Lube oil and fuel oil systems

DOE-HDBK-1012 §3-1

Fluid properties and flow regimes Fluid flow is the study of liquids and gases in motion and the energy relationships within a moving fluid. Key properties are density (mass per unit volume), specific volume (its reciprocal), and viscosity (a fluid's resistance to shearing, i.e. its internal friction). Thick, high-viscosity fluids such as cold lube oil resist flow and require more pumping power; heating a fuel or lube oil lowers its viscosity so it flows and atomizes readily, which is why fuel-oil heaters are fitted ahead of purifiers and burners. Liquids are essentially incompressible (constant density), while gases are compressible and change density with pressure and temperature. Flow through a pipe falls into two regimes distinguished by the Reynolds number, which compares inertial to…

NAVEDTRA 14075 §3-2

Fuel-oil systems, service, and injection timing The fuel-oil system delivers clean, correctly conditioned fuel from the storage tanks to the injectors. Fuel is drawn from bunker (storage) tanks, may be transferred to settling tanks where water and heavy sediment settle out and are drained, and then to service (day) tanks that feed the engine. Heavier fuels are heated to bring their viscosity down to the value needed for good pumping and atomization. From the service tank a supply pump sends the fuel through duplex filters (arranged so one can be cleaned while the other stays in service) to the injection equipment; a water separator removes free water, which otherwise corrodes injectors and disrupts combustion. Clean fuel is essential because the injection plunger and nozzle clearances are…

NAVEDTRA 14075 §3-3

Lubricating-oil systems The lubricating-oil system reduces friction and wear, cools the moving parts, carries away metal and combustion debris, cushions bearing shock loads, and helps seal the piston rings. In a typical wet-sump engine, a gear pump draws oil from the sump through a suction strainer and delivers it under pressure through a full-flow filter and a lube-oil cooler to the main bearings, connecting-rod bearings, camshaft, valve gear, and — through drilled passages or spray nozzles — to the underside of the piston crowns for cooling. A relief valve holds system pressure and a bypass allows oil to keep flowing if the filter or cooler becomes restricted. Large engines use a dry-sump system with a separate lube-oil tank and both pressure and scavenge pumps. Oil condition is monitor…

NAVEDTRA 14075 Ch. 3 — And Controls

The fuel system is one of the most complicated of all engine systems; therefore, special care must be exercised when making adjustments and repairs. Even though manufacturers have designed many different fuel systems, the basic principle involved is the same in all of them. If you understand the basic principle for one system, you will have no difficulty in becoming familiar with other systems. The procedures for the maintenance and repair of the various systems are also similar. Let’s review briefly not only the function of a fuel system but also the various types of fuel systems. As you know the function of a fuel injection system is to deliver fuel to the engine cylinders under specific conditions: at a high pressure, at the proper time, in the proper quantities, and properly atomized. …

NAVEDTRA 14075 Ch. 3 — Lubricating System

To ensure that all the parts of an engine receive adequate lubrication, it is essential that all parts of the lubricating oil system be properly maintained at all times. Some parts which may be a source of trouble are considered in this section. For other information on lubricating systems, see Engineman 3 & 2, NAVEDTRA 10541 (current edition).

NAVEDTRA 14075 Ch. 9 — Engine Maintenance ¶2

Question 4-18 is to be judged True or False. 4-18. The two basic types of heat exchangers used on engines are radiator and tubular. 4-19. In the Harrison-type heat exchanger, how do the liquid coolants pass through the unit? 4-20. 1. Freshwater passes through the tubes, and seawater passes around the tubes 2. Freshwater passes through the tubes, and freshwater passes through the tubes 3. Seawater passes through the tubes, and freshwater passes around the tubes 4. Seawater passes through the tubes, and the seawater passes around tubes How is excessive scale on the cooler of a heat exchanger usually indicated? 1. By a slow increase in freshwater temperature 2. By a similiarity between inlet and outlet pressures 3. By the decrease in freshwater temperature 4. By a rise in the freshwater tank …