WÄRTSILÄ AL20 Assembly instructions

CHARACTERISTICS
Water-cooled 6-, and 8-cylinder in-line-engines.•
Four stroke, direct fuel injection.•
Turbocharger and charge air cooling.•
Cylinder heads with 4-valve technology.•
Power-take off on both ends of crankshaft.•
Engine driven pumps on free end of crankshaft.•
BENEFITS
High reliability of the engine.•
Low operational costs due to easy maintenance and long maintenance intervals.•
Low fuel and lubricating oil consumption.•
Clean combustion, even on part load•
AL20
MDO: 450-820 kW at 720-1000 min-1
HFO: 420-760 kW at 720-1000 min-1
TOTAL SERVICE
SULZER 4-stroke ENGINES

ENGINE DESCRIPTION
Crankcase Single-piece cast-iron crankcase with underslung crankshaft.
Drillings in the block for water and oil distribution to reduce the pipe work.
Crankshaft The crankshaft is of low alloy steel, forged in one piece and fully machined.
Counterweights on all cranks. A torsional vibration damper can be fitted to the free end.
Main bearings Thin-walled bearing shells fitted to both the main bearings and the big end bearings.
Connecting rods Drop-forged from alloyed steel and fully machined.
The big ends have a serrated joint.
Big end bearings Identical to the main bearings.
Pistons One part piston for operation on MDO, two part piston for HFO operation. With 3 chromium
plated piston rings and 2 scraper rings. Fully floating piston pin.
Cylinder heads The cylinder heads are made of special cast iron and are fitted with two inlet and two exhaust
valves. Nimonic alloy valves with rotators for engines operating on HFO.
Camshaft The camshaft consists of individual segments, one for each cylinder.
Fuel injection pumps Individual helix-controlled fuel injection pump for each cylinder.
Governor The governor is of Woodward UG8 / PGA12 type.
Turbocharger The turbocharger is mounted on the front end. ABB VTR type or Napier.
Pump drive The oil pump, cooling water pump and fuel booster pump are mounted on the front end.
Provision is made for driving an extra cooling water pump.
Fuel system The fuel system is pressurized by a built-on feed pump. Fuel circulates over the fuel day tank.
Optionally, external fuel supply is possible.
Lubricating oil system A built-on gear pump supplies oil flow and pressure. Oil flows through a cooler and filter before
entering the engine. Optionally, a centrifugal filter is installed.
Starting air system The engine is started by means of direct air starting. The system supplies starting air to the
individual cylinder heads via the main starting valve. Control air derived from the starting air is
used to control the individual starting valves.
Cooling water system The cooling water system is divided in a high temperature and a low temperature system. High
temperature cooling water is used for jacket cooling, low temperature is used for charge air
cooling and lubricating oil cooling.
Exhaust gas system Exhaust system is of pulse type.
Classification Classification performed by engine manufacturer.
Emission regulations Emission regulations are not applicable for these engines, because most engines were built
before the IMO / EIAPP era (before 2000).

TECHNICAL DATA
TECHNICAL DATA
Engine type AL20
Model 6AL20 8AL20
Number of cylinders 6 8
Bore / stroke mm 200 / 240
Displacement l 45 60
MEP bar 16.39 - 16.80
Direction of rotation Clockwise or counter-clockwise, non-reversible
Power ratings
HFO 1)
at 720 min-1 kW 420 560
at 750 min-1 kW 432 576
at 900 min-1 kW 525 700
at 1000 min-1 kW 570 760
MDO
at 720 min-1 kW 450 600
at 750 min-1 kW 468 624
at 900 min-1 kW 570 760
at 1000 min-1 kW 615 820
General data
Specific fuel consumption 2)
at 900 min-1 g/kWh 213
at 1000 min-1 g/kWh 213
1) Up to 500 cST/50 °C viscosity in marine auxiliary applications and 380 cST/50 °C viscosity in marine propulsion and stationary applications.
2) For net caloric value 42 707 kJ/kg (10 200 kcal/kg) and ISO-standard reference condition.
Power declarations based on the following ISO standard reference conditions:
27 °C intake air temperature, 27 °C charge air coolant temperature, barometric pressure 1000 mbar, relative humidity 60%.
Note: The values given in this document are for information purposes only and not binding.

WARTSILA.COM
Wärtsilä Netherlands B.V.
P.O. Box 10608, 8000 GB Zwolle, The Netherlands zTel. [phone]
zFax [phone] ze-mail [email protected] zwww.wartsila.com
AE
F
B
C
D
DIMENSIONS
0910 WNL0091
PRINCIPAL ENGINE DIMENSIONS (mm) AND WEIGHTS (t)
Engine
type
type A B C D E F
Weight
Weight
6AL20 2780 1620 340 1190 792 1060 6.4
8AL20 3530 1620 340 1350 792 1160 8.2
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