Fuel Injection Equipment; Cooling Water System - Wartsila 31 Product Manual

4. Description of the Engine
See chapter Exhaust gas & charge air systems for more information.
4.2.11

Fuel injection equipment

The fuel injection equipment and system piping are located in a hotbox, providing maximum
reliability and safety when using preheated heavy fuels. In the Wärtsilä electronic fuel injection
rate optimized nozzles system, the fuel is pressurized in the high pressure HP-pumps from
where the fuel is fed to the injection valves. The fuel system consists of different numbers of
fuel oil HP pumps, depending of the cylinder configuration, located at the engine pump cover.
From the HP pumps, high pressure pipes are connected to the cylinder heads.
A valve block is mounted at the fuel outlet pipe, including Pressure Drop and Safety Valve
(PDSV), Circulation Valve (CV) and a fuel pressure discharge volume. The PDSV acts as
mechanical safety valve and the fuel volume lowers the system pressure. The injection valves
are electronic controlled and the injection timing is pre-set in the control system software. The
injector solenoids have a own cooling system.
4.2.12 Lubricating oil system
The engine internal lubricating oil system include the engine driven lubricating oil pump, the
electrically driven prelubricating oil pump, thermostatic valve, filters and lubricating oil cooler.
The lubricating oil pumps are located in the free end of the engine, while the automatic filter,
cooler and thermostatic valve are integrated into one module.
4.2.13

Cooling water system

The fresh water cooling system is divided into a high temperature (HT) and a low temperature
(LT) circuit.
For engines operating in normal conditions the HT-water is cooling the cylinders (jacket) and
the first stage of the low pressure 2-stage charge air cooler. The LT-water is cooling the
lbricating oil cooler, the second stage of the low pressure 2-stage charge air cooler and the
high pressure 1-stage charge air cooler.
For engines operating in cold conditions the HT-water is cooling the cylinders (Jacket). A
HT-water pump is circulating the cooling water in the circuit and a thermostatic valve mounted
in the internal cooling water system, controls the outlet temperature of the circuit. The LT-circuit
is cooling the Lubricating Oil Cooler (LOC), the second stage of the Low Pressure 2-stage
charge air cooler, the High Pressure 1-stage charge air cooler and the first stage of the low
pressure 2-stage charge air cooler. An LT-thermostatic valve mounted in the external cooling
water system, controls the inlet temperature to the engine for achieving correct receiver
temperature.
4.2.14 Exhaust pipes
The exhaust manifold pipes are made of special heat resistant nodular cast iron alloy.
The complete exhaust gas system is enclosed in an insulating box consisting of easily
removable panels. Mineral wool is used as insulating material.
4.2.15 Automation system
The Wärtsilä 31 engine is equipped with an UNIC electronic control system. UNIC have
hardwired interface for control functions and a bus communication interface for alarm and
monitoring. Additionally UNIC includes fuel injection control for engines with electronic fuel
injection rate optimized nozzles.
For more information, see chapter Automation System.
4-4
Wärtsilä 31 Product Guide
Wärtsilä 31 Product Guide - a1 - 18 October 2016