A. upwards/top B. upwards/bottom C. downwards/top D. downwards/bottom
38. For a given size engine, the two-stroke/cycle diesel engine will deliver more power than a four-stroke/cycle diesel engine because ______. A. it has a longer power stroke
B. more air gets into the cylinder each stroke
C. it develops twice as many power strokes at the same speed D. higher combustion pressure is developed
39. Electrically operated safety devices on auxiliary diesel engines function to stop the engine by_____.
A. increasing the volume of intake air B. shutting off the fuel supply C. increasing the engine back pressure D. over-speeding the engine
Lesson 4
Cooling Water System
单项选择题：
1. Heat energy is a source of power, but _______ will cause damage to the engine. A. excessive heat B. insufficient heat C. effective cooling D. high output
2. In a central cooling system, used in some modern ships, sea water is supplied to cool ______ which will circulate to other individual cooler, greatly reducing the corrosion problems. A. fresh water B. sea water C. cooling oil D. emulsion 3. The piston cooling system may employ similar components, except that ______ is used instead of a head tank. A. a sump tank B. a feed well C. a double bottom tank D. a drain tank
4. Those generally used additives for cooling water are either anti-corrosion oils or inorganic ________. A. gases B. paints C. inhibitors D. detergent
5. Vents are led from the engine to _______ for the release of air from the cooling water.
A. the cooling jackets B. the head tank C. the cooling water pump D. the scavenging box
6. With _______, the corrosion problems are much reduced in a central cooling system.
A. no equipment in contact with sea water B. less equipment in contact with fresh water
C. more equipment in contact with sea water D. less equipment in contact with sea water
7. _________ allows for expansion and water make up in the water cooling system. A. A top tank B. A head tank C. A head valve D. A drain tank
8. Acid solution _______ in the system can be tested from time to time by putting some on to a piece of lime.
A. strength B. dense C.percentage D. velocity
9. Air cocks, usually positioned at the _______ in a circulating system, is used to get rid of the air in the system.
A. bending joint B. expansion tank C. weld D. the highest point
10. As a heat engine, ________ energy is the source of power by which the diesel engine can be operated. A. electric B. heat C. mechanical D. exhaust
11. Cooling of engine is achieved by circulating a cooling liquid around internal passages within the ________. A. boiler B. heater C. engine D. cooler
12. Emulsion oils and sodium nitrite are both approved additives, but the latter cannot be used if any pipes are ________ or if any soldered joints exit. A. chromed B. welded C. galvanized D. bolted
13. The jacket water temperature in a diesel engine closed freshwater cooling system is normally controlled by ______.
A. regulating the level of corrosion inhibitor in the primary cooling system B. the level of the freshwater expansion tank
C. varying the engine load to meet temperature requirements D. the operation of the thermostatic valve
14. Sacrificial zinc anodes are used on the saltwater side of diesel engine heat exchangers to ______.
A. reduce electrolytic action on heat exchanger metals B. keep heat transfer surfaces shiny and clean C. prevent rapid accumulation of marine growth
D. provide a protective coating on heat exchanger surfaces
15. Expansion tank should be used to remove ______from cooling water. A. scale B. sludge C. chemicals D. air
16. Cracks in the cylinders and cylinder covers may result from ______.
A. low speed B. unequal heating C. less lubricating D. low charge air pressure
17. Machinery operating features are designed to help conserve（保存） energy. Which of the following results will not contribute to energy conservation? A. Reduction of friction. B. Insulation of hot surfaces. C. Lubrication of moving parts. D. Elevation (升高)of cooler outlet temperatures.
18. Which of the statements listed concerning heat transfer is correct? A. Heat is always transferred at a constant rate.
B. Heat transfer rate increases as temperature difference increases. C. The rate of heat transfer is not affected by temperature difference. D. The high temperature region is known as a heat sink.
19. Improper cooling of a diesel engine cylinder liner due to the accumulation of scale deposits, may cause______. A. low compression pressure B. increased piston wear
C. increased cylinder lube oil consumption
D. poor contact between compression rings and liner
20. Which of the following conditions may need to be reduced when operating a large, low-speed, main propulsion, diesel engine at low loads? A. Injection pressures.
B. Control air supply pressure.
C. Cooling water flow through after-coolers. D. Lube oil temperature.
21. The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed? A. Cross B. Parallel C. Counter D. Circular
22. Which of the following modes of heat transfer does NOT require any physical contact between a warmer and a cooler substance?
