FUEL OIL SYSTEM OF DIESEL ENGINE

lovelymimiko@blogspot.com

The fuel oil system for a diesel engine can be considered in two parts—the fuel supply and the fuel injection systems. Fuel supply deals with the provision of fuel oil suitable for use by the injection system.

Fuel oil supply for a two-stroke diesel

A slow-speed two-stroke diesel is usually arranged to operate continuously on heavy fuel and have available a diesel oil supply for manoeuvring conditions. In the system shown in Figure 2.11, the oil is stored in tanks in the double bottom from which it is pumped to a settling tank and heated. After passing through centrifuges the cleaned, heated oil is pumped to a daily service tank. From the daily service tank the oil flows through a three-way valve to a mixing tank. A flow meter is fitted into the system to indicate fuel consumption. Booster pumps are used to pump the oil through heaters and a viscosity regulator to the engine-driven fuel
pumps. The fuel pumps will discharge high-pressure fuel to their respective injectors. The viscosity regulator controls the fuel oil temperature in order to provide the correct viscosity for combustion. A pressure regulating valve ensures a constant-pressure supply to the engine-driven pumps, and a pre-warming bypass is used to heat up the fuel before starting the engine. A diesel oil daily service tank may be installed and is connected
to the system via a three-way valve. The engine can be started up and manoeuvred on diesel oil or even a blend of diesel and heavy fuel oil. The mixing tank is used to collect recirculated oil and also acts as a
buffer or reserve tank as it will supply fuel when the daily service tank is empty. The system includes various safety devices such as low-level alarms and remotely operated tank outlet valves which can be closed in the
event of a fire.