruction Manual

Page: 315 / 394

20. Exhaust System
20.1 Exhaust manifold
20.1.1 General description
Data and dimension
Multiduct
Material:
Nodular cast iron
Weight: 60 kg
Test pressure: 10 bar
(water side)
Exhaust pipes
Material: Special, heat resis-
tant alloy nodular cast iron
Bellows
Multiply design
Material: Heat resistant steel
The exhaust manifold is fitted between the cylinder head and the
turbocharger. The manifold consists of the multiducts (3) and the
exhaust pipes (2) with expansion bellows (1). The manifold is
enclosed into an insulating box of sandwich design.
The turbocharging concept depends on the type of installation,
alternatively a specific type of pulse charging or a constant
pressure charging are used. The exhaust gases connected to one
pipe are discharged from each cylinder during the period when
the other cylinders connected to the same pipe have the exhaust
valve closed. This gives an equal flow of gases to the turbocharger
without any disturbing gas pulses to the other cylinders connected
to the common pipe.
The multiduct, between the cylinder head and the exhaust
pipes, acts as a bracket for the whole exhaust manifold, including
the insulation box. The multiduct is cooled by the cooling water
discharging from the cylinder head. The multiducts are vented
through a venting pipe along the engine. The cooling water flows
from the multiducts (3) through the water pipes (4) in the cooling
water box. The multiduct also connects the air receiver in the
engine block with the inlet air channel in the cylinder head. All
the surfaces, engine block/multiduct, cylinder head/ multiduct
and exhaust pipes/multiduct are sealed off.
Exhaust manifold
The multiduct is rigidly mounted towards the cylinder head.
The exhaust pipes are cast of special alloy nodular cast iron,
with separate sections for each cylinder. Metal bellows of multiply
type absorb the heat expansion.
1. Bellows
2. Exhaust gas pipe
3. Multiduct
4. Water pipe
1
3
2
4
Fig 20-1
4020019601
32-200045 Exhaust System 20
WÄRTSILÄ 32 20 - 1