A. Radiation B. Conduction C. Natural convection D. Contact directly
Lesson 5 Fuel Oil System
单项选择题：
1. The ________ or balance tank collects the re-circulated fuel oil. A. buffer B. sump C. bilge D. overflowing
2. The fuel oil system for a diesel engine can be considered in two parts—the fuel supply and the _______ systems. A. fuel treatment B. fuel combustion C. fuel injection D. fuel separating
3. The viscosity regulator controls _______ in order to provide oil at the correct viscosity for combustion. A. the engine?s speed B. the engine?s load C. the fuel oil temperature D. the fuel oil flow 4. A ________ ensures a constant pressure at the fuel main. A. transfer pump B. control air bottle C. pressure regulating valve D. nonreturning valve
5. The ability of a fuel particle to travel into the combustion chamber before burning is called _____.
A. penetration B. permanence C. turbulence D. atomization 6. Any carbon built up on surfaces must be washed away by ______ additives and held in suspension by a ______additive.
A. dispersant /detergent B. detergent/dispersant C. dispersant /dispersant D. detergent/detergent 7. Poor combustion in a diesel engine can be caused by ______.
A. high compression pressure B. low intake air temperature
C. low exhaust pressure D. high scavenge air temperature 8. Load control on a diesel engine is accomplished by ______.
A. regulating the speed of the turbocharger B. rotating the fuel injector pump plunger
C. regulating the speed of the fuel oil transfer pump D. changing engine timing
9. The lowest temperature required to cause self-sustained combustion of a substance independent of any outside source of ignition is called ______.
A. explosive range B. flash point C. ignition temperature D. combustion temperature
10. The degree to which the viscosity of an oil will change with a change in temperature is indicated by the ______.
A. weight designation B. viscosity index C. pour point D. thermal change value
11. Diesel fuel is relatively safe to handle due to its low volatility（挥发）, but the fumes will self-ignite and continue to burn steadily if the fuel is heated to the ______.
A. flash point B. auto-ignition point C. volatility point D. upper explosive limit
12. Duty officer informs us that the vessel is out of harbor and in “Full Ahead”. We are going to run ______.
A. diesel oil instead of fuel oil B. fuel oil instead of diesel oil C. diesel oil instead fuel oil D. fuel oil instead diesel oil 13. Which of the following statements is correct regarding an oil with a high viscosity index?
A. A large change of viscosity occurs with a minor change in temperature. B. No change in viscosity occurs with any change in temperature.
C. Very little change in viscosity occurs with a significant（显著的） change in temperature.
D. The viscosity of the oil increases with an increase in temperature.
14. The three basic parts of any eductor are the nozzle, the suction chamber, and the _____________.
A. injector B. compressor C. diffuser D. siphon
15. The third engineer took the ______and checked the tank table in the office and recorded all relevant data, as well as calculated the bunkering.
A. water level B. sump level C. ballast tank level D. ship's trim 16. The flash point of a petroleum product is an indication of its______.
A. viscosity B. pour point C. volatility D. lower explosive limit
17. Oil mist detectors are usually used on board to detect oil mist density within ______.
A. the engine crankcase B. the engine scavenge boxes C. drain tanks D. fuel tanks 18. The volatility of a liquid is the tendency of a liquid to ______.
A. ignite B. explode C. asphyxiate(窒息) D. vaporize
Lesson 6
Purification of Fuel Oils
单项选择题：
1. In a purifier changing to a gravity disc with larger hole diameter will move the interface towards the _______. A. bowl periphery B. bowl center C. upper surface D. lower surface
2. In a purifier, the interface between the liquid seal and the oil should be positioned as close as possible to ______.
A. the outlet of oil B. the outlet of water C. the bowl periphery D. the center of bowl
3. To start the ejection process the oil feed to the centrifuge is first shut off and the oil remaining in the bowl removed by admitting _______. A. flashing water B. operating oil C. flushing water D. sealing water 4. When a centrifuge is arranged to separate impurities and small amount of water from oil, it is known as a ______. A. purifier B. separator C. filter D. clarifier
5. Clean oil is achieved in a clarifier bowl where the impurities and water collect at the bowl _______. A. bottom B. top C. center D. periphery
6. As for turbine oil, contacting with water in the form of steam will be inevitable so good ______ properties will be essential.
A. defrosting B. de-oiling C. demulsifying D. dehumidifying 7. The ______is not a component of an oil separator.
A. sliding bowl bottom B. gravity disc C. separating disc D. scum valve
8. The ______of the gravity disc is too big. It cause oil to flow through the water outlet. We changed the disc and no oil is found in the water outlet. A. gravity B. diameter C. bowl D. cylinder
9. Strainers, sometimes called______, are devices designed to prevent the passage of unwanted solids into or further along a system.
A. dampers B. filters C. stopper circuits D. separators
10. A magnetic strainer is used in the diesel engine reduction gear oil system to remove small particles of ______.
A. water B. babbitt C. iron or steel D. acids 11. The ______has a water damp ring.
A. purifier B. oil/water separator C. incinerator D. distiller 12. The operating water is supplied under the ______of an oil separator.
A. sliding bowl bottom B. bowl hood C. bowl D. filter units
13. For a purifier changing to a gravity disc with smaller hole diameter will move the interface towards the ______.