WÄRTSILÄ WARTSILA32, Руководство по эксплуатации продукта, Страница: 58 / 254

The connecting rods, at the same crank in the V-engine, are arranged side-by-side in order
to achieve standardisation between the in-line and V-engines.
The crankshaft is fully balanced to counteract bearing loads from eccentric masses. If
necessary, it is provided with a torsional vibration damper at the free end of the engine.
4.2.3 Connecting rod
The connecting rod is of forged alloy steel. All connecting rod studs are hydraulically tightened.
Oil is led to the gudgeon pin bearing and piston through a bore in the connecting rod.
The connecting rod is of a three-piece design, which gives a minimum dismantling height and
enables the piston to be dismounted without opening the big end bearing.
4.2.4 Main bearings and big end bearings
The main bearings and the big end bearings are of tri-metal design with steel back, lead-bronze
lining and a soft running layer. The bearings are covered all over with Sn-flash of 0.5-1 µm
thickness for corrosion protection. Even minor form deviations become visible on the bearing
surface in the running in phase. This has no negative influence on the bearing function.
4.2.5 Cylinder liner
The cylinder liners are centrifugally cast of a special grey cast iron alloy developed for good
wear resistance and high strength. Cooling water is distributed around upper part of the liners
with water distribution rings. The lower part of liner is dry. To eliminate the risk of bore polishing
the liner is equipped with an anti-polishing ring.
4.2.6 Piston
The piston is of composite design with nodular cast iron skirt and steel crown. The piston skirt
is pressure lubricated, which ensures a well-controlled lubrication oil flow to the cylinder liner
during all operating conditions. Oil is fed through the connecting rod to the cooling spaces of
the piston. The piston cooling operates according to the cocktail shaker principle. The piston
ring grooves in the piston top are hardened for better wear resistance.
4.2.7 Piston rings
The piston ring set are located in the piston crown and consists of two directional compression
rings and one spring-loaded conformable oil scraper ring. Running face of compression rings
are chromium-ceramic-plated.
4.2.8 Cylinder head
The cylinder head is made of grey cast iron. The thermally loaded flame plate is cooled efficiently
by cooling water led from the periphery radially towards the centre of the head. The bridges
between the valves cooling channels are drilled to provide the best possible heat transfer.
The mechanical load is absorbed by a strong intermediate deck, which together with the upper
deck and the side walls form a box section in the four corners of which the hydraulically
tightened cylinder head bolts are situated. The exhaust valve seats are directly water-cooled.
The valve seat rings are made of specially alloyed cast iron with good wear resistance. The
inlet valves as well as, in case of MDF installation, the exhaust valves have stellite-plated seat
faces and chromium-plated stems. Engines for HFO operation have Nimonic exhaust valves.
All valves are equipped with valve rotators.
A “multi-duct” casting is fitted to the cylinder head. It connects the following media with the
cylinder head:
●
charge air from the air receiver
4-2 Wärtsilä 32 Product Guide - a21 - 7 September 2016
Wärtsilä 32 Product Guide 4. Description of the Engine