Lube oil and fuel oil systems

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 — 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 …

NAVEDTRA 14075 Ch. 9 — Engine Maintenance ¶6

5-36. To reduce torsional fluctuations and 5-43. ensure smoother operation, some diesel engine crankshafts are equipped with which of the following devices? 1. Vibration dampers 2. Flexible couplings 3. Shock absorbers 4. Flywheels 5-37. Which of the following lubricants is/are harmful to the rubber of elastic-type vibration dampers? 5-44. 1. Lube oil 2. Diesel oil 3. Light grease 4. All of the above 5-38. Which of the following engine noises indicates an improperly functioning vibration damper? 1. Grinding noises at low speeds 2. Clinking noises during starting 3. Rumbling noises at normal speeds 4. Humming noises at high speeds Question 5-39 is to be judged True or False. 5-39. Crankshaft failure may result from excessive main bearing clearances that allow an uneven distribution of the e…

NAVEDTRA 14104 Ch. 10 — Lubricating Oils and Greases

Many different kinds of lubricating materials are in use, each of them filling the requirements of a particular set of conditions. Animal and vegetable oils and even water have good lubricating qualities, but they cannot withstand high temperatures. Mineral oils, similar to the oils used in an automobile engine, are the best type of Figure 10-41.—Rotating journals in sleeve-type bearings. lubricant for modern machinery operating at high speeds and high temperatures. Mineral lubricating oils are derived from crude oil in the same process that produces gasoline, kerosene, and fuel oil. They vary according to the type of crude oil and the refining methods used. The same type of oil is usually made in several grades or weights. These grades correspond to the different weights of oil for an aut…