WÄRTSILÄ 46F Series, Product Manual

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exhaust side. The wastegate arrangement permits a part of the exhaust gas to bypass the
turbine in the turbocharger at high engine load.
Variable speed engines are additionally equipped with a by-pass valve to increase the flow
through the turbocharger at low engine speed and low engine load. Part of the charge air is
conducted directly into the exhaust gas manifold (without passing through the engine), which
increases the speed of the turbocharger. The net effect is increased charge air pressure at
low engine speed and low engine load, despite the apparent waste of air.
All engines are provided with devices for water cleaning of the turbine and the compressor.
The cleaning is performed during operation of the engine.
The engines have a transversely installed turbocharger. The turbocharger can be located at
either end of the engine and the exhaust gas outlet can be vertical, or inclined 45 degrees in
the longitudinal direction of the engine.
A two-stage charge air cooler is standard. Heat is absorbed with high temperature (HT) cooling
water in the first stage, while low temperature (LT) cooling water is used for the final air cooling
in the second stage. The engine has two separate cooling water circuits. The flow of LT cooling
water through the charge air cooler is controlled to maintain a constant charge air temperature.
4.2.15 Automation system
This engine is equipped with a modular embedded automation system, Wärtsilä Unified
Controls - UNIC.
The system version UNIC C2 has a hardwired interface for control functions and a bus
communication interface for alarm and monitoring.
An engine safety module and a local control panel mounted on the engine. The engine safety
module handles fundamental safety, for example overspeed and low lubricating oil pressure
shutdown. The safety module also performs fault detection on critical signals and alerts the
alarm system about detected failures. The local control panel has push buttons for local
start/stop and shutdown reset, as well as a display showing the most important operating
parameters. Speed control is included in the automation system on the engine.
All necessary engine control functions are handled by the equipment on the engine, bus
communication to external systems and a more comprehensive local display unit.
Conventional heavy duty cables are used on the engine and the number of connectors are
minimized. Power supply, bus communication and safety-critical functions are doubled on
the engine. All cables to/from external systems are connected to terminals in the main cabinet
on the engine.
4.2.16 Variable Inlet valve Closure, optional
Variable Inlet valve Closure (VIC), which is available as an option, offers flexibility to apply early
inlet valve closure at high load for lowest NOx levels, while good part-load performance is
ensured by adjusting the advance to zero at low load. The inlet valve closure can be adjusted
up to 30° crank angle.
4-4 DAAB605814
Wärtsilä 46F Product Guide 4. Description of the Engine