WÄRTSILÄ WARTSILA32, Руководство по эксплуатации продукта, Страница: 155 / 254

and there is also a risk of compressor surging as the compressor is out of the specified
operation area ().
At low engine loads and during engine starting, the combustion air is still below zero degrees
Celsius after the compressor and it cools down the engine. There is a risk of overcooling the
engine as a result.
Fig 10-4 Example of influence of suction air temp on charge air pressure & firing
pressure at 100% load
10.2.3.1 Ensuring correct compressor performance
The cylinder peak firing pressure can be limited by using waste gates on the engine. Exhaust
gas waste gate (EWG) is used to reduce the turbocharger speed by bypassing the turbine
stage and thus reducing the charge air pressure in the charge air receiver.
Similarly air waste gate (AWG) is used to reduce the charge air pressure by bleeding air from
the charge air receiver. The air from the air waste gate is blown out either to outside of the
vessel or into the engine room. In both cases installing a silencer after the air waste gate is
recommended. If the air waste gate is located before the charge air cooler, the air must be
blown outside of the vessel via a separate air duct as the air temperature right after the
compressor can rise up to 200°C. An example scheme of air waste gate and exhaust gas
waste gate arrangement is shown in the .
Wärtsilä 32 Product Guide - a21 - 7 September 2016 10-5
10. Combustion Air System Wärtsilä 32 Product Guide